• Interaction between nut consumption, TCF7L2 polymorphisms and weight gain in relation to metabolic syndrome incidence: Tehran Lipid and Glucose study
  • Somayeh Hosseinpour-Niazi,1 Parvin Mirmiran ,2,* Fereidoun Azizi ,3
    1. Nutrition and Endocrine Research center a, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences
    2. Department of Clinical Nutrition and Dietetics, Faculty of Nutrition Sciences and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences
    3. ndocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences


  • Introduction: This study aims to assess the association between nut consumption and its numerous kinds and metabolic syndrome risk and show if both weight change and TCF7L2 polymorphisms are involved in modulating the association between nut consumption and the risk of metabolic syndrome (MetS).
  • Methods: Using a prospective design, 1915 participants of the Tehran Lipid and Glucose study aged 19-74 years were followed up for dietary investigation through a validated, semi-quantitative food frequency questionnaire. TCF7L2 rs7903146 and rs12255372 were genotyped in 1008 participants. In accordance with the Joint Interim Statement, diagnosed MetS requires the presence of three or more of the following criteria: 1) elevated glucose concentrations (fasting plasma glucose concentration ≥100 mg/dL or treatment with anti-hyperglycemic medications), 2) elevated serum triglyceride (TG) concentration (≥150 mg/dL or treatment with anti-hypertriglyceridemia medications), 3) reduced serum high-density lipoprotein cholesterol (HDL-C) (<50 mg/dL in women and <40 mg/dL in men), 4) elevated blood pressure (≥130/85 mmHg or treatment with anti-hypertensive medications), and 5) enlarged abdominal circumference (≥95 cm according to the population- and country-specific cut-off points for Iranian adults of both genders). Multivariable adjusted Cox regression was applied for estimating hazard ratios (HRs) for MetS events. By multivariable cox regression models, using joint classification, we further estimated the HRs and their 95% CIs for MetS according to weight changes (≥ or < 7 % during 8.9 of follow-up) with nut consumption (above/below the median values). In all multivariable models, subjects with lower median intakes of nut consumption with weight change < 7% during 8.9 years of follow-up were considered a reference. For assessment of interaction between nut consumption and TCF7L2 polymorphisms (both additive and dominant models) on risk of Mets, Cox proportional hazards regression analyses were used. HR and their 95% confidence interval for the MetS controlled for age, gender, smoking, physical activity, education levels, occupational status, total energy intake, fiber intake, family history of diabetes, and family history of cardiovascular disease.
  • Results: Mean age and BMI of participants (n = 1915, 40.5% male) were 36.5 ± 13 years and 25.6 ± 4.5 kg/m2, respectively and 591 new cases of MetS were documented during 8.9 y follow-up. The median nut consumption was 2.0 g/week (IQR: 1-4 g/week). Nut consumption and its constituents including fiber, polyphenol and PUFA were inversely associated with MetS in multivariable-adjusted models. Among various types of nuts, the multivariable-adjusted HRs of MetS were 0.73 (0.60-0.90) for walnuts, and 0.80 (0.65-0.98) for pistachios, compared with low intake. Among participants with weight gain ≥ 7 % during follow-up, consumption of nuts and walnuts (≥ median intake) reduced risk of Mets by 25 % (0.75; 0.60-0.94) and 21 % (0.79; 0.64-0.98), respectively. Among participants with weight gain < 7%, consumption of both nuts and walnuts (≥ or < of median) reduced the risk of MetS, compared with subjects with lower intakes of nuts and weight change of ≥ 7 %. No significant interaction was found between consumption of nuts and its various types (per se), and TCF7L2- rs7903146 polymorphisms in relation to MetS incidence.
  • Conclusion: Incorporating nuts into dietary patterns prevents the risk of MetS, especially among obese individuals, regardless of their TCF7L2 polymorphisms.
  • Keywords: nuts, metabolic syndrome, TCF7L2 polymorphisms, gene-diet interaction, weight change