Low-dose vitamin B-6 effectively lowers fasting plasma homocysteine in healthy elderly persons who are folate and riboflavin replete

Background: Current data suggest that physiologic doses of vitamin B-6 have no significant homocysteine-lowering effect. It is possible that an effect of vitamin B-6 was missed in previous trials because of a much greater eff ect of folic acid, vitamin B-12, or both. Objective: The aim of this study was to investigate the effect of low-dose vitamin B-6 supplementation on fasting total homocysteine (tHcy) concentrat ions in healthy elderly persons who were made replete with folate and ribof lavin. Design: Twenty-two healthy elderly persons aged 63-80 y were supplemented w ith a low dose of vitamin B-6 (1.6 mg/d) for 12 wk in a randomized, double- blind, placebo-controlled trial after repletion with folic acid (400 yg/d f or 6 wk) and riboflavin (1.6 mg/d for 18 wk); none of the subjects had a vi tamin B-12 deficiency. Results: Folic acid supplementation lowered fasting tHcy by 19.6% (P < 0.00 1). After folic acid supplementation, baseline tHcy concentrations ranged f rom 6.22 to 23.52 mu mol/L and 10 subjects had suboptimal vitamin B-6 statu s (plasma pyridoxal-P < 20 nmol/L). Two-way analysis of variance showed tha t the significant improvement in vitamin B-6 status in response to vitamin B-6 supplementation ton the basis of bath pyridoxal-P and the erythrocyte a spartate aminotransferase activation coefficient was reflected in a signifi cant reduction in plasma tHcy of 7.5%. Conclusions: Low-dose vitamin B-6 effectively lowers fasting plasma tHcy in healthy subjects who are both folate and riboflavin replete. This suggests that any program aimed at the treatment or prevention of hyperhomocysteine mia should include vitamin B-6 supplementation.