European Food Safety Authority Rejects Prostora, a Probiotic Product for Dogs

I have written frequently about probiotics,(1,2) and the health effects of microorganisms seems a promising area of research. The current evidence for meaningful beneficial effects, however, is quite limited. There is reasonable evidence for some benefit in treating antibiotic-associated diarrhea or acute diarrhea of unknown cause(3). The evidence is not very good for many other claimed benefits, such as strengthening of immune system function, treatment of kidney disease(4,5), management of feline upper respiratory viral infections(6), and so on. And there are serious problems with irresponsible, excessive hype(7) and poor quality control(8) for probiotics.

One product I have written about, and used in my own patients, is Prostora from the Iams company. This product is attractive in several ways. It has good quality control and some supportive clinical trial evidence. However, I recently ran across an evaluation of the product produced in 2012 by the European Food Safety Authority (EFSA), which rejected the company’s application for approval to market Prostora in the European Union.

In terms of the efficacy of the product, the EFSA concluded that it could not reach a definitive judgment. According to the report, eight research studies were submitted in support of efficacy. Five of these were rejected for inadequate methodology (lack of a control group, for example). The three evaluated (including one I have reviewed here) did show some evidence of a beneficial effect. However, the effects were inconsistent and not always strong enough to be meaningful even if statistically significant.

More interesting to me was the concern raised in the report about the issue of antibiotic resistance. Apparently, the organism in Prostora has shown some resistance to the antibiotic clindamycin. A number of genes that confer antibiotic resistance have been identified, and some of these can be transmitted from one bacterium to another. The specific source of the resistance to clindamycin seen in the Prostora bacterium is not known, so it is not clear if this resistance could be transmitted to other bacteria in animals or people exposed to Prostora.

Because of this uncertainty, and the serious and growing problem of antibiotic resistance in infectious organisms, the EFSA chose not to approve the sale of Prostora in the EU. It has been approved here in the U.S. under the much less strict laws governing dietary supplements.

The EFSA in general has taken a conservative stance on probiotics, which some argue is appropriate based on the currently available evidence, and which others, notably probiotic manufacturers, have claimed ignores relevant science. There is some scientific evidence indicating that antibiotic resistance can be exacerbated by the use of probiotic organisms with such resistance, though the extent of the risk is not well-documented.

As I have often said about probiotics, because they clearly have the ability to affect the health of people and animals, they undoubtedly have risks as well as benefits. The devil is in the details, and they should neither be rejected out of hand nor embraced unquestioningly as beneficial. The specific risks and benefits of particular organisms for particular health conditions in particular species have to be understood through the careful and laborious process of scientific research. There is nothing intrinsically “alternative” about the use of microorganisms to affect health, but the indiscriminate use of them in the absence of appropriate scientific evaluation would be a mistake in the tradition of the worst kind of alternative medicine.

Posted in Herbs and Supplements | 20 Comments

Evidence Update-Review of Risks and Benefits of Raw Meat Diets for Dogs and Cats

A nice new review of the evidence concerning raw meat-based diets appears in the most recent issue of the Journal of the American Veterinary Medical Association.

Freeman LM, Chandler ML, Hamper BA, Weeth LP. Current knowledge about the risks and benefits of raw meat-based diets for dogs and cats. J Am Vet Med Assoc. 2013 Dec 1;243(11):1549-58.  

The article reviews many of the studies looking at basic issues such as the effects of cooking on digestibility and the risks of nutritional inadequacy and infectious organisms in raw diets. I have previously written about a number of these studies. The bottom line, which is consistent with my own understanding, is that there are no proven benefits of feeding raw diets, a few small but well-established risks, and little direct research evidence involving comparisons of pets fed different kinds of diets. Here are some of the conclusions of this review:

Proponents of RMBDs claim that they are a safe and natural way to promote animal wellness; these claims are made without long-term supportive evidence and largely ignore the potential life-threatening consequences to pets and their human caregivers when contaminated RMBDs are fed.

Pets often consume RMBDs without developing any health problems, but sometimes even healthy adult dogs and cats can develop adverse effects, ranging from relatively benign effects (eg, increased colonic fermentation and gas production with higher protein intakes) to more overtly life-threatening concerns (eg, higher fat diet fed to an animal with a history of pancreatitis), as a result of consumption of these diets. Additionally, raw meat has an inherent risk of bacterial and parasitic contamination, and animals that consume RMBDs may pose a risk to other pets and people in the household and surrounding community, including veterinarians and veterinary support staff.

If a commercial RMBD is formulated to meet AAFCO nutrient guidelines…there should be minimal risk of nutritional inadequacy. However, few manufacturers of raw diets conduct AAFCO feeding trials or digestibility…Thus, the assumption that these diets are truly complete and balanced for long-term feeding relies heavily on the expertise of the individual formulating the original recipe…

If these diets are manufactured in accordance with current FDA regulations for handling of foods and requirements for microbial testing during food manufacturing and storage, there should be minimal risk of exposure to foodborne pathogens. However, variation in quality-control testing practices or inadequate testing conducted by a manufacturer of a raw food may allow for introduction of pathogens into pet-owning households.

On the basis of published diet reviews, most home-prepared diets (both raw and cooked) are deficient in 1 or more essential fatty acids, vitamins, or minerals or a combination thereof. Although the perceived benefits of home-prepared diets may be reinforced daily to owners through a pet’s appetite or coat quality, nutrient deficiencies and excesses in adult animals are insidious and can lead to long-term complications if not detected and corrected.

Posted in Nutrition | 14 Comments

When Hope becomes Delusion and Compassion becomes Deception: An Alternative Medicine Approach to Testing New Therapies

One of the most attractive features of alternative therapies is that they offer hope. CAM treatments, by definition, are almost never validated by the usual scientific research evidence used to test mainstream medical therapies. If they were, they would no longer be alternative. And while there is sometimes in vitro or pre-clinical research to support particular CAM treatments, and always mountains of positive anecdote and individual belief, a distinguishing feature of alternative medicine is that practitioners don’t feel controlled, high-level, high-quality clinical research is necessary to claim therapy is successful. Personal experience and faith count for much more, and CAM practitioners frequently see it as inappropriate to ask for better evidence because this might discourage the use of therapies they believe in.

Conventional medicine, more closely tied to science and mindful of the unreliability of anecdotes and trial-and-error in medicine, is more often reluctant to make strong claims for untested treatments or encourage optimism where there is only hope and desire, but little evidence, to suggest it is warranted. This is a less effective marketing position, but it is arguably more honest and less likely to encourage the use of ineffective or harmful treatments.

There is always, of course, a balance to be struck between the urgency of intervening in a health problem and the uncertainty about the effects of one’s intervention. Doing nothing may work a surprising percent of the time, giving the robust innate healing abilities of living beings, but there are times when choosing not to intervene undoubtedly leads to greater suffering or even death.

On the other hand, rushing to use untested treatments has proven time and time again to cause great harm. And since most new ideas in medicine turn out to be wrong when thoroughly investigated, the odds of not helping or hurting a patient when using an inadequately studies treatment are greater than the odds of helping them.

It seems to me that the most rationale and ethical approach is to stick with well-understood and investigated therapies unless the need to intervene is great, such as when there is significant suffering or a high risk of death or disability. And when using therapies not validated by good science, but only believed to work on the basis of weak and unreliable evidence, it is vital that patients (in human medicine) or clients (in veterinary medicine) be given their right to fully informed consent. Our clients must understand the risks and the uncertainty and be willing to freely choose to take a chance on an unproven treatment, knowing they are as or more likely to harm their pet than help them.

