Natural products and the athlete: facts and folklore

Abstract

Objective: To contrast scientific facts with suggested manufacturers' claims regarding food supplements (natural products) marketed for enhanced athletic prowess.

Data sources: A MEDLINE search was performed to obtain documentation supporting the claims of natural-product manufacturers. In addition, several references pertaining to pharmacognosy, natural products, herbs, pharmacy practice, and sports medicine were reviewed. Claims were obtained from promotional advertisements in bodybuilding magazines, product labels, and fact sheets for sales representatives in nutrition and health-food stores.

Data extraction: We reviewed all of the clinical trials, published between 1966 and 1992, relative to the manufacturers' claims regarding these products.

Data synthesis: Pertinent human and/or animal studies supporting each natural product were compared with the manufacturers' claims.

Conclusions: We found that there was no published scientific evidence to support the promotional claims for a large proportion of the products (8/19, 42 percent). Only 4 of 19 products (21 percent) were associated with any documented human clinical trials supporting their promotional claims. Six of 19 agents (32 percent) had some scientific documentation to support their promotional claims; however, these products were judged to be marketed in a misleading manner.