Impact of cereal fibre on glucose-regulating factors.
OBJECTIVE
Insoluble dietary fibre intake is associated, by unknown mechanisms, with a reduced risk of type 2 diabetes. We investigated whether a short-term dietary intervention with purified insoluble fibres influences acute and delayed responses of glucose, insulin, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1.


METHODS
Fourteen healthy women with NGT were studied for 300 min on six to eight occasions. Subjects consumed three matched portions of control (C) or fibre-enriched bread (10.4-10.6 g/portion; wheat fibre [WF], oat fibre [OF], and, in a substudy [n=9], resistant starch [RS]) followed by control (C-C, C-WF, C-OF, C-RS) on subsequent days.


RESULTS
Fibre enrichment accelerated the early insulin response (fibrextime interaction p=0.026 for WF, p<0.001 for OF, p=0.126 for RS; time of maximal concentration [T(max)], C 57.9+/-5.9, WF 49.3+/-2.5 [p=0.086], OF 46.1+/-2.9 [p=0.026], RS 46.7+/-5.8 min [p=0.029]). It was also associated with an earlier postprandial GIP response after OF (T(max), C 83.6+/-7.2, WF 70.7+/-6.0 [p=0.054], OF 64.3+/-6.9 [p=0.022], RS 60.0+/-5.0 [p>0.15]). Increased fibre intake for 24 h was further associated with a reduced postprandial glucose response on the following day subsequent to ingestion of a control meal (AUC(C-C) 4,140+/-401, AUC(C-WF) 2,850+/-331 [p=0.007], AUC(C-OF) 2,830+/-277 [p=0.011]), with no difference in maximal concentration and T(max) of glucose responses. No differences in insulin responses were observed 24 h after the fibre-enriched diets compared with control (p>0.15). Colonic fermentation was increased only on study days C-OF (p=0.017) and C-RS (p=0.016).


CONCLUSIONS
The consumption of highly purified insoluble dietary fibres accelerated the acute GIP and insulin response and was further associated with enhanced postprandial carbohydrate handling the following day upon ingestion of a control meal.
Weickert
M O
MO
Department of Clinical Nutrition, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany. m.weickert@mail.dife.de
Mohlig
M
M
Koebnick
C
C
Holst
J J
JJ
Namsolleck
P
P
Ristow
M
M
Osterhoff
M
M
Rochlitz
H
H
Rudovich
N
N
Spranger
J
J
Pfeiffer
A F H
AF
D000328:Adult; D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism; D001939:Bread; D003106:Colon / Q000378:metabolism; D018592:Cross-Over Studies; D004043:Dietary Fiber / Q000494:pharmacology*; D002523:Edible Grain / Q000737:chemistry*; D005749:Gastric Inhibitory Polypeptide / Q000097:blood*; D052216:Glucagon-Like Peptide 1 / Q000097:blood*; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D006859:Hydrogen / Q000032:analysis; D007328:Insulin / Q000097:blood; D011897:Random Allocation; D013213:Starch
D001786:Blood Glucose; D004043:Dietary Fiber; D007328:Insulin; D005749:Gastric Inhibitory Polypeptide; D006859:Hydrogen; D052216:Glucagon-Like Peptide 1; D013213:Starch; D005947:Glucose