EFFECT OF ADDED FAT ON PLASMA-GLUCOSE AND INSULIN-RESPONSE TO INGESTED POTATO IN INDIVIDUALS WITH NIDDM

OBJECTIVE - In normal subjects, ingestion of butter with potato result ed in considerably lower blood glucose levels but similar or higher in sulin concentrations compared with those observed in the same subjects after potato ingestion alone. We determined whether butler ingested w ith potato would result in a greater stimulation in insulin secretion than ingestion of potato alone in subjects with NIDDM. RESEARCH DESIGN AND METHODS - Seven male subjects with untreated NIDDM ingested 50 g CHO alone or 50 g CHO with 5, 15, 30, or 50 g fat as a breakfast meal. Fat was ingested in the form of butter, and CHO was given in the form of potato. Subjects received 50 g glucose on two separate occasions f or comparative purposes. The subjects also were given only water and w ere studied over the same time period (water control). Plasma glucose, glucagon, alpha-amino nitrogen, nonesterified fatty acids, serum insu lin, C-peptide, and triglyceride concentrations were determined over 5 h. The integrated area responses were quantified over the 5-h period using the water control as a baseline. RESULTS- The mean plasma glucos e area response after ingestion of potato with or without the various amounts of butter were all similar and were 82% of that observed after ingestion of 50 g glucose. The mean insulin area response to potato a lone was 532 pmol . h . L-1. The mean insulin area responses to potato plus 5,15,30, and 50 g of fat meals were 660,774,750, and 756 pmol . h . L-1, respectively. Thus, the mean insulin areas were all greater t han for ingestion of potato alone, and a maximal response was observed with addition of 15 g fat (1.4-fold). The C-peptide data did not conf irm an increase in insulin secretion. Overall the area responses after ingestion of meals containing fat were not different from the respons e to potato ingestion alone, although the responses were erratic. The glucagon area response was positive after ingestion of alt fat contain ing meats except for that containing only 5 g fat, and there was a dos e-response relationship. The plasma alpha-amino nitrogen and nonesteri fied fatty acid area responses were negative after potato ingestion an d were not significantly different when fat was added. The serum trigl yceride concentration increase was greater after the ingestion of butt er with the potato as expected. CONCLUSIONS - In contrast to the resul ts in normal subjects after ingestion of butter with potato, the gluco se response was not smaller in subjects with NIDDM. The insulin respon se was greater. The insulin area response data indicated the presence of a dose-response relationship. Whether similar responses will be obs erved with other dietary fat and CHO sources remains to be determined.