Difference in postprandial GLP-1 response despite similar glucose kinetics after consumption of wheat breads with different particle size in healthy men

Abstract

PurposeUnderlying mechanisms of the beneficial health effects of low glycemic index starchy foods are not fully elucidated yet. We varied the wheat particle size to obtain fiber-rich breads with a high and low glycemic response and investigated the differences in postprandial glucose kinetics and metabolic response after their consumption.MethodsTen healthy male volunteers participated in a randomized, crossover study, consuming 13C-enriched breads with different structures; a control bread (CB) made from wheat flour combined with wheat bran, and a kernel bread (KB) where 85 % of flour was substituted with broken wheat kernels. The structure of the breads was characterized extensively. The use of stable isotopes enabled calculation of glucose kinetics: rate of appearance of exogenous glucose, endogenous glucose production, and glucose clearance rate. Additionally, postprandial plasma concentrations of glucose, insulin, glucagon, incretins, cholecystokinin, and bile acids were analyzed.ResultsDespite the attempt to obtain a bread with a low glycemic response by replacing flour by broken kernels, the glycemic response and glucose kinetics were quite similar after consumption of CB and KB. Interestingly, the glucagon-like peptide-1 (GLP-1) response was much lower after KB compared to CB (iAUC, P < 0.005). A clear postprandial increase in plasma conjugated bile acids was observed after both meals.ConclusionsSubstitution of 85 % wheat flour by broken kernels in bread did not result in a difference in glucose response and kinetics, but in a pronounced difference in GLP-1 response. Thus, changing the processing conditions of wheat for baking bread can influence the metabolic response beyond glycemia and may therefore influence health.Electronic supplementary materialThe online version of this article (doi:10.1007/s00394-016-1156-6) contains supplementary material, which is available to authorized users.

The impact of starchy food structure on postprandial glycemic response and appetite: a systematic review with meta-analysis of randomized crossover trials

“…Evaluation by the Cochrane RoB 2 tool identified 12 studies (48%) in the current review as having some concerns overall. Of these, 3 studies ( 38, 45, 52 ) had bias due to deviations from the intended intervention and 11 studies ( 32 , 34 , 38 , 39 , 47 , 48 , 50–53 , 56 ) had bias in measurements of outcomes. The other 13 studies were assessed as having low risks.…”

“…Seven studies ( 46 , 47 , 50–53 , 56 ) evaluated the effect of particle size on subjective satiety score iAUCs in healthy subjects. A meta-analysis was completed ( Figure 10 ) on the studies that supplied data ( 46 , 47 , 51–53 , 56 ) ( n = 98), and indicated that the particle size has no significant effect on subjective satiety scores (SMD = 0.02 mm*min; 95% CI: 0.19–0.24; P = 0.83).…”

Incretin Hormones: The Link between Glycemic Index and Cardiometabolic Diseases

“…A study [20] evaluating the five most common breads consumed in Spain, discovered that GIP release was higher after intake of wholemeal rather than white bread. Wheat bread consumption with different particle size elicited a GLP-1 response much lower after bread prepared with flour and 85% broken wheat kernels compared to a control bread made from wheat flour combined with wheat bran to obtain a similar fiber content [21].…”

Insulin Sensitivity and Glucose Homeostasis Can Be Influenced by Metabolic Acid Load

“…As noted above, vegetable-based diets are low acid producing diets, and high fiber consumption constitutes a dietetic strategy to control body weight and help prevent the onset of diabetes and insulin resistance [ 2 , 3 , 4 , 5 , 97 ]. Fiber intake stimulates satiety and it is correlated with decreased post-prandial insulin demand [ 98 ] by modulating glucose absorption and regulating gastrointestinal hormone-like peptides secretion [ 99 , 100 ] such as glucagon-like peptide 1 [ 101 ]. Hence, epidemiological studies reporting amelioration of insulin sensitivity following vegetable-based diet consumption should be interpreted in the context of effects elicited by fiber on energetic metabolism and glucose homeostasis.…”