Research Review by Dr. Shawn Thistle©



Study Title:

Dietary supplements for body-weight reduction: a systematic review


Pittler MH, Ernst E

Publication Information:

American Journal of Clinical Nutrition 2004; 79: 529-536


A question exercise professionals commonly get from clients is: "Can I take a pill to help me lose weight?" Although the thought of popping a pill and watching pounds melt away is attractive to some (or in my opinion, far too many), the reality of it has yet to be established.

Despite this, the marketplace is saturated with products claiming to do just that. Shelves adorning numerous products claiming to assist in weight loss can easily be found at any nutrition or health food store. Unfortunately, the average consumer is not equipped with the level of knowledge required to make an informed decision about these supplements.

This systematic review assessed the evidence from rigorous clinical trials, meta-analyses and other systematic reviews on the effectiveness of dietary supplements in reducing body weight. Five systematic reviews and meta-analyses and twenty-five additional trials were included and reviewed. In order to be included, trials had to be randomized and double-blind in nature.

The identified evidence relates to ayurvedic herbal preparations, chitosan, chromium picolonate, Ephedra sinica, Garcinia cambogia, glucomannan, guar gum, hydroxy-methylbutyrate, plantago psyllium, pyruvate, yerba mate and yohimbe. Of these, the only supplement with any substantial evidence to support its use is Ephedra sinica or other ephedrine-containing supplements. This should be interpreted with caution as the authors mention, as ephedrine can increase the chance of serious adverse effects by as much as 2-3x.

These adverse effects can include psychiatric, autonomic (component of the nervous system), or gastrointestinal symptoms, as well as the recently publicized heart palpitations which can be fatal. The FDA is now in the midst of strictly regulating these supplements due to the risk of these adverse effects.

Conclusions & Practical Application:

The authors conclude that there is "little convincing evidence that any specific dietary supplement is effective in reducing body weight". The combination of uncertain results with possible adverse effects, particularly for ephedrine-containing compounds, should "shift the delicate risk-benefit balance against their use".

In my opinion, no supplement available today can replace hard work and dedication to a properly designed exercise and nutrition program. Talk to your doctor, exercise professional, or registered dietician to begin developing your plan for proper and long-lasting weight loss.