Glycemic and insulinemic meal responses modulate postprandial hepatic and intestinal lipoprotein accumulation in obese, insulin-resistant subjects

BACKGROUND: Exacerbated postprandial lipemia is a risk factor for cardiovascular disease and is linked to insulin status. Limited data on the effect of dietary carbohydrate on postprandial lipoprotein accumulation are available.

OBJECTIVE: We tested the hypothesis that dietary carbohydrates with different glucose availability alter postprandial lipoprotein metabolism differently in obese, insulin-resistant subjects.

DESIGN: After an overnight fast, 9 subjects with central obesity and insulin resistance but normal triacylglycerolemia randomly ingested 2 test meals with comparable amounts of fat (28-29 g) and digestible carbohydrate (91-94 g) but with different quantities of slowly available glucose (SAG) in cereal products (17 or 2 g SAG/100 g for biscuits and wheat flakes, respectively). Blood samples were collected before and for 6 h after meal intakes.

RESULTS: The postmeal 0-2-h areas under the curve (AUCs) for glycemia and insulinemia were significantly lower (P < 0.05) after the biscuit meal than after the flakes meal. Plasma triacylglycerol concentrations increased significantly after the flakes meal but not after the biscuit meal (1.5-fold higher 0-6-h AUC for the flakes meal). Apolipoprotein B-100 concentrations in the triacylglycerol-rich lipoprotein fraction increased significantly 2 h after the flakes meal but not after the biscuit meal (3-fold higher 0-6-h AUC for the flakes meal). Apolipoprotein B-48 concentrations increased (P < 0.05) 4 h after the flakes meal but not after the biscuit meal (2.3-fold higher 0-6-h AUC for the flakes meal).

CONCLUSION: Mixed meals containing slowly digestible carbohydrate that induces low glycemic and insulinemic responses reduce the postprandial accumulation of both hepatically and intestinally derived triacylglycerol-rich lipoproteins in obese subjects with insulin resistance.