California Passes Science-based School Vaccination Law (SB277)

A while ago, I wrote about a bill in the California legislature intended to remove non-medical exemptions to vaccination requirements for children in the state. Despite often vicious and irrational opposition, science and reason and public health have won the day! The bill passed all committees and both houses of the legislature, and it has now been signed into law by the governor.


It wouldn’t surprise me if there are legal challenges to the law ahead, but I am proud of my state and grateful as a parent that the politicians have made the right choice for public health.


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Canine Nutrigenomics by Dr. Jean Dodds: Science as Windowdressing

A number of readers have asked me to review a recent book on canine nutrition:

Canine Nutrigenomics: The New Science of Feeding Your Dog for Optimum Health

The book has two authors. One is Diana Laverdure, a self-described “canine nutrition activist”and “pet food diva.” What this appears to mean is someone who has lots of opinions about animal nutrition which she shares freely. She does list a master’s degree in animal science among her credentials, though no specific background in nutrition or genetics. Among her influences she includes some of the most notorious figures in alternative veterinary medicine, including Dr. Richard Pitcairn and Dr. Shawn Messonier, and of course her co-author for this and a previous book, Dr. Jean Dodds.

I have written about Dr. Dodds before. (1, 2). She is a prime example of a variety of the ailment sometimes called the Nobel Disease. She is obviously a smart and confident person who has made real contributions to veterinary medicine outside of the conventional academic career path. Unfortunately, she has come to embrace a variety of pseudoscientific views, and she has such confidence in her own talents and beliefs that she does not feel obligated to subject her own theories to the usual sort of scientific testing and critique. Her ideas about allergies, thyroid disease and, as we shall see, nutrition, are widely viewed as unproven, unlikely, or outright factually incorrect by experts in these fields, but Dr. Dodds has moved forward with not only books of advice but commercial diagnostic tests without apparently feeling any need to demonstrate her ideas are correct through scientific research.

Despite the lack of scientific evidence to support them, Dr. Dodds’ opinions have influence as a result of her standing and previous work. However, in science the final arbiter of what is true is not the intelligence or achievements of individuals but the results of controlled research and the verdict of scientific evidence. Dr. Dodds’ new book is a seamless blending of legitimate and mainstream science, plausible but unproven hypotheses, unlikely or “long-shot” hypotheses, and outright factual error and nonsense. She uses the language and trappings of science, but often the words she uses don’t mean what they are usually used to mean, and the appearance of scientific validity is only superficial.

It requires a great deal of time and effort to untangle the legitimate from the farfetched in a book like this, and it is more challenging that addressing the outrageous and clearly ridiculous claims of someone like Dr. Will Falconer. However, it is important to make this effort because it is easy for a book like this to mislead pet owners and even veterinary professionals. Dr. Dodds’ reputation and resume and the bits of legitimate science sprinkled throughout her book can generate an undeserved aura of validity to claims she makes which are not scientifically validated. Opinion can be dressed up as fact and nonsense disguised by actual science, and the result can be dangerously misleading.

Since it is impossible for anyone to have expertise in all subjects, I have consulted a number of specialists in relevant disciplines to help me evaluate Dr. Dodds’ claims. Two experts in small animal nutrition, a cancer specialist, and a nutrigenomics researcher contributed their time and expertise to review sections of Dr. Dodds book, and their input has been invaluable. Unless specifically stated otherwise, of course, the opinions in this article are my own.


The general argument of this book can be summarized as follows:

  1. Almost all disease is due to environmental factors, with diet being the most significant.
  2. Most diseases ultimately results from chronic inflammation.
  3. This inflammation is caused by unhealthy gene expression triggered by environmental factors.
  4. Everything we eat is either a “functional superfood” which optimizes our gene expression for good health or a “toxin” which exerts an unhealthy influence on our genes and predisposes us to illness.
  5. By feeding “good” foods and avoiding “bad” foods (as well as other environmental toxins such as vaccines, parasite control medications, many medications, and most of the products recommended by mainstream veterinary medicine), we can “take control” of our dogs’ health and prevent most disease.

The appeal of this argument is obvious. It is simple and clear, with all choices being either good or bad, and it gives us the confidence that if we simply do the right things and avoid the wrong things we can prevent our beloved animal companions from becoming ill. Nothing bad happens by chance or is outside of our control, and we don’t need to wait for more research to identify the causes and preventative actions involved in canine health because we already know all we need to know to protect our pets. Alternative medicine often employs simplistic, black-and-white reasoning and emphasizes that we can control our pets’ fate and prevent those outcomes we fear from happening.

This can be a very encouraging and positive worldview, but it can also be problematic. For one thing, if the specific claims about health and disease and the actions we take turn out not to be true, then our efforts to protect our pets will be ineffective or may even do harm. And reality has not shown itself to be so simple or easily divided into good and bad choices. Chance does play a huge role in our lives, and we can’t always control what happens. As literature throughout the ages has warned us, sometimes the attempt to avoid our fate leads us to it, especially when the actions we take our based on wishful thinking or faulty information.

One of the key problems with Canine Nutrigenomics is that legitimate scientific ideas are either extrapolated far beyond what the research evidence supports in order to promote dubious claims. Another weakness is that complex phenomena are simplified to make good and bad outcomes easy to predict and control. There is accurate information in the book, but it is frequently misused. There is also theory, opinion, and guesswork presented as fact and straightforward nonsense in the book, and the purpose of this article is to help readers separate these out and develop a more accurate and realistic assessment of the subject matter than that presented by the authors.

The most glaring problem with this book is that it really has almost nothing to do with the actual science of nutrigenomics. The word “nutrigenomics” is used here a bit like the word “quantum” is used by homeopaths and other proponents of pseudoscientific practices. Labeling pseudoscience with the name of a legitimate scientific field that most people know little about and don’t really understand allows you to claim a legitimate scientific foundation for your ideas without having to actually explain how they work in detail or adhere to the details of the new or obscure branch of science you are borrowing your legitimacy from.

Nutrigenomics is the study of how compounds in foods affect gene expression, that much is true. And there is great potential in this field for developing nutritional practices which can prevent disease. However, the field is in its infancy, and there is very little understanding of the health effects of specific foods or dietary practices or of how food compounds interact with genes to affect the risk of particular health problems. In other words, when Dr. Dodd’s claims one food is a “superfood” that can prevent illness and another is “non-functional” and promotes disease, she is either extrapolating this from preliminary data that don’t actually support such a claim or simply making it up. She is claiming that the potential inherent in nutrigenomic approaches has already been realized and that she can tell you which foods to feed and which to avoid in order to keep your dog healthy, but this is not true because the research to identify such relationships hasn’t been done. She is borrowing the language of nutrigenomics and the limited findings of lab experiments to support claims which are fundamentally just her beliefs and haven’t been actually tested or proven to be true.

Dr. Dodds does try to create the impression of a science-based book, and specifically designates her work that way more than once:

The information we have provided in this chapter is based on scientific evidence, not folklore or guesswork.

In the following pages, we will reveal the latest scientific findings…

[In reference to anyone who counsels against her recommendations] While these individuals no doubt mean well, they are basing their opinions on incorrect, outdated, or even biased information-no on the latest scientific findings. Trust what you’ve learned in this book…

The problem is that she does not provide evidence that actually supports most of what she claims, and often there is plenty of evidence against it. When she cites papers to support her arguments, they are often not scientific research but opinion pieces by her or other alternative practitioners and advocates. And when she does reference research papers, they are often in vitro or lab animal studies that don’t actually support the strong clinical claims she makes. The superficial appearance of science is everywhere, but actual science is scarce in this book.

In general, the aura of nutrigenomics is used in this book to support a laundry list of alternative nutrition clichés: organic produce is healthier than conventional produce; GMO are dangerous, gluten is harmful; common ingredients are unhealthy (corn, chicken, soy) and exotic ingredients are healthier (bison, goat, venison); “artificial” flavors, colors, and preservatives are dangerous; raw food is better than cooked food; magical “superfoods” or supplements can have powerful health benefits. The evidence for these claims varies from weak to non-existent to clearly showing the claims to be untrue. While I cannot address in detail every single food, supplement, or health claim Dr. Dodds makes, I will try to briefly respond to some of the most pervasive and misleading claims.

Specific Claims

Genetically Modified Ingredients

[Healthy food is] Unadulterated (e.g., non-GMO) and unprocessed or minimally processed.

Remove pro-inflammatory ingredients such as …GMO foods

This is, of course, a topic which deserves multiple posts on its own. However, Dr. Dodds regularly lists GMO ingredients as unhealthy, promoting inflammation and food intolerance, and there is no evidence to support this. While there is always the potential that particular modifications of food crops and animals could lead to health risks, the anxiety about genetically modified organisms is generally ideological and based on misconceptions or poor understanding of the relevant science. It is part and parcel of  the Appeal to Nature Fallacy, and the existing evidence does not support most of the hysterical fears about GMO. Dr. Dodd’s claims are not based on research from nutrigenomics but are simply part of her own beliefs and prejudices, and she provides no compelling scientific evidence to support her claims. Relevant discussion of this issue and the evidence can be found here: 1, 2, 3, 4, 5, 6, 7.

Gluten is Terrible

“…gluten causes the intestines to release a protein called zonulin, which creates openings between the intestinal cells, causing the lining of the gut to become more permeable, or “leaky… If your dog has cancer, he certainly doesn’t need to eat an ingredient known to promote cancer-causing inflammation

“Gluten, which can cause leaky gut syndrome and cancer-causing inflammation, should be eliminated from your dog’s cancer-protective diet”

“But your dog doesn’t have to have wheat-sensitive enteropathy (and you don’t have to have celiac disease) to suffer from the harmful effects of gluten. A less obvious, low-grade autoimmune reaction to gluten can trigger a wildfire of chronic inflammation that affects every organ system in the body, including the brain, heart, joints and digestive tract (Hyman, 2013). It can even create an immune response that causes subclinical brain inflammation, resulting in age-related dementia (Perricone, 2010).”

