Nutritional Genetics: The Case of Alcohol and the MTHFR C677T Polymorphism in Relation to Homocysteine in a Black South African Population

Background/Aims: It is unknown whether the effect of alcohol consumption on homocysteine (Hcy) is modulated by the methylenetetrahydrofolate reductase (MTHFR) C677T. We explored this hypothesized effect by analyzing cross-sectional data of 1,827 black South Africans. Methods: Total Hcy concentrations were determined by fluorescence polarization immunoassay and the genotype through polymerase chain reaction-based RFLP analysis. Results: Subjects harboring the 677 TT genotype had the highest Hcy. Among subjects harboring the 677 CC genotype, men had higher Hcy (p = 0.04). Age and gamma-glutamyltransferase (GGT) correlated best (r = 0.26 and r = 0.27; p < 0.05), while the percentage carbohydrate-deficient transferrin and the B vitamins correlated weakly (r < 0.1; p < 0.05) with Hcy. Hcy was positively associated with the reported alcohol intake (p <= 0.01). There was no interaction between alcohol consumption and the MTHFR 677 CC or CT genotypes (p > 0.05) for Hcy concentrations; however, an interaction was determined for GGT and the MTHFR genotype (p = 0.02). Age, GGT, gender, MTHFR and vitamin B-6 explained 16.8% of the variation in Hcy (p < 0.01). Conclusion: The determined interactions might result in differences in the risk conveyed through Hcy with regard to disease development in those with unfavorable GGT concentrations. Copyright (C) 2013 S. Karger AG, Basel