Medical Miracles: Should We Believe?

Posted on July 14, 2012 by skeptvet

Any time there is discussion of alternative medicine, of treatments that haven’t passed the test of rigorous scientific investigation (or even been tested at all), there are miracle stories. Testimonials, anecdotes, whatever you call them, they are tales of amazing recoveries from illness when everything tried had failed and all hope was lost. The comments on this blog contain many such stories for almost all of the products and methods I have questioned.

And such stories provide emotionally compelling evidence for the effectiveness of these interventions. If an owner has tried a hundred treatments for their pet, or been told there is no hope and nothing can save the animal, and then they try one more thing and their companion recovers, surely this means that final treatment must have worked? And yet, with all these testaments to the power of these alternative methods, I still have doubts. Let’s take a look at why that is.

There are a number of arguments against believing that testimonials prove anything about the effects of a medical treatment. Most of these, of course, will have no effect on the individual experiencing the miracle. It is in the nature of human beings to find their own experiences, and stories from others, deeply compelling, and sadly facts and logical arguments have little impact on that fundamentally emotional and irrational sense of certainty. Still, making the effort to understand the limitations of anecdotes has led us to this point in time, a point in which our medicine is more effective by far than any time in human history. So there is clearly value in understanding the problem of miracle stories even if many people will still find them compelling.

Things Aren’t Always What They Seem
The first classic argument is simply that things aren’t always what they seem. There are many reasons why the fact that a patient gets better after receiving a particular medical treatment doesn’t actually tell us the treatment made the patient better. The notion that if an action preceding an outcome means the action must have caused that outcome is known as the post hoc ergo propter hoc fallacy. In medicine, there is a long list of reasons why this kind of reasoning about causation isn’t trustworthy:

  1. Self-limiting Disease:

Most medical problems ultimately go away by themselves. Certainly minor ones nearly always do, and even major, life-threatening diseases like cancer resolve spontaneously despite our belief that they can’t or shouldn’t. It is natural to assume that whatever we did last, right before the patient got better, is the reason they got better. Natural, but not reliably true. 

  1. Regression to the Mean:

Chronic diseases, especially mysterious ones we don’t fully understand, tend to come and go. In addition to spontaneously going away altogether, which they can even after many years, they commonly tend to get better for a while then worse for a while and back and forth in an unpredictable cycle which we are always trying to understand and predict. Some stories of miraculous results from medical treatments are simply cases in which the patient was having a particularly bad run of symptoms and then felt better after getting treated.

If we systematically followed up all these stories, we would find a fair number of people whose symptoms returned despite continuing the supposedly effective treatment. Just like we find that almost any fad diet works for some people, and yet by a year most of them have gained back the weight they lost initially. Companies and practitioners selling alternative therapies, however, don’t make a point of systematically following up on all their satisfied customers’ testimonials to see which eventually got sick again. I wonder why that is? 

  1. Placebo Effect:

Everyone hates this one because it means you believe something which isn’t actually true. You use a treatment and feel better, but if it’s just a placebo and your disease isn’t actually any different, that means you must be crazy or stupid, right? No! Claiming that a perceived change is only the result of a placebo effect isn’t an insult to the patient. It is simply a fact that all human beings see want we want to see a fair portion of the time, and that sometimes we interpret what we see to mean something that it doesn’t really mean.

In the case of medical therapies, almost anything I give a client, they will perceive some improvement right after simply because we’ve done something and we know we are supposed to be looking hard for any sign of an effect, especially since we really want there to be one. Again, systematically following up all these early responses often reveals no meaningful change, but if you ask at the right time, the answer will almost always be positive and suitable for use as a testimonial.

  1. Misdiagnosis:

Sometimes, the reason a disease went away after an unconventional treatment (or a conventional one, for that matter) was used is because the disease was never there to begin with. Doctors aren’t perfect, and they sometimes diagnose diseases the patient doesn’t have. Any certainly people who aren’t trained medical professionals but who diagnose themselves or their pets are quite likely wrong a lot of the time. It’s easy to cure a disease that a patient didn’t have, so one of the first questions to ask about any miracle story is what hard, objective, tangible evidence is there to support the diagnosis? If your dog had cancer and it was cured by some kind of pseudoscientific nonsense like homeopathy, there had better be extensive imaging and before and after biopsies with long-term follow up before you start claiming homeopathy actually works and all the laws of physics and chemistry are mistakes.

You Can’t Prove It Isn’t a Miracle!
Another problem with miracle stories as proof that specific medical treatments actually work is that such stories can’t ever be proven wrong. And if something can’t be proven wrong no matter what, then you have to believe each and every one equally, which as we will see is probably the biggest problem with anecdotes.

Of course, the main reason you can’t disprove a miracle tale is psychological; cognitive dissonance is such a powerful and ubiquitous feature of the human brain, that it is almost impossible to convince someone they are wrong about a strongly emotional personal experience. Just as it is a great relief and comfort to know that you saved your beloved pet by using an unconventional therapy your vet said wouldn’t work, it is equally terrifying to believe that actually the therapy had nothing to do with your pet getting better and that not only did you waste your money and put your pet at unnecessary risk, but the world is ultimately unpredictable and uncontrollable and “As flies to wanton boys, are we to the gods. They kill us for their sport.” (King Lear) People cling to their miracles largely because these stories give them hope that bad things can be avoided or controlled if we just find the right things to do or believe.

Another reason miracle stories are unfalsifiable, which makes them largely useless as a form of evidence in science, is that they consist of very limited and selective information. By definition, anecdotes presented to show a treatment works contain only information that supports the effectiveness of the treatment. It wouldn’t be a miracle if at the end of the story the disease killed the patient. But does that mean there aren’t stories about the same treatment in which there was no benefit? Or even great harm? No, of course not. Testimonials are a form of “evidence” that is positive by definition, and that necessarily excludes negative evidence no matter how much of it might actually exist.

Of course, for a true believer, it would make no difference even if one could produce a story of failure for every single story of success. Cognitive dissonance would simply move the believer to say, “Well, maybe it doesn’t work for everybody, but it sure worked for me!” But for anyone trying to make an objective decision about how likely a particular therapy is to be effective, it is worth noting that testimonials and other anecdotes leave out all the stories that show the therapy failing, so they are an inherently biased kind of evidence.

Everything Works!
Though it doesn’t always show up on the typical lists of reasons why we shouldn’t trust miracle stories, to me the most damning argument against them is simply that they can be found supporting every medical treatment ever invented. On this blog alone, you can find a testimonial in the comments for nearly every product or therapy I have questioned, despite the fact that most of them have entirely different theories and methods by which they are supposed to work. And if you look at alternative medicine in general, there is not a single practice that you can’t find lots of people with powerful, emotional stories showing positive results.

