Ten normal subjects were given 50 g starch, or 50 g starch + 50 g fat as a breakfast meal. The starch was given in the form of potato; the fat was given in the form of butter. The meals were ingested at 8 a.m. Plasma glucose, insulin, C-peptide, and triglyceride concentrations were measured at various time points for 4 hours after each meal. The net 4-hour postprandial area responses to the ingested meals were determined using the trapezoid rule, with the fasting glucose concentration, measured at the same time points for 4 hours as a baseline. The glucose area response was 2.2 mmol hour/1 following the potato meal. This was significantly reduced following ingestion of the meal containing fat (1.3 mmol hour/1) (p < 0.01). The insulin area response was slightly greater following the meal containing fat (459 pmol hour/1) compared to potato alone (423 pmol hour/1) (p < 0.01). The C-peptide area response following the meal containing fat was 0.80 pmol hour/ml, clearly greater than following potato alone (0.58 pmol hour/ml) (p < 0.01). The triglyceride area response also was much greater following the meal containing fat compared to potato alone (0.74 and 0.08 mmol hour/1, respectively). The mechanism of the attenuated glucose response to carbohydrate ingestion with a fat-containing meal is unknown. It may be due to the release of an enteric hormone that increases glucose disposal, either directly or indirectly, through insulin.
Bibliographical noteFunding Information:
Supported by Merit Review funds from the Department of Veterans Affairs, funds from the National Dairy Promotion & Research Board, administered in cooperation with the National Dairy Council, and Merit Review funds from the National Institutes of Health (DK 43018-01 Al). We wish to thank the staff of the Special Diagnostic & Treatment Unit (SDTU) for their assistance and the volunteers for their participation in this study. The technical assistance of Ms. Marie Matlack, MT, Mrs. Joanna Aretz, BS, and Ms. Nancy Hale, MT, is greatly appreciated.
- Glycemic index
- Relative glucose area (RGA)