Vitamin B6 utilization in active and inactive young men

Abstract

Two groups (22-37 yr) were studied to investigate the use of vitamin B6 with exercise. Four trained men (T) were confined and studied after they ran 10 and 5 miles/day, for two 4-wk periods. They were compared with six free-living inactive men (S) consuming the same diet that provided 4.2 mg of vitamin B6 each day. N-acetyl-L-methionine, was given (60 mg/kg) as a Vitamin B6 challenge on day 28 of each period, and 24-h urinary 4-pyridoxic acid (4-PA) and methionine metabolites were determined before and after the challenge. Basal 4-PA excretion was significantly lower (p less than or equal to 0.05) in T than in S. In T, postmethionine 4-PA was greater than basal, while in S, postmethionine 4-PA was lower. Compared with prechallenge, postchallenge metabolites decreased in T and increased in S. Basal 4-PA excretion provides no conclusive evidence of increased need for vitamin B6 in athletes: the postload excretion suggests that exercise may promote storage of the vitamin that is available for redistribution with increased need.