But let’s go beyond the alternative therapies popular in the US today. Sure, there are plenty of testimonials for, say, Double Helix Water. How about for other kinds of magic water?

Homeopathy (after all, it’s just water)
Lourdes Water
Electron Water
pH Miracle Water
Kangen Water
Hexagon Water
Pranic Water
Ypsilanti Water
And even just Plain Water

So does every kind of water cure disease? Maybe the problem isn’t that testimonials aren’t unreliable. Maybe we’ve just stumbled across the fact that water itself is medicine? Ah, but I wonder then if we can find the same testimonials for every other therapy ever invented? Let’s see.

Christian Spiritual Healing
Islamic Spiritual Healing
Hindu Spiritual Healing
Christian Science Healing
Ancient Greek Healing
Ancient Roman Healing
Norse Magical Healing
Shamanic Healing
Theta Energy Healing
Ritual Child Sacrifice for Healing
Crystal Healing
Laser Healing
Bloodletting Healing
Magnetic Healing
Angel Therapy
Urine Therapy

Anyway, this list could be endless even without including the most popular alternative therapies. But it seems to suggest we should ask this question: If testimonials and miracle stories exist to support every medical treatment ever invented, does that mean every treatment works, or does it mean testimonials aren’t reliable?

Testimonials are useful only to generate hypotheses, or to illustrate theories that must be demonstrated by other means. By themselves, they prove nothing. Not only are they not reliable for all the reasons I’ve discussed, but if we accept them as compelling evidence, we commit ourselves to believing in everything at once, or simply arbitrarily choosing which stories to believe and which to doubt. This does not lead us to separating truth from error.

 

Posted in General | 10 Comments

What do Veterinarians Know About Nutrition?

Posted on July 8, 2012 by skeptvet

It is not unusual for people promoting unconventional, approaches to pet nutrition, such as raw diets, grain free foods, homemade diets, a preference for organic ingredients, and so on, to dismiss objections to these approaches made by veterinarians. These people will often claim that veterinarians know little about nutrition and that what they do know is mostly propaganda fed to them by commercial pet food manufacturers. Like most bad arguments, this one contains a few bits of truth mixed in with lots of unproven assumptions and fallacies.

Most veterinarians do have at least a semester course on nutrition in general. And a lot more information on the subject is scattered throughout other courses in vet school. So the idea that we know nothing about the subject is simply ridiculous. However, it is fair to acknowledge that most veterinarians are not “experts” in nutrition, if by this one means they have extensive specialized training in the subject. The real “experts” in this area are board-certified veterinary nutritionists, individuals who have advanced residency training in nutrition and have passed the board certification exam of the American College of Veterinary Nutrition.

Of course, as I always take great care to point out, expertise is no guarantee of never falling into error, particularly expertise based primarily on experience and a familiarity with the opinions of other experts rather than solid scientific research. Given the limited research data available on many important questions in small animal nutrition, even the real experts are often forced to rely on extrapolation from basic science or research in humans and their own clinical experience, which are important sources of information but always less reliable than studies specifically designed to answer these questions. Nevertheless, boarded nutritionists have a legitimate claim to expert status in this area. And as a group, they generally are skeptical of many of the alternative approaches to nutrition, as they should be give the paucity of data to support them As for the question of the role of the pet food industry in veterinary nutrition education, there is some truth to the claim that much of that education is sponsored by companies who make pet foods. Obviously, most veterinary nutritionists put their training to work researching and evaluating food for veterinary species, so the money and expertise in this area tends to concentrate in industry. And it is not entirely unreasonable to ask the question whether or not this influences the information veterinarians get about nutrition. It quite likely does.

This is not the same thing as saying that veterinarians are all lackeys or dupes of industry and unable to think critically for themselves, however. I am generally as skeptical and critical of pharmaceutical companies and mainstream pet food companies as I am of herb and supplement manufacturers and producers of alternative diets. All of them have both a genuine belief (most of the time) in their products, a genuine interest in the welfare of the animals they serve, and a high risk of bias and cognitive dissonance that impedes their ability to see and accept the flaws in their own reasoning or the data that contradicts their beliefs.

One should always be aware of bias, but that awareness does not justify ignoring the arguments or evidence coming from a source with potential bias, only evaluating it carefully and critically. The reason science is so much more successful than unaided reasoning is precisely because it is a method for compensating for human biases and other cognitive limitations that interfere with our seeing the truth. Mainstream pet food companies undoubtedly have biases, but often they also have good scientific data, which is rarely available for the alternative products and approaches. Ignoring this data in favor of opinion, theory, or personal experience is not a recipe for improving the state of veterinary nutrition.

The real issue is not so much what do general practice veterinarians know about nutrition as what is the evidence supporting the alternative theories and products being promoted? The accusation that vets know little about nutrition, even if it were true, doesn’t invalidate their criticisms. The classis ad hominem fallacy is the strategy of attacking a person and imaging that somehow this attack says anything about that person’s argument. It is the mirror image, in many ways, of the appeal to authority fallacy, which involves claiming some special wisdom or expertise on the part of a person making an argument and then imaging that claim somehow proves the argument. If proponents of raw diets or other unconventional nutritional approaches wish to make a case for their ideas, they have to do it based on logic and facts, not on the presumed expertise of supporters or the supposed ignorance of critics. As always, it is the ideas and the data that matter, not the people involved.

That said, there is a certain hypocrisy to many of these criticisms in that they come from sources with no particular right to claim expertise in nutrition anyway. Proponents of alternative nutritional practices are almost never boarded veterinary nutritionists. Often they are lay people who have labeled themselves as experts without even the training general practice veterinarians have in nutritional science. And while they may not be influenced by the mainstream pet food industry, this only means they are less subject to that particular bias, not that they don’t have other biases. People selling pet food or books on veterinary nutrition are all too often blind to the hypocrisy of claiming their opponents are under the influence of pet food companies while ignoring the fact that they make money selling their own ideas or products.

Others who frequently claim most veterinarians know little about nutrition are themselves general practice veterinarians or specialists in some aspect of veterinary medicine other than nutrition. It may very well be true that they are well-informed about nutrition because they have an interest in it, but this is not evidence that their arguments are true and those of their opponents are false. It is not even evidence that they know more about nutrition than their detractors, who may themselves have studied independently in the area. If you’re not a boarded nutritionist, you can’t claim to be an expert. And whether or not you are an expert, your ideas must stand or fall on their merits and the evidence, not on any presumed superiority in your knowledge over that of your critics.