The anti-gluten fad has raged in human nutrition for a while, though there are signs it is petering out. The evidence shows pretty clearly that apart from people with legitimately diagnosed celiac disease, most of the claims made for harm from gluten are simply not true. And apart from a small group of Irish setters, there is no scientific evidence for any of Dr. Dodds fear-mongering about gluten in dogs.

This topic also illustrates her deceptive use of citations in her book to create the impression of scientific support for her claims. In the last quote above she offers two citations. The first is a blog post by Dr. Mark Hyman, a widely known advocate for pseudoscience and quackery from functional medicine to anti-vaccine advocacy. He is, in short, no more scientific and no more evidence-based in his opinions and writing than Dr. Dodds is in hers, he simply performs on a larger stage. This reference is not research evidence but just another opinion.

Similarly, the second reference is for yet another opinion-based book by someone who peddles pseudoscientific nonsense, Dr. Nicholas Perricone. The reference is to a book called Forever Young: The Science of Nutrigenomics for Glowing, Wrinkle-free Skin and Radiant Health at Every Age. How’s that for hard scientific evidence to back up a dramatic health claim?

Here are some resources discussing the issues and evidence concerning gluten-associated health problems: Leaky Gut Syndrome 1, 2, 3, General Glutenophopbia 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

Raw Diets

A major advantage of raw food is that the nutrients—such as amino acids, vitamins, minerals, prebiotics, probiotics, and enzymes—have not been altered or destroyed by the heat of cooking. Keeping the food in its whole, “pristine” form also makes it much more readily bioavailable, providing our pets with more easily assimilated nutrition per serving than processed foods.

Raw food may also pose much less risk of allergic reaction than its cooked counterparts… cooking food breaks down its cellular integrity and exposes neo-antigens (new antigens) that were not there in the original raw form.

Many respected holistic veterinarians, including the author, WJD, have witnessed first-hand the health and vigor of dogs and cats fed raw diets: these animals just “shine” in all respects. While these observations are shared by a growing number of animal health care professionals as well as experienced dog (and cat) fanciers, they could be considered as merely anecdotal. Perhaps so, but we consider them experiential findings based on years of observations by many dedicated professionals in the holistic veterinary field.

I have covered the subject of raw diets extensively, and there is no real scientific evidence for any of Dr. Dodds’ claims about the benefits of this approach to feeding. But as she clearly states above, that doesn’t bother her because she believes her anecdotal experiences and those of other raw-diet proponents are so compelling that no actual scientific evidence is needed. Despite many claims to the contrary, this is yet another example of how this book is simply a rehashing of theory and opinion, not a presentation of scientifically validated practices.

Saliva Testing for Food Allergies (Nutriscan)

“NutriScan, offered exclusively by author WJD’s Hemolife testing laboratory, is the new gold standard for identifying the cause of food intolerances/sensitivities in dogs. NutriScan is not only the most scientifically accurate method; it is also the most convenient and cost-effective for you, as well as the least invasive and most comfortable for your dog (Dodds, 2014).”

“To date, Nutriscan represents the most scientifically advanced diagnostic phase of assessing functional nutrition for individual dogs. The presence (indicated by an intermediate, medium or strong reaction) or absence (indicated by a negative or weak reaction) of salivary antibodies in response to specific food extracts is an indication of the dog’s changes in gene expression when faced with these foods. NutriScan therefore depends upon the nutritional influences and factors that can alter gene expression (Fekete & Brown, 2007; Swanson, Schook & Fahey, 2003).”

A fair bit of effort in the book goes to promoting a test called Nutriscan, which uses saliva to identify dietary sensitivities in dogs. Unsurprisingly, Dr. Dodds’ company owns Nutriscan, and equally unsurprisingly the mainstream community of veterinary nutritionists and dermatologists do not accept the legitimacy of her test because she has not provided any controlled evidence to show it is an accurate and useful test. She does provide a lot of citations to support her claims for this method, but if one takes the trouble to investigate them, they do not actually turn out to be compelling evidence.

For example, the first citation is to her own article in the Journal of the American Holistic Veterinary Medical Association (JAHVMA) making the same claims. Apart from the fact that the AHVMA is the leading advocacy organization for veterinary pseudoscience and its journal publishes mostly unscientific ideas, it is not considered legitimate to support your opinions in a scientific publication but citing your own opinions printed elsewhere. But Dr. Dodds goes even further when, in the JAHVMA article she says, “Salivary testing for food sensitivity and intolerance in animals differs significantly from all other food allergen tests available for use in animals. It is highly reproducible and clinically relevant.” To support this, she cites two of her own presentations at AHVMA meetings and, you guesses it, her book Canine Nutrigenomics! A clearer example of the forms of science without the content would be harder to imagine.

The other citations above also fail to support the claims she attaches them to. Fekete and Brown (2007) is a review of the concept of nutrigenomics in veterinary medicine which does talk about the general principle that food compounds can affect gene expression and gives some examples, but it has absolutely nothing to do with the idea of saliva testing for food intolerance. The second, Swanson et al. (2003) is a discussion of the potential of nutrigenomics and the importance of further research. Not only does the article say nothing to support Dr. Dodds’ claims about Nutriscan, it specifically contradicts her claims throughout the book that we already know which food have which kinds of genetic and health effects:

Genomics has begun to be applied to nutritional research, but issues specifically relevant to companion animals have not been elucidated thus far. The study of genomics and proteomics will be crucial in areas such as nutrient requirement determination, disease prevention and treatment, functional ingredient testing and others. Nutritional genomics and proteomics will definitely play a vital role in the future of pet foods.

In human medicine, where the research evidence is always more plentiful and better quality than in veterinary medicine, the gold standard for diagnosing food sensitivities is a dietary trial.  Blood testing and skin testing are also used, though they are not as reliable. In veterinary medicine, the best evidence suggests that a dietary trial is the most reliable test, and blood and skin testing have not proven very reliable. Despite this, Dr. Dodds cherry picks a lot of in vitro and lab animal studies, along with opinion pieces from other alternative medicine doctors, to suggest that there is a sound scientific basis for using antibodies in saliva to detect food sensitivities. This might be a useful test, but the evidence does not exist to demonstrate this, and Dr. Dodds’ use of these citations is misleading.

The other main source of evidence Dr. Dodds uses to support her claims about Nutriscan are uncontrolled reports from animals she has tested. This is weak evidence that can suggest hypotheses for controlled testing but cannot prove or disprove the hypothesis. One veterinary dermatologist has performed her own uncontrolled test of Nutriscan, with Dr. Dodds’ knowledge and permission, and found it entirely unreliable. Twelve samples were submitted for testing in a blind manner, from dogs with known food sensitivities based on dietary testing, dogs with environmental allergies, dogs without allergic disease, and one sample of tap water. All samples including tap water, environmental allergy dogs, and normal dogs showed reactivity to beef, corn, milk and wheat. Some samples showed reactivity to soy. In some cases, these obviously false results would have led to recommendations against diets which actually helped these dogs. While this is not a formal, controlled study, it is at least as relevant as the unblended cases Dr. Dodds promotes as evidence Nutriscan works, and it casts serious doubt on this supposed new “gold-standard” allergy test.

Here are some resources illustrating the scientific consensus concerning food sensitivity testing, which is not consistent with Dr. Dodds’ claims: 1, 2, 3, 4, 5, 6, 7, 8

Taking Out the Laundry
Since much of the book is a laundry list of claims for and against the health value of specific foods, supplements, and other substances, it is impossible to respond to every claim. I have picked out a number of claims that are clearly false, unsupported by real evidence, or simply more nuanced and complex than Dr. Dodds suggests in her book. Many I have addressed before as they are standard tenets of the alternative medicine faith. There are plenty of others that I do have not investigated, so these may be true, false, or again uncertain and no judgment on my part should be inferred about anything I don’t specifically talk about.

All About the Bees
Health claims for bee pollen, royal jelly, and various types of honey are a common feature in alternative nutrition and supplement recommendations. In this book Dr. Dodds makes a number of these claims:

The healthful, nutrition-packed honey that can benefit you and your dog originates from wild, unfiltered, raw honey—not from the processed honey so prevalent on supermarket shelves (Mercola, 2009)!

Raw honey (not pasteurized): aids digestion, increases energy

Locally grown honey may help prevent seasonal allergies.

Bee pollen contributes to healthy intestinal function, benefits the blood…strengthens the immune system…treats hay fever and seasonal allergies…increases strength and stamina

Propolis contains a number of therapeutic properties…

Royal jelly possess a number of benefits, including…

Citing one of the worst quack physicians on the internet, Dr. Mercola, in support of these claims is not a good sign, for the claims themselves of for Dr. Dodds’ respect for legitimate science. There no experimental evidence for any significant health benefit, including prevention or treatment of allergies, from any of these substances in the dog. The evidence in humans is, as always, mixed, but these claims are not generally accepted by the science-based medical community, and there is not robust clinical research to support most of them. Here are some resources discussing these claims: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14

Glycemic Index/High Glycemic Foods
The glycemic index is a measure of the tendency of a particular food to raise blood sugar in humans. It has some value in making food choices for diabetics, and diets with a lot of foods with a high glycemic index have been associated with a number of diseases in humans. There are many other factors that influence the effect of food on blood sugar and on overall disease risk, including portion size, total carbohydrate content of the diet, genetics, concurrent disease, and many others, so the glycemic index cannot be relied on in isolation, but it is a useful tool for human dietary planning.

