Dietary supplements.

For the athlete training hard, nutritional supplements are often seen as promoting adaptations to training, allowing more consistent and intensive training by promoting recovery between training sessions, reducing interruptions to training because of illness or injury, and enhancing competitive performance. Surveys show that the prevalence of supplement use is widespread among sportsmen and women, but the use of few of these products is supported by a sound research base and some may even be harmful to the athlete. Special sports foods, including energy bars and sports drinks, have a real role to play, and some protein supplements and meal replacements may also be useful in some circumstances.

Ingestion of a dietary supplement containing dehydroepiandrosterone (DHEA) and androstenedione has minimal effect on immune function in middle-aged men.

Objective: This study investigated the effects of four weeks of intake of a supplement containing dehydroepiandrosterone (DHEA), androstenedione and herbal extracts on immune function in middle-aged men.

Design: Subjects consumed either an oral placebo or an oral supplement for four weeks. The supplement contained a total daily dose of 150 mg DHEA, 300 mg androstenedione, 750 mg Tribulus terrestris, 625 mg chrysin, 300 mg indole-3-carbinol and 540 mg saw palmetto.