So I think it is fair to say that most general practice veterinarians have only a fairly general knowledge of veterinary nutrition. And it is fair to acknowledge that much of this information comes from a source with a significant risk of bias, that is the pet food industry. However, I see no evidence that proponents of alternative approaches to nutrition have a reason to claim they know more about nutrition than most veterinarians, or that they are free from biases of their own. Only boarded veterinary nutritionists can legitimately claim to be “experts,” and even this is no guarantee of perfect objectivity or the truth of everything they believe. Claims about who is or is not smart or informed enough to have an opinion on a subject are mostly a superficial distraction from the important elements of any debate, what are the arguments and data behind each position. Awareness of potential bias only serves to make one more careful and cautious in examining someone’s arguments and data, it doesn’t get one a free pass to ignore what they have to say.

Posted in Nutrition | 36 Comments

From SBM: Alternative Medicine Claims to “Individualize” Therapy, but Does It?

Posted on July 6, 2012 by skeptvet

Posted today on the Science-Based Medicine Blog

Testing the “Individualization” of CAM Treatments

 

One of the common claims of alternative medicine practitioners is that they individualize their treatment while conventional medicine treats all patients the same. This is nonsense on several levels, but it is also a common excuse for why randomized clinical trials cannot be performed, or cannot be viewed as reliable evidence, in evaluating some alternative therapies. However, some trials have been done that attempt to account for this supposed individualization of therapy, and generally they have failed to show a benefit to the supposedly individualized approach. One of those, involving Traditional Chinese Medicine (TCM) was recently discussed by Edzard Ernst, one of few, and most productive researchers in the CAM field applying an evidence-based approach.

Matthias Lechner, MD, Iva Steirer, MD, Benno Brinkhaus, MD, Yun Chen, CMD, Claudia Krist-Dungl, MS, Alexandra Koschier, MS, Martina Gantschacher, MA, Kurt Neumann, MS, and Andrea Zauner-Dungl, MD. Efficacy of Individualized Chinese Herbal Medication in Osteoarthrosis of Hip and Knee: A Double-Blind,Randomized-Controlled Clinical Study. The Journal of Alternative and Complementary Medicine. 2011;17(6): 539–547.

First, why is the notion that CAM is somehow more individualized than conventional care total nonsense? Well, to begin with, any good doctor considers the particular history, physical examination findings, diagnostic test results, known medical problems, and concurrent therapies of each patient. If individualized treatment simply means considering the unique circumstances and values of the particular patient you are treating, then all good medicine is individualized. That concept is even built into the common definitions of evidence-based medicine:

Evidence based medicine is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research. (Sackett)

[EBM is] the integration of the best research evidence with our clinical expertise and our patient’s unique values and circumstances.(Strauss)

However, when CAM practitioners claim that formal scientific research and science-based medicine ignore individual variation, they are usually referring to the practice of studying groups of patients under controlled conditions and then applying lessons learned from those studies to the care of individuals. They claim that since we are all snowflakes, utterly unique, what is learned from groups cannot tell us anything useful about individuals.

This argument fails most dramatically on the simple evidence of the tremendous effectiveness of science-based medicine. Tens of thousands of years of looking at patients one by one and trying to figure out based on those experiences what to do for the next patient failed to control or eliminate any common diseases or meaningfully improve the length and quality of human life and health. A couple of centuries of gradually relying on formal scientific research instead of such haphazard individual experiences has wiped out or dramatically reduced many common and deadly diseases, nearly doubled average life expectancy (at least for those who can afford to use science-based medicine), and in many other ways unequivocally improved our health. It requires deep self-delusion to deny that science works better than prescientific, unstructured ways of figuring out how to preserve and restore health.

On a more theoretical level, however, consider this. Statistics can indicate the probability of winning or losing a game of chance very precisely, on the group level. As an individual, of course, you can’t know with certainty whether you will win or lose if you go to Las Vegas and play these games because these statistics only describe what happens over the course of many trials, that is what will happen on average when large numbers of people play. They don’t predict for you, as a unique individual, what your results at blackjack or roulette will be. This is very much like the situation in science, where controlled studies look at outcomes on the level of the group but can’t precisely predict the results of a therapy in an individual patient.

And yet, casinos make enormous sums of money by playing the odds and expecting that most people will lose. This is a successful strategy for them. And many people lose, some with disastrous personal consequences, by imagining that they are exempt from the statistical rules that apply to groups and that some special individual factor will allow them to beat the odds. Choosing to believe that general statistical principles don’t apply to them because they are special and unique ruins people’s lives in Vegas, and in medicine. Choosing to play with or against the odds, as defined by formal research, is no guarantee, but it is much more likely to lead to a good outcome than imagining the odds don’t matter because each of us is unique.

Finally, when a CAM practitioner claims they treat every individual patient based on that patient’s unique characteristics and that science-based medicine treats all patients as if they were the same because it bases treatment guidelines on research done on groups, they are simply mistaken. If a series of controlled studies indicates that Treatment X is better than Treatment Y for a certain diseases, and if I use this to support giving patients with that disease Treatment X most of the time, then yes I am applying information gained from population research to individuals. I am playing the odds.

However, if a CAM practitioner looks at a patient and evaluates their particular characteristics and then decides on a specific treatment, where do they come up with the connection between the patient’s characteristics and the treatment? They use their personal experience, gained from seeing what happens with prior patients, or they use rules laid down by other practitioners based of their own experiences, or they rely on general rules based on the theoretical ideas behind the style of therapy they use. In other words, they extrapolate from observations made on other patients to the individual they are currently treating.

This is exactly the same as what a science-based practitioner does with one important difference: the generalizations that scientific medicine applies to individual patients come from formal, controlled research designed to compensate for the unreliability of individual observations and judgments, whereas the generalizations used by CAM come from informal, unstructured observations with no control for bias or the many common errors that mislead us when we study disease. CAM practitioners are using generalizations based on the study of groups to decide how to treat each new case, they are just relying on poorer quality group evidence.

Ok, so how does this apply to the clinical study that looked at supposedly individualized TCM herbal therapy for arthritis of the knee? Well, the study started by randomly assigning patients to either receive individualized herbal treatment based on the judgment of experienced practitioners in each case, or a standard herbal mixture believed, again based on past experience with groups of patients, not to have any benefits for arthritis. The experimental formula consisted of a number of herbs selected in advanced based on TCM theory which the investigators expected might be useful for the kind of disease they were studying. However, individual patients received particular combinations of these ingredients based on the judgment or practitioners at the time they were evaluated.

