Effect of Dietary Fatty Acids on Serum Lipids and Lipoproteins

To calculate the effect of changes in carbohydrate and fatty acid intake on serum lipid and lipoprotein levels, we reviewed 27 controlled trials published between 1970 and 1991 that met specific inclusion criteria. These studies yielded 65 data points, which were analyzed by multiple regression analysis using isocaloric exchanges of saturated (sat), monounsaturated (mono), and poly unsaturated (poly) fatty acids versus carbohydrates (carb) as the independent variables. For high density lipoprotein (HDL) we found the following equation: AHDL cholesterol (mmol/1) =0.012x(carb->sat) + 0.009x (carb—'mono) + 0.007 x(carb—»poly) or, in milligrams per deciliter, 0.47x(carb-»sat) + 034 x (carb-»mono) + 0.28x (carb-*poly). Expressions in parentheses denote the percentage of daily energy intake from carbohydrates that is replaced by saturated, cis-monounsaturated, or polyunsaturated fatty acids. All fatty acids elevated HDL cholesterol when substituted for carbohydrates, but the effect diminished with increasing unsaturation of the fatty acids. For low density lipoprotein (LDL) the equation was ALDL cholesterol (mmol/1) =0.033 x(carb-»sat)- 0.006 x (carb->mono)- 0.014 x (carb-»pory) or, In milli-grams per deciliter, L28x(carb->sat)- 0.24x(carb-»mono)- 0.55x(carb-»poly). The coefficient for polyunsaturates was significantly different from zero, but that for monounsaturates was not For triglycerides the equation was Atriglycerides (mmol/1) = — 0.025 x (carb—»sat) — 0.022 x (carb—»-mono)