Effect of peanut oil and randomized peanut oil on cholesterol and oleic acid absorption, transport, and distribution in the lymph of the rat

Peanut oil was shown to be atherogenic in cholesterol-fed rats, rabbits, an d monkeys. However, after randomization, a process in which the fatty acids in peanut oil are randomly rearranged, its atherogenicity was significantl y reduced in cholesterol-fed rabbits and monkeys. The mechanism for this ef fect remains unknown; This study was designed to investigate whether the ab sorption, transport and distribution of dietary cholesterol and oleic arid in the lymph were altered in the presence of peanut oil or randomized peanu t oil. Previous Investigators collected lymph through the mesenteric duct f or 6 h and analyzed lymph for cholesterol. In the present study, lymph flui ds were collected at timed intervals for up to 8h and then at 24 h via the thoracic duct. Cholesterol and oleic acid (fatty acid) were estimated not o nly in the whole lymph but also in lymph lipoprotein fractions and in major lipid fractions. A 24-h lymph lipid absorption will not affect the results . Thoracic duct lymph collection is quantitative compared to mesenteric duc t lymph collection, which provides only a fraction of the total lymph. Rats were given a lipid emulsion containing either peanut oil or randomized pea nut oil. The emulsion also contained cholesterol, oleic acid, and sodium ta urocholate in saline and was given through a duodenal catheter. Results sho w that absorption, transport, and distribution of cholesterol and oleic aci d in the lymph fluids were similar in both dietary groups. These results su ggest that the atherogenicity of peanut oil may be due to other events taki ng place subsequent to the release of cholesterol-containing chylomicrons a nd very low density lipoprotein by the small intestinal epithelial cells in to the blood or may be due to the triglyceride structure itself.