Increased plasma pyridoxal 5′-phosphate and vitamin B6 in male adolescents after a 4500-meter run

Abstract

To investigate the effect of running on vitamin B6 metabolism, plasma pyridoxal 5′-phosphate and total vitamin B6 levels were determined in male adolescent trained athletes before and immediately after a 4500-m run. Six to seven subjects were studied twice during the fall and once during the spring training seasons. A mean increase in pyridoxal 5′-phosphate of 0.77 ± 0.31 to 1.83 ± 0.77 nmol/100 ml of plasma was observed after the three runs (p < 0.01). Similarly, significant increases (p < 0.05) in plasma total vitamin B6 were seen in all three runs. These increases were not solely due to changes in plasma volume. From urine samples collected on two runs, urinary 4-pyridoxic acid excretion in this group of adolescents was found to be similar to that reported for male adults. While changes in plasma glucose were not significantly correlated with changes in vitamin B6 metabolites, it is hypothesized that the significant changes in vitamin B6 metabolites found in this study were related to an increased need for cofactor for gluconeogenesis. The changes found in this study do not provide evidence for or against an increased need for vitamin B6 in persons that exercise, but does show, for the first time, that exercise in the form of long distance running dramatically alters plasma levels of pyridoxal 5′-phosphate.