To review efficacy studies of antioxidant and antiinflammatory dietary supplements used to manage osteoarthritis (OA) and rheumatoid arthritis (RA) and make conclusions about their place in therapy. Glucosamine, chondroitin, and methyl sulfonyl methane were excluded.
A literature search was conducted using MEDLINE (1996 through January 2009), EMBASE, Cochrane Library, Natural Medicines Comprehensive Database, and Natural Standard, with bibliographic review of relevant articles. Cited studies from before our search range were included if they represented the only published human data available. Search words included "antioxidant," "antiinflammatory," "cat's claw," "ginger," "fish oil," "omega-3," "turmeric," "vitamin E," "vitamin C," "Baikal skullcap," "barberry," "Chinese goldthread," "green tea," "Indian holy basil," "hu zhang,""oregano," and"rosemary."
Efficacy studies published in English were included provided they evaluated the dietary supplements in patients with OA or RA.
Our search strategy yielded 16 clinical studies (11 randomized, placebo-controlled clinical trials, three crossover trials, one case-controlled study, and one open-label study) in addition to one meta-analysis and one review article.
Three studies support cat's claw alone or in combination for OA, and two studies support omega-3 fatty acids for the treatment of RA. We cannot recommend use of vitamin E alone; vitamins A, C, and E in combination; ginger; turmeric; or Zyflamend (New Chapter, Brattleboro, Vermont) for the treatment of OA or RA or omega-3 fatty acids for OA. Whether any of these supplements can be effectively and safely recommended to reduce nonsteroidal antiinflammatory drug or steroid usage is unclear and requires more high-quality research.