Randomized Clinical Trials on the Effects of Dietary Fat and Carbohydrate on Plasma lipoproteins and cardiovascular disease.
Randomized Clinical Trials on the Effects of Dietary Fat and Carbohydrate on Plasma lipoproteins and cardiovascular disease.
Year: 2002
Authors: F Sacks, M Katan.
Publication Name: Am J Med.
Publication Details: Volume 113; Page 13S.
Abstract:
A number of dietary approaches utilized in highly controlled clinical trials have focused on increasing the intakes of vegetable oils, n-3 fatty acids, carbohydrates, or other plant foods or nutrients in order to risk of various coronary disease factors. Improvement in blood lipid profiles is an important mechanism that explains the positive effects observed in many of these trials. This article provides a review of randomized clinical trials investigating the effect of diet, primarily polyunsaturated (PUFA) and monounsaturated fats (MUFA), n-3 fatty acids, and carbohydrates, on plasma lipoproteins and cardiovascular disease. In reviewing the data, a number of observations were made regarding the effect of dietary intervention on lipid profiles. Decreasing saturated fat was consistently found to lower LDL cholesterol values. Replacing saturated fat with carbohydrate lowered HDL to the same extent as it lowered LDL cholesterol, and therefore no improvement in the ratio of LDL to HDL was observed. Triglycerides (TGs) were also seen to increase with the consumption of high glycemic index starches and sugars. Fish oil fatty acids were found to have little effect on LDL or HDL cholesterol, but did lower TG levels. Furthermore, n-3 fatty acids from fish oil also suppress cardiac arrhythmias. Alpha linolenic acid from vegetable oils has been shown to exert similar favorable effects as n-3 from fish oil. Replacing saturated fat with MUFA or PUFA fat primarily reduced LDL cholesterol values and slightly lowered HDL cholesterol values, ultimately producing a reduction in LDL to HDL ratio. No increase in TG levels was observed. Trans unsaturated fats produced by hydrogenating vegetable oils increased LDL and decreased HDL cholesterol values. Overall, replacing saturated and trans fat in the diet with unhydrogenated MUFAs and PUFAs produced the most favorable changes in plasma lipid concentrations. Reductions in cardiovascular disease (CVD) risk factors through dietary therapy (primarily via improvements in blood lipid profiles) compare favorably with drug treatments. Based on these data, recommendations are made to reduce saturated fats, cholesterol, meats, and fatty dairy foods, and increasing PUFA, MUFA and n-3 fatty acids for the prevention of CVD.
