We investigated the hypothesis that the hypocholesterolemic activity of corn oil and other unsaturated vegetable oils is related to effects of their nontriglyceride components on intestinal lipid absorption. To test this hypothesis, corn, sunflowerseed (sun) and soybean oils (soy) were separated chromatographically into their pure triglycerides (TGs) and 4 nonTG fractions. For each native oil, a 7-membered series was prepared: native oil, pure TGs, pure TGs plus each of the 4 nonTG fractions, and pure TGs plus all 4 nonTG fractions. Three groups of lymph duct-cannulated rats received continuous (9-10 d) intraduodenal infusions of oils with added cholesterol (equivalent to a diet containing 20% fat +0.4% cholesterol) in a randomized Latin Square design. Each oil was infused for 18 h before lymph was sampled. There were no significant differences in chylomicron TG, phospholipid (PL) and cholesterol (total, unesterified or esterified) transfer rates (μmole/h) or in relative chylomicron size (molar ratio of PL/TG) within any of the 3 series. Recovery of TG and cholesterol in chylomicrons, relative to the rates of infusion, averaged 91 and 99% (corn), 77 and 72% (sun) and 90 and 79% (soy). Our results indicate that, at the level present in these 3 oils, the nonTG components do not significantly influence chylomicron lipid composition or size, or the rate of intestinal secretion of lipid components.
All Science Journal Classification (ASJC) codes
- Endocrinology, Diabetes and Metabolism
- Nutrition and Dietetics