The Interaction between Dietary Fiber and the Mediterranean Dietary Pattern Score with FTO Gene Polymorphisms in Relation to Obesity Phenotypes

Introduction: Although variants in the FTO gene have been found to be associated with susceptibility to obesity, however, recent studies suggest that dietary intakes may modify the association. This study aimed to investigate the interaction of the Mediterranean dietary pattern (MD) and fiber intake with FTO gene polymorphisms in relation to obesity phenotypes. Materials and Methods: Participants of this nested case-control study (n=1254) were selected among adult participants of the Tehran Lipid and Glucose Study. All (n=627, generally obese, BMI≥30 kg/m2) were individually matched with controls (n=627, normal weight). Six selected SNPs (rs1421085, rs1121980, rs17817449, rs8050136, rs9939973, and rs3751812) were genotyped. The MD score was computed and Genetic Risk Scores (GRS) were calculated using the weighted method. Results: Adherence to the MD could modify the association of three SNPs (rs17817449, rs8050136, and rs3751812) with general and abdominal obesity (Waist circumference≥95 cm) (P interact­ion=Pi<0.05). The odds of abdominal obesity in risk allele carriers of rs3751812 (TG+TT) decreased along with increasing dietary fiber intake (Pi=0.01), compared to subjects with no risk alleles. The risk of general obesity in participants with a high GRS decreased during the MD score quartiles, compared to those with a low GRS (Pi<0.05). The risk of developing general obesity in people with GRS≥6 was reduced by increasing fiber intakes (P trend<0.05). Conclusion: A higher adherence to the MD pattern and fiber intakes can decrease obesity risk in risk allele carriers of three FTO polymorphisms, rs17817449, rs8050136 and rs3751812.