Vigorous Physical Activity Mitigates Susceptibility to Obesity Associated with Risk Genotypes of FTO and MC4R, and SREBF1 Is Hypermethylated: A Cross-Sectional Pilot Study

Aim: The aim of this study was to correlate single-nucleotide polymorphisms (SNPs) in the FTO and MC4R genes with body composition (BC) in populations with various levels of physical activity, and to investigate associations of SREBF1 methylation with the level of physical activity (PA) and BC. Methods: Fifty-six participants aged 18–65 years old with no underlying medical conditions were included in the study and were classified into sedentary/light PA (SLPA), moderate PA (MPA) and vigorous PA (VPA) groups using the International PA questionnaire (IPAQ). Anthropometric measures such as age, gender, body mass index (BMI) and body fat percentage (BFP) were recorded at the time of recruitment. Venous blood samples were collected during participant recruitment and DNA was extracted. Genotyping assays were performed for SNPs in FTO (rs9939609) and MC4R (rs17782313) using Taqman® RT qPCR and TaqMan Genotyper software 1.7.1. Methylation analysis assay for CpG sites in the SREBF1 gene was performed on 56 samples using PyroMark® Q48 Autoprep (Qiagen, Venlo, The Netherlands). The results were statistically analysed to identify any associations between FTO/MC4R genotypes and the level of PA, and between SREBF1 methylation status and the level of PA. This is the first study to investigate links between PA and quantitative methylation of SREBF1. Results: According to IPAQ guidance, the 56 participants were classified into SLPA n = 14, MPA n = 11 and VPA n = 31. The correlation analysis revealed that the FTO rs9939609 ‘A’ risk allele had a significant negative association with BFP in the VPA group (p = 0.0387); the MC4R rs17782313 ‘C’ risk allele had a significant positive association with BMI in the VPA group (p = 0.0256). In the SREBF1 pyrosequencing analysis, higher levels of methylation were observed in the VPA group (p = 0.07). Conclusions: We concluded that SNPs associated with obesity identified in FTO rs9939609 and MC4R rs17782313 could help to predict the molecular effects of PA. A high frequency of FTO risk variants in the cohort was observed and the VPA group could help maintain a healthy BFP.