Canine Nutrigenomics by Dr. Jean Dodds: Science as Windowdressing

Introduction
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.

Overview

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 by 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 unblinded 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.

 

 

 

 

 

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52 Responses to Canine Nutrigenomics by Dr. Jean Dodds: Science as Windowdressing

  1. Kat Holmes says:

    Hello, hope you don’t mind me askin,I’m doing a diploma in canine nutrition. Could you recommend some good books to read ?! Dr Dodds has come up in my course work as a resource. I’m a little reluctant to use Dodds now ?.

  2. skeptvet says:

    Yes, Dr. Dodds has no credentials in nutrition and makes up a lot of stuff. One of my favorites is Dog Food Logic: Making smart decisions for your dog in an age of too many choices.

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