This systematic review with meta-analysis of randomized controlled trials (RCT) aimed to analyze the effect of fiber intake on glycemic control in patients with type 2 diabetes. Databases were searched up to November 2012 using the following medical subject headings: diabetes, fiber, and randomized controlled trial. Absolute changes in glycated hemoglobin and fasting plasma glucose were reported as differences between baseline and end-of-study measures. Pooled estimates were obtained using random-effects models. Of the 22,046 articles initially identified, 11 (13 comparisons; range of duration, 8-24 weeks) fulfilled the inclusion criteria, providing data from 605 patients. High-fiber diets, including diets with foods rich in fiber (up to 42.5 g/day; four studies) or supplements containing soluble fiber (up to 15.0 g/day; nine studies), reduced absolute values of glycated hemoglobin by 0.55% (95% CI -0.96 to -0.13) and fasting plasma glucose by 9.97 mg/dL (95% CI -18.16 to -1.78). In conclusion, increased fiber intake improved glycemic control, indicating it should be considered as an adjunctive tool in the treatment of patients with type 2 diabetes.

Obesity-associated adipose tissue enlargement is characterized by an enhanced proinflammatory status and an elevated secretion of adipokines such as leptin and cytokines such as TNF-alpha. Among the different mechanisms that could underlie the interindividual differences in obesity, epigenetic regulation of gene expression has emerged as a potentially important determinant. Therefore, twenty-seven obese women (age: 32-50 years; baseline Body Mass Index, BMI: 34.4±4.2 Kg/m 2 ) were prescribed an eightweek Low-Calorie-Diet and epigenetic marks were assessed. Baseline and endpoint anthropometric parameters were measured and blood samples were drawn. Genomic DNA and RNA from adipose tissue biopsies were isolated before and after the dietary intervention. Leptin and TNF-alpha promoter methylation were measured by MSP after bisulfite treatment and gene expression was also analyzed.Obese women with a successful weight loss (≥5% of initial body weight, n=21) improved the lipid profile and fat mass percentage (-12%, p<0.05). Both systolic (-5%, p<0.05) and diastolic (-8%, p<0.01) blood pressures significantly decreased. At baseline women with better response to the dietary intervention showed lower promoter methylation levels of leptin (-47%, p<0.05) and TNF-alpha (-39%, p=0.071) than the non-responder group (n=6), while no differences were found between responder and non-responder group in leptin and TNF-alpha gene expression analysis. These data suggest that leptin and TNF-alpha methylation levels could be used as epigenetic biomarkers concerning the response to a Low-CalorieDiet. Indeed, methylation profile could help to predict the susceptibility to weight loss as well as some comorbidities such as hypertension or type 2 diabetes.

A diet rich in fibre seems to protect against the metabolic syndrome (MetS), but there is scarce information about the role of fibre intake in patients with the MetS and diabetes. The aim of the present study was to evaluate the effects of soluble fibre from partially hydrolysed guar gum (PHGG) on the MetS and cardiovascular risk factors in patients with type 2 diabetes. In the present randomised controlled clinical trial, forty-four patients with type 2 diabetes (males 38·6 %, age 62 (SD 9) years, diabetes duration 14·2 (SD 9·6) years) and the MetS underwent clinical, laboratory and dietary evaluations at baseline, 4 and 6 weeks. All patients followed their usual diet and the intervention group (n 23) received an additional 10 g/d of PHGG. In the intervention group, waist circumference (WC), glycated Hb (HbA1c), 24 h urinary albumin excretion (UAE) and serum trans-fatty acids (FA) were reduced in comparison with baseline after 4 and 6 weeks: WC 103·5 (SD 9·5) to 102·1 (SD 10) to 102·3 (SD 9·7) cm; HbA1c 6·88 (SD 0·99) to 6·64 (SD 0·94) to 6·57 (SD 0·84) %; 24 h UAE 6·8 (interquartile range 3·0-17·5) to 4·5 (interquartile range 3·0 -10·5) to 6·2 (interquartile range 3·0 -9·5) mg; trans-FA 71 (interquartile range 46-137) to 67 (interquartile range 48 -98) to 57 (interquartile range 30-110) mg/l (P,0·05 for all). The only change in the control group was weight reduction: 77·0 (SD 13·5) to 76·2 (SD 13·3) to 76·1 (SD 13·4) kg (P¼0·005). Other MetS components (blood pressure, TAG, HDL-cholesterol, fasting plasma glucose), total and LDL-cholesterol, C-reactive protein and endothelin-1 did not change in either group. In patients with type 2 diabetes and the MetS, the addition of PHGG to the usual diet improved cardiovascular and metabolic profiles by reducing WC, HbA1c, UAE and trans-FA.