M. Scott Echols, DVM, DABVP (Avian)
The Role of Nutrition in Disease Prevention
The news is everywhere describing the role of nutrition and nutritional supplements in disease prevention and sometimes even treatment. As this discussion will point out, there are truths and mistruths regarding these headlines. Before making nutritional supplementation recommendations for animals, one should better understand the nutritional supplement industry.
Weeding through the facts and labels of nutritional supplements can be difficult and frustrating for consumers. What is printed on the label of a supplement may not necessarily represent what is in the bottle. Claims made by supplement companies range from realistic to outrageous, but the questions remain "are these statements true or false and/or misleading?" and "can this product help me and my family (including pets)?"
The facts are that many impressive studies have shown the value of nutritional supplementation, especially in humans. Some of these studies have their origin in animals which naturally leads to some conclusions of the use of supplements in pets. The only problem is that well designed studies that focus on the use of select supplements for use in pets under realistic (clinical and not lab or research) situations are far fewer in number.
Several impressive studies on human supplements include the following:
A 2000 scientific review noted that over 4500 studies have been generated to research the effects of omega-3 fatty acids and human health since the late 1970s. After reviewing numerous studies on omega-3 fatty acids relating to cardiac disease, the authors made the following conclusions: "fatty acids, when incorporated into the diet, seem to be able to stabilize myocardial membranes electrically, resulting in reduced susceptibility to ventricular dysrhythmias, thereby reducing the risk of sudden death." So how much did omega-3 fatty acid supplementation help..... In 2002, researchers published results of 17 years of data from the Physicians' Health Study involving over 22,000 men. In their study, the authors reported that men consuming the most omega-3 fatty acids (and subsequently those who had the highest blood levels of omega-3 fatty acids) from food and supplements had an 81% decrease chance of sudden death compared to those with the lowest levels.
Currently the human literature is filled with positive statements about omega-3 fatty acids supplements. Supplementation with omega-3 fatty acid supplements has been shown to produce a "statistically significant reduction in systolic blood pressure," and "may provide rapid protection in patients with acute myocardial infarction," "modestly mitigates (improves) the course of coronary atherosclerosis in humans," "are beneficial on the lipid and immune abnormalities secondary to chronic renal failure and may also have a useful effect on the progression of chronic renal damage," slow "the rate of renal function loss in high-risk patients with IgA nephropathy (kidney disease), particularly those with moderately advanced disease," and results in "improvements in clinical status in patients with rheumatoid arthritis." The studies are seemingly endless, but point to the true value of this one nutrient (omega-3 fatty acids) and its positive effects on several disease problems in humans.
Three 3-year studies using glucosamine sulfate showed that this nutrient alone improved symptoms (pain) and physical joint abnormalities over placebo in patients with osteoarthritis.
Two papers published in the Journal of the American Medical Association in 2002 made some startling recommendations to the medical community. In a scientific review of studies on nutritional supplementation and disease from 1966 to 2002, the authors made the following conclusions: "Inadequate intake of several vitamins has been linked to chronic diseases, including coronary heart disease, cancer and osteoporosis" "Many physicians may be unaware of common food sources of vitamins or unsure which vitamins they should recommend for their patients".
The authors then made the following clinical statements: "Suboptimal folic acid levels, along with suboptimal levels of vitamins B6 and B12, are a risk factor for cardiovascular disease, neural tube defects, and colon and breast cancer; low levels of vitamin D contribute to osteopenia and fractures; and low levels of the antioxidant vitamins (vitamins A, E and C) may increase the risk for several chronic diseases;" and "it appears prudent for all adults to take vitamin supplements."
Nutritional Supplements: A Poorly Regulated Industry
Dietary supplements have clearly shown benefit in both human and animal studies in both disease prevention and treatment. While dietary supplements are "intended to supplement a normal diet," they are unlike drugs which require FDA regulation. This lack of FDA regulation has brought up serious concerns within the industry.
