title: Nutrition and sports supplements: fact or fiction.
abstract: BACKGROUND
  In an age of highly competitive sports, whether it be the high school student, the weekend warrior, or the professional athlete, more individuals are using "performance-enhancing" nutritional supplements. Many feel they are gaining a "competitive edge," without thinking of the potential consequences. Consumers are inundated with claims of strength, weight loss, and improved body definition, but they are rarely given information on the potentially harmful side effects. There are few large, multicenter, randomized trials of these various nutritional supplements that look at the purported claims and potential side effects.
  
  
  METHODS
  We reviewed the available studies, including case reports, and researched data on five of the most popular performance-enhancing supplements, including androstenedione, creatine, chromium, ephedra, and protein and amino acid supplements.
  
  
  CONCLUSIONS
  Of the reviewed supplements, only creatine may be marginally beneficial. The potential benefit would probably only be useful to the professional athlete and not the average person. All of the supplements reviewed have potentially harmful side effects; however, certain supplements clearly show harmful effects, and use should strongly be cautioned. In addition, ephedra should be withdrawn from the marketplace. At this time, without better-designed studies, these agents cannot be recommended.
mesh_terms: D000293:Adolescent; D000328:Adult; D019587:Dietary Supplements / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009747:Nutritional Physiological Phenomena; D013177:Sports