Chronic multivitamin-mineral supplementation does not enhance physical performance.

The effects on physical performance of 90 d of supplementation with a high potency multivitamin-mineral supplement were studied in a double-blind, placebo-controlled design. Twenty-two healthy, physically active men were randomly assigned to a supplement (S) or placebo (P) group; both groups had similar physical characteristics. Performance was assessed from maximal aerobic capacity, endurance capacity, and isokinetic tests. Supplementation did not affect maximal aerobic capacity: pre and after approximately 12 wk of supplementation values for maximal oxygen consumption (48.5 +/- 1.3 vs 46.2 +/- 1.1 ml.kg-1.min-1), maximal heart rate (186 +/- 2 vs 187 +/- 2 beats.min-1) or treadmill time (19.96 +/- 0.48 vs 19.99 +/- 0.37 min) did not differ in the S group; similar findings were noted in the P group. Performance during the 90-min endurance run, as assessed from heart rates, rectal temperatures, and plasma glucose, lactate and adrenocorticotropin values, was not affected by treatment. Similarly, muscle strength and endurance were not affected. Thus, supplementation did not affect physical performance in well-nourished men who maintained their physical activity.