title: Vitamin B-12 status is inversely associated with plasma homocysteine in young women with C677T and/or A1298C methylenetetrahydrofolate reductase polymorphisms.
abstract: Methylenetetrahydrofolate reductase (MTHFR) polymorphisms may negatively influence one-carbon metabolism and increase health risks in women of reproductive age. The effect of MTHFR single nucleotide polymorphisms at bp 677 and/or 1298 and differences in folate and vitamin B-12 status on plasma homocysteine concentration in women of reproductive age (20-30 y; n = 186) were investigated. From the multivariate regression model, homozygotes (n = 23) for the C677T MTHFR variant had plasma homocysteine concentrations that were higher (P < 0.05) than those observed in the other 5 genotype groups, including those who were heterozygous for both variants (677CT/1298AC; n = 32). Plasma homocysteine was negatively associated with plasma vitamin B-12 concentration (P = 0.015) and serum folate (P = 0.049), with the degree of correlation between plasma vitamin B-12 and homocysteine concentrations dependent on MTHFR genotype. The C677T and A1298C MTHFR polymorphisms were significant predictors (P < 0.05) of plasma homocysteine when regression analysis was used to model plasma homocysteine concentration as a function of genotype, supplement use, serum folate and plasma vitamin B-12 concentration. Plasma homocysteine decreased as vitamin B-12 concentration increased (P = 0.0005) in individuals who were heterozygous for both the C677T and A1298C variants with nonsignificant trends (P = 0.114-0.128) in individuals homozygous for either the C677T or A1298C variants. In contrast, within the group of individuals with the wild-type genotype for both the C677T and A1298C MTHFR variants, homocysteine was not associated with changes in plasma vitamin B-12 concentrations. These data suggest that enhancing vitamin B-12 status may significantly decrease homocysteine in young women with C677T and/or A1298C MTHFR polymorphisms, even when vitamin B-12 concentrations are within the normal range.
authors.affiliation: Food Science and Human Nutrition Department, and. Department of Statistics, University of Florida, Gainesville 32611, USA. LBBailey@mail.IFAS.UFL.EDU
authors.forename: Lynn B
authors.initials: LB
authors.lastname: Bailey
authors.forename: Robert L
authors.initials: RL
authors.lastname: Duhaney
authors.forename: David R
authors.initials: DR
authors.lastname: Maneval
authors.forename: Gail P A
authors.initials: GP
authors.lastname: Kauwell
authors.forename: Eoin P
authors.initials: EP
authors.lastname: Quinlivan
authors.forename: Steven R
authors.initials: SR
authors.lastname: Davis
authors.forename: Aisha
authors.initials: A
authors.lastname: Cuadras
authors.forename: Alan D
authors.initials: AD
authors.lastname: Hutson
authors.forename: Jesse F
authors.initials: JF
authors.lastname: Gregory
mesh_terms: D000328:Adult; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000097:blood; D005544:Forecasting; D005838:Genotype; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D009994:Osmolar Concentration; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000502:physiology*; D012044:Regression Analysis; D014805:Vitamin B 12 / Q000097:blood*
chemical_list: D006710:Homocysteine; D005492:Folic Acid; D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D014805:Vitamin B 12