title: Nutritional genetics: the case of alcohol and the MTHFR C677T polymorphism in relation to homocysteine in a black South African population.
abstract: OBJECTIVE
  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 B6 explained 16.8% of the variation in Hcy (p < 0.01).
  
  
  CONCLUSIONS
  The determined interactions might result in differences in the risk conveyed through Hcy with regard to disease development in those with unfavorable GGT concentrations.
authors.affiliation: Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa. cornelie.nienaber@nwu.ac.za
authors.forename: Cornelie
authors.initials: C
authors.lastname: Nienaber-Rousseau
authors.forename: Pedro T
authors.initials: PT
authors.lastname: Pisa
authors.forename: Christine S
authors.initials: CS
authors.lastname: Venter
authors.forename: Suria M
authors.initials: SM
authors.lastname: Ellis
authors.forename: Annamarie
authors.initials: A
authors.lastname: Kruger
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Moss
authors.forename: Alida
authors.initials: A
authors.lastname: Melse-Boonstra
authors.forename: G Wayne
authors.initials: GW
authors.lastname: Towers
mesh_terms: D000328:Adult; D000428:Alcohol Drinking; D044383:Black People; D003430:Cross-Sectional Studies; D005260:Female; D005838:Genotype; D006710:Homocysteine / Q000097:blood; D006801:Humans; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D008875:Middle Aged; D054647:Nutrigenomics; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D013019:South Africa
chemical_list: D006710:Homocysteine; D042965:Methylenetetrahydrofolate Reductase (NADPH2)