Mechanisms of action of beta-glucan in postprandial glucose metabolism in healthy men.
OBJECTIVE
To assess whether beta-glucan (which is fermented in the colon) lowers postprandial glucose concentrations through mechanisms distinct from a delayed carbohydrate absorption and inhibits de novo lipogenesis.


METHODS
Administration of frequent small meals each hour over 9 h allows a rate of intestinal absorption to be reached which is independent of a delayed absorption. A group of 10 healthy men received either an isoenergetic diet containing 8.9 g/day beta-glucan or without beta-glucan for 3 days. On the third day, the diet was administered as fractioned meals ingested every hour for 9 h.


METHODS
Laboratory for human metabolic investigations.


METHODS
Ten healthy male volunteers.


METHODS
Plasma glucose and insulin concentrations, glucose kinetics, glucose oxidation, de novo lipogenesis.


RESULTS
On the third day, plasma glucose and free fatty acid concentrations, carbohydrate and lipid oxidation, and energy expenditure were identical with beta-glucan and cellulose. Plasma insulin concentrations were, however, 26% lower with beta-glucan during the last 2 h of the 9 h meal ingestion. Glucose rate of appearance at steady state was 12% lower with beta-glucan. This corresponded to a 21% reduction in the systemic appearance rate of exogenous carbohydrate with beta-glucan, while endogenous glucose production was similar with both diets. De novo lipogenesis was similar with and without beta-glucan.


CONCLUSIONS
Administration of frequent meals with or without beta-glucan results in similar carbohydrate and lipid metabolism. This suggests that the lowered postprandial glucose concentrations which are observed after ingestion of a single meal containing beta-glucan are essentially due to a delayed and somewhat reduced carbohydrate absorption from the gut and do not result from the effects of fermentation products in the colon.
Battilana
P
P
Institute of Physiology, School of Medicine, University of Lausanne, Switzerland.
Ornstein
K
K
Minehira
K
K
Schwarz
J M
JM
Acheson
K
K
Schneiter
P
P
Burri
J
J
Jéquier
E
E
Tappy
L
L
D001786:Blood Glucose / Q000187:drug effects*; D003106:Colon / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005285:Fermentation; D005936:Glucans / Q000008:administration & dosage / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism* / Q000493:pharmacokinetics; D006801:Humans; D007328:Insulin / Q000097:blood*; D007408:Intestinal Absorption / Q000187:drug effects*; D008055:Lipids / Q000097:blood; D008297:Male; D010084:Oxidation-Reduction; D019518:Postprandial Period
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D005936:Glucans; D007328:Insulin; D008055:Lipids; D005947:Glucose