This is where I feel alternative practitioners often fail in their ethical duty, even when they are acting out of compassion and an honest desire to help their patients and clients. There is a point where optimism and hopefulness becomes delusion, and where doing everything possible to help becomes irrational and potentially harmful. It is widely believed that false beliefs are harmless, though there is plenty of reason to believe this is a dangerous misconception. And who could argue with hope and optimism even when completely unjustified? Well, if sustaining hope means ignoring the truth and grasping at straws, there is also reason to believe this can do more harm than good (for example).

An illustration of the different perspectives on epistemology (the philosophy of how we find and test what we know) and ethics between science-based and alternative medicine appeared in a recent Huffington post blog by well-known CAM practitioner and activist Dr. Richard Palmquist. In my interactions with Dr. Palmquist, I have found him pleasant, intelligent, well-informed, and sincere in his desire to help his patients. Given our frequent disagreements, it might surprise him the extent to which we agree on many topics outside of veterinary medicine. However, Dr. Palmquist is also deeply committed to a variety of medical practices which range from the promising-but-unproven to complete quackery.

A major difference in our approaches is that he views individual case reports and anecdotes as reliable evidence and comfortably, confidently exposes patients to treatments that have not been systematically tested. He appears to feel he is giving hope and “a chance” where science has nothing to offer. In my view, however, he is exposing patients to unnecessary risk and unintentionally misleading clients into believing the straws they are grasping at are really stout ropes that can pull their pet to safety. Unjustified hope may be comforting, but it is a cheat that denies clients the right to fully informed choice and leads us to make bad decisions.

In his latest blog post, Dr. Palmquist exhibits his characteristic mix of the reasonable and the absurd. He begins by stating, quite correctly, that most new potential medications (like other proposed novel medical therapies) turn out not to work. It is estimated that 95% of new drugs put through the appropriate premarket testing process fail to demonstrate sufficient safety or efficacy to justify approval, and the cost of bringing a drug from initial hypothesis to marketed product may be close to $5 billion. Most good ideas turn out to be wrong, and in medicine finding out which those are is difficult and expensive.

However, even on this point Dr. Palmquist shows his innate optimistic bias. He states, “if there are not enough cases of a disease to make it possible to recoup the expense of approval, many good drugs just languish in the patent office.” But if we haven’t done the clinical trials to get approval, or equivalent studies, we don’t know these are “good drugs.” The approval process is rigorous because failure to test drugs adequately can easily lead to such dramatic disasters as the thalidomide debacle. Given the cases of drugs which survived the approval process turning out to have unexpected dangers or less than expected benefits once brought to market, it is likely that the process is not tough enough.

Of course, there will always be limits to how much uncertainty we can eliminate from medicine, and we must always act on imperfect evidence. And there is no doubt that companies fail to even seek therapies for conditions when they don’t believe they will ultimately make a profit from doing so. But it is not really the case that therapies which work fail to get approved when the potential market is too small but that they either never get invented or are not tested sufficiently to determine if they work.

Dr. Palmquist also makes the usual claim that “The problem is even larger for natural therapies as the profit potential is much smaller.” This is likely untrue simply because so-called “natural” products have already proven to be extremely profitable even when they rarely have good evidence showing they actually work. Billions of dollars are made on likely worthless supplements which are not required to prove safety and efficacy as drugs are. And producers of herbal remedies and supplements have demonstrated they are happy to spend more of their money on marketing and less on research event than the pharmaceutical industry.  This argument is simply an attempt to imply that rigorous testing of these therapies will not be done by commercial firms, which then allows proponents of such remedies to claim that we should feel free to use such therapies without such testing. Neither is correct or in the best interests of patient health.

Next, Dr. Palmquist displays the feature of CAM philosophy I have previously called “panepistemia,”  the notion that scientific and non-scientific sources of evidence are equivalent. “Integrative medicine investigates the use of…forms of healing that have some scientific basis in support of their use.” This is often true, though even the phrase “forms of healing” contains the implication that these are effective. However, he goes on to say, “This type of practice involves doing a lot of research, both of traditional literature as well as reading publications far off the beaten path. Integrative doctors even read anthropology literature as we seek knowledge from indigenous cultures…”

Here, “research” means reading the opinions and experiences of individuals and, in most cases, basing one’s choices predominantly on this form of evidence rather than controlled scientific evidence. This is, of course, often necessary in veterinary medicine when we lack good quality scientific data, but it requires us to have great humility and skepticism about the treatments we offer on such a basis, which CAM practitioners generally do not have. Optimism generally triumphs over skepticism, which sounds like a good thing until you remember all the harm done by inadequately tested medical treatments.

The blog post then talks about the viral disease known as canine distemper, which Dr. Palmquist appropriately characterizes as uncommon, thanks to vaccination, but quite serious. This positive stance on vaccination is uncharacteristic of veterinarians who practice homeopathy, as is repeatedly demonstrated by the anti-vaccine propaganda put out by the Academy of Veterinary Homeopathy. However, this sound information and advice is seamlessly paired with a statement that is unfounded and, in one respect, complete nonsense; “distemper does not need to be a death sentence for a dog. A combination of homeopathic, nutritional, herbal and conventional drugs and support often does the trick.”

There is no evidence beyond unreliable anecdote to suggest herbal therapies have any benefits in treating canine distemper. Homeopathy, as I have discussed in detail many times, is a completely worthless practice that has more in common with faith healing than medicine. What is meant by “nutritional” therapy is unclear. Certainly, nutritional support is essential in any critical illness, but this term is often used as a code for use of supplements which have not been shown to have any benefits. This is “integrative” medicine at its core, suggesting without evidence that whatever untested or even disproven therapies one likes are effective and add value to conventional care.

Dr. Palmquist then comes to the core subject of his post, the “new hope” that may be offered by an experimental anti-viral therapy. PVX (previously known as Panavira) is an experimental drug described in a patent application as a collection of polypeptides (subunits of proteins) derived from snake venom (this apparently counts as “natural origins” from a holistic vet perspective). The patent application posits a wide range of possible medical conditions that could be treated with this product, from viral infections to cancer. It is currently owned by the company Nuovo Biologics.

PVX appears to be undergoing the process of evaluation as an Investigational New Animal Drug, which is intended to lead to FDA approval for clinical use. Though some pilot trial results and case series have been made public, there is little information available on this product. It has not yet been approved for any specific use, and the information upon which FDA evaluation is based is all confidential and proprietary. At this point, it seems a worthwhile substance to investigate, and the company appears to be taking a scientifically appropriate path to establishing safety and efficacy. I am absolutely in favor of such research. Unfortunately, as is so often the case, optimistic tidbits about early, uncontrolled use are easier to find than actual data, and they tend to encourage an unjustifiably optimistic expectation for the ultimate results of this research.

Despite acknowledging that most promising medications never survive to market, Dr. Palmquist seems quite confident in claiming PVX works before the results of clinical trials are available: “veterinarians who are using it have seen many cases where it worked.” What he means, of course, is that veterinarians who have used it have seen patients get better after the drug was given. That is often considered the gold standard of evidence in alternative medicine, with clinical trials seen as a nice extra or even outright unnecessary. Unfortunately, this view ignores the evidence of history, in which innumerable ineffective therapies persisted for many years despite having no measurable effect on health. Clinical trials exist precisely because “I tried it and the patient got better” is an unreliable measure of efficacy. It is such a well-recognized reasoning error, it has its own name, the Post Hoc Ergo Propter Hoc Fallacy.

