Mediterranean diet-gene interactions: A targeted metabolomics study in Greek-Cypriot women.

SCOPE: A high adherence to the Mediterranean diet (MD) was previously associated with a decreased risk of breast cancer (BC) among Greek-Cypriot women. Additionally, particular polymorphisms were shown to modulate this MD-BC association. Herein, we aimed to investigate the effect of polymorphisms-MD interactions on the levels of specific metabolites that could be related to dietary adherence or enzymatic activity, which is itself modulated by polymorphisms. METHODS AND RESULTS: Greek-Cypriot women who were BC controls and had the lowest or the highest MD adherence (vegetables, fruit, legumes, fish) as assessed by principal component analysis (n = 564) were included. Participants were previously genotyped for nine polymorphisms of the one-carbon metabolism, oxidative stress, and xenobiotic metabolism. The serum levels of 14 metabolites that are key players in the aforementioned pathways were measured by UPLC-MS/MS. ANCOVA was used to assess polymorphism-MD interactions on metabolites' levels within a multivariate linear regression model. Statistically significant interactions between GSTM1 (where GST is glutathione S-transferase) deletion polymorphism and MD on flavin mononucleotide and on 5-methyltetrahydrofolate (5-MTHF) concentrations were observed. The MTHFR rs1801133 interacted significantly with MD on 5-MTHF concentration. CONCLUSION: Serum levels of flavin mononucleotide and 5-MTHF were shown to be influenced by interactions between GSTM1 deletion or MTHFR (rs1801133) polymorphisms and a dietary pattern, characteristic of MD.