Adaptation of colonic fermentation and glucagon-like peptide-1 secretion with increased wheat fibre intake for 1 year in hyperinsulinaemic human subjects

Br J Nutr. 2010 Jan;103(1):82-90. doi: 10.1017/S0007114509991462. Epub 2009 Aug 7.


High cereal fibre intake is associated with reduced risk for type 2 diabetes, but wheat fibre had little or no effect on glycaemic control or oral glucose tolerance in clinical trials lasting 4-12 weeks. To explain this discrepancy, we hypothesised that colonic adaptation to increased wheat fibre intake takes many months but eventually results in increased SCFA production and glucagon-like peptide-1 (GLP-1) secretion. Thus, the primary objective was to determine the time-course of the effects of increased wheat fibre intake on plasma acetate, butyrate and GLP-1 concentrations in hyperinsulinaemic human subjects over 1 year. Subjects with fasting plasma insulin >or= 40 pmol/l were randomly assigned by computer to receive either a high-wheat fibre cereal (fibre group; 24 g fibre/d; twenty assigned; six dropped out, fourteen included) or a low-fibre cereal (control group; twenty assigned; six dropped-out, fourteen included) daily for 1 year. Acetate, butyrate and GLP-1 were measured during 8 h metabolic profiles performed every 3 months. There were no differences in body weight in the fibre group compared with the control group. After 9 months baseline-adjusted mean 8 h acetate and butyrate concentrations were higher on the high-fibre than the control cereal (P < 0.05). After 12 months on the high-fibre cereal, baseline-adjusted mean plasma GLP-1 was 1.3 (95 % CI 0.4, 2.2) pmol/l (P < 0.05) higher than at baseline (about 25 % increase) and 1.4 (95 % CI 0.1, 2.7) pmol/l (P < 0.05) higher than after 12 months on control. It is concluded that wheat fibre increased SCFA production and GLP-1 secretion in hyperinsulinaemic humans, but these effects took 9-12 months to develop. Since GLP-1 may increase insulin sensitivity and secretion, these results may provide a mechanism for the epidemiological association between high cereal fibre intake and reduced risk for diabetes.

Trial registration: NCT00247455.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Glucose / metabolism
  • Carboxylic Acids / blood
  • Colon / physiopathology*
  • Dietary Fiber*
  • Edible Grain
  • Energy Metabolism
  • Exercise
  • Fatty Acids, Nonesterified / blood
  • Female
  • Glucagon-Like Peptide 1 / blood
  • Glucagon-Like Peptide 1 / metabolism*
  • Humans
  • Hyperinsulinism / blood
  • Hyperinsulinism / diet therapy*
  • Hyperinsulinism / physiopathology*
  • Insulin / blood
  • Male
  • Ontario
  • Reference Values
  • Surveys and Questionnaires
  • Triticum


  • Blood Glucose
  • Carboxylic Acids
  • Dietary Fiber
  • Fatty Acids, Nonesterified
  • Insulin
  • Glucagon-Like Peptide 1

Associated data