Vitamin B6 status and static muscle function. 2 case reports.

2 young adult females, identified as vitamin B6 deficient based on xanthurenic acid excretion levels following a loading dose of tryptophan, were tested twice during each of 3 menstrual cycles for static muscle strength and endurance of the handgrip muscles. During each of the last 2 cycles either a 25-mg dose of pyridoxine hydrochloride or a placebo were administered daily in the double-blind fashion. Measurement of 24-hour xanthurenic acid and 4-pyridoxic acid excretion levels indicated correction of the biochemical indicators of vitamin B6 deficiency. Results of the tests of static muscle strength and endurance indicated no substantial improvement following vitamin B6 supplementation.