Dietary intake and major food sources of polyphenols in people with type 2 diabetes: The TOSCA.IT Study.

PURPOSE: Proper evaluation of polyphenols intake at the population level is a necessary step in order to establish possible associations with health outcomes. Available data are limited, and so far no study has been performed in people with diabetes. The aim of this work was to document the intake of polyphenols and their major food sources in a cohort of people with type 2 diabetes and in socio-demographic subgroups. METHODS: We studied 2573 men and women aged 50-75 years. Among others, anthropometry was measured by standard protocol and dietary habits were investigated by food frequency questionnaire (EPIC). The intake of polyphenols was evaluated using US Department of Agriculture and Phenol-Explorer databases. RESULTS: The mean total polyphenol intake was 683.3 ± 5.8 mg/day. Non-alcoholic beverages represented the main food source of dietary polyphenols and provided 35.5% of total polyphenol intake, followed by fruits (23.0%), alcoholic beverages (14.0%), vegetables (12.4%), cereal products and tubers (4.6%), legumes (3.7%) and oils (2.1%); chocolate, cakes and nuts are negligible sources of polyphenols in this cohort. The two most important polyphenol classes contributing to the total intake were flavonoids (47.5%) and phenolic acids (47.4%). Polyphenol intake increased with age and education level and decreased with BMI; furthermore, in the northern regions of Italy, the polyphenol intake was slightly, but significantly higher than in the central or southern regions. CONCLUSIONS: The study documents for the first time the intake of polyphenols and their main food sources in people with diabetes using validated and complete databases of the polyphenol content of food. Compared with published data, collected in people without diabetes, these results suggest a lower intake and a different pattern of intake in people with diabetes.

Influence of dietary fat and carbohydrates proportions on plasma lipids, glucose control and low-grade inflammation in patients with type 2 diabetes-The TOSCA.IT Study.

PURPOSE: The optimal macronutrient composition of the diet for the management of type 2 diabetes is debated, particularly with regard to the ideal proportion of fat and carbohydrates. The aim of the study was to explore the association of different proportions of fat and carbohydrates of the diet-within the ranges recommended by different guidelines-with metabolic risk factors. METHODS: We studied 1785 people with type 2 diabetes, aged 50-75, enrolled in the TOSCA.IT Study. Dietary habits were assessed using a validated food-frequency questionnaire (EPIC). Anthropometry, fasting lipids, HbA1c and C-reactive protein (CRP) were measured. RESULTS: Increasing fat intake from <25 to ≥35 % is associated with a significant increase in LDL-cholesterol, triglycerides, HbA1c and CRP (p < 0.05). Increasing carbohydrates intake from <45 to ≥60 % is associated with significantly lower triglycerides, HbA1c and CRP (p < 0.05). A fiber intake ≥15 g/1000 kcal is associated with a better plasma lipids profile and lower HbA1c and CRP than lower fiber consumption. A consumption of added sugars of ≥10 % of the energy intake is associated with a more adverse plasma lipids profile and higher CRP than lower intake. CONCLUSIONS: In people with type 2 diabetes, variations in the proportion of fat and carbohydrates of the diet, within the relatively narrow ranges recommended by different nutritional guidelines, significantly impact on the metabolic profile and markers of low-grade inflammation. The data support the potential for reducing the intake of fat and added sugars, preferring complex, slowly absorbable, carbohydrates.

Dietary fat differentially modulate the mRNA expression levels of oxidative mitochondrial genes in skeletal muscle of healthy subjects.

BACKGROUND AND AIMS: Different types of dietary fats exert differential effects on glucose and lipid metabolism. Our aim was to evaluate the impact of different dietary fats on the expression of skeletal muscle genes regulating mitochondrial replication and function in healthy subjects. METHODS AND RESULTS: Ten healthy subjects (age 29 ± 3 years; BMI 25.0 ± 3 kg/m(2)) received in a random order a test meal with the same energy content but different composition in macronutrients and quality of fat: Mediterranean (MED) meal, SAFA meal (Lipid 66%, saturated 36%) and MUFA meal (Lipid 63%, monounsaturated 37%). At fast and after 180 min, a fine needle aspiration was performed from the vastus lateralis for determination of mitochondrial gene expression by quantitative PCR. No difference in glucose and triglyceride response was observed between the three meals, while NEFA levels were significantly higher following fat-rich meals compared to MED meal (p < 0.002-0.0001). MED meal was associated with an increased expression, albeit not statistically significant, of some genes regulating both replication and function. Following MUFA meal, a significant increase in the expression of PGC1ß (p = 0.02) and a reduction in the transcription factor PPARδ (p = 0.006) occurred with no change in the expression of COX and GLUT4 genes. In contrast, SAFA meal was associated with a marked reduction in the expression of COX (p < 0.001) PFK (p < 0.003), LPL (p = 0.002) and GLUT4 (p = 0.009) genes. CONCLUSION: Dietary fats differentially modulate gene transcriptional profile since saturated, but not monounsaturated fat, downregulate the expression of genes regulating muscle glucose transport and oxidation.

Coronary vasoreactivity is not altered in young people with type 1 diabetes.

BACKGROUND AND AIM: Abnormal coronary microvascular circulation has been demonstrated in diabetes and is associated with increased rate of cardiovascular events. Our objective was to evaluate coronary vasoreactivity in young people with type 1 diabetes with and without microvascular complications. METHODS AND RESULTS: Twenty-five type 1 diabetic patients without microvascular complications (DC-), 23 with microvascular complications (DC+), and 18 control subjects (C) were studied. Coronary vasoreactivity was assessed by means of coronary flow reserve (CFR). Blood flow velocity in the left anterior descending coronary artery was measured at rest and after high-dose dipyridamole using transthoracic color-guided pulsed Doppler echocardiography. CFR was defined as the ratio of hyperaemic to resting diastolic peak flow velocities. The three groups had similar cardiac function parameters, and also systolic and diastolic blood pressure at rest, which remained unchanged during dipyridamole infusion. Resting coronary flow velocity was comparable in C, DC-, and DC+ (p=ns). Dipyridamole infusion produced a threefold increase in coronary diastolic peak velocity, which reached similar values in C (0.69±0.16 m/s), DC- (0.69±0.18 m/s), and DC+ (0.66±0.11 m/s). Mean CFR ratio was similar in C (3.33±0.66), DC- (3.30±0.51), and DC+ (3.24±0.60). At multiple linear regression analysis, no association was found between CFR and age, sex, HbA(1c), duration of diabetes, and complications. CONCLUSION: Coronary vasodilatory function is preserved in young D patients, even those with early microvascular complications, suggesting that coronary vasoreactivity deteriorates at more advanced stages of microvascular complications and/or in the presence of other cardiovascular risk factors.