However, we cannot simply assume that principles of human nutrition and health automatically apply to dogs. Dogs are obviously quite different from humans in terms of anatomy, physiology, and evolutionary history, and while there are many similarities due to shared evolutionary history as mammals, long-term association between our species, and intensive deliberate breeding of dogs, not all nutritional guidelines for humans apply to our canine companions. The concept of glycemic index and the role of high glycemic index foods in disease risk for dogs have not been established through sound scientific research. We don’t know which foods have a high index in dogs and which don’t because the effect of different foods on blood glucose have mostly not been evaluated in this species.

The evidence does suggest that such foods promote certain diseases in humans, including diabetes and cancer, and the same relationship may be found in dogs. As of now, however, there is virtually no research on the subject in dogs. While it is plausible that high quantities of such foods may have undesirable health effects, and some of these claims may well be true, when such claims are little more than speculation and opinion, they should not be presented as settled scientific fact. Recommendations against feeding high glycemic index foods should be acknowledged to be speculative and supported only by weak evidence.

Here are some resources on the subject of glycemic index: 1, 2, 3, 4, 5

The Menacing Powers of Corn, Wheat, and Soy
Yes, this is an actual quote from Dr. Dodds’ book:

But the menacing powers of corn, wheat and soy go even further than you might imagine.

Obviously, this sort of simplistic characterization of foods as inherently good or evil is not scientific in tone, and in the case of the particular claims she makes about these ingredients they are not consistent with mainstream opinion or the evidence. Veterinary nutritionists agree that particular sources of protein and carbohydrate in canine diets are not intrinsically harmful or beneficial and that the health effects of diet are a complex set of interactions between many factors. Duck and bison are no more nor less likely to trigger food intolerance than chicken or beef, and tapioca or potatoes or green peas are no better nor no worse than corn and wheat and soy as carbohydrate and protein sources.

Here are some reliable sources of information about these pet food ingredient myths (And yes, some of these folks have some connection to the pet food industry. Dr. Dodds also sells products that she promotes in her book. Everyone has a perspective and biases, and it is facile and useless to dismiss opinions we disagree with based on our perceptions of the source’s biases when we accept the opinions of those w do agree with even though they have just as much potential bias. The measure of the reliability of a source of information is not how biased or unbiased we believe they are, nor whether or not we agree with them, it is the quality of the evidence they provide): 1, 2, 3, 4, 5, 6, 7

Organic Ingredients are Healthier/More Nutritious
I have written about the subject of organic foods several times. The evidence of extensive research does not support claims that organically produced ingredients are healthier or more nutritious than conventionally produced foods.  The assumption that they should be is an example of the Appeal to Nature Fallacy, which falsely supposes that the less manipulation of something engaged in by humans, the more “natural” and the healthier something is. It is easy to see that this assumption is false when one considers those things that are clearly unhealthy despite being entirely natural (botulism and salmonella, radioactivity, polio virus, etc.) and those which are clearly beneficial despite being arguably “unnatural” (antibiotics, polio vaccine, clean drinking water and sewage control systems, etc.).

There may be some advantages to organic food production in terms of environmental resources, pesticide use, and other factors, but there is no reason to believe that seeking dog foods with organic ingredients benefits your pet or that foods with conventionally produced ingredients present any health risks. Here are some resources discussing the evidence concerning health effects and nutrient content of organically produced foods: 1, 2, 3, 4, 5, 6, 7, 8

Artificial Preservatives
Just as Dr. Dodds likes to laud the supposed health benefits of “natural” things like organically produced foods, so she also likes to imply negative health effects from things she deems “artificial.” This is simply the Appeal to Nature Fallacy again, and while human-made substances certainly can have negative health effects (just like natural substances), this cannot simply be assumed. While she is rarely specific about these supposedly dangerous substances, there are a few she mentions by name, though no evidence is provided to support the allegations of harm.

BHA and BHT have been used as preservatives in human and animal foods…for more than 30 years. While many countries have banned them from use in human foods, they are still allowed in pet foods…[and] have been indicated as carcinogenic in animal experiments and are suspected of contributing to cancer and tumor growth.

The purpose of these compounds is to function as anti-oxidants and prevent spoilage, which is itself a potential health risk. Extensive research has been done to investigate any dangers from these compounds, and the research generally does not support a significant risk at levels of exposure likely to be seen with use as a food preservative. In fact, there is even tenuous evidence that these compounds may be protective against cancer under some circumstances. It is never possible to exclude all possibility of risk, of course, but avoiding potentially beneficial products without any evidence of risk is not a rational way to make decisions about food safety.

Here is some of the evidence concerning these compounds: 1, 2, 3, 4, 5

Ethoxyquin is another preservative implied to have negative health effects despite a lack of evidence for the truth of such claims. Much is made of the fact that it is permitted in the U.S. but not in Europe, suggesting real risks have been identified but the FDA has somehow failed to acknowledge them. There is no reason to think, however, that European regulatory decisions are any more evidence-based than those made in the U.S., or more effective in protecting public safety. It is easy to find examples of the opposite being true, such as the case of thalidomide, a drug approved for use in pregnant women in Europe, but not in the U.S., in the 1950s and 1960s which turned out to cause significant birth defects. In any case, the evidence does not support claims that ethoxyquin is harmful at levels used in pet foods: 1, 2, 3, 4, 5, 6, 7

Fluoride Causes Cancer
Fluoride has been a focus of fear since its introduction in municipal water supplies for prevention of dental disease in the 1950s. Despite all of this fear, the evidence is clear that the benefits of water fluoridation far outweigh the risks. Dr. Dodds suggests in her book that fluoride is a significant risk factor for the bone cancer osteosarcoma:

Fluoride likely contributes to osteosarcoma

…exposure to high levels of fluoride can certainly be considered a risk factor for osteosarcoma. The dangers may be particularly high in large breed puppies that are rapidly forming new bone (EWG, 2009; EWG, 2009a).

Fluoride found in bone meal, meat meal or meat byproduct meal could be contributing to skyrocketing cases of canine osteosarcoma, especially for dogs who eat the same fluoride-containing kibble day-in and day-out. Be sure to remove all foods containing bone meal or animal by-products from your dog’s diet, and switch to low-fluoride or fluoride-free bottled water.

Despite the “could be” above, Dr. Dodds pretty clearly believes fluoride is contributing to osteosarcoma in dogs and recommends avoiding it. Her references, as usual, do not provide any scientific evidence for this suggestion. Rather than research, she cites opinion pieces by the Environmental Working Group, an advocacy group that promotes fear of GMO, childhood vaccines, and other pseudoscientific positions as well as legitimate environmental concerns. More reliable sources do not support a causal link between fluoride in food and water and bone cancer risk: 1, 2, 3, 4

The Beat Goes On
The list of unsupported or outright untrue health claims for specific substances in Dr. Dodds’ book is lengthy, and I cannot possible address them all. The following is a list of some of these substances and brief collections of resources discussing the evidence concerning them:

  1. Menandione (synthetic Vitamin K)- I’ve already discussed this in a previous article.
  2. A1 vs A2 cow’s milk- 1, 2, 3
  3. BPA- 1, 2
  4. Coconut oil; Another I’ve discussed before.
  5. Resveratrol- I’ve written several articles on this promising but still unproven compound.
  6. White bean extract- 1
  7. Avocado-soybean unsaponifiables- No benefit seen in horses and unclear benefits in humans. There are some promising results from an artificial model study in dogs, but there is no clinical trial evidence from the real world.
  8. Deer Antler velvet- Similarly, in humans there is some promising preliminary evidence, but the real risks and benefits are unclear. One study in dogs did show some evidence of benefit for arthritis, but the outcomes measures were inconsistent (some positive and others not), and there were a couple of mysterious unexplained deaths in the treatment group which raise the possibility of adverse effects which need further investigation.
  9. Glucosamine/Chondroitin- Naturally, Dr. Dodds still recommends this supplement despite abundant evidence suggesting it has no real benefit.
  10. Green-lipped mussel- Evidence is inconsistent in both human studies and veterinary studies.
  11. Fish oil- One of the few supplements with some pretty good supporting evidence, though there is still some uncertainty about dose, form, and the range of indications for which it is useful.
  12. SAME-e for arthritis- Some supporting evidence in humans though overall weak data, and little veterinary research.
  13. Spirulina- Despite the bold claims, they are based entirely on in virtro and animal model research, not clinical evidence.
  14. Vitamin C- Dr. Dodds disputes the mainstream consensus that additional dietary Vitamin C is not beneficial to dogs able to produce sufficient quantities of this vitamin on their own, but her claims don’t seem consistent with the evidence.
  15. Curcumin/Turmeric- I’ve discussed this one before.
  16. Zeel- Previously discussed.
  17. I’M Yunity and hemangiosarcoma- Previously discussed.
  18. Tryptophan in turkey makes you sleepy- Just a myth she passes along uncritically. 1, 2 
  19. “Sugar-high” in kids- Another myth, which she uses to support claims about high-glycemic index foods despite the fact that it is not true. 1, 2
  20. Antioxidant and brain aging- Discussed previously several times: 1, 2, 3, 4
  21. Coenzyme Q10 and heart disease- Also previously discussed: Like most dietary supplements, coenzyme Q10, also known as ubiquinone, is recommended for a wide range of apparently unrelated conditions. It is recommended in humans for cardiovascular disease, Alzheimer’s disease, migraines, diabetes, and many others, as well as a general tonic and, of course, the inevitable “boosting” of the immune system. In dogs and cats it has primarily been recommended for treatment or prevention of heart disease and age-related cognitive dysfunction. There is controversy about many of the recommended uses in humans, with mixed and generally low-quality clinical trial evidence for most uses. And, as you will no doubt have anticipated by now, there is virtually no reliable research on its use in pets. One small experimental study failed to find evidence of decreased Coenzyme Q10 levels in dogs with congestive heart failure. There appear to be no clinical trials for any specific indication, and the recommendations for this supplement are again based entirely on theory, anecdote, and pre-clinical research or clinical research conducted in humans.

