1.
Effects of whole-grain cereal foods on plasma short chain fatty acid concentrations in individuals with the metabolic syndrome.
Vetrani, C, Costabile, G, Luongo, D, Naviglio, D, Rivellese, AA, Riccardi, G, Giacco, R
Nutrition (Burbank, Los Angeles County, Calif.). 2016;(2):217-21
Abstract
OBJECTIVE Short chain fatty acids (SCFAs) derived from dietary fiber fermentation by gut microbiota have been identified as one of the mechanisms behind the association between habitual whole-grain intake and a lower risk of cardiometabolic diseases. The aims of the present work are: (1) to evaluate whether a whole-grain wheat-based diet may increase SCFAs concentration, and (2) to identify possible associations between SCFAs and metabolic changes observed after the nutritional intervention. METHODS Fifty-four subjects participated in the trial. They underwent a 12-wk dietary intervention based on whole-grain or refined cereal products. At baseline and after the intervention, glucose, insulin, triacylglycerol, inflammatory markers (hs-CRP, IL-1 ra, IL-6, and TNF-α), and SCFAs plasma concentrations were evaluated. RESULTS After the intervention, in the whole-grain group fasting plasma propionate concentrations were higher than at baseline, whereas a reduction was detected in the control group. The absolute changes (end of trial minus baseline) in fasting plasma propionate concentrations were significantly different between the two groups (P = 0.048). The absolute changes of fasting propionate correlated with cereal fiber intake (r = 0.358, P = 0.023), but no significant correlations with clinical outcomes were found. However, postprandial insulin was significantly decreased in the group having the absolute changes of fasting propionate concentration above the median value (P = 0.022 versus subjects with fasting propionate changes below the median value). CONCLUSIONS A 12-wk whole-grain wheat-based diet increases fasting plasma propionate. This increase correlates with the cereal fiber intake and is associated with lower postprandial insulin concentrations.
2.
A whole-grain cereal-based diet lowers postprandial plasma insulin and triglyceride levels in individuals with metabolic syndrome.
Giacco, R, Costabile, G, Della Pepa, G, Anniballi, G, Griffo, E, Mangione, A, Cipriano, P, Viscovo, D, Clemente, G, Landberg, R, et al
Nutrition, metabolism, and cardiovascular diseases : NMCD. 2014;(8):837-44
Abstract
BACKGROUND AND AIM Until recently, very few intervention studies have investigated the effects of whole-grain cereals on postprandial glucose, insulin and lipid metabolism, and the existing studies have provided mixed results. The objective of this study was to evaluate the effects of a 12-week intervention with either a whole-grain-based or a refined cereal-based diet on postprandial glucose, insulin and lipid metabolism in individuals with metabolic syndrome. METHODS AND RESULTS Sixty-one men and women age range 40-65 years, with the metabolic syndrome were recruited to participate in this study using a parallel group design. After a 4-week run-in period, participants were randomly assigned to a 12-week diet based on whole-grain products (whole-grain group) or refined cereal products (control group). Blood samples were taken at the beginning and end of the intervention, both fasting and 3 h after a lunch, to measure biochemical parameters. Generalized linear model (GLM) was used for between-group comparisons. Overall, 26 participants in the control group and 28 in the whole-grain group completed the dietary intervention. Drop-outs (five in the control and two in the whole-grain group) did not affect randomization. After 12 weeks, postprandial insulin and triglyceride responses (evaluated as average change 2 and 3 h after the meal, respectively) decreased by 29% and 43%, respectively, in the whole-grain group compared to the run-in period. Postprandial insulin and triglyceride responses were significantly lower at the end of the intervention in the whole-grain group compared to the control group (p = 0.04 and p = 0.05; respectively) whereas there was no change in postprandial response of glucose and other parameters evaluated. CONCLUSIONS A twelve week whole-grain cereal-based diet, compared to refined cereals, reduced postprandial insulin and triglycerides responses. This finding may have implications for type 2 diabetes risk and cardiovascular disease.