The control treatment (not really a placebo since it contained chemicals which might or might not have real physiological effects, since none have been thoroughly evaluated in scientific studies) was a collection of herbs not believed to have benefit for arthritis based on prior experience and TCM theory It was made to taste similar to the herbs pre-selected for the experimental treatment to help make it harder for patients to know which they were receiving. I can already hear the complaints of some herbalists that this makes it an inappropriate control since taste is one of the guiding principles for the use of herbs in some approaches to herbal medicine. I’ll leave that pseudoscientific objection aside for now since it’s not directly relevant to the point here.

Baseline characteristics were similar between the two groups of patients, and randomization and blinding appeared to be properly conducted. Overall the study was well-done methodologically, with a formal accounting of patients lost to follow-up and a reasonable effort to use standard and predefined outcome measures. 

So what were the results? Well, as is usual in a study looking at a subjective measure like pain, all patients improved. There was, however, no difference between those who received individualized treatment and a random herbal concoction not expected to have any effect on arthritis. This most likely indicates nothing happening here other than nonspecific effects associated with participating in a trial, including placebo, regression to the mean, the Hawthorne effect, and all the usual suspects that fool us in clinical trials, and in real life.

This study nicely illustrates several of the issues associated with supposed individualization of CAM treatment. First, it shows that such treatment is not, in any meaningful sense, any more individualized than good quality science-based medical treatment. Choosing a selection of herbs based on previous experience, historical use, tradition, and the unscientific theories of Traditional Chinese Medicine, and then selecting which of these herbs to give each patient based on the same prior experience and unscientific theory, is still applying generalizations based on groups to individuals. It simply uses generalizations based on unreliable sources of data.

The study also illustrates that individualizing therapy in this way doesn’t add any efficacy to the treatment. Not surprisingly, the study showed, as the others mentioned early have as well, that tailoring treatment to individuals based on generalizations derived from biased and unreliable sources of information leads to a therapy no more effective than randomly picking herbs out of a hat.

The difference between effective science-based medicine and ineffective medicine of any kind, conventional or alternative, is that the general principles used to guide therapy are derived from formal, controlled research that compensates for the weaknesses in our individual, informal, and unstructured judgment. If individualized medicine is just a code for using informal group observations instead of structured scientific ones to guide therapy, than it is not surprising that it doesn’t work any better than just making up a treatment haphazardly with no guiding principles at all.

 

Posted in General, Herbs and Supplements | Leave a comment

New Study on Raw Diets for Dogs Adds Little to Ongoing Debate

Posted on July 3, 2012 by skeptvet

I am always on the lookout for research studies concerning raw diets for dogs and cats. A lot of claims are made about the health benefits of raw diets, but there is no substantive body of evidence to justify these claims. In particular, claims that raw diets are healthier than commercial dry or canned pet foods are common, despite no clinical studies making this comparison. I hope eventually such studies will be done, and while I am skeptical raw diets will prove superior, I will be happy to start recommending them if they prove to have benefits that outweigh their risks.

Unfortunately, a recent study of raw diets doesn’t add much information directly relevant to the debate.

Beloshapka, AN. et al. Effects of inulin or yeast cell-wall extract on nutrient digestibility, fecal fermentative end-product concentrations, and blood metabolite concentrations in adult dogs fed raw meat-based diets. American Journal of Veterinary Research 2012;73(12):1016-1023.

The study compared raw beef and chicken-based diets with or without a couple of prebiotics (not probiotics) in research dogs. All dogs were fed each of the diets, and measurements were made of body weight, fecal consistency, nutrient digestibility, and fecal chemicals associated with the presence of prebiotics.  

The short version of the results is:

  • The diets were highly digestible (though previous studies have suggested commercial and cooked fresh diets are also highly digestible, and no clinically significant effects on health have been shown to be associated with any differences in the digestibility of these different forms of pet food.
  • Over the three weeks of time on each diet, all of the dogs remained healthy on all of the diets.
  • The beef-based diet varied more than expected from the predicted nutrient composition, likely due to variation in the nutrient profile of individual ingredients. This is a big problem for homemade diets generally, which are not nutritionally consistent and aren’t monitored for any nutrient excesses or deficiencies on an ongoing basis as commercial diets are.
  • Fecal consistency (but not amount) varied with diet composition, but feces were normal for all dogs on all diets.
  • Fecal volume was lower than previously reported for dry commercial diets, though again the relevance of this for health hasn’t been established. Given the risks of raw diets, feeding them just to have less poop to pick up doesn’t seem sensible.
  • The prebiotics increased the levels of certain compounds in feces, as they have previously been shown to do. This is hypothesized to have health effects, but these have not been demonstrated.
  • Skin and coat quality did not appear to be affected by diet.
  • Interestingly, the mean urine specific gravity on all of these diets was greater than 1.046 for all diets. This is highly concentrated urine for dogs, suggesting potentially inadequate fluid intake. Interestingly, another study from the same institution, one comparing fresh cooked and raw diets with dry kibble in cats, also found unusually concentrated urine, and no difference between raw/fresh and dry diets. This certainly isn’t consistent with the claims that one benefit of raw diets is greater moisture content and less work for the kidneys. 

It is not clear from this report whether or not the diets were formulated to be nutritionally adequate as defined by AAFCO standards, though levels of calcium and phosphorus were reported to be within acceptable limits (though variable based on the specific ingredients in each of the diets). Obviously, nutritional adequacy would be an important issue in evaluating the quality of any diet.

So overall, this study shows that raw diets are highly digestible (which is not surprising, but of questionable importance), that short-term feeding of them under controlled circumstances doesn’t seem to have any negative effects or any benefits unless one considers less poop an important benefit or buys into the still unproven health benefits of prebiotics. There is nothing wrong with studying the variables this project looked at, of course, but it doesn’t have much direct bearing on the controversy over feeding dogs and cats raw diets.

Posted in Nutrition | 6 Comments

FDA Finds Widespread and Serious Violations of Safety and Quality Control Regulations for Dietary Supplements

Posted on July 2, 2012 by skeptvet

Despite the possibility that some dietary supplements could have real health benefits, there are many reasons to be skeptical of the safety and value of most supplements on the market. Most have not been tested scientifically to an extent that marketing claims made about them are truly legitimate. Unfortunately the legal framework for regulating these products almost guarantees that most never will be adequately tested. Thanks to the politicking that has led to the Dietary Supplement Health and Education Act (DSHEA), this “travesty of a mockery of a sham” masquerading as public health regulation makes it possible for the multibillion dollar industry that is Big Supplement to profit from selling supplements without ever having to prove they do what the companies claims, so long as the claims are sufficiently vague and the Quack Miranda Warning is appended I small print at the bottom of the page. As a consequence, the supplement industry can make a sizeable sum of money without having to turn around and invest much of that in research or quality control.

