Mediterranean diet adherence modulates anthropometric measures by TCF7L2 genotypes among Puerto Rican adults

Authors: SOTOS-PRIETO, MERCEDES - Harvard University; SMITH, CAREN - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; Lai, Chao Qiang; TUCKER, KATHERINE - University Of Massachusetts; ORDOVAS, JOSE - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; MATTEI, JOSIEMER - Harvard University

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2019
Publication Date: 8/28/2019
Citation: Sotos-Prieto, M., Smith, C.E., Lai, C., Tucker, K.L., Ordovas, J.M., Mattei, J. 2019. Mediterranean diet adherence modulates anthropometric measures by TCF7L2 genotypes among Puerto Rican adults. Journal of Nutrition. 150(1):167-175. https://doi.org/10.1093/jn/nxz210.
DOI: https://doi.org/10.1093/jn/nxz210

Interpretive Summary: Complex conditions like obesity and type 2 diabetes result from a combination of factors that include both genetics and environment. A gene called Transcription factor 7 like 2 (TCF7L2) has been shown to be associated with type 2 diabetes in many populations, but its association with obesity is less consistent. In some cases, associations between genetic variants and health conditions like obesity can be ameliorated by particular dietary conditions, such as adherence to a Mediterranean Dietary pattern. We refer to this result as a gene-diet interaction. In the current study, we investigated the relationships between two well-established TCF7L2 variants and Mediterranean Diet adherence for body weight and waist circumference in 1,120 participants (45-75 years old) of the Boston Puerto Rican Health Study. We found a significant gene by diet interaction between the genetic variants and adherence to a Mediterranean-like diet. Thus, among people with a high MedDiet score (representing high adherence to this dietary pattern), those carrying the high risk genetic variants had similar body weight and waist size compared to people without the high risk genetic variants. Results from this study suggested that adherence to a MedDiet can offset a genetic predisposition towards obesity. The long-term objective of gene-diet interaction studies such as this one is to more effectively prevent obesity through the development of tailored dietary recommendations that are based on the genetic background of the individual.

Technical Abstract: Background: Transcription factor 7 like 2 (TCF7L2) genetic variants that predispose to type 2 diabetes (T2D) show inconsistent associations with anthropometric markers. Interaction between TCF7L2 genotypes and dietary factors may resolve these observations. Objective: We aimed to examine the potential modulation of TCF7L2-rs7903146 and rs12255372 on anthropometric markers by a Mediterranean diet (MedDiet). Methods: Cross-sectional analysis was done in 1,120 participants (45-75y) of the Boston Puerto Rican Health Study. Anthropometric parameters were measured, and polymorphisms were genotyped using standardized protocols. Diet was assessed using a validated food frequency questionnaire. The MedDiet was defined based on adherence to nine food and nutrient components using sex-specific population-based median cutoffs; high adherence was defined as meeting >/=4 components. Haplotypes were tested for association with obesity traits, independently and in interaction with MedDiet. Results: TCF7L2 rs7903146 showed significant interaction with MedDiet influencing BMI, weight, and waist circumference. The T risk-allele carriers (CT+TT) with high MedDiet score had lower weight (77.3 +/- 1.0 vs. 80.9 +/- 1.0 Kg; P=0.013) and waist circumference (99.2 +/- 0.9 vs. 102.2 +/- 0.9 cm; P=0.021), when compared to CC participants. At a low MedDiet score there were no significant differences between genotypes. For TCF7L2-rs12255372, we found significant interactions with MedDiet for weight (P-interaction = 0.034) and BMI (P-interaction = 0.036). The T allele carriers with a higher MedDiet score showed a trend of lower BMI, weight, and waist circumference, but no significant differences when compared to CC participants. We found significant interactions between two risk-carrying haplotypes and MedDiet compared to the common haplotype, with lower BMI (P-interaction = 0.024), weight (P-interaction = 0.019), and waist circumference (P-interaction = 0.042) at high MedDiet score. Conclusions: Puerto Ricans with the TCF7L2-rs7903146 and rs12255372 T2D risk genotypes had better anthropometric profiles when adhering to a MedDiet, suggesting that this diet may offset unfavorable predisposition.