Saturated fat feeding, hyperlipidemia and hyperinsulinemia.

The effects of feeding saturated and eucaloric unsaturated fat-rich diets on lipemia and insulinemia in female Brown Norway rats have been compared. The relative hyperlipemia in the unsaturated fat group at 8 a.m. has declined at 10 a.m., whereas the saturated fat group at 8 a.m. gives lower values than at 10 a.m. It suggests that saturated fat feeding requires a longer absorption period. The insulin levels in the unsaturated fat groups are higher at 8 a.m. than at 10 a.m., whereas insulin levels in the saturated fat group are higher at 10 a.m. than at 8 a.m. It also suggests retarded resorption of food in the saturated fat group. The relative hyperlipemia at 10 a.m. in the saturated fat group applies to triacylglycerol, free cholesterol, free fatty acids and particularly phosphatidylcholine. It was almost 50% higher than phosphatidylcholine in the unsaturated fat group and coincided with the accumulation of an apolipoprotein E-rich high density lipoprotein.