Abstract 18256: Importance of Controlling Dietary Intake of Saturated Fat for Prevention of Coronary Heart Disease: Lessons From the Metabolic Ward Studies
Background:Recent studies of dietary fat and coronary heart disease (CHD) have questioned the relevance of limiting the intake of saturated fatty acids (SFA) for prevention of CHD.
Objective: To re-examine the metabolic ward trials assessing the effects on plasma levels of LDL-C or of high-density lipoprotein cholesterol (HDL-C) of replacement of dietary intake of SFA, trans fats (TFA) and dietary cholesterol by PUFA, monounsaturated fats (MUFA) or by carbohydrate.
Methods: In a meta-analysis of 103 metabolic ward studies involving 500 controlled dietary trials, the effects on plasma levels of total cholesterol, LDL-C, HDL-C and total/HDL-C ratio of isocaloric replacement of calories as SFA or TFA by PUFA, MUFA or carbohydrate were assessed using multivariate regression analysis.
Results:Higher intakes of SFA, dietary cholesterol and TFA were each significantly associated with higher LDL-C levels, but higher intakes of PUFA were associated with lower LDL-C, and MUFA had no effect on LDL-C. Isocaloric replacement of TFA (2% calories) by PUFA had twice the effect on total/HDL ratio than by carbohydrate (-0.13 [0.03] vs -0.07 [0.02]). By contrast, isocaloric replacement of 5% of calories as SFA by PUFA had a much greater effect on both LDL-C and on the total/LDL-C ratio than the elimination of TFA. Taken together, isocaloric replacement of SFA (5% calories), TFA (2% calories) and dietary cholesterol (100 mg) by PUFA should lower LDL-C by about 0.5 mmol/L (20 mg/dL) and the total/HDL-C ratio by 0.33.
Conclusions: Excessive intakes of SFA remain a major public health problem and public health strategies for prevention of CHD should not neglect the importance of limiting SFA intake which will result in a greater reduction in LDL-C than the elimination of TFA alone.
- © 2011 by American Heart Association, Inc.