Palmquist then proceeds to relate an anecdote of a single patient, sent to him when conventional medicine had nothing to offer, who got PVX and a variety of other treatments, both conventional and alternative, and recovered. As wonderful as this story is, it of course proves nothing about any of the treatments employed. Reported mortality rates for distemper cases with neurologic symptoms are about 50%. While this is very high, it still means that at least half of patients survive with supportive care. And given that these figures are quite old, and supportive care is more sophisticated and available than it used to be, it may well be that current figures are better (as is the case with parvoviral enteritis, another important viral disease seen rarely in insufficiently vaccinated puppies). In any case, the fact that the patient appeared to improve following use of the PVX does not demonstrate the PVX was responsible.

This seems especially questionable given that the story continues with a marked worsening of the patient’s symptoms. Rather than considering the treatment might not be working, Dr. Palmquist ,”intervened quickly with additional doses of PVX at twice the normal dosage.” This is a completely reckless way to use an experimental drug, and while the patient fortunately survived, it does not demonstrate PVX works or justify this kind of irresponsible use of an investigational agent.

The anecdote strays even farther from the reasonable compassionate use of an unproven drug with additional claims like these:

Sheena’s seizures were controlled almost immediately with homeopathic medicine (Belladonna Homaccord). Her ravaged body responded to nutritional care that supported her organs and immune system and helped drain the toxins away before they overwhelmed her.

There is, of course, absolutely no reason to believe homeopathy is effective in treating seizures, and using a demonstrated placebo for a serious, life-threatening problem is completely unjustifiable regardless of the delusional belief that homeopathy might work. The vague, mystical concept of “toxins” is a modern day version of “evil humours” that explains nothing, and the idea that nutritional supplements can combat the symptoms of viral distemper by draining away toxins is pure fantasy. Any benefit such supplements might have, for which there is currently zero evidence, will certainly not be through this sort of magical purification.

Even while acknowledging the uncertainty about the effects of a drug still undergoing clinical trials, Dr. Palmquist cites a purported “success rate,” as if such a number could be known at this stage: “Participating veterinarians have treated over 50 cases with an incredible 80 percent success rate.” Once again, this goes beyond hopeful investigation of a promising new drug and amounts to a deceptive portrayal of yet another “wonder drug.”  

If PVX fails to fulfill its promise, as the overwhelming majority of new drugs do, this will simply erode further the public’s confidence in the scientific process. Instead of giving reasonable, evidence-based assessments as the process unfolds, and generating appropriate expectations about the difficulty of rigorous science and the odds of success, the media and practitioners such as Dr. Palmquist stir up hype and expectations that are repeatedly dashed, and people come to believe that it is the scientific process, rather than this hype, which is unreliable. Of course, this suits practitioners of alternative therapies since they generally don’t rely on rigorous science to prove their therapies are effective, and in fact often prefer to ignore it when it finds they are not.

Dr. Palmquist quite explicitly claims a moral high ground for the experimental use of unproven therapies.

It took love enough to ask for more options and persistence to check out things on the Internet, do research in rare literature and dedication to drive Sheena two hours to our clinic. It also took a pioneering spirit to take chances and work with others regardless of the outcome and odds against us.

He characterizes a desperate experimentation with untested remedies and completely disproven treatments as a brave expression of love. This, of course, implies that choosing not to roll the dice with such treatments shows a cowardly character or a deficit of love for one’s animal companions. Faith and hope are, in Dr Palmquist’s view, unquestionable virtues, and doubt and caution vices, or at least weaknesses. I believe this is a perspective deeply connected to a faith-based spiritual world view, and while I respect Dr. Palmquist’s right to his beliefs, in bringing this approach to medicine I think he has fallen into error.

Finding the truth means seeing what is there, not what we wish to see. Helping our pets means accurately understanding the illnesses that afflict them and the risks and benefits of our therapies. Science reaches truth more reliably than hope or instinct or trial-and-error because it compensates for our tendency to substitute our hopes and desires for reality. With a scientific perspective, we may have lost some of the comfort of the placebo (though not all!), but we have gained far more in terms of reducing suffering and improving our health and longevity by understanding the world as it is rather than as it seems to be or as we wish it were. And the kind of hopeful, uncontrolled, “try it and see” approach Dr. Palmquist supports has led us into every useless and damaging therapy in history, from bloodletting to bear bile to laetrile to homeopathy. Sometimes, hope becomes delusion and compassion becomes deception, and when this happens they do more harm than good.

Attempted Pre-emption of Angry Comments Based on Misunderstanding
Since I can already see the hostile comments from people who object to my perspective and do not read my arguments carefully, I will try to be very simple and clear about what I am saying:

  1. I am not making any judgment about whether PVX/Panavira is a useful therapy for any disease. In the absence of any published research evidence, I would only be guessing. While Dr. Palmquist and others are comfortable projecting an optimistic future for the product on the basis of pre-clinical and uncontrolled use, I am not. It may truly be a wonder drug, and I certainly hope it is. If reliable evidence eventually shows this to be the case, I will be first in line to give it to my patients. If not, as is so often the case, I will not be disillusioned or discouraged because I understand the value of the process of separating truth from hope through science.
  2. I am not saying Dr. Palmquist is stupid, unethical, or deliberately misleading anyone. I am saying he is completely wrong about the value of homeopathy, and given the extensive evidence showing this I believe it is not too strong to call faith in the value of this therapy a delusion. I also believe he is strongly biased in favor of believing therapies which meet his somewhat arbitrary definition of “natural” or “holistic” work if he or anyone else has positive personal experiences using them. I believe this way of approaching the evaluation of new therapies consistently leads to false beliefs in the value of ineffective therapies and that the approach of scientific skepticism (withholding judgment until reliable scientific evidence is available) works better to find the truth and serve the interests of our patients.
     
  3. I am not against people hoping for the best or striving hard to help their pets or their patients. I am against people being led by their doctors to believe in the value of therapies based on unreliable evidence (anecdotes and uncontrolled trial-and-error) because again I think this encourages the use of useless and even harmful therapies. While hope is comforting, and we all deserve to be comforted, encouraging unjustified hope denies people the chance to make fully informed choices and to develop a genuine acceptance of the inevitable limitations of our abilities. It is unfair to our animal companions to expose them to risky and untested treatments without extremely good cause, since we are likely only to prolong or increase their suffering. And it is unfair to our clients to tell them, “This may help and can’t hurt” when we don’t have good evidence to know that’s true.

 

 

Posted in General | 7 Comments

“One and Done” Approach to Rabies Vaccination is Misguided and Dangerous

Recently, I wrote about claims made by a veterinary homeopath that booster vaccination was unnecessary because single, initial vaccination provides lifelong immunity for our pets. There is ample evidence that this is frequently untrue, but today I ran across an article that illustrates quite nicely that this claim is false.

