Effects of meal size and composition on incretin, alpha-cell, and beta-cell responses.
The incretins glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) regulate postprandial insulin release from the beta-cells. We investigated the effects of 3 standardized meals with different caloric and nutritional content in terms of postprandial glucose, insulin, glucagon, and incretin responses. In a randomized crossover study, 18 subjects with type 2 diabetes mellitus and 6 healthy volunteers underwent three 4-hour meal tolerance tests (small carbohydrate [CH]-rich meal, large CH-rich meal, and fat-rich meal). Non-model-based and model-based estimates of beta-cell function and incremental areas under the curve of glucose, insulin, C-peptide, glucagon, GLP-1, and GIP were calculated. Mixed models and Friedman tests were used to test for differences in meal responses. The large CH-rich meal and fat-rich meal resulted in a slightly larger insulin response as compared with the small CH-rich meal and led to a slightly shorter period of hyperglycemia, but only in healthy subjects. Model-based insulin secretion estimates did not show pronounced differences between meals. Both in healthy individuals and in those with diabetes, more CH resulted in higher GLP-1 release. In contrast with the other meals, GIP release was still rising 2 hours after the fat-rich meal. The initial glucagon response was stimulated by the large CH-rich meal, whereas the fat-rich meal induced a late glucagon response. Fat preferentially stimulates GIP secretion, whereas CH stimulates GLP-1 secretion. Differences in meal size and composition led to differences in insulin and incretin responses but not to differences in postprandial glucose levels of the well-controlled patients with diabetes.
Rijkelijkhuizen
Josina M
JM
EMGO Institute, VU University Medical Center, 1081 BT Amsterdam, The Netherlands.
McQuarrie
Kelly
K
Girman
Cynthia J
CJ
Stein
Peter P
PP
Mari
Andrea
A
Holst
Jens J
JJ
Nijpels
Giel
G
Dekker
Jacqueline M
JM
D000368:Aged; D019540:Area Under Curve; D002096:C-Peptide / Q000032:analysis; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D002149:Energy Intake; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D050416:Glucagon-Secreting Cells / Q000502:physiology*; D006801:Humans; D054795:Incretins / Q000097:blood*; D007328:Insulin / Q000097:blood; D050417:Insulin-Secreting Cells / Q000502:physiology*; D008875:Middle Aged
D002096:C-Peptide; D004040:Dietary Carbohydrates; D054795:Incretins; D007328:Insulin; D052216:Glucagon-Like Peptide 1