The supplement industry is known to spend a far smaller share of its profits on research that the larger, and much more closely watched, pharmaceutical industry, since the law requires little evidence of safety and efficacy for its products. However, even DSHEA requires some minimal quality control standards for herbal remedies and dietary supplements as well as placing some limits on the marketing claims that can be made. The GAO has previously reported that, despite this, contamination with dangerous substances and illegal marketing practices are common in the herbal medicine industry.

And now FDA inspection reports have shown that the dietary supplement industry also has serious and widespread problems with quality control, safety, and regulatory compliance.

The Chicago Tribune has published an article detailing the failings of the supplement industry to meet even its minimal obligations under DSHEA. Here are some examples: 

  • The FDA has found violations in nearly half of the 450 firms it has inspected.
  • 1 in 4 supplement companies have been issued a formal warning letter for violations, a significant enforcement action under the limitations placed on FDA by DSHEA.
  • Violations of good manufacturing practices were found in nearly two-thirds of 204 inspections conducted this year alone.
  • About 1 in 4 products the company tests have a significant problem, said Tod Cooperman, president of ConsumerLab.com. Some contain significantly less of an ingredient than is promised on the label, some far more. Sometimes the product contains contaminants, like lead. Some are rancid. Some have the correct ingredients but are “bedpan bullets” — incorrectly formulated pills that won’t break up in the body.

There is a huge body of evidence showing that inadequately tested supplements and an insufficiently regulated supplement industry can not only fail to help but can actively harm people (see below). And the limited evidence from the veterinary field is certainly no better than that for the human supplement market.

There is a dangerous double standard that requires chemicals called drugs to be extensively and expensively tested (which isn’t always sufficient to prevent harm even with great efforts) and yet chemicals called “herbs” or “supplements” can essentially avoid any testing of safety or efficacy. Even attempts to require basic accuracy in labeling, quality control in manufacturing, or honesty in advertising are routinely ignored by this industry. Without more serious efforts to control the supplement companies, people will continue to waste their money, and even sometimes damage their health, by using these unproven and uncontrolled products. 

Some of the Harm Caused by Vitamins, Supplements, and Herbal Remedies
Vitamin C can interfere with chemotherapy.

Vitamin E can increase cancer risk

.Vitamin E not useful for prevention for prostate cancer and can increase risk of congestive heart failure.

Vitamin E supplements increase risk of hemorrhagic stroke

Vitamin E supplements may increase risk of heart attacks and stroke

Vitamin E increases risk of prostate cancer

Vitamin supplements may associated with overall increase in mortality and no benefit in preventing gastrointestinal cancer.

Omega-3 Fatty Acids may increase risk in ventilator patients with acute lung injury

Mursu J, et al. Dietary supplements and mortality rate in older women: The Iowa Women’s Health Study. Archives of Internal Medicine. 2011;17(18):1625-33.

Widespread Failures in Quality Control of Dietary Supplements Herbal Preparations, Including Ayurvedic and Traditional Chinese Medicine (TCM) Herbs:

Aliye Uc, MD, Warren P. Bishop, MD, and Kathleen D. Sanders, MD, Camphor hepatoxicity. South Med J 93(6):596-598, 2000,

Angers RC, Seward TS, Napier D, Green M, Hoover E, Spraker T, O’Rourke K, Balachandran A, Telling GC. Chronic wasting disease prions in elk antler velvet. Emerg Infect Dis. 2009 May;15(5):696-703.

Angkana R, Lurslurcharchai L, Halm E, Xiu-Min L, Leventhal H, et al. Use of herbal remedies and adherence to inhaled corticosteroids among inner-city asthmatic patients. Annal Allerg Asthma Immunol 2010:104(2);132-138.

Berberine. Inbaraj JJ, Kukielczak BM, Bilski P, Sandvik SL, Chignell CF. Photochemistry and photocytotoxicity of alkaloids from Goldenseal (Hydrastis canadensis L.) Chem Res Toxicol 2001 Nov;14(11):1529-34

Booth JN 3rd, McGwin G. The association between self-reported cataracts and St. John’s Wort. Curr Eye Res. 2009 Oct;34(10):863-6.

Burkhard PR, Burkhardt K, Haenggeli CA, Landis T.Plant-induced seizures: reappearance of an old problem. J Neurol 1999 Aug;246(8):667-70

Chung-Hsin Chen,Kathleen G. Dickman,Masaaki Moriya, Jiri Zavadil, Viktoriya S. Sidorenko, Karen L. Edwards,Dmitri V. Gnatenko, Lin Wu, Robert J. Turesky, Xue-Ru Wu, Yeong-Shiau Pu, Arthur P. Grollman. Aristolochic acid-associated urothelial cancer in Taiwan. Proceedings National Academy of Sciences, April 2012.

Panax ginseng: A Systematic Review of Adverse Effects and Drug Interactions. Drug Saf 2002;25(5):323-44 Drug Saf 2002;25(5):323-44

Cupp MJ Herbal remedies: adverse effects and drug interactions. Am Fam Physician 1999 Mar 1;59(5):1239-45

Debelle FD, Vanherweghem JL, Nortier JL.Aristolochic acid nephropathy: a worldwide problem. Kidney Int. 2008 Jul;74(2):158-69. Epub 2008 Apr 16.

Emery DP, Corban JG Camphor toxicity. J Paediatr Child Health 1999 Feb;35(1):105-6

Ernst E Adverse effects of herbal drugs in dermatology. Br J Dermatol 2000 Nov;143(5):923-

Fugh-Berman A Herb-drug interactions. Lancet 2000 Jan 8;355(9198):134-8

Huang WF, Wen KC, Hsiao ML. Adulteration by synthetic therapeutic substances of traditional Chinese medicines in Taiwan. J Clin Pharmacol. 1997 Apr;37(4):344-50

Kutz GD. Herbal dietary supplements: Examples of Deceptive or questionable marketing practices and potentially dangerous advice. General Accounting Office. May 26, 2010.

Lai MN, Lai JN, Chen PC, Tseng WL, Chen YY, Hwang JS, Wang JD. Increased risks of chronic kidney disease associated with prescribed Chinese herbal products suspected to contain aristolochic acid. Nephrology (Carlton). 2009 Apr;14(2):227-34.

