High dietary inflammatory index (DII) scores increase odds of overweight in adults with rs9939609 polymorphism of FTO gene.
BACKGROUND: Obesity/overweight is a public health problem globally. Dietary induced inflammation is among the most critical risk factors modulating overweight/obesity. Some people genetically are at higher risk for obesity/overweight. The first gene contributing to conventional forms of human obesity is the FTO gene. The associations between genes like the FTO, inflammation, and obesity/overweight have been investigated in limited studies. We aimed to investigate the association between the dietary inflammatory index (DII) and odds of obesity/overweight in adults with rs9939609 polymorphism of the FTO gene. METHODS: A valid 168-item semi-quantitative food frequency questionnaire was used to assess dietary intake. To investigate the role of diet in the development of inflammation, we used the DII, which is predictive of serum inflammatory markers' levels. The Inclusion criteria were defined as body mass index (BMI) from 24.9 to 29.9 kg/m(2), age from 20 to 45 years, not participating in a weight management program during two past months, and no weight loss greater than 5%. We determined the genotypes of FTO rs9939609 polymorphism via amplification refractory mutation system polymerase chain reaction (ARMS-PCR) in a retrospective chart review. RESULTS: Results obtained from modeling the DII as a continuous variable and odds of obesity/overweight showed a significant association after multivariate adjustment for sex, height, fat mass, systolic blood pressure (SBP), and total energy intake (OR = 2.83 CI = 1.16-6.91). In addition, logistic regression models with the DII as a dichotomous variable adjusting for sex, height, fat mass, SBP, and total energy intake showed subjects with the DII score<0.49 were at 2.5 times higher odds of having overweight compared to subjects with the DII >/=0.49 (ORDII<0.49/>/=0.49 = 2.44 CI = 1.12-5.32). CONCLUSION: Dietary induced inflammation significantly is related to odds of overweight in adults with rs9939609 polymorphism of the FTO gene. Suggesting an anti-inflammatory diet containing vitamins and minerals such as vitamin A, thiamine, niacin, and zinc, manganese, and selenium and recommending a reduction in the most inflammatory factors of diet, including saturated and trans fatty acids, could be a new strategy in the treatment and or controlling of obesity/overweight as a public health problem.