Low vitamin B intake lowers performance?

How does a diet low in B vitamins affect exercise performance?

B vitamins are involved in several processes of energy production. Therefore, these vitamins might be essential for optimal exercise performance.

This study investigated the effect of a 11-week diet restricted in vitamin B1, B2, and/or B6 on exercise performance.

24 health men were recruited and provided a of normal food products and adequate energy intake. The food products were selected so that one or more of the B vitamins were restricted (<55% RDA). Exercise performance was measured with a maximal test on a cycle ergometer.

The vitamin B restricted diets lowered maximal workload and maximal oxygen consumption (VO2max) during the 11-weeks by 6% and 7%, respectively.

A big limitation of the study design was the absence of a control group with adequate vitamin B status. However, the vitamin B restriction is the most plausible explanation for the observed detrimental effects.

This study suggests that a diet low in vitamin B may be detrimental to exercise performance. It remains to be established if an increased intake of B vitamins may improve exercise performance.

Study:
van der Beek et al. Thiamin, riboflavin and vitamin B6: impact of restricted intake on physical performance in man, J Am Coll Nutr, 1994

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