Effects of Dietary fatty acids & carbohydrates on the ratio of Serum total to HDL cholesterol & on serum lipids & apolipoproteins: a meta-analysis of 60 controlled trials.
Effects of Dietary fatty acids & carbohydrates on the ratio of Serum total to HDL cholesterol & on serum lipids & apolipoproteins: a meta-analysis of 60 controlled trials.
Year: 2003
Authors: R Mensink, P Zock, A Kester, M Katan.
Publication Name: Am J Clin Nutr.
Publication Details: Volume 77; Page 1146.
Abstract:
There appears to be scientific consensus that increasing the concentration of HDL cholesterol through diet will lower the risk of CAD. The ratio of total to HDL cholesterol is considered more important than the total or lipoprotein cholesterol concentrations in estimating the risk of CAD. In this study, data from publications by investigators in 11 countries from 1970 through 1998 were assessed to estimate the effect of fats on total:HDL cholesterol. The effects of dietary fatty acids on plasma apolipoprotein (apo) B and apo A-I were also evaluated. Sixty trials met the study criteria yielding 159 diet data points and including 1672 volunteers, at a ratio of men to women of 70:30. From this meta-analysis the total:HDL cholesterol ratio did not change if carbohydrates replaced saturated fatty acids, but decreased if cis unsaturated fatty acids replaced saturated fatty acids. The effect on total:HDL cholesterol of replacing trans fatty acids with a mix of carbohydrates and cis unsaturated fatty acids was almost twice as large as that of replacing saturated fatty acids. Lauric acid greatly increased total cholesterol, but much of its effect was on HDL cholesterol. Oils rich in lauric acid decreased the ratio of total to HDL cholesterol. Myristic and palmitic acids had little effect on the ratio, and stearic acid reduced the ratio slightly. Replacing fats with carbohydrates increased fasting triacylglycerol concentrations. This study which analyzed the effects on surrogate lipid markers, epidemiologic findings and the results of controlled clinical trials once again confirmed that the replacement of SFAs with cis unsaturated fatty acids such as found in canola oil reduces CAD risk. However, studies such as this can predict the effects of fats on plasma lipids, but cannot determine whether a fat will cause CAD. Thus the effects of dietary fats on total:HDL cholesterol appears to differ markedly from their effects on LDL. These findings should be confirmed by prospective observational studies or clinical trials. Such studies have shown that risk is reduced most effectively when trans fatty acids and saturated fatty acids are replaced with cis unsaturated fatty acids. The effects of carbohydrates and of lauric acid–rich fats on CAD risk remain uncertain.