Ippei Watanabe, Kentaro Yamada, Akira Aso, Okio Suda, Takashi Matsumoto, Takaaki Yahiro, Kamruddin Ahmed, and Akira Nishizono. Relationship between Virus Neutralizing Antibody Levels and the Number of Rabies Vaccinations: a Prospective Study of Dogs in Japan. Jpn. J. Infect. Dis., 66, 17-21, 2013

This study involved sampling blood from 756 dogs and evaluating the rabies antibody levels. This antibody level, and the proportion of dogs with enough antibody to be protected from rabies, was then compared to the number of rabies vaccinations the dogs had received, the age and sex of the dog, the time since the last rabies vaccine, and other factors. The results illustrate the need for a rational, evidence-based approach to determining the number and frequency of vaccinations.

The authors found that puppies who had never been vaccinated for rabies almost never had protective antibody levels despite receiving some antibodies through nursing.

we found that only 1 unvaccinated dog exhibited protective VNA levels whereas many unvaccinated dogs exhibited inadequate VNA levels…we set the VNA level of 0.25 IU/ml as the cutoff value…Of the 72 unvaccinated puppies aged 90 days or less, 11 samples (15.3z) exhibited VNA levels of Æ0.25 IU/ml. In contrast, only 1 of the 35 unvaccinated puppies aged over 90 days (2.9z) exhibited VNA levels of Æ0.25 IU/ml.

Of the dogs vaccinated only once, between 33% and 77% exhibited protective antibody levels at various time points during the 13 months after vaccination. Of the five time points sampled, only at one (13 months) did the proportion of protected dogs reach a level above the 70% believed to be necessary to prevent rabies from becoming established in the population at large. When the dogs who are not vaccinated are considered, it is unlikely that 70% of the population will ever be protected if only one rabies vaccine is given to vaccinated dogs.

Of the dogs vaccinated more than once, the proportion protected ranged from 79% to 100%. However, of the 7 time points sampled, the proportion of dogs protected was greater than 97% at all but one (25 months after vaccination). This indicates that giving at least two vaccinations to each dog ensures that nearly all dogs will be protected for at least two years. Since the rabies vaccine has elsewhere been demonstrated to protect the vast majority of dogs for at least three years, this is a reasonable minimum frequency for vaccination. However, better data is needed to determine how often we should be recommending revaccination since there is some evidence adequate population protection may last quite a bit longer than three years.

Interestingly, there did not appear to be any difference in the proportion of the population with protective antibodies between dogs receiving two vaccinations and dogs receiving more than two, so this suggests that two vaccines per dog may be sufficient to provide herd immunity. However, the specific details of how long protection lasts in what percentage of dogs aren’t clearly known, and this information is needed to make reliable decisions about limiting rabies vaccination to two vaccines only.

Because a high antibody titer is indicative of protection from disease for rabies (which is not true for all other diseases), individual dogs could have their titers measured to confirm they are protected and don’t require repeat vaccination. However, a low titer does not necessarily mean the dog is susceptible to the disease, so it isn’t necessarily a good indication of when a vaccine is needed. And, of course, the majority of the long-term health risks attributed to vaccination by vaccine opponents like Dr. Falconer have not actually been shown to be cause by vaccines, so choosing not to vaccinate based on these purported risks is not a rational, evidence-based decision.

This study, of course, does not provide all the answers about how often and when to vaccinate even for rabies, much less all the answers about all vaccines. It illustrates, however, both the kind of information that has to be accumulated to make rational decisions about vaccination and the nonsense of Dr. Falconer’s claims that one vaccine can be assumed to provide lifelong immunity for most dogs. As always, reality is complex and nuanced, with inevitable uncertainty, but we still make better decisions for our dogs if we accept this and try to work with the evidence we have rather than making simplistic and mistaken generalizations about medical procedures like vaccination.

 

 

Posted in Vaccines | 29 Comments

Evidence Update: Resveratrol

In the first year of this blog, I wrote about a supplement called resveratrol, calling it “a promising but unproven compound.” Last year, I reported on a scandal in which a major researcher of resveratrol retracted over 100 research articles for fraud. At that time, I concluded the product was “still promising but unproven.” Last July, the most recent review of the evidence concerning resveratrol was published in a special issue of the Annals of the New York Academy of Sciences (Vol. 1290). The overall conclusion of this very thorough review seems to support much the same bottom line: there is lots of laboratory research suggesting resveratrol should have all kinds of health benefits, but the actually clinical research showing real-world benefits in humans is still lacking, and virtually no companion animal clinical research appears to exist.

Here are some of the conclusions of various authors contributing to the special issue.

Despite the substantial preclinical evidence, human clinical data are very scarce, and even though the compound is widely distributed as an over-the-counter human nutritional supplement, its therapeutic rationale has not been well characterized.

…the likelihood of benefiting from resveratrol as a result of ordinary dietary intake appears dubious, since a conventional diet at best provides a few milligrams of resveratrol daily.

At the preclinical level, resveratrol has demonstrated reproducible effects in modifying various aspects of metabolic health. This finding is consistent overall with the suggestion that resveratrol acts as a [calorie restriction] mimetic. In terms of cellular experiments, various aspects of resveratrol action have been investigated. Resveratrol seems to be a strong anti-inflammatory compound in cell culture as well as in animal models.

Another prominent effect of resveratrol is the improvement of glucose homeostasis, which has been demonstrated in diverse animal models. Due to the close association between diabetes and obesity, a range of obesity-related measures have also been explored, but only very few studies have been able to demonstrate an antiobesity potential for resveratrol.

Furthermore, resveratrol has demonstrated chemopreventive potential in relation to diverse cancer types, including mammary and colonic cancer. Resveratrol has been shown to provide neuroprotection, and in cardiovascular health, resveratrol has demonstrated cardioprotective potential, partly due to antihypertensive and lipid-lowering properties.

The three most methodologically robust intervention studies were published in December 2011 by Timmers et al., in October 2012 by Yoshino et al., and our own contribution published in December 2012. In the study by Timmers et al….Significant albeit moderate improvements were recorded in various metabolic markers…

In the work by Yoshino et al., 29 nonobese (BMI < 30 mg/m2) postmenopausal women with normal glucose tolerance were randomized…Resveratrol supplementation failed to affect any physiological parameters or putative molecular targets.

This is consistent with the findings in our own human clinical trial: in an investigator-initiated, randomized, double-blinded, placebo-controlled, parallel-group design, 24 male volunteers were randomly assigned treatment for four weeks…Insulin sensitivity was similar in both groups, and endogenous glucose production and the turnover and oxidation rates of glucose remained unchanged. Resveratrol supplementation also had no effect on blood pressure, resting energy expenditure, and oxidation rates of lipid, ectopic, and visceral fat content, or inflammatory and metabolic biomarkers.

In terms of human safety and pharmacokinetic properties, the available data are fairly solid, and both acute exposure to high doses of resveratrol (5 g daily for 28 days)as well as more chronic exposure to lower doses (8 mg daily for one year) have not induced any observable adverse events.

Taken as a whole, this paper—and research on resveratrol in general—serves as an illustrative example of the major challenges associated with translating basic research into human clinical practice. Moreover, there are numerous examples in modern medicine of major discordance between treatment effects obtained in animal and human studies.

In contrast to the first review, written by academic researchers (Aarhus University, Denmark), the authors of this review are employed by “DSM Nutritional Products Ltd., a supplier of resveratrol.”  Not surprisingly, this review of the same evidence is somewhat more positive.

Numerous animal and in vitro studies suggest that resveratrol could improve cardiovascular and metabolic health in humans. In view of this compelling preclinical evidence, several human studies investigating the effects of resveratrol on vascular and metabolic health have been initiated. Collectively, the animal, human epidemiological, and first human intervention studies support a role of resveratrol in vascular and metabolic health.

