Wednesday, July 7, 2010

Dietary Supplements for Arthritis Pain Examined

Briefly NotedResearchers examined all available clinical trial reports exploring the efficacy of various antioxidant and anti-inflammatory dietary supplements promoted to help manage painful osteoarthritis (OA) and rheumatoid arthritis (RA). Credible research evidence was found only for cats claw in aiding OA and omega-3 fatty acids for RA.

An extensive literature search spanning 1996 through January 2009 was conducted to discover efficacy trials of the following agents purported to have antioxidant and/or anti-inflammatory properties: cat's claw, ginger, fish oil, omega-3, turmeric, vitamin E, vitamin C, Baikal skullcap, barberry, Chinese gold thread, green tea, Indian holy basil, hu zhang, oregano, and rosemary [Rosenbaum et al. 2010]. Glucosamine, chondroitin, and methyl sulfonyl methane were excluded from the search since their mechanisms of action are not antioxidant or anti-inflammatory.

The search yielded 16 clinical studies having a control group (11 randomized, placebo-controlled clinical trials; 3 crossover trials; one case-controlled study; one open-label study) in addition to one meta-analysis and one review article. Three studies supported cat's claw alone or in combination specifically for OA, and two studies supported omega-3 fatty acids for the treatment of RA. The authors note that due to a lack of evidence they cannot recommend the use of vitamin E alone; vitamins A, C, and E in combination; ginger; turmeric; or Zyflamend (a combination of 10 different herbs, including the others listed above) for the treatment of either OA or RA. Whether any of the supplements can be effectively and safely recommended to reduce nonsteroidal anti-inflammatory drug (NSAID) or steroid usage is unclear and requires more high-quality research.

COMMENTARY: As noted in the above study, relatively few dietary (or, nutritional) supplements have been adequately demonstrated in controlled clinical trials as being helpful aids for pain management. Previously, we have discussed some research that does support vitamin D in this regard [here]. However, there are always questions about the optimal dose, the best formulation or quality of ingredients, and the duration of therapy needed to achieve beneficial outcomes; what seems to work in controlled research trials may not be realized by typical patients in everyday application. For example, we recently discussed some reservations about the use of ginger supplements for reducing pain and inflammation [blogpost here].

Dietary supplements are unregulated — at least not in the United States by the FDA — and they can be legally marketed only if no claims are made about their offering a cure, mitigation, treatment, or prevention of disease. The U.S. Government Accountability Office (GAO) has recently issued strong warnings about deceptive or questionable marketing practices and the proffering of dangerous advice when it comes to dietary supplements [documents here]. Furthermore, the GAO found that 37 of 40 herbal dietary supplements that they tested were contaminated by trace amounts of potentially toxic ingredients. So, caution is needed when recommending or purchasing any dietary supplements expected to aid in pain management.

REFERENCE: Rosenbaum CC, O'MathĂșna DP, Chavez M, Shields K. Antioxidants and antiinflammatory dietary supplements for osteoarthritis and rheumatoid arthritis. Altern Ther Health Med. 2010 Mar-Apr;16(2):32-40 [abstract].