Studies on soy and arthritis-relief supplements give negative results

Recent studies have cast doubt on the purported benefits of soy and glucosamine supplements. The Nutrition Committee of the American Heart Association (AHA) has released a statement indicating that soy and soy-based products, such as soy milk, tofu, vegetarian meat substitutes, and supplements containing soy, may not be as helpful in the fight against unhealthy levels of cholesterol as had been hoped.

A panel set up by the Nutrition Committee reviewed studies that were conducted over the past ten years and concluded that the findings of those investigations did not support the claim that a diet consisting of twenty-five grams or more of soy protein could lower cholesterol for the average person. A journal report from the AHA states that "large amounts of soy protein in the diet reduced low-density lipoproteins (LDL), or 'bad cholesterol,' only 3 percent and had no effect on high-density lipoproteins (HDL), or 'good cholesterol.'" This is a significantly smaller effect than had been expected--and less than what's advertised for many soy products. Similar results were obtained in the committee's review for soy isoflavones, molecular compounds that are found in soy.

In 2000, a statement released by the same committee recommended the addition of soy proteins to a diet that's low in saturated fats and cholesterol as a way to combat heart disease.

The Food and Drug Administration may alter its rules in response to this study, no longer allowing manufacturers of soy products to claim cholesterol reduction in advertising or on packaging.

The report notes that many people who regularly consume soy and soy-based products do so to substitute soy proteins for those found in less healthy fare and that this is good, but other benefits are not what had been hoped for. Frank M. Sacks, M.D., a member of the panel that released the statement, said: "Soy products may have other benefits when replacing foods such as hamburgers. Soy products have no cholesterol or saturated fats and have high amounts of fiber."

The statement, "Soy Protein, Isoflavones, and Cardiovascular Health: An American Heart Association Science Advisory for Professionals from the Nutrition Committee," appears in the AHA's journal, Circulation, volume 113, issue 7 (February 21, 2006), and was authored by Frank M. Sacks, Alice Lichtenstein, Linda Van Horn, William Harris, Penny Kris-Etherton, and Mary Winston for the American Heart Association Nutrition Committee.

And a team of researchers, led by Daniel O. Clegg of the University of Utah School of Medicine, has published the results of a nearly four-year study of the effectiveness of the popular supplements chondroitin and glucosamine in the treatment of osteoarthritis of the knee. Their findings: reported relief of symptoms in the groups that received the two supplements, separately or together, was not significantly higher than those of control groups that received celecoxib (a non-steroidal anti-inflammatory drug that's commonly prescribed for mild osteoarthritis) or a placebo. The only positive finding for the supplements was: "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."

GAIT (Glucosamine/chondroitin Arthritis Intervention Trial) was a multicenter, double-blind study, using 1,583 patients who reported pain from osteoarthritis of the knee. Each participant received either glucosamine sulfate, chondroitin sulfate, a combination of the two compounds, celecoxib, or a placebo. The outcome that was sought was a 20-percent decrease in pain in the affected joint over the twenty-four-week study period. The patients' mean age was fifty-nine years and the female-to-male ratio was sixteen to nine.

These results could have a broad impact, considering that twenty million people in the United States alone suffer from osteoarthritis. And that number is expected to increase in coming decades, as the Baby Boom generation comes into its arthritis-prone years. The government estimates that $86 billion dollars was spent on arthritis treatment in 2004, and the nutrition industry states that Americans spent $730 million on glucosamine and chondroitin in that same year. The investigators admit that the study had a number of limitations, and further investigations will be needed to determine its accuracy and relevance. (Even the potentially positive findings for the moderate-to-severe-pain group are somewhat mitigated by the small sample size of that category in the study.)

GAIT was funded by the National Center for Complementary and Alternative Medicine (NCCAM) and the National Institute of Arthritis and Musculoskeletal Diseases (NIAMD), which are both divisions of the National institutes of Health (N1H), and was published in The New Fmgland Journal of Medicine (volume 354, number 8 [February 23, 2006]).

David Park Musella is an editorial assistant with the SKEPTICAL INQUIRER.

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