The study indicates that resveratrol, at doses that can be readily achieved in humans, mimics some aspects of the action of CR and may be a useful micronutrient to help prevent age-related chronic diseases.

Recently, Timmers et al. showed that the metabolic benefits observed in animal obesity models could also be translated into effects in humans…resveratrol significantly reduced systolic blood pressure and improved blood glucose levels as well as insulin…Moreover, a significant decrease in liver fat and inflammatory markers was observed.

However, Yoshino et al. found that 75 mg/day of resveratrol after three months of supplementation did not improve metabolic function in nonobese healthy women with normal glucose tolerance. Moreover Poulsen et al. observed no effect on glucose turnover and insulin sensitivity with a high dose of resveratrol (1 g/day).

Future studies need to further evaluate the effects of different doses of resveratrol and discriminate possible distinct effects in various target populations like the obese, diabetics, children, and the elderly.

…many clinical trials investigating the beneficial effects of resveratrol are ongoing (see: www.clinicaltrial.gov database). As of April 2013, there were 15 studies in the field of metabolic health and four studies in the area of cardiovascular diseases, indicating relatively high interest.

Bottom Line
So the bottom line appears to be similar to my conclusion from four years ago. There is ample reason to think resveratrol might be a beneficial supplement based on in vitro and animal model studies. There is inconsistent evidence as to whether any beneficial effects actually occur in humans taking it as a supplement. And there is no direct evidence that it is beneficial for companion animals. Additional clinical studies are certainly warranted, and hopefully they will coalesce around a finding of real benefits. In the meantime, supplementation is probably not justified for most people or for our pets, however there is no convincing evidence of harm associated with the supplement so any risk from taking it is probably very small.

The pace of careful, thorough scientific investigation is slower than those of us treating patients in the clinical setting might wish, but the long-term benefits of reliable, trustworthy information are worth waiting for.

Posted in Herbs and Supplements | 3 Comments

Please Support S. 1425: The Dietary Supplement Labeling Act of 2013.

I have written previously about the woefully inadequate regulation of dietary supplements in the U.S. under the Dietary Supplement Health an Education Act (DSHEA). Much has previously been written at the Science-Based Medicine Blog on the subject of the Dietary Supplement and Health Education Act of 1994 (DSHEA) (e.g. 1, 2, 3, 4). Essentially, the supplement industry and sympathetic lawmakers created this law to pretend to regulate herbal remedies and other dietary supplements while effectively stripping the FDA of the ability to control the sale of these products for the prevention or treatment of disease. This was accomplished by classifying all such products as foods and codifying the principle that they must be assumed to be safe unless the government can generate substantial evidence to the contrary. There are some restrictions on the medical claims manufacturers can make on the labels of these remedies, but they are routinely ignored and the resources and will behind enforcement of them are manifestly inadequate.

Proponents of supplements claim they are inherently safe because they are “natural,” but this is patent nonsense. There is ample evidence of the harm such unregulated products can cause. While it is likely some of these products will have real benefits (as has been shown for fish oils and probiotics, for example), there is no reason not to require the same standards of evidence for safety and effectiveness applied to any other medical therapy.

Attempts to require some reasonable evidence of safety and efficacy before marketing supplements as medical therapies have been made, and these have consistently been defeated by the supplement industry and lawmakers influenced by their campaign donations. This year, another bill has been introduced to require just a little bit of oversight to these potentially dangerous products. It doesn’t, in my opinion, go far enough, but it is absolutely a step in the right direction. I urge everyone to call and write your U.S. Senators and urge them to support S. 1425: Dietary Supplement Labeling Act of 2013.

Here are some of the provisions of this law:

 1.      Manufacturers of dietary supplements will be required to list their facilities in a public registry so we can know who is producing supplements and what they are making.

 2.      Within one year of passage, the government will compile a list of supplement ingredients and mixtures that could potentially cause serious adverse effects, interfere with prescription medications, or harm vulnerable groups such as children or pregnant women.

 3.      Within 18 months after passage, the independent, non-artisan, non-profit Institute of Medicine will produce an evidence-based report evaluating the risks of potentially dangerous supplement ingredients or blends.

 4.      Within 2 years of passage, the Institute of Medicine will establish mandatory warning labels for potentially dangerous supplements.

Posted in Herbs and Supplements, Law, Regulation, and Politics | 5 Comments

Medical Use of Marijuana/Cannabis for Pets?

The medical use of marijuana has long been a “hot-button” issue in human medicine. Now, the subject has become a growing focus of debate in the veterinary field as well. As is all too common in such debates, however, scientific facts get muddled and lost in the tempest of opinion, personal experience, and arguments about values. My attention was drawn to the issue recently when I was asked to look at the web site for a related product, Canna-Pet: Medical Cannabis for Pets.

What Is It?
Canna-Pet is claimed to consist of “100% organic hemp.” Though there are hundreds of chemical compounds in this plant, the web site refers only to general ingredient classes (phytocannabinoids and terpenes), except for claiming a level of THC (the compound primarily responsible for the psychoactive effects of marijuana) less than 0.2% by weight. The company specifically states that the raw material is minimally processed because they claim processing destroys the value of the compounds: 

Nearly every process of extraction will destroy many of these fragile and scarce compounds. Concentrated oils, tinctures, and pharmaceuticals have the natural terpenes absent (destroyed by refinement process), or may have a few supplemental terpenes added back in artificially. Likewise, refinement involving exessive heat, alcohol or harsh chemicals will reduce natural phytocannabinoid diversity and abundance.

Nevertheless, they claim, “we are able to vary the mix of phytocannabinoids and terpenes for each client, completely custom…the correct dosing of the product based upon the animal’s medical history, age and the pathophysiologic process is crucial. Phytocannabinoids and/or terpenes are significantly less effective when they are used in a ‘one size fits all’ approach.”

How this is done, and how the particular mixture appropriate for each individual is determined, is not addressed in the materials available on the web site. While it is certainly likely that the particular mixture of chemical compounds which is safest and most beneficial will differ from patient to patient, the problem with such claims of individualized treatment is that they are often based on completely haphazard, unscientific, and unproven methods of determining which therapy is best for which patient. This is the case with homeopathy, Traditional Chinese Veterinary Medicine, and many other CAM therapies that claim to individualize treatment. It is unclear if Canna-Pet is any different since no information is provided about how the best mixture for a particular patient is determined.

Does It Work?
The general subject of the medicinal value of marijuana and its constituent compounds is an area of active research. There is good in vitro and animal model research to suggest that many of the compounds found in Cannabis plants have significant biological effects, and that some of these may be beneficial. The clinical research in humans is limited in quantity and quality, but beneficial effects have been demonstrated for some compounds and some conditions. Good overview of the existing research can be found in this Institute of Medicine review from 1998 and on the web site of the National Cancer Institute (though it must be mentioned that this review was put together by an independent board largely composed of CAM proponents and does not represent official NCI or NIH policy).

