Abstract
The level of plasma total homocysteine (tHcy), long known to be B vitamin dependent, has recently been shown to be inversely associated with plasma selenium (Se) concentration in human subjects. We therefore, chose to investigate the interaction between Se, tHcy and B vitamins in a double‐blind, placebo‐controlled trial where 501 healthy UK elderly volunteers were randomly allocated to receive 100, 200, or 300 μg Se/day as high‐Se‐yeast, or placebo‐yeast for 6 months. Plasma Se, tHcy, folate, vitamin B‐12, pyridoxal‐5′‐phosphate (PLP) and its catabolite, 4‐pyridoxic acid, were measured in all participants at baseline and in samples from the placebo, 100 and 300 μg Se/day groups, at follow‐up. At baseline, Se was inversely correlated with tHcy but only in males (p < 0.001). Before supplementation, tHcy concentration was significantly lower in the highest compared to the lowest Se tertile in males (p < 0.05), and in females when folate concentrations were also in the top tertile (p < 0.05). The effect of folate, PLP and vitamin B‐12 concentrations on plasma tHcy correlated with Se concentration at baseline. After 6 months of Se supplementation, only Se concentration had changed significantly. Supplementation with Se does not affect tHcy concentration in the UK elderly population.