In this study, researchers from England assessed the effectiveness of dietary supplements in reducing body weight.
The team performed a systematic review.
They conducted literature searches on Medline, Embase, Amed, Cinahl, and the Cochrane Library up to March 2003.
In addition, the team performed hand searches of medical journals, the authors’ own files, and bibliographies of identified articles.
All trials had to be randomized and double-blind.
The team also included systematic reviews and meta-analyses of dietary supplements if they were based on the results of randomized, double-blind trials.
They identified 5 systematic reviews and meta-analyses and 25 additional trials.
They identified data on several dietary supplements, including chitosan, chromium picolinate, Ephedra sinica, Garcinia cambogia, glucomannan, guar gum, hydroxy-methylbutyrate, plantago psyllium, pyruvate, yerba maté, and yohimbe.
The researchers determined that the reviewed studies provided some encouraging data.
However, there was little evidence that a specific dietary supplement was effective for reducing body weight.
They also found that E. sinica and ephedrine-containing supplements are associated with an increased risk of adverse events.
Drs Max Pittler and Edzard Ernst concluded, "The evidence for most dietary supplements as aids in reducing body weight is not convincing".
"None of the reviewed dietary supplements can be recommended for over-the-counter use".