Plasma vitamin B-6 forms and their relation to transsulfuration metabolites in a large, population-based study
2007 (English)In: American Journal of Clinical Nutrition, ISSN 0002-9165, E-ISSN 1938-3207, Vol. 86, no 1, 131-138 p.Article in journal (Refereed) PublishedText
Background: Vitamin B-6 exists in different forms; one of those forms, pyridoxal 5'-phosphate (PLP), serves a cofactor in many enzyme reactions, including the transsulfuration pathway, in which homocysteine is converted to cystathionine and then to cysteine. Data on the relations between indexes of vitamin B-6 status and transsulfuration metabolites in plasma are sparse and conflicting.
Objective: We investigated the distribution and associations of various vitamin B-6 species in plasma and their relation to plasma concentrations of transsulfuration metabolites.
Design: Nonfasting blood samples from 10 601 healthy subjects with a mean age of 56.4 y were analyzed for all known vitamin B-6 vitamers, folate, cobalamin, riboflavin, total homocysteine, cystathionine, total cysteine, methionine, and creatinine. All subjects were genotyped for the methylenetetrahydrofolate reductase (MTHFR) 677C -> T polymorphism.
Results: Plasma concentrations of the main vitamin B-6 vitamers-PLP, pyridoxal, and 4-pyridoxic acid-were strongly correlated. Among the vitamin B-6 vitamers, PLP showed the strongest and most consistent inverse relation to total homocysteine and cystathionine, but the dose response was different for the 2 metabolites. The PLP-total homocysteine relation was significant only in the lowest quartile of the vitamin B-6 distribution and was strongest in subjects with the MTHFR 677TT genotype, whereas cystathionine showed a graded response throughout the range of vitamin B-6 vitamer concentrations, and the effect was not modified by the MTHFR 677C -> T genotype.
Conclusion: This large population-based study provided precise estimates of the relation between plasma concentrations of vitamin B-6 forms and transsulfuration metabolites as modified by the MTHFR 677C -> T genotype.
Place, publisher, year, edition, pages
Bethesda: American society for nutrition , 2007. Vol. 86, no 1, 131-138 p.
vitamin B-6, homocysteine, cystathionine, cysteine, methylenetetrahydrofolate reductase, trans sulfuration
Nutrition and Dietetics
IdentifiersURN: urn:nbn:se:umu:diva-118200ISI: 000247981900019PubMedID: 17616772OAI: oai:DiVA.org:umu-118200DiVA: diva2:920388