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.