Animal supplement sales

Huge gains/scant evidence

A recent headline article in a veterinary news source trumpets the large gains in sales animal supplement manufacturers have been experiencing the last several years. The article states that “…animal supplements saw double digit increases- up to 35 percent and 40 percent. Several factors fueled the growth, consumer demand among them.” Quoting Robert Devlin, veterinary products marketing manager at Nutramax Laboratories, it adds “There’s a growing awareness and acceptance of complementary medicine. It’s becoming more mainstream.” If true, this is sad news indeed.

The article goes on to state “Today, science sells. Companies stress their ingredients’ purity, independent testing, and dedication to quality control.” In fact, as it goes through a description of several companies and their products, quality control is emphasized just as much if not more than references to claims of efficacy.

Though this seems like a small matter, it raises a red flag. Questions of quality control have long been a problem plaguing the nutritional supplement industries. The fact that it is mentioned so frequently here is a small indicator that it remains a problem manufacturers are still struggling with- at least in the eyes of consumers as companies like consumerlabs continue to reveal some big deficiencies in ingredient label claims. If this basic requirement isn’t being fulfilled by some in the industry, those that do strive for high standards in manufacturing are affected by association.

Another, more concerning problem though goes deeper and entails the use of science as a marketing tool. “Science sells” or at least the veneer of science, and it is sprinkled throughout the statements of many of the featured industry representatives. Companies such as Nutramx, Vetri-science Laboratories, GLC Direct, Petlabs 360, and Rx Vitamins for Pets are among those propping the importance of “quality control”. Nutramax and GLC add to the tenor of scientific legitimacy by mentioning a variety of limited studies that seem to support evidence of efficacy. Interestingly, though they tout a variety of specialty products designed for a variety of immune disorders, liver, cognitive, skin, and behavioral maladies most of these studies refer to the old familiar joint supplement products, glucosamine and condroitin.

Indeed, though the mention of these studies may seem impressive at first glance, they are far less so upon closer scrutiny. Vetri-science “announced results of a three year study on hounds at Washington State. The results of the study support that Glyco-flex 111 may reduce the severity of cartilage breakdown and synovitis and help normalize joint function in dogs with stifle joints affected by osteoarthritis.”

GLC Direct describes a study where “a private practitioner studies 10 competitive hunter/jumpers over eight years to determine the effect of oral supplementation on the frequency of therapeutic injections in joints. The frequency of…injections decreased from a mean of 1.7 injections a year prior to glucosamine/chondrotoin supplementation to 0.85 per year.”

Nutramax “has a 16 page booklet of abstract of clinical studies of the products [Cosequin] effectiveness on its website.” The company emphasizes that they follow manufacturing purity standards similar to those used by the pharmaceutical industry.

All good and well, but a closer look raises some questions. For example, the study Vetri-science refers to is not directly mentioned as part of the North American Veterinary Conference Proceedings, although there was a lecture by Dr John Innes titled “Evidence for nutraceuticals in osteoarthritis- cutting through the sales platter.” Though the transcript to this lecture is not immediately available, Dr. Innes et al, have published a review in the Critical Reviews in Food Science and Nutrition in 2005 titled “ Nutraceutical therapies for degenerative joint diseases: a critical review."

Here, the authors describe the current state of knowledge regarding nutraceuticals and highlight the need for further research “so that current therapy and future treatments may be better focused.” A related study done in 2007 evaluated the current state of evidence for nutraceutical supplementation and osteoarthritis and echoed the need for further study. There was work done at Washington State University regarding a dietary supplement and canine osteoarthritis, but there are no readily available published reports or abstracts as of yet. At any rate, that the product used in the study “may reduce… and help” hardly constitutes the evidence needed to promulgate it as heavily as it is for osteoarthritis.

The GLC Direct study is small, offering little detail as to the study parameters. There may be a variety of confounding factors affecting these results and at any rate is only more of an anecdotal mention in the article.

The broad abstract described by Nutramax provides more information and an accumulation of data. Even these studies, though, are not the convincing mass of positive evidence one would think. A numbers of these abstracts deal only with the safety of their product. One study evaluates possible interactions of several substances, including Cosequin, with thyroid hormone levels. A variety of studies do discuss possible positive conclusions related to product efficacy in canines and equines that need to be weighed and analyzed for quality and significance.

A search of the Pubmed, Cochrane, and Relemed data bases reveal limited animal related published efficacy studies and reviews. Those that exist offer a mixed bag of findings. Essentially, they are negative or indicate there is not enough information gathered as of to yet make a solid conclusion.

