Saturated Fat Consumption and Risk of Coronary Heart Disease and Ischemic Stroke: A Science Update

Posted on: February 01, 2017

At the SAFA Expert meeting, organised by EPOA, IEM and MVO in 2015, 20 leading experts on dietary fat and health assessed the scientific state of the art on the effect of saturated fatty acid (SAFA) consumption on health. The proceedings of the meeting are now published in the Annals of Nutrition & Metabolism.

The authors Joyce A. Nettleton, Ingeborg A. Brouwer, Johanna M. Geleijnse and Gerard Hornstra, conclude that higher intakes of SAFA are not associated with higher risks of CHD or stroke apparently, but studies don't take macronutrient replacement into account. When compared to carbohydrates and cis-unsaturated fatty acids, SAFA raise plasma LDL-C, a causal risk factor for CHD. Individual SAFA affect plasma lipoprotein levels differently, with each major dietary SAFA except stearic acid resulting in higher levels of LDL- and HDL-C and lower levels of TG.

The authors state that the effect of reducing dietary SAFA is most strongly affected by the macronutrients that replace them. The greatest reduction in CHD risk occurs when cis-PUFA replace dietary SAFA. In intervention studies replacement of 10%E from SAFA by cis-PUFA reduced CVD events by 27% and the replacement of 5%E from SAFA by cis-PUFA decreased CHD risk by 10%. According to the scientists data are insufficient to confirm a significant benefit for CHD risk by substituting cis-MUFA for SAFA. Emerging evidence suggests that the food matrix may modify the risk of CHD associated with some SAFA-rich foods. The consumption of several dairy foods has been associated with a lower risk of CVD, but data are insufficient to justify dietary recommendations, authors state.

There are several risk factors for CHD and ischemic stroke. HDL-C levels are inversely related to CHD risk in healthy populations, but causality is presently doubted. Therefore, the clinical interpretation  of the increased HDL-C associated with SAFA consumption is uncertain and warrants further research. Increasing evidence suggests that TG-rich lipoproteins may be a causal risk factor for CHD and stroke.

Authors state that other markers for CHD risk, such as LDL particle size and several hemostatic, thrombotic, and inflammatory factors lack a confirmed causal relationship to CHD risk. Consistent evidence for specific effects of SAFA on any of these markers has not been reported.

Furthermore the publication points out that studies on SAFA intakes and risk of ischemic stroke are inconsistent. Compared with the abundant data on SAFA consumption and risk of CHD, there is insufficient evidence to support dietary SAFA recommendations to reduce stroke risk. For the partial replacement of SAFA-rich foods with those rich in cis-PUFA to lower LDL-C and reduce CHD risk, the scientific evidence is strong.