Glucosamine may be hurting more than your wallet.
November 14, 2012
At the recent North American Spine Society annual meeting, a paper was presented about the supplement Glucosamine. Glucosamine has been promoted as a treatment for Osteoarthritis. It is widely sold as a supplement in combination with chondroitin. It is also marketed and promoted as treatment for mechanical low back pain. Glucosamine, an amino sugar, is thought to promote the formation and repair of cartilage. Chondroitin, a carbohydrate, is a cartilage component that is thought to promote water retention and elasticity and to inhibit the enzymes that break down cartilage. Both compounds are manufactured by the body. Glucosamine supplements are derived from shellfish shells; chondroitin supplements are generally made from cow cartilage.
Laboratory studies suggest that glucosamine may stimulate production of cartilage-building proteins. Other research suggests that chondroitin may inhibit production of cartilage-destroying enzymes and fight inflammation too. Some human studies have found that either one may relieve arthritis pain and stiffness with fewer side effects than conventional arthritis drugs. Other studies have shown no benefit. As the research accumulated, expert review bodies have been cautious because, although positive reports outnumbered negative ones, the negative ones have been larger and better designed .NIH GAIT trial is a good example of a well structured study. http://www.ncbi.nlm.nih.gov/pubmed/20525840. In addition, whether glucosamine offers any advantages over established drugs such as acetaminophen, traditional NSAIDS, or selective Cox-2 inhibitors has not been established.
Many of my patients take glucosamine to relieve chronic joint and back pain. There have been no proven risks to taking Glucosamine outside of allergic responses. Overall this supplement has been perceived as relatively safe. Recently at the North American Spine Society meeting an animal study was presented. It indicated that there may be a previously unknown problem with glucosamine. This well structured study demonstrated worrisome damage to vertebral discs in an animal model.
In the Supplement Proceedings of the NASS 27th Annual Meeting/The Spine Journal - September 2012 (Vol. 12, Issue 9, Supplement, Page S75, DOI: 10.1016/j.spinee.2012.08.214). Primary investigator was Dr. Gwendolyn Sowa MD, PhD. Her study demonstrated a significant negative effect on disc matrix both by imaging and tissue histological analysis. The Data Raised surprising concerns about the safety of Glucosamine in treatment of lower back pain. I spoke to Dr. Sowa after the meeting and expressed surprise about the results. She admitted this result was surprising to her. The focus of the research was to explore the efficacy of Glucosamine in lower back pain. She was astonished by the seeming negative effect of the supplement in the study.
Unfortunately this study cannot be found on pub med just yet. I have included it as a PDF file, Oral Glucoasmine Study.
From a science standpoint there are several issues with this study. It is an animal model. It is a single study that has not been duplicated. Rabbit discs are close analogs to human discs, but they do not walk upright.
What can we learn from this study?
I am not yet ready, on the basis of one study, to tell my patients that Glucosamine causes damage to their spine. I do express concern about this study's findings if they ask me specifically about glucosamine. In general I tell my patients that Herbal Supplements are an unknown. They are not risk free. You cannot depend on warning labels. Their benefits are unknown, and the dangers are unknown. Frequently the theoretical benefit has been proven untrue.
My patients often presume safety using the "naturalistic fallacy"(Natural=Good). Arsenic is 100% natural but I wouldn't take it. Supplement takers are generally heavily emotionally invested in this fallacy. It would be good for them to know that many supplements are manufactured chemically not "naturally" and there is no way for the consumer to tell. It is acceptable in the US, under FDA guidelines to synthetically produce vitamins that can legally have an "Organic" label. Worse in some cases the supplement's risks are known and product left unlabeled, such as elemental mercury in Krill oil, or shellfish allergies and Glucosamine.
If you get a drug in the US you get a three page dissertation about the side effects from the pharmacy. If a patient or a provider find that drug X gave you side effect Y either of us can contact the FDA with this problem. The FDA compiles side effect statistics from providers and patients about drugs. Over time complaints affect the dosage, recommendations and warnings about the drug. It occasionally exposes unknown problems. This system is not perfect, but at least there is a system. The only system in the supplementation business is "try it".
Going forward more research will be able to answer specifically if Glucosamine is in fact a problem for your spine. If it is, it will be shining example of how these supplements need to have rigorous experimental standards and monitoring. More importantly it is a good reminder that taking untested unregulated supplements are risky at best.
In my opinion, taking glucosamine and other unregulated herbal supplements is accepting that the people who have the greatest financial gain in this industry are looking out for your best interest. That gives me good reason to be skeptical.
@Skeptoid Media, a 501(c)(3) nonprofit