22. Abdominal Epilepsy- This is a stark example of a real medical issue that Dr. Dodds either does not understand correctly or chooses to misrepresent in order to support her beliefs.

…did you know that imbalances in intestinal flora can also produce seizures? The condition is known as “abdominal epilepsy,” and it occurs due to the gut-brain connection. Abdominal epilepsy occurs when an unhealthy microbial environment in the gut creates toxins that cross into the brain…Many veterinarians misdiagnose—and thus mistreat—this type of seizure because rather than looking in the gut, they only look at the patient “from the neck up.” If your dog suffers from seizures in combination with ulcerative colitis, manic itching or GI trouble (e.g., constipation and/or diarrhea) he may have abdominal epilepsy.

While abdominal epilepsy is a real condition, it is not a type of seizure due to “unhealthy” gastrointestinal flora or “toxins.” It is a type of epilepsy that affects the region of the brain associated with autonomic functions, and it manifests as GI symptoms, such as nausea, vomiting, and abdominal pain. It is recognized in children and in dogs, though it is quite rare, and it has absolutely nothing to do with the kinds of positive and negative nutritional claims made in the chapter in which it is mentioned. It is also a classic example of the alternative practitioner claiming conventional clinicians are ignorant of a key and important cause of disease or don’t bother to look at the entire patient. Veterinary neurologists routinely evaluate the entire patient and their state of health when investigating neurologic problems. They do not simply look at their patients only “from the neck up,” and it is dishonest to suggest this.

23. Vaccines and autoimmune disease- I have discussed this previously: 1, 2, 3, 4, 5

Bottom Line
While Dr. Dodds’ book is a mixture of fact and fiction, science and pseudoscience, plausible ideas and outright nonsense, overall the work is deeply misleading. It has little at all to do with nutrigenomics or epigenetics, despite the title and claims to the contrary, and it uses real science primarily to give an aura of legitimacy or authority to claims which are unproven or outright false. References are employed in a manner that suggests an academic research summary with conclusions based on scientific evidence. The reality is that the book is a collection of opinions, some plausible and some not, supported in most cases by very little evidence and in some cases clearly contradicted by this evidence. The references employed are often simply other people’s opinions or, in some cases, Dr. Dodds’ own opinions reprinted elsewhere.

The recommendations made for and against specific feeding practices and dietary supplements are mostly typical for proponents of alternative medicine, and they stem from ideology and philosophical beliefs rather than scientific evidence. Occasionally, such claims turn out to be true, in the manner of a broken clock which happens to be right twice a day but this has little to do with the underlying principles. And while there are a few evidence-based claims here and there in the book, and some recommendations I would agree with, overall Canine Nutrigenomics is misleading, misguided, and in conflict with the best evidence and expert consensus in veterinary nutrition.






Posted in Book Reviews | 9 Comments

Why We’re Often Wrong: Can We Trust Clinical Experience?

This is an article I originally posted on a preliminary SkeptVet website which I no longer update since it has been replaced by this blog. I have copied it here since the links to the prior site no longer function.

Acquiring clinical experience is a major part of improving one’s medical knowledge and skills. Unfortunately, extensive practical experience can often lead to the erroneous the belief that we can reliably determine the safety and efficacy of a particular therapy based on our personal experiences or those of other doctors, especially specialists or experts. “I’ve used it, and I know it works/doesn’t work” is the most common response by doctors or clients to the suggestion that research evidence contradicts what we believe about a given medical practice. Another common response from experienced veterinarians is “I don’t need to run Test X. I know what this is because I’ve seen a hundred cases like it.” Such personal experiences are very compelling, but science is built on the premise that our imperfect brains can make mistakes and that careful use of appropriate research techniques can compensate for our limitations. Here are a few reasons to be skeptical of one’s own clinical impressions and those of “experts” and to look for guidance in good quality research evidence when it is available. (much of this has been adapted from “Why Bogus Therapies Often Seem to Work” by Barry Beyerstein, Ph.D.)

1. Self-Limiting Disease Many diseases are self-limiting. If the condition is not chronic or fatal, the body’s own recuperative processes usually restore the sufferer to health. Thus, to demonstrate that a therapy is effective, its proponents must show that the number of patients improved exceeds the number expected to recover without any treatment at all. Without detailed records of successes and failures for a large enough number of patients with the same complaint, someone cannot legitimately claim to have exceeded the norms for unaided recovery.

2. Waxing and Waning Chronic Disease (also known as Regression to the Mean) Such conditions as arthritis, allergies, and gastrointestinal problems normally have “ups and downs.” Naturally, clients tend to seek therapy during the period or greatest clinical symptoms. In this way, a treatment will have repeated opportunities to coincide with upturns that would have happened anyway.

3. Placebo Effect Through suggestion, belief, expectancy, cognitive reinterpretation, and diversion of attention, people given biologically useless treatments often experience measurable relief. Some placebo responses produce actual changes in the physical condition; others are subjective changes that make patients feel better even though there has been no objective change in the underlying pathology. Of course, in veterinary medicine, the effect is mostly “by proxy,” in which the owner’s beliefs and desires lead to a report of improvement in the pet’s symptoms when none has actually occurred.

4. Multiple Concurrent Therapies If improvement occurs after a pet has had several interventions, and probably other unremarked changes in the owner’s treatment of the sick pet, one or another of the changes often gets a disproportionate share of the credit or blame. Frequently, the latest in a series of interventions or the newest thing tried is credited with improvement even though many things were done.

5. Misdiagnosis Scientifically trained veterinarians are not infallible. A mistaken  diagnosis, followed by an irrelevant intervention, can lead to a glowing testimonial for curing a condition that would have resolved by itself. In other cases, the diagnosis may be correct but the time frame, which is inherently difficult to predict, might prove inaccurate.

6. Human Psychology Even when no objective improvement occurs, people with a strong psychological investment in the pet can convince themselves the treatment has helped. And doctors, who want very much to do the right thing for their patients and clients, have a vested interest in the outcome as well. A number of common cognitive phenomena can influence one’s impression of whether a treatment helped or hurt a patient. Here’s a brief list of common cognitive errors in medical diagnosis. Any of these sound familiar.

7. Cognitive Dissonance When experiences contradict existing attitudes, feelings, or knowledge, mental distress is produced. People tend to alleviate this discord by reinterpreting (distorting) the offending information. If no relief occurs after committing time, money, and “face” to a course of treatment internal disharmony can result. Rather than admit to themselves or to others that their efforts have been a waste, many people find some redeeming value in the treatment.

8. Confirmation Bias is another common reason for our impressions and memories to inaccurately represent reality. Practitioners and their clients are prone to misinterpret cues and remember things as they wish they had happened. They may be selective in what they recall, overestimating their apparent successes while ignoring, downplaying, or explaining away their failures. Or they may notice the signs consistent with their favored diagnosis and ignore or downplay aspects of the case inconsistent with this.

9. Anchoring This is the tendency to perceptually lock onto salient features in the patient’s initial presentation too early in the diagnostic process, and failing to adjust this initial impression in the light of later information. This error may be severely compounded by the confirmation bias.

10. Availability The disposition to judge things as being more likely, or frequently occurring, if they readily come to mind. Thus, recent experience with a disease may inflate the likelihood of its being diagnosed. Conversely, if a disease has not been seen for a long time (is less available), it may be underdiagnosed.

11. Commission Bias results from the obligation toward beneficence, in that harm to the patient can only be prevented by active intervention. It is the tendency toward action rather than inaction. It is more likely in over-confident veterinarians. Commission bias is less common than omission bias.

12. Omission Bias the tendency toward inaction and rooted in the principle of nonmaleficence. In hindsight, events that have occurred through the natural progression of a disease are more acceptable than those that may be attributed directly to the action of the veterinarian. The bias may be sustained by the reinforcement often associated with not doing anything, but it may prove disastrous.

13. Diagnosis Momentum Once diagnostic labels are attached to patients they tend to become stickier and stickier. Through intermediaries (clients, techs, other vets) what might have started as a possibility gathers increasing momentum until it becomes definite, and all other possibilities are excluded.

14. Feedback Sanction Making a diagnostic error may carry no immediate consequences, as considerable time may elapse before the error is discovered, if ever, or poor system feedback processes prevent important information on decisions getting back to the decision maker.

15. Gambler’s Fallacy Attributed to gamblers, this fallacy is the belief that if a coin is tossed ten times and is heads each time, the 11th toss has a greater chance of being tails (even though a fair coin has no memory). An example would be a vet who sees a series of patients with dyspnea, diagnoses all of them with a CHF, and assumes the sequence will not continue. Thus, the pretest probability that a patient will have a particular diagnosis might be influenced by preceding but independent events.

16. Posterior Probability Error Occurs when a vet’s estimate for the likelihood of disease is unduly influenced by what has gone on before for a particular patient. It is the opposite of the gambler’s fallacy in that the doctor is gambling on the sequence continuing.

17. Hindsight Bias Knowing the outcome may profoundly influence the perception of past events and prevent a realistic appraisal of what actually occurred. In the context of diagnostic error, it may compromise learning through either an underestimation (illusion of failure) or overestimation (illusion of control) of the decision maker’s abilities.

18. Overconfidence Bias A universal tendency to believe we know more than we do. Overconfidence reflects a tendency to act on incomplete information, intuitions, or hunches. Too much faith is placed in opinion instead of carefully gathered evidence. The bias may be augmented by both anchoring and availability, and catastrophic outcomes may result when there is a prevailing commission bias.

19. Premature Closure A powerful error accounting for a high proportion of missed diagnoses. It is the tendency to apply premature closure to the decision making process, accepting a diagnosis before it has been fully verified. The consequences of the bias are reflected in the maxim: ‘‘When the diagnosis is made, the thinking stops.’’

20. Search Satisfying Reflects the universal tendency to call off a search once something is found. Comorbidities, second foreign bodies, other fractures, and coingestants in poisoning may all be missed. Also, if the search yields nothing, diagnosticians should satisfy themselves that they have been looking in the right place.