There is reasonable evidence to support clinical benefit in humans of some compounds from Cannabis for:

  1. Chronic pain– “Currently available evidence suggests that cannabis treatment is moderately efficacious for treatment of chronic pain, but beneficial effects may be partially (or completely) offset by potentially serious harms. More evidence from larger, well-designed trials is needed to clarify the true balance of benefits to harms.”
  2. Pain associated with Multiple Sclerosis– “Cannabinoids including the cannabidiol/THC buccal spray are effective in treating neuropathic pain in MS.”
  3. Chemotherapy-associated nausea– “The superiority of the anti-emetic efficacy of cannabinoids was demonstrated through meta-analysis.” However, this review also showed, “The adverse effects were more intense and occurred more often among patients who used cannabinoids.”

Another review found, “In selected patients, the cannabinoids tested in these trials may be useful as mood enhancing adjuvants for controlling chemotherapy related sickness. Potentially serious adverse effects, even when taken short term orally or intramuscularly, are likely to limit their widespread use.”

For a number of other conditions tested, the evidence has not supported the benefits of cannabis or cannabis-derived treatments: 

  1. Epilepsy– “No reliable conclusions can be drawn at present regarding the efficacy of cannabinoids as a treatment for epilepsy. The dose of 200 to 300 mg daily of cannabidiol was safely administered to small numbers of patients, for generally short periods of time, and so the safety of long term cannabidiol treatment cannot be reliably assessed.”
  2. Dementia– “This review finds no evidence that cannabinoids are effective in the improvement of disturbed behaviour in dementia or in the treatment of other symptoms of dementia. More randomized double-blind placebo controlled trials are needed to determine whether cannabinoids are clinically effective in the treatment of dementia.”
  3. Tourette’s Syndrome– “Not enough evidence to support the use of cannabinoids in treating tics and obsessive compulsive behaviour in people with Tourette’s syndrome.”
  4. Morbidity and mortality associated with HIV/AIDS– “…evidence for the efficacy and safety of cannabis and cannabinoids in this setting is lacking. Such studies as have been performed have been of short duration, in small numbers of patients, and have focused on short-term measures of efficacy. Long-term data, showing a sustained effect on AIDS-related morbidity and mortality and safety in patients on effective antiretroviral therapy, has yet to be presented. Whether the available evidence is sufficient to justify a wide-ranging revisiting of medicines regulatory practice remains unclear.”
  5. Schizophrenia-“At present, there is insufficient evidence to support or refute the use of cannabis/cannabinoid compounds for people suffering with schizophrenia. This review highlights the need for well designed, conducted and reported clinical trials to address the potential effects of cannabis based compounds for people with schizophrenia.”
  6. Pain– “Cannabinoids are no more effective than codeine in controlling pain and have depressant effects on the central nervous system that limit their use. Their widespread introduction into clinical practice for pain management is therefore undesirable. In acute postoperative pain they should not be used. Before cannabinoids can be considered for treating spasticity and neuropathic pain, further valid randomised controlled studies are needed.”

There is a large amount of clinical research evidence not yet appraised in systematic reviews such as these which suggests other possible benefits, though as always this evidence contains limitations and inconsistencies. Overall, there is reason to believe compounds derived from cannabis may have a clinically meaningful benefit in humans for a number of medical conditions, but there is still a great deal of uncertainty, and the evidence is not strong or definitive for most of the suggested uses.

As usual, I have not been able to find any formal clinical research involving cannabis-derived products and companion animals. Some of the basic science studying these compounds has been done in dogs, so there is some information about the effects of these chemicals on this species, but no formal studies designed to identify safety and efficacy of clinical use of specific compounds or products.

As for the Canna-Pet product, the marketing for this raises many of the red flags of snake oil. Dramatic claims of wide-ranging benefits with absolutely no risk of undesirable effects are made, which is the hallmark of questionable therapies:

We find medical benefits, behavioral benefits, prolonged life, reduced stress, and improved quality of life with our pets.

Improved vitality and overall health. Reduction in aggression, anxiety and behavior problems. Reduction of arthritic pain and digestive issues (IBD, diarrhea and constipation), reduction in nausea and improved appetite, improved quality of life, outstanding for palliative care.

Helps with aggression disorders, noise phobias, anxiety, self-trauma, cognitive disorders and dementia (canine), marking and spraying (feline), sleep disorders, OCD, excessive vocalization and inappropriate urination.

…phytocannabinoids often allow for much lower dosing of drugs that have potential negative side effects. Canna-Pet™ augments other medications…

We recommend Canna-Pet™ supplements as a daily food additive for all pets…

100% Safe. There are ZERO negative side effects and NO medical conflicts.

The evidence provided to support this apparently miraculous therapy appears, at first glance, to be impressive. A long list of links to research on cannabis-derived compounds is provided. However, much of this research is test tube, lab animal, or animal model studies which at best only suggest some compounds in hemp might have potentially useful biological effects. None of the studies linked to are clinical trials of Canna-Pet in companion animals.

The web site does seem to suggest that such studies exist:

Seventeen years in development, five years of clinical trials, now available OTC.

However, after failing to find these clinical trials in databases of published veterinary research or on the Canna-Pet website, I found a statement from one of the developers of Canna-Pet which suggests that this use of the term “clinical trials” is a bit misleading.

Six years ago I started using phytocannabinoids and terpenes with my own pets and the frequent rescues and fosters with which I deal. Finally, I started recommending this adjunctive and palliative therapy for the pets of family, friends and specific clients. The results have been universally positive and this is in part why I helped develop a specific mixing process and dosing regimens for animals.

This statement would appear to suggest that by “clinical trials” the company means uncontrolled individual trial-and-error use. It is not uncommon for promoters of new or unconventional therapies to suggest there is “research” showing that their therapies work when they really mean only that they have used it in their own patients and believe it works. If it were truly that easy to identify effective therapies, clinical trials wouldn’t be necessary, but unfortunately that’s not the case.

As far as I can tell, then, there is no evidence to establish the safety and efficacy of this product beyond pre-clinical research (which is suggestive but never definitive), extrapolation from limited and often conflicting research in humans (which is common in veterinary medicine), and anecdotal experience (which is highly unreliable). The most appropriate interpretation of the evidence, then, is that the product might work or might not, it might be safe or it might not, but no firm conclusion can be made. Use of such a product is risky but can be appropriate in some circumstances. It is simply unfortunate that the company makes claims for the product that go far beyond anything that can be reasonably substantiated by real scientific data.

The company does put a few caveats on its claims. The Quack Miranda Warning required by the Dietary Supplement and Health Education Act is present:

FDA Disclosure: These statements have not been evaluated by the Food and Drug Administration (FDA). These products and statements are not intended to diagnose, treat, cure, or prevent any disease.

The web site also appropriately points out that, “these compounds are not a cure-all wonder drug. They are to be used as directed and they are to be used expressly with any and all currently prescribed therapies and medications. As directed by your attending veterinarian.” Still, such warnings seem a bit tepid compared with the much more dramatic, assertive, and prominent claims of safety and benefits for the product.

Is It Safe?
Marijuana intoxication is relatively common in dogs and can be serious, though rarely life-threatening. It is likely that the primary compound responsible for the clinical symptoms is the THC, so a product with low levels of this compound might be safer than ordinary marijuana, but there is little research on the subject. And without direct studies of particular compounds or products, it is impossible to establish long-term safety.

The makers of Canna-Pet assure pet owners of complete and absolute safety, which is unrealistic for any product that has any biological effects at all. They appear to base this on the fact that it is “natural,” which of course is a completely arbitrary and meaningless claim, and that their own uncontrolled anecdotal observations haven’t identified any negative effects. This is certainly not a level of safety assurance that would be accepted for any drug, and it is no more appropriate to accept it for a gemish of chemicals found in an herbal product.

