ALTERATIONS IN THE FATTY ACID COMPOSITION OF HUMAN LYMPH AND SERUM LIPOPROTEINS BY SINGLE FEEDINGS*

Abstract

The acute effect of single feedings of fats on the fatty acid composition of human thoracic duct lymph and serum was studied in 3 subjects. Corn oil, a highly unsaturated fat, and coconut oil, a markedly saturated fat, were used as the test meals. The lymph and sera were fractionated into lipoprotein classes by ultracentrifugation, and each of the lipoproteins was separated into triglycerides, cholesterol esters and phospholipids by silicic acid column chromatography. The fatty acids were identified and quantified by gas liquid chromatography. The fatty acid composition of the thoracic duct chylomicrons was almost identical with that of the test meal 6 to 8 hours after ingestion. The serum lipoproteins d < 1.005, "chylomicrons", also reflected the composition of the test meal, but the change in composition was not so complete as that observed in thoracic duct chylomicrons. Other lymph and serum lipoprotein classes also showed alterations in composition after the single test meal. The density class 1.019 to 1.063 was the most stable of the lipoprotein classes. Within each density class, the triglycerides were altered to the greatest extent, with less change noted in the cholesterol ester fraction.