Lawrence JD. Potentiation of warfarin by dong quai. Page RL 2nd, Pharmacotherapy 1999 Jul;19(7):870-6

Means C. Selected herbal hazards.Vet Clin North Am Small Anim Pract 2002 Mar;32(2):367-82

Nizsly N, Grizlak B, Zimmerman M, Wallace R. Dietary Supplement Polypharmacy: An Unrecognized Public Health Problem? eCAM 2010 7(1):107-113

Norred CL, Finlayson CA Hemorrhage after the preoperative use of complementary and alternative medicines. AANA J 2000 Jun;68(3):217-20

O’Connor A, Horsley CA. Yates, KM “Herbal Ecstasy”: a case series of adverse reactions. N Z Med J 2000 Jul 28;113(1114):315-7

Pittler MH. Ernst, E Risks associated with herbal medicinal products. Wien Med Wochenschr 2002;152(7-8):183-9

Poppenga RH.Risks associated with the use of herbs and other dietary supplements. Vet Clin North Am Equine Pract. 2001 Dec;17(3):455-77, vi-vii

Pies R Adverse neuropsychiatric reactions to herbal and over-the-counter “antidepressants”. J Clin Psychiatry 2000 Nov;61(11):815-20

Prakash S, Hernandez GT, Dujaili I, Bhalla V. Lead poisoning from an Ayurvedic herbal medicine in a patient with chronic kidney disease. Nat Rev Nephrol. 2009 May;5(5):297-300.

Raman P, Patino LC, Nair MG. Evaluation of metal and microbial contamination in botanical supplements. J Agric Food Chem. 2004 Dec 29;52(26):7822-7

Ruschitzka F, Meier PJ, Turina M, Luscher TF, Noll G Acute heart transplant rejection due to Saint John’s wort. Lancet 2000 Feb 12;355(9203):548-9
Saper RB, Phillips RS, Sehgal A, Khouri N, Davis RB, Paquin J, Thuppil V, Kales SN. Lead, mercury, and arsenic in US- and Indian-manufactured Ayurvedic medicines sold via the Internet.JAMA. 2008 Aug 27;300(8):915-23.

Shad JA, Chinn CG, Brann OS Acute hepatitis after ingestion of herbs. South Med J 1999 Nov;92(11):1095-7

Smolinske SC J Am Med Womens Assoc 1999 Fall;54(4):191-2Dietary supplement-drug interactions.

Tachjian A, Maria V, Jahangir A. Use of herbal products and potential interactions in patients with cardiovascular disease. J. Am. Coll. Cardiol. 2010 55: A32

Wang JD, Lo TC, Chen PC. Increased mortality risk for cancers of the kidney and other urinary organs among Chinese herbalists. J Epidemiol. 2009;19(1):17-23. Epub 2009 Jan 22.

Zhang SY, Robertson D. A study of tea tree oil ototoxicity. Audiol Neurootol 2000 Mar-Apr;5(2):64-8

Kidney failure from aristolochia in TCM herbals preparations.Lead, mercury and arsenic in herbal preparations.

Lead in TCM preparations.

Lead in ayurvedic preparations.

Lead in herbal preparations.

Tea Tree Oil Can be toxic to cats.

Toxic metals in Brazilian herbal preparations.

Contamination of herbal products with undisclosed pharmaceuticals.

Widespread contamination of supplements with undisclosed toxins and parmaceuticals

Unpredictable levels of coumarin in cinnamon bark, even within the same tree, pose risk of liver damage

 

Posted in Herbs and Supplements, Law, Regulation, and Politics | 2 Comments

Dowsing and Homeopathy: Using Magic to Test Magic

Posted on June 29, 2012 by skeptvet

Like the subject of pet psychics, the subject of dowsing is one I never thought it would be necessary to write about. This form of divination, like casting rune stones or knuckle bones and examining the entrails of sacrificial animals, is so clearly superstitious nonsense incompatible with science that it is hard to imagine even the most extreme advocates of alternative medicine taking it seriously.

Sadly, my ability to imagine the credulity of others has proven insufficient. A recent article in the Journal of the Royal Society of Medicine has chosen to treat dowsing, as employed by practitioners of another bit of folk magic, homeopathy, as a proper subject for serious scientific inquiry. (The paper is in the April issue, so I still secretly hope it was intended as an April Fool’s joke)

R McCarney, P Fisher, F Spink, G Flint, R van Haselen. Can homeopaths detect homeopathic medicines by dowsing? A randomized, double-blind, placebo-controlled trial. J R Soc Med 2002;95(4):189-191.

The authors describe dowsing this way.

Dowsing is a method of problem-solving that uses a motor automatism, amplified through a pendulum or similar device. In a homeopathic context, it is used as an aid to prescribing and as a tool to identify miasm or toxin load….Dowsing, also known as divining, water witching or rhabdomancy, has been defined as a ‘problem solving technique which apparently utilizes a motor automatism in conjunction with a mechanical instrument to obtain information otherwise unknown to the dowser’

I prefer this definition, from the Skeptic’s Dictionary:

Dowsing is the action of a person–called the dowser–using a rod, stick or other device–called a dowsing rod, dowsing stick, doodlebug (when used to locate oil), or divining rod–to locate such things as underground water, hidden metal, buried treasure, oil, lost persons or golf balls, etc. Since dowsing is not based upon any known scientific or empirical laws or forces of nature, it should be considered a type of divination and an example of magical thinking.

The authors of the dowsing study list several theories for how dowsing “works:”

Theories on dowsing come into three categories. Normal inference theory suggests that the dowser processes a large amount of information pertinent to the scenario at a subconscious level and moves the instrument accordingly. The physical theory sees the movement in the device being due to the amplification of minute reactions in the human body, with the precise nature of the reaction being unclear. It could be an electromagnetic field, or some form of vibrational energy.

According to the theory of psionic medicine, every living thing and inanimate object is continuously vibrating at a molecular level. This vibration is sensed subconsciously by the dowser, and it is then amplified through the pendulum or other dowsing device. Some proponents of this explanation suggest that this sense originally developed as a survival tool because it enabled individuals to find water. As the vibrational pattern can change with disease, it is purported to be a useful tool for clinical practice.

Finally there is the psychical theory which suggests the dowser employs some form of extrasensory perception.

They have, however, omitted one very important theory:

The ideomotor effect refers to the influence of suggestion or expectation on involuntary and unconscious motor behavior. The movement of pointers on Ouija boards, of a facilitator’s hands in facilitated communication, of hands and arms in applied kinesiology, and of some behaviors attributed to hypnotic suggestion, are due to ideomotor action… The term “ideomotor action” was coined by William B. Carpenter in 1852 in his explanation for the movements of rods and pendulums by dowsers, and some table turning or lifting by spirit mediums (the ones that weren’t accomplished by cheating). Carpenter argued that muscular movement can be initiated by the mind independently of volition or emotions. We may not be aware of it, but suggestions can be made to the mind by others or by observations. Those suggestions can influence the mind and affect motor behavior.

