Protein and total sugars intake modulate the rs9939609 single nucleotide polymorphism effect at the fat mass and...

The A allele of the rs9939609 single nucleotide polymorphism (SNP) at the fat mass and obesity-associated gene (FTO) has been linked to a higher body mass index (BMI). Still, some environmental factors could modulate this effect. This study aimed to find gene-nutrient interactions on BMI, visceral fat (VF), skeletal muscle (SM), and body fat (BF).

The data were obtained from a cross-sectional investigation performed on Argentinian adults of both sexes. Body composition measurements were collected by bioelectrical impedance analysis, dietary variables by a food frequency questionnaire, and genetic data by real-time polymerase chain reaction (qPCR). Multiple linear regression was used to assess the per-allele effect on body composition, and covariance (ANCOVA) analysis was used to find gene-diet interactions.

The minor A variant increased BMI (1.4 kg/m² [0.50-2.2], p = 0.002), BF (2.5 % [0.8-4.2], p = 0.004), and VF (0.7 arbitrary units [0.09-1.4], p = 0.026) and decreased SM (1.5 % [-2.5, 0.6], p = 0.009). Gene∗nutrient interaction terms were statistically significant for protein intake on BMI (η_p² = 0.051, p = 0.027) and VF (η_p² = 0.069, p = 0.005), for total sugars intake on BMI (η_p^{2 =}0.051, p = 0.026), BF (η_p^{2 =}0.062, p = 0.01) and VF (η_p^{2 =}0.053, p = 0.018), and saturated fatty acids (SFA) intake on SM (η_p²⁼0.056, p = 0.018). Consistently, interactions were found for "milk and yogurt" (η_p² = 0.052, p = 0.041) and "meat and eggs" (η_p² = 0.039, p = 0.049) on BMI and for "meat and eggs" (η_p² = 0.069, p = 0.006) and "fruits" (η_p² = 0.054, p = 0.013) on VF.

The A allele contributes to body composition variability, and diet modulates its effect.