Effects of supplemented isoenergetic diets differing in cereal fiber and protein content on insulin sensitivity in overweight humans

Abstract

Greater changes in insulin sensitivity after intake of an isoenergetic HCF than after intake of an HP diet might help to explain the diverse effects of these diets on diabetes risk. This trial is registered at clinicaltrials.gov as NCT00579657.

Impact of Diet Composition on Blood Glucose Regulation

“…An 18-week randomized controlled intervention in healthy subjects having increased intake of insoluble cereal fiber, supplemented by cereal fiber extracts twice daily, significantly improved whole-body insulin sensitivity, as measured using euglycemic-hyperinsulinemic clamps (Weickert et al, 2011a(Weickert et al, , 2011b. A previous intervention by Pereira and colleagues showed comparable results when investigating the effects of whole grain diets on whole-body insulin sensitivity (Pereira et al, 2002).…”

“…This effect also contributes to improved glucose metabolism ). However, in the Profimet study whole-body insulin sensitivity (Weickert, 2012) was significantly improved independent of various markers of colonic fermentation, SCFA profiles in faecal samples, and dominant groups of the gut microbiota (Weickert et al, 2011a(Weickert et al, , 2011b, indicating that further factors were involved in conveying improved insulin sensitivity upon the consumption of insoluble cereal fiber.…”

“…Improved whole-body insulin sensitivity by insoluble cereal fiber was suggested to be related to interference with the digestion and/or absorption of dietary protein and consequently reduced amino acid induced activation of the mammalian target of rapamycin (mTOR) S6 kinase 1 (S6K1) signaling pathway (Weickert et al, , 2011a(Weickert et al, , 2011b) that directly results in insulin resistance both in animal models and human intervention studies (Krebs et al, 2002;Um et al, 2004;Tremblay et al, 2005). Further mechanisms that may be involved could be cereal-fiber induced binding of bile acids and fiber-induced effects on gut hormones and metabolite profiles but this will need to be investigated in future studies.…”

External validation of the fatty liver index and lipid accumulation product indices, using 1H-magnetic resonance spectroscopy, to identify hepatic steatosis in healthy controls and obese, insulin-resistant individuals

“…We recruited healthy controls and individuals with components of the metabolic syndrome including being overweight/obese (BMI O25 kg/m 2 ), with a waist circumference O80 cm in females and O94 cm in males, and with at least one additional feature of the metabolic syndrome according to International Diabetes Federation criteria (22). Clinical characteristics of the cohorts have been presented previously in detail (23,24). All participants gave written informed consent, and ethical approval was obtained from the respective local ethics committee.…”

The Geometry of Human Nutrition

“…Hence, underconsumption is costly because protein is the only macronutrient to contain nitrogen, which is essential for growth and reproduction. On the other hand, excess protein consumption has been shown to have associated performance costs in some animals [eg 26, 27] -and perhaps also in humans, and suggested risks include increased insulin resistance, kidney damage, bone decalcification, ketoacidosis, cardiovascular disease and some cancers [28][29][30][31].…”