FTO genotypes (rs9939609 T>A) are Associated with Increased Added Sugar Intake in Healthy Young Adults

Single-nucleotide polymorphism (SNP) rs9939609 in the FTO gene has been associated with dietary intake and appetite traits, mainly in participants with obesity; however, it remains widely unexplored in normal weight participants. Thus, the aims of this study were (1) to compare the changes in subjective appetite sensations, ghrelin, and insulin concentrations according to the SNP rs9939609 T>A in FTO and (2) to compare dietary intake between rs9939609 genotype groups in normal weight young participants.

We conducted a quasi-experimental study involving 88 normal weight participants to analyze subjective perception of appetite, hormonal response for hunger and satiety, and dietary intake according to the rs9939609 SNP. Participants received a standardized single breakfast. Visual analogue scales (VAS) were utilized for assessing the subjective perception of appetite at fasting and immediately after breakfast and at 30, 60, 90, and 120 min postprandially. Glucose, lipid profile, ghrelin, and insulin were measured at fasting and at 120 min after breakfast. Dietary intake was assessed with a 3-day food record. The SNP was determined by allelic discrimination with TaqMan probes. To compare dietetic, biochemical, and the subjective appetite sensations, Student t test, ANCOVA test, and the repeated measures ANOVA were used. The linear regression model and the linear mixed model were used for the association analysis. Pearson correlation was used to test the correlation between two quantitative variables.

A total of 88 people participated, 81.8% were female, with a mean body mass index of 21.8 ± 2.0 kg/m2 and a mean age of 20.6 ± 2.0. Genotype frequencies of the rs9939609 SNP were 52% for the TT allele and 48% for the TA/AA. The subjective perception of appetite named hunger, fullness, satiety, desire to eat, and prospective food consumption were similar between genotypes of the rs9939609. Participants with the TA/AA genotype showed a higher intake of added sugar (p = 0.039) than TT participants. No differences were found in ghrelin, insulin, glucose, or lipid parameters between genotypes.

Carriers of the A allele from FTO gene SNP rs9939609 may have an increased preference for foods, specifically for added sugars.