Prior short-term consumption of resistant starch enhances postprandial insulin sensitivity in healthy subjects.
OBJECTIVE
Diets rich in insoluble-fibre are linked to a reduced risk of both diabetes and cardiovascular disease; however, the mechanism of action remains unclear. The aim of this study was to assess whether acute changes in the insoluble-fibre (resistant starch) content of the diet would have effects on postprandial carbohydrate and lipid handling.


METHODS
Ten healthy subjects consumed two identical, low-residue diets on separate occasions for 24 h (33% fat; <2 g dietary fibre). Of the diets one was supplemented with 60 g resistant starch (Novelose 260). On the following morning a fibre-free meal tolerance test (MTT) was carried out (59 g carbohydrate; 21 g fat; 2.1 kJ) and postprandial insulin sensitivity (SI(ORAL)) assessed using a minimal model approach.


RESULTS
Prior resistant starch consumption led to lower postprandial plasma glucose (p=0.037) and insulin (p=0.038) with a higher insulin sensitivity(44+/-7.5 vs 26+/-3.5 x 10(-4) dl kg(-1) min(-1) per micro Uml(-1); p=0.028) and C-peptide-to-insulin molar ratio (18.7+/-6.5 vs 9.7+/-0.69; p=0.017). There was no effect of resistant starch consumption on plasma triacylglycerol although non-esterified fatty acid and 3-hydroxybutyrate levels were suppressed 5 h after the meal tolerance test.


CONCLUSIONS
Prior acute consumption of a high-dose of resistant starch enhanced carbohydrate handling in the postprandial period the following day potentially due to the increased rate of colonic fermentation.
Robertson
M D
MD
Oxford Lipid Metabolism Group, OCDEM, Churchill Hospital, Oxford, UK. denise.robertson@oxlip.ox.ac.uk
Currie
J M
JM
Morgan
L M
LM
Jewell
D P
DP
Frayn
K N
KN
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D002149:Energy Intake; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D012016:Reference Values; D016037:Single-Blind Method; D013213:Starch / Q000494:pharmacology*
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D007328:Insulin; D013213:Starch