Dietary supplements (vitamins, minerals, anti-oxidants, herbs, etc.) are legally defined as "foods" according to the Dietary Supplement Health and Education Act (DSHEA) of 1994. The regulations governing dietary supplement manufacturing are for food grade and mimic the guidelines for the production of Twinkies, Cupcakes, etc. As a result, dietary supplements are not required to go through rigorous testing and guarantees as are seen with OTC drugs. These guarantees include proving potency (what is on the label is in the bottle), disintegration (the product will dissolve in a time considered normal for digestion), and uniformity (each pill, bottle and lot are the same).
According to the Federal Food, Drug and Cosmetic Act, "foods are products used for food while drugs are products intended to diagnose, treat, cure or prevent disease." Foods are: "assumed to be safe" and are "eaten primarily for taste, aroma, and nutritive value." Drugs are: "intended for therapeutic benefits, and must be proven in clinical trials to provide those benefits."
DSHEA was established to be the first "regulatory structure that applies specifically to dietary supplements." This act has proven to be a watershed for the dietary supplement industry in the United States and has significantly helped drive the continued expansion of the market.
While it may seem that DSHEA has provided a "regulatory structure" for the supplement industry (and it has to some degree), this act has not necessarily guaranteed protection to the consuming public. DSHEA has: "grandfathered" all dietary supplement ingredients marketed in the United States before October 15, 1994, just as food additive amendments "grandfathered" food additives already on the market before 1958. Any new ingredients first marketed in dietary supplements on or after October 15, 1994 are considered "new dietary ingredients." Before marketing a supplement containing a new dietary ingredient, the manufacturer must determine that the ingredient is "reasonably expected to be safe." However, no formal approval by FDA is required prior to marketing the new dietary ingredient.
DSHEA added new safety provisions specifying that a dietary supplement is adulterated if it "presents a significant or unreasonable risk of illness or injury" when used according to label directions. DSHEA provides that FDA will bear the burden of proof in any court action claiming that a product is "adulterated." This has always been the FDA's burden in a formal enforcement action.
In essence DSHEA helped spawn the massive growth of the dietary supplement industry by grandfathering in products and limiting regulation. The FDA is not required to regulate nutritional supplements and it becomes the FDA's burden to prove fault with the product in question.
New Rules From the USDA
In June 2007, the USDA issued the final rule establishing regulations to require current good manufacturing practices (CGMPs) for dietary supplements. The CGMPs final rule will require that proper controls are in place for dietary supplements so that they are processed in a consistent manner, and meet quality standards.
The following are direct quotes from the FDA's website:
"The CGMPs apply to all domestic and foreign companies that manufacture, package, label or hold dietary supplements, including those involved with the activities of testing, quality control, packaging and labeling, and distributing them in the U.S." "The rule establishes CGMPs for industry-wide use that are necessary to require that dietary supplements are manufactured consistently as to identity, purity, strength, and composition."
"The requirements include provisions related to: the design and construction of physical plants that facilitate maintenance, cleaning, proper manufacturing operations, quality control procedures, testing final product or incoming and in-process materials, handling consumer complaints, and maintaining records."
"To limit any disruption for dietary supplements produced by small businesses, the rule has a staggered three-year phase-in for small businesses. The final CGMPs are effective in June 2008 for large companies. Companies with less than 500 employees have until June 2009 and companies with fewer than 20 employees have until June 2010 to comply with the regulations."
"The interim final rule establishes a petition process for a manufacturer to apply for exemption from the 100 percent identity testing requirements for dietary ingredients used in manufacturing dietary supplements."
"If a manufacturer is granted an exemption, the manufacturer would still be responsible for ensuring the quality of the final dietary supplement product."
"The manufacturer would have to provide data in its petition demonstrating that less than 100% identity testing does not materially diminish assurance that the dietary ingredient is the correct dietary ingredient."
While the rules have been set in place, an enforcement policy has not been established. Time will tell whether or not dietary supplement manufactures adhere to these new guidelines.
Can Consumers Feel Safe About Taking Supplements?
This question has been answered by numerous studies. Unfortunately, these studies bring up more concerns about the nutritional supplement industry.
