Matéria publicada no The New York Times em 21 de janeiro de 2008
Estudo completo: http://www.aafp.org/afp/20080115/177.pdf
Arthritis sufferers are routinely targeted by the $20 billion supplement industry, which has introduced more than 800 purported remedies for arthritis in recent years.
With so many different products promising relief, it’s tough to know which are worth trying. This month, American Family Physician, a medical journal, offers some guidance. A new review article sifts through the research to determine which supplements really work.
The review article’s top pick — glucosamine sulfate — is typically derived from crustacean shells. Unlike many products sold by the supplement industry, this one has been widely studied. According to the authors, researchers at Creighton University in Omaha, glucosamine has been the subject of more than 20 randomized controlled trials involving over 2,500 patients.
The findings have been inconsistent, however, likely because of varying formulations and study methods. The research does show that the type of glucosamine matters. Studies using a product called Dona consistently showed benefits for arthritis sufferers, the authors note, while glucosamine hydrochloride formulations have not performed as well.
"The evidence supports the use of glucosamine sulfate for modestly reducing osteoarthritis symptoms and possibly slowing disease progression," the authors write. "However, there isn’t enough evidence to recommend the use of other glucosamine formulations."
The evidence for another popular supplement, chondroitin, is inconsistent, as well. The supplement, made from cow cartilage, often is sold in combination with glucosamine. The study authors find little evidence that the combination is more effective than glucosamine sulfate alone.
Another promising supplement reviewed in the study is SAMe, which stands for S-adenosylmethionine. In one recent study, SAMe was compared with the anti-inflammatory drug Celebrex. During the first month of treatment, Celebrex users did better; after two months of use, the authors note, there was no difference in pain relief between the two agents.
SAMe appears to have fewer gastrointestinal side effects than most anti-inflammatory drugs, but it can cause headache and insomnia, among other side effects, and has the potential to interact with antidepressants and other drugs. SAMe can also be expensive: the authors note that a one-month supply typically costs $60 to $120. By comparison, glucosamine ranges from $9 to $35 monthly.
But the biggest downside of SAMe is that product quality is inconsistent. "Products on store shelves may contain little or none of the active ingredients," the researchers write. One solution is to buy SAMe in a form called butanedisulfonate salt, which is more stable.
The report also covers the research on MSM, devil’s claw, turmeric and ginger, but concludes there isn’t enough evidence to support their use.
If you’re interested in trying supplements to relieve arthritis pain, it’s worth reading the full article, which is free. It contains useful charts listing the supplements with notes on the quality of the science backing them. For the report, click here.