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Unformatted text preview: Vitamin and mineral supplementation: effect on the 192 Am J Clin Nutr l988;47: 192-5. Printed in USA. C 1988 American Society for Clinical Nutrition running performance of trained athletes13 Lindsay M Weight, MS(Med); Kathryn H Myburgh, BSc; and Timothy D Noakes, MD ABSTRACT There is limited scientific justification for the widespread use of vitamin and mineral supplements by athletes. We used a 9-mo, placebo-controlled crossover study design to determine whether a multivitamin and mineral supplement influenced the athletic performance of 30 competitive male athletes. At 0, 3, 6, and 9 mo the runners performed a progressive treadmill test to volitional exhaustion for measurement of maximal oxygen consumption, peak running speed, blood lactate turnpoint, and peak postexercise blood lactate level. Running time in a 15 km time trial was also measured. None of these variables was influenced by 3 mo of active supplementation. We conclude that 3 mo of multivitamin and mineral supplementation was without any measurable ergogenic effect. Am J Clin Nutr l988;47:192-5. KEY WORDS Vitamin and mineral supplementation, athletic performance, maximal oxygen consumption, blood lactate turnpoint, long-distance running Introduction The belief is widespread that the consumption of vi- tamins in addition to those supplied in the diet is essential for both optimal health and enhanced athletic perfor- mance (1-4). This belief has been encouraged by several scientific reports recommending the use of vitamin and mineral supplements often in very large doses (4-6). One result of this “vitamythology” (7) has been that the use of vitamin and mineral supplements by athletes has become widespread (1, 4, 5); one report concluded that 84% of Olympian athletes use vitamin supplements (4). There is little firm scientific evidence to support this practice. Although it is established that clinically apparent vitamin deficiencies, most notably those of the B group, impair physical work capacity (3, 8-13), there is no evi- dence that the physical performance ofathletes even with low serum levels ofcertain vitamins (so-called subclinical vitamin deficiency) is enhanced by correction of the de- ficiency (14, 15). There have been comparatively few well-controlled studies ofthe effects ofmultiple vitamin and mineral sup- plernentation on athletic performance (1, 3) and the pos- sibility that such supplementation could have an ergogemc effect has not been disproved entirely (3, 4). We use a double-blind, placebo-controlled crossover study design to determine whether the chronic ingestion of a compre- hensive multivitamin and mineral supplement had a measurable effect on the running performance of trained athletes....
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This note was uploaded on 10/25/2011 for the course AMERICAN H 100 taught by Professor Dr,holland during the Fall '08 term at BYU.
- Fall '08