Nutrient homeostasis: long-term interrelations between pancreatic hormones, blood glucose and dietary wheat bran in men.

Postprandial plasma somatostatin (SLI), pancreatic glucagon, insulin (IRI) and blood glucose (BG) were measured at 0, 30, 60, 120 and 180 min after a test meal in 10 healthy men before and after 1, 3 and 7 wk of ingestion of a balanced diet supplemented daily with 20 g wheat bran. BG response to the test meal was significantly and consistently lower after the first week of consuming bran, with a maximum drop after 3 wk. After 1 wk of bran, when compared with the prebran values, SLI secretion was decreased, and glucagon response was significantly enhanced at 120 and 180 min after the meal. IRI secretion did not change significantly until the third week. After consuming bran for 7 wk, postprandial SLI concentrations returned to prebran values, and glucagon levels were not significantly different from those of the first meal. IRI during the fourth test meal (after 7 wk of bran consumption) was significantly higher than after the third meal (after 3 wk of bran ingestion), at 60 min and at 120 min. BG levels remained low. Chronic bran ingestion was therefore associated with an improved glucose tolerance. Its effects on pancreatic hormones varied with time for each hormone, and somatostatin was the only one to return to the prebran values.