Association of Dietary Polyphenol Intakes with Metabolic Syndrome and its Components: Tehran Lipid and Glucose Study.

BACKGROUND: This study was conducted to assess the prospective association between dietary polyphenols intakes and risk of metabolic syndrome (MetS) and its components. METHODS: Participants in this study (n=4559) were selected from among the adults of the Tehran Lipid and Glucose Study (TLGS) with an average follow-up of 5.9+2.5 years. Biochemical and anthropometric variables were measured at baseline and follow-up examinations. A reliable and valid semi-quantitative food frequency questionnaire was used to evaluate dietary intakes. The incidence of MetS and its components in relation to polyphenols and its subclasses (phenolic acids, flavonoids, lignans, and stilbenes) was evaluated using multivariable Cox proportional hazard regression models. RESULTS: Of the 4559 subjects who enrolled in the present study, 1765 were male aged 38.6+14.2 y and 2794 were female aged 35.9+11.7 y. The hazard ratios of MetS were 25% lower in Q2 (HR, 95% CI: 0.75, 0.64‒0.88), 22% lower in Q3 (HR, 95% CI: 0.78, 0.65‒0.94) and 24% lower in Q4 (HR, 95% CI: 0.76, 0.61‒0.95) in comparison to Q1, whereas the results for subclasses of polyphenol were non-significant. The risk of high blood pressure (BP) reduced from quartiles 1 to 4 for phenolic acid (HR: 1.00, 0.88, 0.79, 0.80, Ptrend=0.03). The risk of low high-density lipoprotein cholesterol (HDL-C) increased across quartiles of phenolic acid (HR: 1.00, 1.22, 1.07, 1.30, Ptrend=0.02). CONCLUSION: This study highlights the potential protective role of total dietary polyphenols in the prevention of MetS. These findings could be the starting point of upcoming trials to illuminate the optimal level of polyphenols deriving from the intake of polyphenol-rich diets to prevent MetS.

Weight gain, but not macronutrient intake, modifies the effect of dietary branch chain amino acids on the risk of metabolic syndrome.

AIMS: The aim of this study was to investigate whether both weight change and the background intakes of macronutrient modulate the association between dietary branch chain amino acids (BCAAs) and the risk of metabolic syndrome (MetS). METHODS: This prospective study was conducted within the framework of theTehranLipidand Glucose Study. BCAA intakes were collected using a valid and reliable semi-quantitative food frequency questionnaire. MetS components were defined according to the modified national Cholesterol Education Program Adult Treatment Panel III. Weight change was categorized as weight gain (≥ or <7% over 8.9 year follow-up). Dietary fat and carbohydrate intake were categorized as above/below the median intake. RESULTS: Among participants with weight gain ≥ 7% during follow-up, intakes of both dietary BCAAs and its various sources (below or above the median intake) were associated with higher risk of MetS, compared with subjects with lower intakes of BCAAs and weight change ≤ 7%. Background dietary fat and carbohydrate did not modify the association of dietary BCAAs and its various sources with the risk of MetS. CONCLUSIONS: Weight change, but not dietary macronutrient intake, modulates the association between dietary BCAAs and risk of MetS among adults.

Red meat and dietary iron intakes are associated with some components of metabolic syndrome: Tehran Lipid and Glucose Study.

BACKGROUND: This study was conducted to investigate whether the daily consumption of haem, non-haem, total iron and red meat can affect the occurrence of metabolic syndrome (MetS) and its components. METHODS: Eligible adults (n = 4654) were selected from among participants of the Tehran Lipid and Glucose Study with an average follow-up of 3.8 years. Dietary intakes were assessed using a valid and reliable semi-quantitative food frequency questionnaire. Anthropometrics and biochemical variables were evaluated at baseline and follow-up examinations. The occurrence of MetS and its components were assessed in relation to haem, non-haem, total iron and red meat intakes. RESULTS: There was no relationship between different types of dietary iron and red meat intakes and the incidence of MetS in the Tehranian population. Risk of hypertension decreased from quartiles 1 to 4 for haem iron (HR: 1.00, 0.92, 0.81, 0.80, Ptrend < 0.01) and red meat intake (HR: 1.00, 0.89, 0.84, 0.77, Ptrend < 0.01). The association between hyperglycemia and the fourth quartile of total iron intake was significant (HR = 1.98, 95% CI 1.08-3.63); and the risk of high triglyceride appeared to increase in higher quartiles of total iron intake (HR: 1.00, 1.17, 1.49, 1.75, Ptrend = 0.01) compared to lower quartiles. CONCLUSION: Our study suggests a potentially protective relationship of haem and moderate red meat intake against development of high blood pressure; and higher intake of total iron is related to hyperglycemia and high triglyceride.

The interaction of cholesteryl ester transfer protein gene variations and diet on changes in serum lipid profiles.