An interesting 2007 systematic study that utilized FDA evidenced based ranking system found that, as a group, a number of studies focusing on a variety of nutraceuticals and one non-steroidal anti-inflammatory fall under the type two level of evidence. The good news here is that this indicates a fairly high confidence level relating to test quality and objectives (i.e.; validity for discerning efficacy). However, the bad news is very large caveats exist due to the extremely low number of quality published studies to date.

In these situations, it is helpful to observe the results of larger studies and reviews, if they exist, in other animals. obviously, the human research perspective has a plethora of pooled information. In theses cases, the results are far clearer and reveal very little support for the efficacy of at least glucosamine and chondroitin.

It is also interesting to mention that the nutraceutical industry is just as able to twist the facts and spin the available research in the best light possible for their products as any other industry. For example according to the Nutramax website, the recent NIH funded GAIT study concludes:

National Institutes of Health GAIT Study Results

Clegg DO, Reda DJ, Harris CL, et al. Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. New England Journal of Medicine 2006;354(8):795-808.

"In this double-blinded study sponsored by The National Institutes of Health (NIH) and led by various clinical investigators at 16 U.S. rheumatology centers, safety and efficacy were assessed on both glucosamine hydrochloride and chondroitin sulfate individually as well as in combination (all ingredients required to meet pharmaceutical standards). The chondroitin sulfate selected for use in this study is found in Cosequin.

Men and women over 40 years of age with knee pain persisting at least 6 months and with radiographic evidence of cartilage breakdown were each randomized to receive one of five agents: a placebo, celecoxib (a positive control), glucosamine hydrochloride, chondroitin sulfate, and the combination of glucosamine hydrochloride and chondroitin sulfate. The study concluded that the combination of glucosamine hydrochloride and chondroitin sulfate is effective in managing moderate to severe knee pain. Of note, response to either glucosamine or chondroitin sulfate alone was not significant. This study provided further support for Cosequin research documenting effects and benefits of using low molecular weight chondroitin sulfate and glucosamine hydrochloride in combination over using the individual agents alone."

The GAIT study actually states:

RESULTS: The mean age of the patients was 59 years, and 64 percent were women. Overall, glucosamine and chondroitin sulfate were not significantly better than placebo in reducing knee pain by 20 percent. As compared with the rate of response to placebo (60.1 percent), the rate of response to glucosamine was 3.9 percentage points higher (P=0.30), the rate of response to chondroitin sulfate was 5.3 percentage points higher (P=0.17), and the rate of response to combined treatment was 6.5 percentage points higher (P=0.09). The rate of response in the celecoxib control group was 10.0 percentage points higher than that in the placebo control group (P=0.008). For patients with moderate-to-severe pain at baseline, the rate of response was significantly higher with combined therapy than with placebo (79.2 percent vs. 54.3 percent, P=0.002). Adverse events were mild, infrequent, and evenly distributed among the groups.

CONCLUSIONS: Glucosamine and chondroitin sulfate alone or in combination did not reduce pain effectively in the overall group of patients with osteoarthritis of the knee. Exploratory analyses suggest that the combination of glucosamine and chondroitin sulfate may be effective in the subgroup of patients with moderate-to-severe knee pain. (ClinicalTrials.gov number, NCT00032890.). Copyright 2006 Massachusetts Medical Society.

Dan Hurley (Natural Causes) notes: “The new study was by far the biggest and best ever conducted on the substances...No statistically significant difference was seen between those taking any of the supplements and those taking placebo, but the study indicated why so many people think they benefit from it: a whopping 60 percent of those taking just a placebo said they felt better. The only sign of real benefit from the supplements came from an analysis of just the patients with moderate to severe pain, for whom those taking the glucosamine-chondroitin combination reported slightly less pain compared to those taking placebo. However, the number of patients in that category was relatively small, and experts have generally put little credence in such sub-group analysis, because one or another subgroups of patients in any study, if sifted through carefully enough, will turn out- simply by chance- to have fared better following a treatment."

The bottom line is that these are not the clear cut supporting threads of evidence supporting the use of oral joint supplements in animals suffering osteoarthritis. As more information trickles in, it could be that the weight of evidence swings positively for these supplements. On the other hand, initially favorable human studies later turned out to be far less accurate than assumed as more data came in. Additionally, these questionable joint supplements are among the most researched within the realm of the innumerable products available in the supplement industry. Indeed, a skeptical outlook remains the most prudent approach when encountering these products.

Justifying the amount of money spent on products claiming a medical benefit that have very little evidence backing them are of concern. Consumer choice in medicine needs to be limited to those modalities that have an acceptable level of evidence for efficacy demonstrable beyond placebo. Otherwise, often limited consumer funds, are directed away from those therapies that can do some good.