In other words, dowsing is yet another example of people fooling themselves into believing that outside forces are accomplishing actions which, in fact, they are generating through their own unconscious need to see what they want and expect to see.

Dowsing has been studied a number of times, in as scientific a way as it is possible to study magic. The studies have pretty consistently shown that with any reasonable controls for bias (such as blinding of the dowsers), dowsing doesn’t work. Dowsers have not demonstrated the ability to find anything with an accuracy better than chance if they don’t know in advance where it is.

Naturally, dowsers often complain that this failure is due to the effects of the testing situation, which in some undefinable way muddies the psychic waters so they can’t perform. In the current study, this concern was accommodated.

In discussions before the study began, dowsers expressed concern that the pressure of an experimental situation might be detrimental to the dowsing sense. For this reason the study packs were mailed to the volunteers for evaluation in their own time in relaxed conditions…there was generally a high level of confidence in the responses (n=99, 63.5%), which suggests that we were successful in making the dowsers feel relaxed about the study.

So how was the study conducted? Well, six registered homeopaths with experience in the medical applications of dowsing were sent 26 pairs of unlabeled bottles containing either a homeopathic solution (a 12C preparation of Bryonia which, as the authors put it, “is ‘ultramolecular’…a dilution of 10-24…very unlikely to contain any molecule of the starting material”) and a placebo (prepared in an identical way except from distilled water instead of the Bryonia mother tincture).

In other words, they received two bottles of water one with magic powers and one without. They also received a pair of labeled bottles to practice on. They were then instructed to identify the magic water (I mean the homeopathic remedy) by magic (I mean dowsing).

And how did they do? Of 156 selections between pairs of bottles,

48.1% responded correctly (n=156; 95% confidence interval 40.2%, 56.0%; P=0.689)….percentage of correct responses ranged from 34.6% (n=26; 95% CI 15.77%, 53.4%; P=0.170) to 61.5% (n=26; 95% CI 42.4%, 80.6%; P=0.327). Of responses given with high confidence, 45.0% were correct (n=99; 95% CI 35.6%, 55.3%; P=0.421).

So, almost eerily close to perfect chance levels, with performance no better for those who were confident in their choices versus those who knew they were guessing. In fact, “High confidence was slightly more associated with an incorrect response.”

Since this is science, the authors made some comments about the potentially inappropriate application of statistics (using a method which assumes independent samples for samples that are actually associated), but as they put it,

The data were in fact so far from showing any type of effect of dowsing that the assumption of independence was probably met, so the more appropriate clustered analysis is unlikely to show a different effect.

So does this close the book on “medical dowsing?” Undoubtedly not. It does serve, however, as an excellent illustration of the premise of this blog. The application of scientific study to the highly implausible only seems justifiable if resources are unlimited or if the results, when negative, will influence peoples belief in implausible practices. Neither of these conditions is met in the real world.

In an ideal world, it might make sense to study every idea no matter how unlikely to be truth based on established knowledge, since once in a great while crazy ideas actually turn out to be right. But in the real world, they usually don’t. Since we have to conserve our resources and use them as efficiently as possible in investigating potential therapies, and since scientific evidence against magic does little to reduce people’s belief in magic, conducting and publishing studies like this seems a pointless and unconscionable waste of time and effort which only conveys an inappropriate sense of legitimacy to the hypotheses being studied. On the other hand, it is entertaining.

Posted in Homeopathy | 9 Comments

New Survey: What Do Vets Think About Evidence-Based Medicine?

Posted on June 24, 2012 by skeptvet

A couple of years ago, I conducted a small pilot survey of veterinarians to investigate their attitudes and knowledge concerning evidence-based medicine (EBM). While not a representative sample of the profession, the survey identified some interesting issues worthy of further investigation. While respondents were generally very positive about the idea of evidence-based medicine, they generally had little knowledge or training in EBM methods. Many practitioners felt that research information was potentially useful in general practice but was overwhelming in quantity and difficult to access of interpret in an efficient, timely manner. A recent qualitative survey of decision-making processes used by veterinarians in Belgium also found that few were applying EBM methods to their clinical practice.

Vandeweerd JM, Vandeweerd S, Gustin C, Keesemaecker G, Cambier C, Clegg P, Saegerman C, Reda A, Perrenoud P, Gustin P. Understanding veterinary practitioners’ decision-making process: implications for veterinary medical education. J Vet Med Educ. 2012 Summer;39(2):142-51.

Over two-hundred veterinarians were interviewed by telephone, and a small number (31) were interviewed in person. The authors major conclusions were these:

First, veterinarians in this population were far from applying the principles of EBM…The results of this study showed that the EBM approach (asking questions, searching the literature, critically appraising the internal validity of the identified publications, assessing the external validity of the scientific information) was rarely used to inform decisions.

In this study, veterinarians preferred colleagues, the Internet, and textbooks to peer-reviewed journals and literature searches.

This study suggests that veterinarians also use two modalities of decision making: either by (1) recognizing the similarity to a past situation or (2) choosing the most likely solution among a list of possible options, sometimes excluding options in a hypothetico-deductive approach, sometimes proceeding by trial and error.

The study also identified several pragmatic factors that strongly influenced veterinarians’ decision-making. One was time. Veterinarians reported the perception that clinical decisions must generally be made quickly, and that the time needed to employ EBM methods might be incompatible with the demands of private practice.

Another factor was the perception that a methodical, rigorous scientific approach might not satisfy clients. As the authors reported, “[Respondents] perceived that owners want to see immediate action, which does not allow any delay in decision making; as one participant stated, ‘If I am called, it is to give an answer to the owner. It is not possible to say or do nothing, even if you are not sure. Owners request an action.”

Such concerns about the time required to make proper use of scientific research results in formulating decisions and the perceived antipathy of owners to delay or uncertainty are certainly real issues veterinarians must face. Unfortunately, they can easily lead away from a rational, thoughtful science-based approach to clinical decision making and favor a more reflexive, automatic, and opinion-based strategy, which is less likely to lead to the best results.

The study authors make a number of reasonable suggestions for improving the usefulness of EBM to veterinarians. The obvious first step is to improve the quantity and quality of scientific research information in the field. Then it is necessary to make this information available to ordinary practitioners in a clear and simple form that can be applied to the needs of specific patients with minimal time and effort. And veterinary students should be trained in the methods and benefits of epidemiology and an EBM approach and reminded of the weaknesses of informal and unstructured decision-making based primarily on experience and opinion.