BACKGROUND/OBJECTIVES: Gene-diet interactions may have an important role in the disparities between the lipid responses of individuals to diet. This study aimed to investigate whether polymorphisms (rs5882 and rs3764261) in the cholesteryl ester transfer protein (CETP) gene modify the association of diet with changes in serum lipid profiles. SUBJECTS/METHODS: A total of 4700 individuals aged ≥18 years were selected from among participants of the Tehran Lipid and Glucose Study. After 3.6 years of follow-up, changes in serum lipid profiles were evaluated. Usual dietary intake was assessed using a validated food frequency questionnaire. DNA samples were genotyped with HumanOmniExpress-24-v1-0 bead chips (containing 649,932 SNP loci). RESULTS: No significant interaction was found between CETP polymorphisms and dietary patterns in changing lipid profiles. Mean changes of total cholesterol (TC) decreased in higher quartiles of fish intake in A allele carriers (Q1:8.02, Q4:5.58, Ptrend = 0.01) compared to the CC genotype (Q1:3.65, Q4:8.93, Ptrend = 0.11) (Pi = 0.02). There are ascending trends of changes in triglyceride (TG) concentrations across quartiles of total fat, monounsaturated and saturated fat consumption in G allele carriers of rs5882 compared to the AA genotype. There was a declining trend for mean changes in TG concentrations across quartiles of carbohydrate intake in G allele carriers of rs5882 compared to the AA genotype (Pi = 0.01). CONCLUSIONS: Our data demonstrated that minor allele carriers of rs5882 had a better TG value than AA homozygote individuals when consuming a low fat and high carbohydrate diet. Fish intake modifies the association of rs3764261with TC concentrations.

Cholesteryl ester transfer protein gene variations and macronutrient intakes interaction in relation to metabolic syndrome: Tehran lipid and glucose study.

OBJECTIVES: There are controversial results regarding the effect of the interaction of CETP polymorphisms with dietary fats on the lipid profiles. The aim of this study was to examine the effect of CETP polymorphisms (rs5882 and rs3764261) and macronutrient intakes interaction in relation to metabolic syndrome (MetS) or its components. MATERIALS AND METHODS: In this nested case-control study, subjects were selected from among participants of the Tehran Lipid and Glucose Study. Cases (n=441) were individually matched with two controls (844 non-MetS subjects). DNA samples were genotyped with HumanOmniExpress-24-v1-0 bead chips, including 649,932 SNP loci. RESULTS: The mean ages at baseline were 38.1±10 and 37.0±10 years in women and 36.2±11 and 36.3±11 years in men, respectively in cases and controls. We did not find significant gene-diet interactions between rs5882 and dietary macronutrient intakes in relation to MetS risk. The risk of low HDL-C was lower in the first quartile of MUFA and total fat intake in G allele carriers, compared to AA genotype group. The risk of high BP appeared to increase significantly in higher quartiles of trans-fatty acid intakes (>1.81% of total energy intake) in G allele carriers compared with the AA genotype group. No significant interactions were found between rs3764261 and macronutrient intakes in association with MetS or its components. CONCLUSION: Our findings demonstrate that dietary fats modify the association of rs5882 and risk of low HDL-C and high blood pressure.

Genetic variations of cholesteryl ester transfer protein and diet interactions in relation to lipid profiles and coronary heart disease: a systematic review.

Data on diet-genotype interactions in the prevention or treatment of dyslipidemia have increased remarkably. This systematic review aimed to assess nutrigenetic studies regarding the modulating effect of diet on cholesteryl ester transfer protein (CETP) polymorphisms in relation to metabolic traits. Data were collected through studies published between 2000 and SEP. 2016 using five electronic databases. The quality of eligible studies was assessed using a 12-item quality checklist, derived from the STrengthening the REporting of Genetic Association Studies (STREGA) statement. CETP variants that had associations with lipid profiles in previous studies were extracted for drawing of the linkage disequilibrium (LD) plot. Among CETP variants, the rs9989419 best represented this genome wide association signal across all populations, based on LD r2 estimates from 1000 genomes references. In the 23 found eligible studies (clinical trials and observational), the TaqIB and I405V polymorphisms were the two most intensively studied. Two studies reported the effect of interaction between rs3764261 and diet on lipid levels. Regarding the rs708272 (Taq1B), individuals with the B1 risk allele showed better responses to dietary interventions than those with B2B2 genotype, whereas with I405V, inconsistent results have been reported. Modest alcohol consumption was associated with decreased risk of coronary heart disease among B2 carriers of rs708272. It is concluded that variations in the CETP gene may modulate the effects of dietary components on metabolic traits. These results have been controversial, indicating complex polygenic factors in metabolic response to diet and lack of uniformity in the study conditions and designs.