From: Kofi on 11 Mar 2010 21:36
Might be mediated via AMPK.
Br J Nutr. 2010 Jan;103(1):82-90. Epub 2009 Aug 7.
Adaptation of colonic fermentation and glucagon-like peptide-1 secretion
with increased wheat fibre intake for 1 year in hyperinsulinaemic human
Freeland KR, Wilson C, Wolever TM.
Department of Nutritional Sciences, University of Toronto, Toronto,
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
PMID: 19664300 [PubMed - indexed for MEDLINE]
From: Tim on 12 Mar 2010 15:11
Check backposts by Thomas Carter He brings up whole grains I think as
a source of butyrate in the gut.