ConsumerLab.com, an independent reviewer of nutritional supplements, reported that 6 of 20 omega-3 fatty acid products did not contain the label stated amount of one or more essential fatty acids. In fact, the website states "two of the products that failed made claims on their labels that their 'potency' had been 'tested' or 'verified'." In 2007, a study of 44 omega-3 fish oil products showed that only 2 had failed (one for spoilage and one for containing only 53% of the label claim of EPA).
In two separate studies that examined prescription prenatal vitamins, approximately two thirds of all supplements evaluated did not even dissolve. That is to say that despite what was on the label, these doctor-prescribed supplements did not even meet basic dissolution standards and the main ingredient (folic acid) would not likely be available to the consumer.
Two studies evaluating dietary calcium supplements made some frightening discoveries. In review of 70 and 136 brands of calcium supplements, 25% and a whopping 67% (respectively) of the products evaluated had unacceptably high lead levels!
In the March 24, 2003 Archives of Internal Medicine, 59 commercial Echinacea products were studied. The following findings were published: none of the 59 products offered consumers what was promised on the label, 6 contained no Echinacea whatsoever and 28 failed to contain the specific species listed on the label. The authors made the following conclusion "Echinacea from retail stores often does not contain the labeled species. A claim of 'standardization' does not mean the preparation is accurately labeled, nor does it indicate less variability in concentration of constituents of the herb."
In a study of 880 products containing frequently purchased herbs (Echinacea, St John's wort, Ginkgo biloba, garlic, saw palmetto, ginseng, goldenseal, aloe, Siberian ginseng and valerian), there was only a 20% consistency between the label information and the product ingredients.
Numerous papers have cited problems with probiotics but two studies in particular note serious deficits in these products sold within North America. In a review of 13 commercial probiotics, only 2 accurately labeled their ingredients. In fact, 5 of the veterinary products did not specifically list their ingredients, 5 failed to contain 1 or more of the stated organisms and 3 contained additional organisms. Contents of only 9 of 21 human and 2 of 23 veterinary probiotic products were adequately identified. Interestingly, the authors found that the contents of 5 of 20 human and 3 of 17 veterinary products were misspelled on the label.
Researchers looked at 32 chondroitin-containing products and found that "the amounts of glucosamine and chondroitin found after analysis were significantly different from their label claim in some products." In this study, half of the products contained less than 40% of the labeled claim. Two of the most expensive products contained less than 10% of the labeled claim.
ConsumerLab.com has specifically evaluated 6 glucosamine and/or chondroitin containing products. According to the 2000 report, the following statement was made: "Shockingly, no chondroitin sulfate could be detected in two pet supplements despite each displaying a 'guaranteed analysis' showing a significant amount of chondroitin sulfate." In 2007, ConsumerLab.com performed a similar study of joint products. This time, 73% of the chondroitin containing products failed. Three of the 6 veterinary/pet joint health products failed because only 47.2%, 2.1% and 0.7% of the label claim of chondroitin was actually in the product.
How to Select High Quality Supplements
Look for the "Meets USP Specifications for Potency, Uniformity and Disintegration, Where Applicable" label on the supplement as a minimum. These guidelines are voluntarily met by dietary supplement manufacturers.
Determine if the company manufacturing the supplements follows Good Manufacturing Practices for drug grade and not food dietary supplement grade standards. This is voluntary on the part of supplement manufacturers.
Determine if the supplement manufacturer is currently regulated by a governmental agency.
Health Canada (Canadian FDA) and the Therapeutic Goods Administration (Australian FDA) regulate supplements sold in their country and often inspect the respective manufacturing facilities. You can ask the manufacturer for proof of governmental inspection.
Look for companies that have third party verification. Companies that submit their products and manufacturing plant to third party evaluation and verification provide better evidence of product quality to the public. Several companies have created dietary supplement testing and verification programs to fill this need. Of the numerous verification programs currently available. Several levels of NSF testing are available and NSF arguably has the most stringent requirements for a company to pass certification. Companies that have products which passed NSF certification (especially the NSF Certified for Sport program), typically set high benchmarks for quality control and testing of their nutritional supplements. Go to www.NSF.org for more details.
References are available upon request.