21. Yin-Yang Out When patients have been subjected to exhaustive and unavailing diagnostic investigations, they are said to have been worked up the Yin-Yang. The Yin-Yang Out is the tendency to believe that nothing further can be done to throw light on the dark place where, and if, any definitive diagnosis resides for the patient, i.e., the vet is let out of further diagnostic effort. This may prove ultimately to be true, but to adopt the strategy at the outset is fraught with the chance of a variety of errors.


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Dr. Nancy Scanlan Shows us How to Talk Sciency Without Actually Accepting Science

I have written frequently about the tendency of leaders in the alternative veterinary medicine community to talk about science as if they valued it while really either not understanding how science actually works or simply rejecting its basic principles (e.g. 1, 2). Alternative medicine, at its heart, is philosophically opposed to the method for understanding nature that has been so successful when applied through science. Supporters of alternative therapies will cite scientific evidence when it supports their beliefs, but they generally ignore or dismiss it when it does not, and they nearly always believe individual personal experience is a better guide to the nature of reality than controlled research. Science is more a means to advertise and promote their beliefs than a method for discovering which of those beliefs are true and which false.

A recent article in the Integrative Veterinary Care Journal by Dr. Nancy Scanlan, another leading figure in the alternative veterinary medicine community, illustrates this problem.

Choosing the Best Models for Integrative Research. IVC Summer 2015, 60-62. By Nancy Scanlan

It sounds pretty good, right? Looking for the best approach to do scientific research on so-called integrative therapies? However, the piece starts and ends by questioning the basic premises of medical research and suggesting science isn’t really needed to understand the truth about alternative therapies.

Conventional medicine focuses on separating out the individual actions of substances that have an effect on systems or diseases defined by conventional research.

To an extent, this is quite true. Science does make use of the principle of reductionism, minimizing the number of variables and potential sources of error in research studies to help separate out which effects are most significant. This does not deny the importance of complex interactions within systems, but it does recognize that human beings simply don’t have the ability to keep track of every element and every interaction in such systems, and when we try to view them without simplification, we are often wildly wrong about the true cause and effect relationships at work. Reductionism does have limitations, but it’s been a very successful tool in compensating for our own limitations in understanding how nature works.

Dr. Scanlan also tosses in the phrase “defined by conventional research” to suggest that this is simply one arbitrary way to define health and disease and that there may be others equally legitimate. This is a very post-modern view that rejects the concept of a stable and definable natural world that has whatever properties it has regardless of our beliefs and instead suggests that all human understanding should be viewed as no more than metaphor, with one set of metaphors being as “real” as another (though they often inconsistently choose to prefer their own paradigm over that of science-based medicine even while insisting that scientific rejection of their claims is merely bias in favor of one of multiple legitimate world views). She expands on this later in the article:

When traditional medicine [whatever that is] looks on disease and physiology as circular, as seen in the Five Element cycle of Traditional Chinese Medicine (TCM), different practitioners may decide to attack the same disease process at different parts of that cycle. The treatments may be seen as different by conventional medicine, but…final conclusions should be based on two criteria: were the cases treated successfully, and were all cases within the series consistent based on the traditional, not the conventional, view?

Essentially what she is saying here is that the problem, the method of treatment, and the outcome should all be defined by the standards of the alternative therapy being tested, not that of scientific medicine. We should view a series of case reports that have, by scientific standards, different diseases and which receive different herbs or other treatments and have success defined differently and however the practitioner chooses to define it, as legitimate scientific proof of the practice being tested. It is just like real science, except it ignores all the principles of scientific research and presumes the legitimacy of its own principles from the beginning.

Similarly, Dr. Scanlan argues that it is not legitimate to try and isolate individual compounds, or even individual herbs, when testing herbal remedies because the effects we are evaluating likely come from the specific combination of herbs ina  remedy. And how do we know this? Because, “If a formula has withstood the test of time and has been used for decades or even hundreds or thousands of years, it is most likely there’s a reason for using a specific combination of herbs.” In other words, if people claim to have used an herbal remedy successfully for a long time, without any proof of this claim, then the only appropriate way to test that remedy is to assume those claims are true and structure our research around them, rather than following the standard scientific practices that have so far proven far more successful in improving human health than thousands of years of uncontrolled, trial-and-error folk medicine did.

While Dr. Scanlan makes a few reasonable suggestions, such as encouraging standardization of herbal formulas so different researchers studying them are at least studying the same thing, she makes it clear throughout the article that the purpose of research is not to find the truth but to use the marketing value of science to convince others of what alternative practitioners already “know” through unscientific means. The possibility that these therapies might not work or that research results may necessitate abandoning any practice is never once even hinted at in this article.

“Studies structured to meet the expectations of conventional medicine…will encourage a better understanding and wider acceptance of integrative medicine.”

“When designing a study for integrative medicine, this approach can help satisfy both the conventional method of choosing treatments, and traditional methods that ensure better outcomes.”

“A standardized formulation and dose meets the conventional need for studies of a standard disease with a standard treatment. Once acceptance occurs, individual variations can be introduced.”

“In order for acceptance to occur, initial research may need to be more standardized…the fact that a remedy consistently “improves” (to the conventional eye) symptoms of a specific “disease” (as defined by conventional medicine) may open the door to acceptance of homeopathy as a valid part of integrative medicine.:”

“Echinacea…has usually been studied with the expectation that it will increase immune reactions in some way. [based, she neglects to mention, on claims by herbalists that it “boosts” or “strengthens” the immune system] However, it may have more of an immune-modulating effect, as evidence by at least one trial showing a decrease in WBC activity. Instead of viewing this as conflicting evidence, it would be better to examine herbal tradition…to see whether this herb has been used as an immune “normalizer.” If so, the conflicting evidence is actually supporting evidence for the original premise.” [In other words, any result can be viewed as supporting the hypothesis if we simply interpret it through the lens of pre-scientific folk medicine texts or our own experiences, and we never have to judge any practice to be inconsistent or ineffective.]



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Canine Influenza and Quack Vets

The recent canine influenza outbreak in the Chicago has generated a lot of anxiety among dog owners around the country. Unfortunately, the understandable and appropriate stream of questions from dog owners about this disease has generated a great deal of misinformation in the media and on the internet, and sadly some of it has come from veterinarians. While there is much we do not know, there are some things which are certainly not true and not helpful to dog owners.

To begin with, the most reliable sources of information about this disease are reputable veterinary infectious disease experts. Cornell University’s Animal Health Diagnostic Center (AHDC) has been the gold-standard lab for testing samples from dogs involved in this outbreak, and this is a great source of information. The Centers of Disease Control (CDC) and American Veterinary Medical Association AVMA) are also reliable sources. In brief, the current outbreak is a new variety (H3N2) of the previously identified canine influenza virus (H3N8), which itself originated in horses. Neither has been shown to be transmissible to people or most other animals, though the H3N2 variant can infect cats. The vast majority of infected dogs will show mild to now symptoms. Affected dogs typically have a mild persistent cough for 10-30 days, though the rare case that develops serious illness can show high fever and pneumonia. There is no direct treatment for the disease, but supportive care and treatment of secondary infections is very important in severely affected dogs. There is a vaccine which can reduce the risk of disease from the H3N8 strain, but it is not clear if there is any cross-protection against the H3N2 strain.

Since dogs do not travel as widely and readily as humans, influenza outbreaks are much less prone to spreading in this species. Unfortunately, as in humans, during an outbreak every dog with any symptoms that even vaguely resemble influenza is often assumed by its owners to have the disease. This leads to a lot of claims about the disease being present in places where it is not, as well as claims about animals either dying from the illness or being cured of it when they likely have not had it at all. Only appropriate diagnostic testing, as done through the AHDC, can confirm the presence of canine influenza, so we cannot make decisions about managing outbreaks or individual patients by assuming the disease is present based on compatible symptoms. These same symptoms are caused by many other, far more common, illnesses. The most up-to-date summary of cases tested and confirmed by the AHDC can be found on their web site.

As an example of egregious and dangerous misinformation about canine influenza, we can turn to our old model of veterinary quackery, Dr. Will Falconer. This fellow regularly attacks science-based veterinary medicine and essentially recommends magic as a substitute. He has a fondness for homeopathy, despite the abundant evidence that it is useless pseudoscience, and he has a particular loathing for vaccines. Predictably, he recommends homeopathy as treatment and prevention for canine influenza, providing an excellent model of the ridiculous fake science of homeopathy, and he derides vaccination as a preventative measure with arguments that are clearly and demonstrably false.

To begin with, he has posted his process for determining which homeopathic products to use to treat canine influenza. This involves the usual nonsense of listing symptoms which are in no way unique to this disease and then turning to collections of substances organized by the symptoms they are supposed to cause in healthy individuals based on so-called provings. Extremely dilute versions of these substances are then given one at a time. If the pet gets better, the treatment gets the credit. If not, another remedy is chosen just as capriciously and on and on until the patient either recovers or dies or the owner realizes that they are being scammed.

Dr. Falconer used this process to select a classic homeopathic remedy, Nux vomica (the poison strychnine diluted into non-existence), as the “cure” for canine influenza. However, after a couple of clients tried a different product (phosphorus, also diluted into non-existence) and their dogs got better, he decided this was the first choice cure. The fact that none of these patients were ever actually tested to see if they had influenza doesn’t bother Dr. Falconer, which given his demonstrated belief in magic isn’t surprising. One can easily see how this sort of extended process of trying one fake remedy after another without obtaining a real diagnosis or making any effort to employ real medical treatment could be dangerous for a dog who actually has influenza, or any other serious illness. It is ethically inexcusable for a veterinarian to practice this way, and it astounds and depresses me that Dr. Falconer is permitted to do so.

