The relationship of dietary fat to plasma lipid levels as studied by factor analysis of adipose tissue fatty acid composition in a free-living population of middle-aged American men

We have used adipose tissue biopsies to assess the quality of fat in the diet and its influence on plasma lipid levels in 413 free-living normolipidemic male subjects. Factor analysis identified three factors which separated the fatty acids on the basis of their chemical stucture. F₁-monounsaturates - animal fats: F₂-saturates - carbohydrates: F₃-polyunsaturates - vegetable oils. An increase in F₁ was associated with an increase in plasma triglycerides (TG), plasma total cholesterol (TC), and VLDL-C: an increase in F₂ led to a decrease in VLDL-C. A rise in F₃ was associated with lowered TG, VLDL-C, and HDL-C, and HDL-C but increased LDL-C. However, the contribution of each of these factors to the variance in TG, TC, LDL-C, and HDL-C was small, namely: 5.48, 1.30, 2.57, and 2.02%, respectively. A special relationship between F₃ and VLDL-C was found such that 16.22% of its variance could be attributed to F₃. Our conclusion is that adipose tissue composition and, by implication, the type of dietary fat intake, explains only a small proportion (1-19%) of the variance in plasma lipids in normolipidemic subjects.