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 effect 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) concentrations in healthy elderly persons who were made replete with folate and riboflavin.


METHODS
Twenty-two healthy elderly persons aged 63-80 y were supplemented with 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 microg/d for 6 wk) and riboflavin (1.6 mg/d for 18 wk); none of the subjects had a vitamin B-12 deficiency.


RESULTS
Folic acid supplementation lowered fasting tHcy by 19.6% (P < 0.001). After folic acid supplementation, baseline tHcy concentrations ranged from 6.22 to 23.52 micromol/L and 10 subjects had suboptimal vitamin B-6 status (plasma pyridoxal-P < 20 nmol/L). Two-way analysis of variance showed that the significant improvement in vitamin B-6 status in response to vitamin B-6 supplementation (on the basis of both pyridoxal-P: and the erythrocyte aspartate aminotransferase activation coefficient) was reflected in a significant 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 hyperhomocysteinemia should include vitamin B-6 supplementation.
Northern Ireland Centre for Diet and Health, University of Ulster, Coleraine, United Kingdom.
M C
MC
McKinley
H
H
McNulty
J
J
McPartlin
J J
JJ
Strain
K
K
Pentieva
M
M
Ward
D G
DG
Weir
J M
JM
Scott
D000368:Aged; D000369:Aged, 80 and over; D015930:Diet Records; D019587:Dietary Supplements; D004311:Double-Blind Method; D005215:Fasting; D005260:Female; D005492:Folic Acid / Q000097:blood*; D005494:Folic Acid Deficiency / Q000097:blood / Q000150:complications; D006710:Homocysteine / Q000097:blood* / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D011736:Pyridoxine / Q000008:administration & dosage / Q000494:pharmacology*; D012256:Riboflavin / Q000097:blood*; D012257:Riboflavin Deficiency / Q000097:blood / Q000150:complications
D006710:Homocysteine; D005492:Folic Acid; D011736:Pyridoxine; D012256:Riboflavin