Of course, practicing voodoo in place of medicine doesn’t work nearly as well if you don’t try to mislead and frighten people away from actual medicine, and Dr. Falconer has shown himself cheerfully willing to do that before. In the case of canine influenza, he asserts that vaccines are useless and potentially dangerous and only considered because of the malign influence of, you gussed it, Big Pharma:

The Influence of Big Pharma

it’s widely known there’s no cross immunity between flu virus strains.

But, [a reporter sufficiently naïve to interview Dr. Falconer] went with, “experts don’t know” if the current vaccine will help.


Here we with go with the “uncertainty” again, that keeps the doors open for lots of dogs to be unnecessarily vaccinated for this flu. With all the inherent risks vaccination carries.

The current vaccine will not prevent it. Any vet who’s uncertain about that is shining you on.

Despite what is “widely known” in homeopathy fantasyland, cross protection between vaccines for different influenza strains is common, and the CDC, AVMA, and AHDC have no reason to “shine us on” when they admit that the protective value of the H3N8 vaccine against the H3N2 strain is unknown.

Bottom Line
There is no need to panic about canine influenza. The current outbreak is not spreading like wildfire across the country, most dogs who have coughing and other respiratory symptoms do not have influenza, most dogs exposed to influenza do not get seriously ill, and it is probably not worthwhile vaccinating your dog if you live outside of the area where confirmed cases have been detected or if your dog does not have extensive contact with other dogs. There are plenty of reliable sources of information, but you cannot assume that just because someone is a veterinarian that they have the facts about this disease. Certainly, anyone claiming miraculous cures, effective prevention, or some sort of vast conspiracy or willful ignorance on the part of mainstream infectious disease and public health experts is not someone you should consider a reliable source of information about this or any other health risk to your dog.

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The Rise (and Fall?) of Alternative Medicine Terminology

As I’ve discussed before, the terminology associated with alternative medicine is complex and inconsistent, so it makes discussing and debating the subject that much more challenging. Terms like “alternative,” “holistic,” “integrative,” “natural,” etc. are often used interchangeably, but they tend to have subtle distinctions in meaning or in the underlying ideology they represent, and their popularity varies over time.

Mostly for fun, but hopefully to generate at least a little insight into the use of such terms, I have been playing around with Google’s ngram viewer to track the use of common alternative medicine terms over time. This tool identifies the frequency of occurrence of words of phrases in the enormous collection of published books digitized by Google. While it is not a complete collection of everything ever published, since no such resource is likely even possible, it does include a large enough sample of books published in the last two centuries to provide a rough guide to the popularity of specific terms in published writing.

My understanding has long been that the terms used to label, and to market, alternative therapies have changed in response to ideological shifts and to changes in the perception of these practices. For example, I would guess that the earliest term would be “alternative,” which arose to suggest such therapies could be used in place of science-based medicine. When people proved unwilling to give up conventional medicine, the term “complementary and alternative” and ultimately just “complementary medicine” arose to suggest one could benefit by using both science-based and other therapies. This, however, carries the implication that alternative medicine is subsidiary or an afterthought to conventional treatment, which some CAM practitioners dislike. The most recent innovation, in my view, has been “integrative medicine,” a term which implies that alternative and science-based therapies are equally legitimate and that there is some advantage to using them together despite the lack of evidence for many specific CAM practices and for any real improvement in outcomes to mixing these with conventional medicine.

In general, the ngram view supports this understanding, though with some interesting twists. First, the term “alternative medicine” yields this result:

alt med

Clearly, the term came into use during the late 1970s and was used with markedly increasing frequency starting in the early 1990s. Interestingly, it appears to have declined in frequency beginning in the early 2000s, which I would not have expected. Of course, given the limitations of the ngram viewer, it is not clear if this is entirely a real change in the popularity of the term or simply an artefact of the database. However, looking at the results for other CAM terms might shed some light on this question. For example, here is the result for “complementary and alternative medicine:”


As expected, this term seems to have appeared later than “alternative medicine,” emerging in the mid 1990s. Unlike “alternative medicine,” this term does not yet appear to have peaked or started to decline in popularity.

Interestingly, my assumptions about the term “integrative medicine” appear to have been mistaken, as the usage of this term follows a pattern almost identical to that of “complementary and alternative medicine,” whereas I would have expected it to have arisen later.

integrative med

Another popular term, “holistic medicine,” shows features of both the patterns seen with the previous terms:

holistic medicine

This term appears to have shown up slightly before “alternative medicine” and reached its peak popularity earlier, though it was never nearly as popular as “alternative medicine.” However, this term too appears to have begun declining in use beginning in the early 2000s. One might hope this represents a decline in the popularity of these questionable concepts as well, but of course this data cannot really determine that.

The slightly more common term “natural medicine” shows pattern similar to that of “alternative medicine:”

natural medicine

natural meidince since 1980

Though this one has been around at a low level for longer than either “holistic medicine” or “alternative medicine,” it appeared to have a big jump in usage in the 1990s and to have had a drop in popularity since about 2000:



I also thought that checking the usage of the names for specific alternative therapies might help sort out whether the apparent patterns seen in the use of these more general terms are accurate, and the results suggest they may be. First, acupuncture:


acupuncture since 1960

This term takes off in frequency in the 1970s, likely stimulated by the writings of journalist James Reston, who wrote glowingly, and somewhat inaccurately, about the use of acupuncture following his surgical treatment for appendicitis in China. A second step up in usage seems to have occurred in the late 1990s, similar to that seen for most of the general terms examined above. Also similar to the patterns for these terms, the use of “acupuncture” in published writing seems to have declined since about 2000. The related term “traditional Chinese medicine” follows a very similar pattern:


Though the terms “chiropractic” and “homeopathy” appear somewhat earlier, these too show a marked increase in usage in the 1990s followed by a decline since 2000.




Once again, it is possible that the apparent decline in the appearance of these terms represents an artefact of the database, so to test this idea I also evaluated a few common terms from science-based medicine. These show marked increases in use associated with their introduction, but no apparent decline such as that seen for CAM terms.


Mainstream MedTx

So what does all of this tell us? Well, given the limitations in the underlying database, we cannot make any confident pronouncements. However, what these data suggest is that terms associated with alternative medicine as a general ideological concept, and with specific alternative therapies, have experienced a significant increase in frequency of appearance in published English in the last few decades, primarily in the 70s-90s. Interest in these approaches seems to have increased as a function of larger cultural trends, including the increase in cross-cultural communication and awareness, the counterculture movement, the rise of post-modernism, and so on. Arguably, there has also been a growing anti-science and anti-intellectual trend, at least in the U.S., over the same time period, which would likely increase the attractiveness of pseudoscientific approaches that question the meaning of specialized expertise and the privileging of scientific evidence over belief and personal experience that is an intrinsic part of science-based medicine.

I would like to see some glimmer of hope in the apparent decline in the use of these terms which has occurred for most of them since about 2000. The idea that the cultural pendulum may be swinging back towards science and reason and away from opinion-based and faith-based medicine is appealing, but these data alone are not sufficient to demonstrate such a shift is really happening. Nevertheless, for the sake of human and veterinary patients, I will continue to hope this is the case!

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Evidence Update: Cold Laser Therapy for Dogs & Cats

I first summarized the scant evidence concerning low-level or “cold” laser therapy in companion animals in 2010, and I reviewed a couple of small studies in 2011. A recent checked showed only a couple of studies looking at cold laser since. All of these were small trials, and I am not able to access the full reports, so I cannot thoroughly evaluate the quality of the study design or conduct. None of these studies provide a definitive answer to the usefulness of laser therapy for the problems evaluated, but since we must work with the evidence we have rather than the evidence we would like, I thought I would briefly discuss this new research.

The first is a study from India looking at laser effects on wound healing in dogs.

Efficacy of low level LASER therapy on wound healing in dogs. Indian Journal of Veterinary Surgery 2011 32 2 103-106 Singh, M., Bhargava, M. K., Sahi, A., Jawre, S., Singh, R., Chandrapuria, V. P., Kocchar, G.


The study was undertaken to assess the efficacy of low level LASER therapy on wound healing in 30 dogs. The dogs were randomly divided into five groups, each consisting of six dogs. The dogs of group 1 were treated as control, whereas the dogs of groups II, III, IV and V were treated with low level LASER therapy for 2 min, 10 Hz, 1.2 Joules; 4 min, 10 Hz, 2.4 Joules; 2 min, 30 Hz, 1.2 Joules; and 4 min, 30 Hz, 2.4 joules, respectively. The clinical parameters were recorded on day 0 (control) and subsequently on days 3rd, 5th, 7th, 10th and 14th in the animals of all groups. Increased healing percentage, decreased inflammation and exudation with clinically no scab during healing and minimal scar at wound site after healing, early regeneration of granulation tissue, better organization, compactness and intense epithelial regeneration were observed in dogs treated with laser therapy as compared to control animals. Significant increase in rectal temperature with non-significant variation in pulse and respiratory rates were observed in all the groups. The maximum decrease in the size of the wounds was observed in groups III and V, with a maximum healing rate of 94.84% and 88.01%, respectively up to 14 days, with maximum efficacy at 4 min, 10 Hz, 2.4 joules protocol followed by 4 min, 30 Hz, 2.4 joules.

The groups were small, it is unclear if the assessment was blinded, the outcome measures appear to be subjective, and there is no reported statistical analysis to indicate how likely it is that the differences between the groups are due to chance. The authors report a beneficial effect from the laser therapy, but again how reliable this conclusion is cannot be determined from the available information.

The next study was also done in India and evaluated laser therapy for wound healing in dogs.