The specific claim is actually made that it is actually an advantage of the product that it is a complex mixture of chemical compounds: “When we apply ALL of these phytocannabinoids and terpenes simultaneously, the cumulative effects are exponential.” This is a common claim for herbal remedies. While it is true that sometimes multiple compounds in a mixture can have synergistic effects (working together to improve efficacy and decrease undesired effects), it is just as true that such compounds can interfere with one another or have additive undesired effects. It is important to determine the actual clinical actions of a particular product through appropriate clinical research. It is not wise or safe to assume that the more complex a mixture is the better and safer it will be.

Bottom Line
Like so many plant-based alternative therapies, there is sufficient pre-clinical basic research to suggest compounds derived from cannabis might be medically useful. And like many medically useful chemicals, these are likely to have risks and benefits, both desirable and undesirable effects. There is nothing about such supposedly “natural” products that makes them inherently safer or better than purified compounds. And there is nothing about cannabis that makes it any more or less likely to be a useful medical therapy or to have both benefits and risks.

The current research evidence supports a couple of uses in humans, including treatment of nausea and poor appetite and possibly pain. Most other uses are poorly supported by clinical research. And there are unquestionably side effects that make marijuana often less useful than isolated cannabinoids or other unrelated treatments.

There is virtually no useful research evidence in companion animals, so any use of cannabis products is based entirely on theory and extrapolation from the limited research results in humans. Canna-Pet as a specific product, is being marketed with very dramatic and aggressive claims about safety and efficacy that do not appear to be supported by specific research on the product but, again, are based entirely on theory and anecdote, both notoriously unreliable sources of evidence.

There are recognized behavioral and medical risks associated with marijuana use in humans. While the behavioral risks do not apply to use in companion animals, and the medical issues associated with THC do not apply to products with negligible amounts of this compound, the risks of cannabis-derived compounds in dogs and cats are largely unknown. Any use of such products, then, should be undertaken with a clear understanding of the high levels of uncertainty about the results, and claims should not be made for these products that go beyond the available evidence.

Finally, the moral and political issues associated with the use and regulation of cannabis are real, but they have little direct relevance to a scientific evaluation of the risks and benefits of any medical use. Even if one supports legal recreational use of marijuana, that doesn’t imply one should support medical use without adequate evidence of safety and efficacy. And if one is opposed to recreational use of marijuana, that doesn’t make it appropriate to deny the possibility of medical benefits or to obstruct appropriate research into this possibility. As is always the case, a rational use of science to determine the facts is necessary to make an informed judgment, independent of any other concerns.

 

 

 

Posted in Herbs and Supplements | 83 Comments

Another Reminder of the Real Dangers of Veterinary Homeopathy

The biggest danger of homeopathy is not, of course, the remedies themselves, which are nothing more than placebos in most cases. The real danger is that many homeopaths have the delusion that their therapies can replace real medical care, and they sometimes convince others of this. There are many examples of this leading to unnecessary suffering and even death. (1, 2) Of course, many homeopaths deny that they reject or discourage conventional therapies, and some claim their methods are scientifically validated, though these claims don’t stand up under close scrutiny. However, the mainstream representatives of veterinary homeopathy regularly promote the myth that homeopathy can replace real medical care even in the case of serious illness. The Academy of Veterinary homeopathy often goes even farther, as seen recently on its Facebook page, promoting the claim that conventional veterinary treatment is not only ineffective but actually the cause of much disease.

The AVH recently promoted a series of web articles entitled Stop Killing Your Pet. When I followed the link, this turned out to come from Dr. Will Falconer, the same veterinarian I recently discussed regarding his claims that his advice and “homeopathic emergency kit” can replace conventional emergency medical care. In this series of articles, he hits on a number of popular, and mostly unfounded, beliefs about the dangers of conventional methods for preventing infectious disease and infestation with common parasites.

The Top Five Ways to Healthy Pets

Here are the five things that will have the greatest impact in keeping your animal vital, healthy, and living a long, joyful life with you.

(doing the opposite has been the biggest predictor of illness and dying too soon that I’ve seen in my 30+ years of practice)

1.      Stop Vaccinating Them.

2.      Feed Them What Their Ancestors Ate.

3.      Stop Using Pesticides to Kill Fleas.

4.      Stop Using Poisons for Heartworm Prevention.

5.      Give Them Raw Bones (for the whitest teeth and freshest breath ever).

 Dr. Falconer goes into more detail about several of these recommendations. His page discussing vaccination is chock full of misleading oversimplification. He claims that  initial vaccination generates lifelong immunity and so only one vaccine is ever needed to protect your pet. This is likely true for some vaccines and some individuals, and most certainly not true for others. Vaccines are given as a series to puppies and kittens because some have varying levels of antibodies gotten from their mothers through nursing, and these antibodies can temporarily block the effect of vaccination. Exactly how much of this maternal immunity a given pet has, and for how long, can’t be determined, so the series of vaccines given to young animals ensures that the majority will develop effective protection against common and serious diseases.

This issue of duration of immunity and booster vaccination is much more complicated. Immunity from vaccination is probably lifelong for some diseases, lasts from a few to many years for others, and can fail to develop even with an appropriate series of puppy or kitten vaccinations in some animals. In our local area, we recently had a dog infected with rabies who had received an appropriate puppy vaccination but not a booster at one year, and who clearly did not get lifelong effective immunity from that first vaccine. How many vaccines are needed is a complex and often uncertain issue for any individual pet, and simplistic claims that one vaccination provides lifelong immunity for every pet and every vaccine are dangerously wrong.

Of course, the reason this issue is of interest to CA proponents like Dr. Falconer is that they want to discourage vaccination because they believe it to be actively harmful. In this series of articles, he claims vaccines are responsible for all kinds of chronic diseases, from allergies, to autoimmune anemia, to cancer. Once again, this is an argument that builds a misleading web of deception on top of a tiny core of truth. Like all medical therapies, vaccines have risks. We know about some of these (such as acute allergic reactions, vaccine-associated fibrosarcomas). We suspect some others, though the evidence is weak and inconsistent (some autoimmune disease). And there are many that are pure fantasy (such as the catch-all “vaccinosis,” a meaningless term used to blame any and every disease imaginable on vaccination).

Balancing the potential risks of vaccination against the benefits can only happen with an accurate understanding of both. Dr. Falconer and the AVH routinely exaggerate the risks, including blaming many diseases on vaccines for which there is zero evidence of a connection, and they fail to acknowledge the dramatic benefits, including prevention of serious, sometimes deadly diseases which are common when vaccines are not available or not used.

Adding to the distorted picture created by this misrepresentation of the risks and benefits of vaccines, these homeopaths recommend (and sell) all kinds of alternatives which have no demonstrated benefit. This includes supposed “immune boosters” (a term which Dr. Mark Crislip has eloquently shown to be egregiously nonsensical pseudoscience) which have never been tested to verify any protective benefits against the disease pet owners are being told not to vaccinate against. Homeopathic nosodes are also recommended, despite the fact that these are as magically inert as most other homeopathic remedies and have never been shown to prevent serious disease. This trifecta of exaggerating the risks and underrating the benefits of vaccines along with selling unproven or completely ineffective alternatives is the perfect strategy for bringing back all kinds of infectious diseases that have been brought under control by vaccination.