The study authors conclude, quite reasonably:

Veterinarians make decisions in a complex environment, often quickly and rarely with an EBM approach. Obviously, this cannot mean that most practitioners make poorly

informed decisions…Two separate worlds seem to exist, academic research and the reality of practice, that need to join, probably by making the effort to include data from practice into research. Both worlds should also meet more in the field of education, where students should be trained in the complexity of contextualized decision making. More important, aside from those efforts to facilitate the development of evidence-based, accountable, and transparent veterinary medicine, there should be initiatives to scientifically demonstrate the benefits of an EBM approach for animals and owners, which would probably facilitate its adoption by veterinary practitioners.

Adequate information and EBM tools are needed to optimize the time spent in query and assessment of scientific information, and practitioners need to be trained in their use.

 

Posted in Science-Based Veterinary Medicine | 7 Comments

USDA Confronts Misleading Hype about Antioxidants in Foods

Posted on June 17, 2012 by skeptvet

I have commented a few times on the issue of antioxidant supplements. While the theory that some diseases are caused by, or at least involve in some way, oxidative damage is reasonable, and there are lots of in vitro studies showing both the negative effects of free radicals and the antioxidant effects of many chemicals found in foods, the clinical data that one can prevent or treat specific diseases with antioxidant supplements is virtually nonexistent. The hype about antioxidants far exceeds the evidence (c.f. this article also) of any real value, and some evidence has developed showing that they have significant potential risks, including increasing the likelihood of some diseases and interfering with some kinds of medical therapy. So while the potential uses of antioxidants deserve further study, the automatic assumption that they are a good idea is increasingly contradicted by the evidence.

So it makes sense that the US Department of Agriculture has withdrawn a public database it had maintained since 2010 showing one possible measure of the antioxidant capacity of certain foods. The Oxygen Radicals Absorbance Capacity (ORAC) consisted of a variety of in vitro chemical measures for the potential antioxidant effects of certain foods. While this might be useful information in planning research, it was not appropriate as support for health claims, and yet this is how the data was routinely being misused. The USDA notice makes the following important points:

[There is] mounting evidence that the values indicating antioxidant capacity have no relevance to the effects of specific bioactive compounds, including polyphenols on human health.

There is no evidence that the beneficial effects of polyphenol-rich foods can be attributed to the antioxidant properties of these foods.

The data for antioxidant capacity of foods generated by in vitro (test-tube) methods cannot be extrapolated to in vivo (human) effects and the clinical trials to test benefits of dietary antioxidants have produced mixed results.

We know now that antioxidant molecules in food have a wide range of functions, many of which are unrelated to the ability to absorb free radicals.

All of these points simply acknowledge that the evidence from epidemiological studies that consuming certain foods is associated with lower risk of certain diseases may have nothing at all to do with the antioxidant hypothesis of the antioxidant capacity of chemicals in these foods. In fact, the evidence is growing that whatever the health benefits may be of eating such foods, it probably has little to do with their antioxidant activity.

However, the most important reason for taking down the database was not simple scientific accuracy but the deliberate misuse of the information to support unproven health claims. As the USDA announcement put it,

ORAC values are routinely misused by food and dietary supplement manufacturing companies to promote their products and by consumers to guide their food and dietary supplement choices.

Because uncritical acceptance of the notion that antioxidants are good for you is widespread, despite limited supporting data and some data against this hypothesis, supplement manufacturers have been using the USDA ORAC data to add legitimacy to unfounded marketing claims about the health value of their products. Undoubtedly, of course, manufacturers of supplements with purported antioxidant activity will find other ways to promote this as having health benefits despite the lack of string evidence to back up such claims. But it is encouraging to see the government acknowledge that such marketing strategies are not consistent with good science and to make an effort not to accidentally support them.

 

 

 

 

Posted in Herbs and Supplements | Leave a comment

Latest Review Finds Fish Oils Don’t Help Dementia

Posted on June 13, 2012 by skeptvet

Fish oils are the current wonder supplement, good for all that ails you. I have actually taken them when the evidence appeared to support a benefit in prevention of cardiovascular disease, but the evidence is not looking as strong these days even for that indication, which has been the most strongly supported of the many suggested uses in humans. Other uses include prevention or treatment of dementia, arthritis, inflammatory diseases, and many others.

I have reviewed in detail suggestions that fish oils might have a benefit for arthritis in dogs, and it is weak but not definitive either way. Others have reviewed the use of fish oils in dogs with allergic skin disease, and there is reasonable evidence of some mild benefits for that condition. There have been suggestions that fish oils, as supplements or added to dog food, can affect the development of canine cognitive dysfunction, but there is no robust research evidence to support this.

A recent Cochrane review looking at fish oil supplementation and dementia in humans did not find evidence to support a beneficial effect despite a number of quite large clinical studies.

Emma Sydenham. Alan D Dangour. Wee-Shiong Lim. Omega 3 fatty acid for the prevention of cognitive decline and dementia.

Three randomized clinical trials involving over 4000 people were reviewed. Some subjects were supplemented and followed for as long as 2 ½ years. Despite this, no evidence of benefit was found. Few adverse events were seen either, apart from gastrointestinal upset. The conclusion of the review was:

Direct evidence on the effect of omega-3 PUFA on incident dementia is lacking. The available trials showed no benefit of omega-3 PUFA supplementation on cognitive function in cognitively healthy older people. Omega-3 PUFA supplementation is generally well tolerated with the most commonly reported side-effect being mild gastrointestinal problems.

Certainly not the last word, but yet another fairly strong piece of evidence suggesting that even one of the most intensively studied and widely used supplement has yet to definitively demonstrate the benefits claimed for it. And while data of similar strength is unlikely to be developed for dogs with cognitive dysfunction, the tentative conclusion based on extrapolating from the human research has to be that fish oils could have benefits in this condition, but it is at least as likely that they do not.

 

 

 

Posted in Herbs and Supplements | 7 Comments

Thank You Lewis Carrol

Posted on June 12, 2012 by skeptvet

Comments like the latest in the Double Helix Water thread always make me think of this:

“Alice laughed: “There’s no use trying,” she said; “one can’t believe impossible things.”

“I daresay you haven’t had much practice,” said the Queen. “When I was younger, I always did it for half an hour a day. Why, sometimes I’ve believed as many as six impossible things before breakfast.”

Alice in Wonderland.

Posted in Humor | 1 Comment