| January 24, 2002
James A. Guest, President
100 Truman Avenue
Yonkers, NY 10703-1057
Dear Mr. Guest:
The American Nutraceutical Association (ANA) is an organization composed of physicians, pharmacists, academicians, and researchers striving to educate healthcare professionals and consumers about the latest research in the growing field of nutraceutical science.
We've recently read the article titled "Joint Remedies" in the January 2002 issue of Consumer Reports. While we applaud your effort to differentiate glucosamine and chondroitin supplements on the basis of their labeled claims and cost to consumers, we take exception to the concluding statement in this article that advises consumers: "While no one knows which formulation works best, it makes sense to try one of the least expensive combination products." In essence, this recommendation by your respected publication guided the consumer in their purchasing decisions exclusively on the price of products that matched label claim. While price and content of the product as compared to label claim are important issues, they are not enough, for it is equally important to evaluate bioavailability, which in turn can impact the efficacy of these products, especially those containing chondroitin.
Taber's Medical Dictionary defines bioavailability as "the rate and extent to which an active drug or metabolite enters the general circulation, permitting access to the site of action." Bioavailability is determined either by measurement of the concentration of the ingredient in body fluids, or by the magnitude of the pharmacologic response. Simply put, when a product is not absorbed by the body, it will not produce the desired effect.
The board members of ANA are concerned that the approach to product selection suggested in your article does not adequately address the complex issue of bioavailability. We agree that a product must contain the amounts stated on the label. However, the bioavailability and "efficacy" of a nutrient is in many cases dependent on more than the quantity of the ingredient found in the tablet or capsule. This is an important consideration, for the level of bioavailability can affect the cost of the compound. This is especially true for chondroitin sulfate, as discussed in our peer-reviewed journal in a study that evaluated the potential intestinal transport of several marketed sources of chondroitin sulfate. In an original research study published in the Journal of the American Nutraceutical Association (Vol. 3, No. 1, 2000, 37-44.), Adebowale and colleagues at the University of Maryland School of Pharmacy reported that the permeability coefficient for transport of chondroitin sulfate is affected by the molecular weight of the raw materials used, demonstrating that the bioavailability can be related to the size of the molecule. Several products examined in this study that passed "label claim" failed in an absorption model. This means that although a product meets its labeled claim, its molecular weight, size, or configuration can impact its bioavailability, with little or none of the ingredients actually absorbed, negatively impacting the product's intended clinical effect. Well-researched parameters that can affect bioavailability include molecular size, shape, and weight, excipients in the formulation, and the manufacturing process. We have all heard of tablets compressed so hard that they do not dissolve in the GI tract, and therefore have no bioavailability even when they meet label claims for quantity. The University of Maryland study concluded that the bioavailability of chondroitin sulfate is increased by using a product that has a smaller molecular weight. The important point that was not reflected in your article ("Joint Remedies") is that other factors can be just as important as meeting the label claim of a dietary supplement, especially so in the case of chondroitin sulfate.
The research team at the University of Maryland School of Pharmacy also evaluated the % label claim of chondroitin sulfate vs. price in retail dollars per daily dose. They found that most products costing less than $1.00/dose of 1200 mg of chondroitin sulfate were significantly below label claim. They also found that products costing more than $4.00/daily dose of 1200 mg were clearly below label claims. This showed that there was no clear relationship between product costs and content. Enclosed for your review is a copy of the Adebowale et al. study.
A problem unique to dietary supplements is that there is no "bioavailability standard" or monograph that dietary supplement manufacturers are required to follow. Good examples of the "bioavailability standard" concept for prescription drugs are digoxin, coumadin, and thyroxine. These generic pharmaceutical products all meet accepted bioavailability standards set by the United States Pharmacopeia (USP). It is important for the consumer to know that quantitative equivalency is not synonymous with either bioequivalency or bioavailability, and no such standards for either currently exist for dietary supplements, or "nutraceuticals."
In our opinion, Consumer Reports inappropriately and incorrectly related truth of label claim and price to bioavailability in its report. By doing this, Consumer Reports may have accomplished exactly the opposite of its intent.
It is clear that when evaluating dietary supplements, each brand should stand on its own original research, and not be assessed by the research of other brands. To compare bioavailability and make an accurate recommendation to buy the least expensive product that is bioavailable when consumed, Consumer Reports would have to test each product for bioavailability. We hope that in future comparisons of dietary supplements containing glucosamine and chondroitin, this fundamental error is not repeated.
We applaud Consumer Reports for attempting to guide the consumer through the maze of dietary supplements now used for joint health. However, when providing consumers with advice on efficacy we refer to the Arthritis Foundation's statement: "When a dietary supplement has been studied with good results, find out which brand was used in the study, and buy that."
In our opinion, until USP or another independent third party develops a "bioavailability standard" or monograph that dietary supplement manufacturers are required to follow for glucosamine/chondroitin products, this is the only safe recommendation to make that incorporates the issues of price, label claim and product content, bioavailability of the product, and efficacy.
Allen Montgomery, RPh
CEO & Executive Director
Mark Houston, MD
Editor-in-Chief, Journal of the American Nutraceutical Association (JANA)
Clinical Professor of Medicine
Vanderbilt University School of Medicine, Nashville, Tennessee
David S. Hungerford, MD
Member, JANA Editorial Board
Professor, Orthopaedic Surgery
Johns Hopkins School of Medicine
Natalie D. Eddington, PhD
JANA Editorial Board Member
Associate Professor of Pharmaceutics, University of Maryland, Baltimore
Chris Foley, MD
Coeditor (medicine), JANA
Medical Director, Integrative Care, St. Paul, Minnesota
Clinical Assistant Professor, University of Minnesota College of Pharmacy
Barry Fox, PhD
Chair, ANA Consumer Advisory Council
Coauthor, The Arthritis Cure, Calabasas, California
Robert Krueger, Ph.D.
Cochair, ANA Pharmacy Advisory Council
Professor of Pharmacognosy, Ferris State University College of Pharmacy
Big Rapids, Michigan
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