Dr. Falconer’s claims about pet nutrition are equally erroneous and misleading. He falls into the myth that our canine companions are really just wolves in funny outfits and that the best way to keep them healthy is to feed them what wolves eat. This is exactly as ridiculous as it sounds, as I have discussed many times before.

The same tired and vapid reasoning is applied to the issue of flea and tick preventatives and heartworm prevention. Risks are implied or exaggerated well beyond anything established by any kind of scientific evidence, based mostly on the mythology that conventional parasite controls contain “chemicals” and “toxins” while supposed “natural” alternatives (which haven’t actually been proven to do anything) are somehow magically safe and effective. Once again, the risks are misrepresented or exaggerated, the benefits are ignored, and unproven or completely useless alternatives are suggested with no evidence to show they are of any use at all, much less better than existing preventatives.

The bottom line is that there is a quasi-religious mentality at work here that makes belief sufficient evidence in itself for any claim regardless of the absence of supporting scientific evidence, or even evidence disproving the claim. Homeopathy works not because it’s been shown to in good quality research studies but because the people using and selling think it does. “Chemicals” are bad (despite the fact this term is arbitrarily and capriciously applied to some substances and not others), whereas “natural” things (again, arbitrarily defined) are good; you know, like radium, botulism, rattlesnake venom, and the plague. And the gold standard of proof is the opinion of people who have “tried it for themselves,” despite the overwhelming historical and experimental evidence that this is an unreliable way to prove or disprove medical claims.

It is important that pet owners consider the underlying point of view when deciding whether or not to believe the claims made by these homeopaths. It is, of course, everyone’s right to reject the determination of science and follow recommendations based on faith, intuition, anecdote, and other less trustworthy kinds of evidence. But at least pet owners should be able to make such a choice fully informed, and not be misled into thinking there is any scientific legitimacy to these claims. Homeopathy is not a scientific medical practice. It is a faith-based belief system inconsistent with established science. Veterinarians who practice it have chosen to reject the mainstream use of science as the foundation for medicine, and as examples like the AVH and Dr. Falconer illustrate, they often recommend pet owners reject conventional medicine as unnecessary, or even actively harmful.  Such a perspective, in my opinion and based on the evaluation of scientific investigation, threatens the health of our animal companions.

 

 

 

 

 

Posted in Homeopathy | 27 Comments

Encouraging Study of Platelet Therapy for Arthritis in Dogs

Though I write frequently about potential arthritis therapies, particularly emerging treatments and those that are established but seem to have a questionable evidence base, I haven’t yet run across the therapy evaluated in a study recently published in the journal of the American veterinary Medical Association: injection of a dog’s own platelets into an arthritic joint.

Fahie MA, Ortolano GA, Guercio V, et al. A randomized controlled trial of the efficacy of autologous platelet therapy for the treatment of osteoarthritis in dogs. JAVMA 2013;243(9):1291-7.

This was a small but nicely done trial which involved dogs with documented symptomatic arthritis in a single joint. Though this is an unusual situation, since most dogs with arthritis have it in multiple joints, this population was selected to minimize confounding variables and simplify the evaluation of the test treatment.

 Subjects were appropriately randomized to placebo or the test treatment, and all treatments and evaluations were done by individuals blind to the treatment group. This helps to minimize potential bias or placebo effects. At the start of the study, two subjective measures of comfort and function (questionnaires) were completed by owners, and an objective measure (amount of weight placed on the affected leg) was also evaluated. Dogs in the test group received a single injection of their own concentrated blood platelets in the affected joint, and control group dogs received a saline injection in the affected joint. The subjective and objective measures were repeated at 12 weeks after treatment.

One encouraging feature of this study was the consistency of the outcomes. Both subjective and outcome measures were statistically improved in dogs in the treatment group and not in dogs in the control group. Subjective measures improved by 55%, and the objective measure improved by 12%.

There are, of course, a few caveats. The study was quite small, and in some of the objective tests only 5 dogs were evaluated in each group. The influence of chance on the results, and the potential applicability of the results to the general population, are always uncertain with such a small number of subjects.

And there is also always the question about the clinical significance of the effect. A 55% change in perceived symptoms seems a large enough difference to be meaningful, though as always it is being assessed indirectly through the owner, so whether the discomfort experienced by the dog is truly that much improved is impossible to know. However, a 12% difference in the measure of weight bearing is quite a bit smaller, and it is not clear how significant such an improvement would be in the comfort and function of a dog with arthritis.

Overall, this is a well-done study that provides an encouraging tidbit of evidence for this particular treatment. The authors’ conclusion is supported by the data, and they do not oversell the results. Larger studies will certainly need to be done to confirm the findings, and studies of more typical patients with multiple arthritis joints and other concurrent medical conditions will be needed before we can confidently predict the results of such a therapy in the general population. As with stem cell therapy, autologous platelet therapy seems promising, but hopefully the scientific research will lead the way forward rather than the commercialization and marketing efforts for this therapy.

 

 

Posted in Science-Based Veterinary Medicine | 13 Comments

Raw Diets for Pets

I have covered the raw diet debate since the beginning of this blog, and the evidence has been remarkably consistent:

  1. There is no evidence to support claims that raw diets are healthier than cooked commercial foods.
  2. There is consistent evidence that raw diets are contaminated with potentially harmful bacteria.
  3. It is not yet clear what the likelihood of infections in people or pets from these bacteria.
  4. Raw bones, often included in raw diets, may reduce calculus and periodontal disease risk, though this isn’t clearly demonstrated. However, they also present a real danger of injury, including broken teeth.
  5. Most homemade raw diets, and some commercial raw diets, may have significant nutritional deficiencies.

The bottom line so far is that there are not convincingly demonstrated benefits to feeding raw, and some potential risks, though it isn’t clear how serious these risks are. Most of the claims made for why raw diets are better are myths and nonsense or based entirely on anecdote. Overall, there seems little reason to feed raw when there is more evidence of risk than benefit.

 

Raw Diet Posts

Raw Diets for Dogs and Cats

Give a Dog a Bone (Not!)–FDA warns of dangers of feeding bones to dogs

Raw Meat and Bones Diet for Dogs: It’s Enough to make you BARF

Raw Pet Diet and “Natural” Pet Product Recalls

Raw Diets for Pets: Still No Evidence of Benefit but a Real Risk of Harm

Salmonella and Other Risks of Raw Pet Diets

Cooking increases the caloric value of meat and starches

Veterinary News Network (VNN) Video Discussing Raw Pet Diets

Raw Pet Diets Often Contaminated with Dangerous Bacteria: Campylobacter

Misleading Advertising for Raw Pet Food (again)

Raw, Cooked, and Dry Cat Diets–A New Study Examined

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

FDA Study Shows Raw Pet Diets Contaminated with Potentially Deadly Bacteria Much More Frequently than Cooked Pet Foods

Evidence Update-Review of the Risks and Benefits of Raw Diets for Dogs and Cats

More Evidence of the Risk of Infectious Diseases Associated with Raw Pet Foods

Yet Another Study Shows the Real Dangers of Raw Diets for Dogs

Actually, Raw ChickenLikely Can Lead to Paralysis for Dogs

New DogRisk Study Compares Risk of Allergies in Dogs Associated with Raw and Processed Foods

Are Unconventional and Raw Diets Becoming More Popular?

From SkeptVet TV- Raw Diets for Pets

Posted in Topic-Based Summaries | 44 Comments