Madhya Pradesh Pashu Chikitsa Vishwavidyalaya, Jabalpur, MP, India. Low level laser therapy for the healing of contaminated wounds in dogs: histopathological changes. Indian Journal of Veterinary Surgery. 2013 34 1 57-58


The study was conducted on 18 dogs, divided into three groups comprising of 6 animals each. In group 1 – dressing of contaminated wounds was done with antiseptic liquid and antibiotic injected parenterally. In group 2, dressing of contaminated wound was done+low level laser therapy (10 Hz+5 min, 3 Joule, for 5 consecutive days)+parenteral antibiotic. In group 3, dressing of contaminated wound was done along with low level laser therapy (20 Hz+10 min, 6 Joule, for 5 consecutive days)+parenteral antibiotic. The biopsy punch was collected from the site on days 0 and 14. No apparent differences could be observed between the non-laser treated group and the laser treated groups with respect to histopathological examination except for the thicker epidermis noticed in five cases of the laser treated group as compared to that in non-laser treated group. It was concluded that low level laser therapy has no significant effect on healing of contaminated wounds in dogs.

Like the previous study, this was a small trial with limited information available about how it was conducted. This study, unlike the first, did not find any benefit from laser therapy on wound healing.

The evidence in humans is mixed and inconclusive on the benefits of lasers for facilitating wound healing, so while some benefit is possible, it is not yet clear if there actually is a clinically meaningful benefit in dogs.

The third article evaluated laser therapy for reducing foot itching in dogs with environmental allergies.

Stich AN, Rosenkrantz WS, Griffin CE. Clinical efficacy of low-level laser therapy on localized canine atopic dermatitis severity score and localized pruritic visual analog score in pedal pruritus due to canine atopic dermatitis. Vet Dermatol 2014 Oct;25(5):464-e74. doi: 10.1111/vde.12144. Epub 2014 Jun 9.


Canine atopic dermatitis is a genetically predisposed inflammatory skin disease often requiring multimodal treatment. There is a need to find further low-risk adjunctive therapies.

To evaluate the localized effect of low-level laser therapy (LLLT) on the paws of dogs with atopic dermatitis using a localized canine atopic dermatitis severity score (LCADSS) and owner localized pruritic visual analog score (LPVAS) in comparison to treatment with a placebo.

Thirty client-owned dogs with symmetrical pedal pruritus due to canine atopic dermatitis.

Dogs were randomly assigned into two groups. In each group, one paw was treated with LLLT and one paw treated with a placebo laser (comparing either both fore- or hindpaws). Treatments were administered at 4 J/cm(2) (area from carpus/tarsus to distal aspect of digit 3) three times per week for the first 2 weeks and two times per week for the second 2 weeks. Scores were assessed for each paw at weeks 0, 2, 4 and 5.

There were no significant differences in LCADSS or LPVAS between LLLT and placebo treatments between weeks 0 and 5 (P = 0.0856 and 0.5017, respectively). However, LCADSS and LPVAS significantly decreased from week 0 at weeks 2, 4 and 5 in both LLLT and placebo groups (P < 0.0001 for all).

Low-level laser therapy is not an effective localized treatment for pedal pruritus in canine atopic dermatitis.

The study appears to have been well-controlled, though there is no mention of blinding, and the outcome measures are subjective but commonly standardized assessment tools. The study found improvement on both active and placebo treatment, which is almost always the case in clinical trials involving skin allergies, but did not see any benefit of laser beyond that of the placebo.

Finally, another dermatology study looked at cold laser therapy for an ill-defined set of disorders in which dogs have inadequate hair growth. Since the cause of these problems is not understood, and there is no well-demonstrated effective treatment, something like cold laser may be worth trying even without a solid reason to think it will be of benefit.

Olivieri L, Cavina D, Radicchi G, Miragliotta V, Abramo F. Efficacy of low-level laser therapy on hair regrowth in dogs with noninflammatory alopecia: a pilot study. Vet Dermatol. 2015 Feb;26(1):35-9, e11. doi: 10.1111/vde.12170. Epub 2014 Sep 16.


Canine noninflammatory alopecia (CNA) is a heterogeneous group of skin diseases with different underlying pathogenesis. The therapeutic approach is challenging, and new options for treatment are desirable.

To test the clinical efficacy of low-level laser therapy (LLLT) on hair regrowth in CNA.

Seven dogs of different ages, breeds and genders with a clinical and histopathological diagnosis of noninflammatory alopecia.

Each dog was treated twice weekly for a maximum of 2 months with a therapeutic laser producing the following three different wavelengths emerging simultaneously from 21 foci: 13 × 16 mW, 470 nm; 4 × 50 mW, 685 nm; and 4 × 200 mW, 830 nm. The fluence given was 3 J/cm(2) , frequency 5 Hz, amplitude of the irradiated area was 25 cm(2) and application time was 1.34 min. A predetermined alopecic area was left untreated and served as a control area. From one dog, post-treatment biopsies of treated and untreated sites were obtained for histological evaluation of hair density and the percentage of haired and nonhaired follicles.

At the end of the study, coat regrowth was greatly improved in six of seven animals and improved in one of seven. By morphometry, the area occupied by hair follicles was 18% in the treated sample and 11% in the untreated one (11%); haired follicles were (per area) 93% in the treated sample and only 9% in the control sample.

Our clinical and histological data document promising effects of LLLT on hair regrowth in CNA. Further studies investigating the biological mechanism underlying the effect of LLLT on hair follicle cycling are warranted.

The results suggest laser therapy may have stimulated hair growth in these dogs. However, only 7 dogs were involved, and only one provided skin biopsies, so this study merely hints at the potential for laser therapy, and further work with appropriate controls would be needed to demonstrate there is real benefit to be had.

Bottom Line
The research into cold laser in dogs and cats is sparse and generally low quality. Most studies are small and have minimal or uncertain controls for bias and error. Some show promising results, others do not. At this stage, as I concluded in my initial discussion of this topic, there is enough evidence to warrant further study but not enough to support routine clinical use of cold laser. If vets want to try this therapy, they have an obligation to be clear with client that the risks and benefits have not been established and that the treatment is essentially experimental. There is nothing wrong with using such a treatment given appropriate informed consent, but the aggressive marketing of laser equipment to vets as a profitable treatment is ethically questionable given the lack of good evidence that it is a truly safe and effective treatment for any condition.


Posted in General, Science-Based Veterinary Medicine | 11 Comments

Faces of Vaccine Denialism

Been seeing a lot of these folks lately….


faces of vaccine denialism

Posted in Humor | 1 Comment

SkeptVet Gets Hate Mail: Update 2015

As regular readers will know, I don’t allow abusive comments or personal rants on the site. Primarily, this is because such nonsense contributes nothing productive, and I am under no obligation to provide angry or crazy people with a forum for their vitriol. Such comments lower the tone of debate and shift the focus away from salient issues and towards personalities, which dumbs down any discussion. Some mainstream science publications have actually blocked all comments on their sites because vacuous attacks come to dominate and crowd out any thoughtful discussion or debate. People are welcome to disagree with me, and I daily allow comments that do so. But as I try to be substantive and civil in my criticism of others, focusing on their ideas and claims, not their personalities, so I hold commenters here to a similarly adult standard of behavior.

That said, I think it is instructive to periodically look at the sort of bile spewed at me by people who have no real evidence or intelligent argument to offer but just want to express their anger at my challenging some of their beliefs. These are the people who drive society away from science and reason, who make compromise and cooperation so difficult in politics that we end up with a dysfunctional government, and who threaten the functioning of a society in which civil disagreement is possible and productive. These folks also illustrate how distant many of the alternative ideologies they espouse are from science and how much more like fundamentalist religion they really are. And, finally, sometimes they are simply funny. Enjoy!

Short and Sweet?
There is one word for you the author of this article….”””IDIOT””””

Skeptvet is a dumb fuck

You’re an idiot.

Are you living under a rock dude?

Homeopathy has healed my dog AND myself. Take your Big Pharma and shove it.

Go take your drugs and destroy your kidneys and liver. And kill all our animals that way as you promote drugs and surgery and toxic immunization a. You are a total moron.

Skepvet, you are an absolute fool. The fact that you would happily prescribe…makes you a complete moron…An education beyond University of Phoenix should be your next life goal.

[This one was creative enough to invent an email to represent me abusing myself!] From: skeptvet@dispostaba.fuck

I am truly a motherfucker… I Have cancer and dying. Im trily sorry I trust in protandim now

Tinfoil Hat Wearers
How much are Hills, Purina and the pharmaceutical companies like Merck slipping you on the side? Clearly, you are attempting to manipulate an uneducated, easily led, public with your claptrap disguised as science.

Your site tag says, “A Vet Takes a Science-Based Look at Veterinary Medicine”. It should more accurately say, “A Vet Takes a Pharmaceutically Skewed Prospective of Veterinary Medicine.” That would be more accurate. You’re sole reason to exist is to try to hold back the tide that threatens your alternative medicine buddies in big pharma.

And for every “expert” that has “scientific” proof that ACTION A is best, there will always be another “expert” that has “scientific” proof that ACTION B is best. Look closely at who pays which “expert” for the proof and you’ll have the answer as to why which ACTION is best. It’s all about the bottom line, folks. Now that the pet industry is a multi-billion dollar a year industry, unfortunately it appears the vets and “pet-care” companies are using our pets in the same way the human medical establishment has done…cause confusion and watch the big bucks roll in!

You are a skeptic because it could put you out of business.

The FDA is a sub contractor for Monsanto. Come to think, so is this website!

Huh, sounds a lot like what you say you aren’t – a pet food company lackey. The strong reason in favor of healthy, appropriate, homemade diets is the health of our pets…the strong reason against is two-fold – money and sickness – both of which I am sure you have no problems with. Sick animals are good for business.

What a HORRID article! If everyone in this world was healthy and living without chronic disease, then how would the pharmaceutical companies make money?

Who is paying you to write all this crap? The AMA? Jeez.

