Chapter 2 - Dairy fats and health

Abstract

Cardiovascular diseases (CVD) and type 2 diabetes (T2D) are a major cause of death and morbidity worldwide and most dietary guidelines aim to limit the intake of saturated fatty acids (SFA) as they are regarded as a key risk factor for CVD primarily due to their association with increased blood cholesterol. In many parts of the world, dairy foods are the major contributor to dietary intake of SFA, and accordingly, there have been proposals to reduce the consumption of these foods. However, there is now a general consensus that the effects of reducing intake of SFA are best interpreted by knowledge of what replaces them. Reduced CVD risk has been associated with the replacement of SFA with cis-polyunsaturated fatty acids (cis-PUFA) and/or cis-monounsaturated fatty acids (cis-MUFA), with replacement by carbohydrate leading to no reduction or even increased CVD risk, especially with refined carbohydrate. Most studies examining the effect of diet/food on CVD risk have used total cholesterol (TC) and/or low-density lipoprotein cholesterol (LDL-C) in blood as the marker(s) of risk. However, because of potentially attenuating effects of other components in the dairy foods (e.g. effect of protein on blood lipids and blood pressure; food matrix effects on fat bioavailability) a wider range of markers is needed to more fully evaluate disease risk. Nevertheless, whilst evidence from long-term prospective studies shows either a reduced or no increase in CMD risk associated with high dairy consumption, it is still unclear whether replacing a proportion of SFA in dairy fat with cis-MUFA will lead to a reduced CVD risk. The few randomised controlled trials that have examined this using mainly TC/LDL-C as predictors of risk do give indications of reduced CVD risk from consumption of milk and dairy products with such modified fatty acid composition, compared with those of normal milk fat composition.