Does a single vitamin B-supplementation induce functional vitamin B-deficiency?

In a pilot study we measured the effect of three different combinations of the vitamins B-6, folate and B-12 on the serum concentrations of homocystei ne, cystathionine and methylmalonic acid in five healthy young men without hyperhomocysteinemia. The results indicate that there are still undescribed interactions between vitamin B-6 and follate, suggesting that these two vi tamins should be given together to avoid depletion of the one not given. Wi th regard to the well known metabolic pathways of methionine and cysteine, this confirms the hypothesis that a combined supplementation with the vitam ins B-6 and folate (and B-12) is superior to folate alone in order to lower homocysteine.