Another example of Government out of control serving Big Pharma both in an alliance and both disserving the unknowing blinded public while they RAKE IN $BILLIONS IN PROFITS. It’s the Government and its Agencies like the FDA THAT CANNOT BE TRUSTED! Do we need any more evidence for this? No, it is clear. SkeptVet clearly takes THEIR side.

You are a typical vet who just wants to stand behind the prescriptions that pay for your lifestyle.

I know one thing for sure……Vets scoff because it is about the $$$$…..they focus on keeping us coming back for the prescription food, meds and their $$$’s…….I do not trust doctors for humans let alone for my precious little ones. They are ALL about the money

To all you ignorant people bought off by Big Pharma . It is getting old by now you all not getting it. America is a fat, diseased very sick nation. The irony of thinking we are this Great nation when we are the international laughing stock. Europe has a seperate factory for making send out food to America because the Ingredients we allow are not allowed in their country due to most are toxic. Even the little cashier at World Market know’s this… If people were well and did not need prescription medicine their would be no money to be made in this billion dollar Big Pharma Industry. They want us sick!

Another sellout medical doctor…Medical doctors and mainstream people are so arrogant. They think they know everything, when behind closed doors, the people who fund these foods and treatments are actively trying to harm them.

Keep being oblivious, so people like me have to live in a perpetual hell, where I can’t even know what is in my food or water. Because of people like you, they have total control… as long as you keep supporting the corporations aspirations, nothing will EVER change.

Maybe you should go through your records and see how many of those dogs you vaccinate develop an illness within 12 weeks of the vaccine.  I think you’d find it more eduational than blindly working for the pharmaceutical industry who are constantly being sued for lying about test results on their products.  Why would they lie if their products have been properly tested and proved to be safe?  I don’t suppose it’s occurred to you that they’re not in the business of healing.  They’re in the business of making as much money as they can… Most vets who switch to a holistic practice earn far less money than you do, so what possible reason could they have for changing?  Has it occurred to you that they have actually bothered to pay attention and have realised that they are hurting our animals with unnecessary medications? That their consciences have stepped in and prevented them from continuing to cause chronic disease in our pets?  Obviously not. Our animals need healers working with us owners, not drug sales people.

Who’s paying you!!?? Talk about biased. I’d like to know the serious side effect of taking cats claw… I always read opposing info when researching but this is so slanted its crazy. So I figure you are either a vet or you are paid/paid off by them. Let’s all feed science diet, shall we!… Seriously, who pays you!!??

If you don’t get a payment from the drug company, it’s not worth recommending.

Big devious lie of an article!!! Probably working for the misinformation industries!!!!!!

Typical hate spewing from the medical field, these studies are only argued against because it affects the medical industries bottom line and making them lose money (and to keep their monopoly of the healthcare market).

After reading this blog and these testimonials, I think the skeptics here are for the most part, on someones payroll. Science has been Hijacked long ago, and the truth is being continually sacrificed on the alter of Corporate profits. I dont know what they are paying you to slander this company, too much if you ask me,

The drug industry ARE the quacks. Its a protection racket. This skepvet is a living testament to that. Ignore them and do what works not what their rigged trials tell you should work.

Someone is paying you to discredit vitamins, glandulars and minerals as beneficial remedies. You probably are a stupid medic. Breast feeding at age 80 off the pharmaceutical TIT. Die quickly so u can be reborn and do something to help someone.go pop a pill. You are an idiot.

Another sellout medical doctor…. These people probably promote heavy metal-laden vaccines; liver destroying drugs and toxic foods that contain genetically modified organisms. Go ahead, be ignorant and take the medical industries junk. They will be happy to benefit off of your illnesses. Big pharma and agribusiness work hand-in-hand… Medical doctors and mainstream people are so arrogant. They think they know everything, when behind closed doors, the people who fund these foods and treatments are actively trying to harm them.

Why do you attack natural products? The conspiracy is for all the chemicals with the phony white papers. I have seen many a healthy person and or pet die from chemical meds and would have survived had they been given a real natural product that actually works.

Unemployed Psychotherapists
I understand your need to feel as if you are flying the EBVMA flag in your posts and blog in general. To be quite honest, it comes across as if you were not able to obtain a real medical position so you chose to rant on “evidence based veterinarian medicine.”… .” If you don’t understand the origin from which we were created you might not see the total picture doc. God actually gave our bodies their own defense mechanism from many diseases, enhanced by utilizing another thing God created that assist this healing process, there called nutrients.

Maybe if you spent more time actually observing the animals and building your practice instead of blogging this nonsense you could find the success and attention you so obviously crave.

This blog is such non-sense and sounds like it has been written by an angry veterinarian with an unsuccessful practice.

You sir, are a disgrace to your profession. Your ego and agenda have overcome your common sense.

Taking pot shots at Nutriscan and scoffing at people who have found flea meds to be dangerous to their pets might make you feel superior but from here you look like an a__.

This treatment is now being used by vets who are not arrogant and close-minded such as you are, with much success. You know–you aren’t always right just because you got a degree in Veterinary Science.

There’s a lot that isn’t thoroughly taught in either vet or (human) medical school. I’ve noticed that the medical professionals who know the least are the ones who are the most arrogant!

I’m a pet parent, not a vet, and whoever wrote this article seems very upset and angry… Do everyone a favor and get over yourself.








Posted in General | 30 Comments

Everything We Eat Cures Cancer! (or Causes it?)

Central to the nutritional and general healthcare philosophy of most alternative practitioners is that anything we eat is either good or bad. They often quote that cutting edge physician Hippocrates saying “Let food be thy medicine” (though they less commonly quote him saying “A physician without a knowledge of Astrology has no right to call himself a physician” or “What medicines do not heal, the lance will; what the lance does not heal, fire will.” for some reason). So-called “super foods” are lauded as having nearly magical healing properties, whereas foods like high fructose corn syrup, or even entire categories of foods such as grains are considered off-limits in a healthy diet. One of the most common scare tactics used to promote alternative approaches to pet nutrition is the claim that commercial pet food causes cancer.

So what is the evidence to support these claims that foods cause or cure cancer or other serious disease? Well, often there is little or no evidence at all, but occasionally there will be an observational study (one without any controls for chance, bias, or other sources of error). Usually these studies are done in humans, and they tend to drive food fads for both humans and, to a lesser extent, pets despite the dangers of extrapolating from human research to veterinary patients. However, as has often been pointed out, research studies are only as good as the quality of their design and conduct, and single studies, especially observational studies, are rarely solid enough evidence to justify major changes in behavior. I recently ran across a systematic review which has examined the human nutrition literature and has shed some light on why it sometimes seems like everything we causes or cures cancer.

Schoenfeld JD, Ioannidis JP. Is everything we eat associated with cancer? A systematic cookbook review. Am J Clin Nutr. 2013 Jan;97(1):127-34. doi: 10.3945/ajcn.112.047142. Epub 2012 Nov 28.

This clever little study selected recipes at random from a popular cookbook and then evaluated all the ingredients to see if there was any research literature suggesting they increased or decreased cancer risk. Here are the ingredients for which some research studies were found:

veal, salt, pepper spice, flour, egg, bread, pork, butter, tomato, lemon, duck, onion, celery, carrot, parsley, mace, sherry, olive, mushroom, tripe, milk, cheese, coffee, bacon, sugar, lobster, potato, beef, lamb, mustard, nuts, wine, peas, corn, cinnamon, cayenne, orange, tea, rum, and raisin.

Of these, there were more than 5 studies for 65% of the ingredients, with over 216 publications altogether. About 40% of the studies found an increased risk of cancer associated with one of these ingredients, 33% found a decreased cancer risk, and about 25% found no clear evidence either way. When a risk was identified, the statistical support was weak or not technically significant in 80% of the studies, so most individual did not show very robust results. About half of the meta-analyses included, however, had stronger statistical results, which is not surprising since the whole point of meta-analyses is that evaluations of multiple studies give stronger evidence than the results of individual studies. The distribution of effects reported in the meta-analyses centered around zero, suggesting random variation but no clear real effect.

The authors’ discussion summarizes very well not only the results of this study but the general problem with much of the observational and pre-clinical research often used to justify specific practices in the absence of clinical trials:

80% of ingredients from randomly selected recipes had been studied in relation to malignancy and the large majority of these studies were interpreted by their authors as offering evidence for increased or decreased risk of cancer. However, the vast majority of these claims were based on weak statistical evidence. Many statistically insignificant “negative” and weak results were relegated to the full text rather than to the study abstract. Individual studies reported larger effect sizes than did the meta-analyses.

…the credibility of studies in this and other fields is subject to publication and other selective outcome and analysis reporting biases, whenever the pressure to publish fosters a climate in which “negative” results are undervalued and not reported. Ingredients viewed as “unhealthy” may be demonized, leading to subsequent biases in the design, execution and reporting of studies. Some studies that narrowly meet criteria for statistical significance may represent spurious results, especially when there is large flexibility in analyses, selection of contrasts, and reporting. When results are overinterpreted, the emerging literature can skew perspectives and potentially obfuscate other truly significant findings. This issue may be especially problematic in areas such as cancer epidemiology, where randomized trials may be exceedingly difficult and expensive to conduct; therefore, more reliance is placed on observational studies, but with a considerable risk of trusting false-positive or inflated results.

Overinterpretation of individual studies with often small effects that are only marginally significant statistically and may be insignificant clinically is a major problem in all areas of medicine, and it manifests especially dramatically in alternative medicine, where any data is good data so long as it supports existing beliefs. To find out what is actually true and what will real improve health, we must be mindful of the limitations in the evidence and seek to improve the design, conduct, and reporting of clinical studies. That is a job for the researchers. However, the job for the rest of us is to know at least enough about research evidence to be wary of overinterpretation and placing excessive confidence in data that does not merit it. This will hopefully dampen the wild swings back and forth between claims like “Food X will kill you” and “Food X will make you live forever.”



Posted in Nutrition | 7 Comments