Saturated fats, dairy foods and health: A curious paradox?

Abstract

Cardiovascular diseases (CVD) remain a major cause of death and morbidity worldwide. Dietary guidelines aim to restrict the intake of saturated fatty acids (SFA) as they are regarded as an important risk factor for CVD due to their association with increased blood cholesterol. As dairy foods are major contributors of dietary SFA, there have been guidelines to reduce consumption of these foods. However, it is now generally accepted that the effects of reducing intake of SFA are dependent on what replaces them in the diet. Reduced CVD risk has been associated with 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. Most studies on 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 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 prospective evidence shows no increase in CVD risk from high dairy consumption, it is still unclear whether replacing a proportion of SFA in dairy fat with cis-MUFA will lead to reduced CVD risk. The relatively few randomised controlled trials that have examined this using TC/LDL-C as risk markers give some indications of reduced CVD risk from consumption of milk and dairy products with modified fatty acid composition, compared with those of normal milk fat composition. The results of ongoing studies will add valuable new evidence on this issue.

Draft reports from the UK's Scientific Advisory Committee on Nutrition and World Health Organization concur in endorsing the dietary guideline to restrict intake of saturated fat

“…). This study attributed its negative findings to SFA being derived from dairy foods, such as cheese, a result that was consistent with the consensus view that SFA from fermented dairy foods is of lower CVD risk than its counterparts in other foods (Givens ). While the examination of foods and individual SFAs was beyond the remit of the SACN and WHO reports, a move away from macronutrient‐specific guidelines towards more food‐based recommendations seems inevitable.…”

“…When a metaanalysis of The Netherlands cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC) trial agreed with the conclusions of other meta-analyses in finding no significant association between SFA and CVD, it went further to investigate the possible effects of SFA substitution, individual dietary fatty acids and food sources of these fats (Praagman et al 2016). This study attributed its negative findings to SFA being derived from dairy foods, such as cheese, a result that was consistent with the consensus view that SFA from fermented dairy foods is of lower CVD risk than its counterparts in other foods (Givens 2017). While the examination of foods and individual SFAs was beyond the remit of the SACN and WHO reports, a move away from macronutrient-specific guidelines towards more foodbased recommendations seems inevitable.…”

The big fat debate

“…; Li et al . ; Givens ), with little evidence available to conclude on the relative effect of replacement with n ‐6 PUFAs versus n ‐3 PUFAs.…”

“…A case in point is dairy products as reviewed by Givens in his article Saturated fats, dairy foods and health: A curious paradox? (Givens ), where despite having a high SFA:total fat ratio, they are not associated with increased CVD risk, with odd‐chain SFAs and bioactive peptides being apparently cardioprotective.…”

“…1). In simple terms, each 1% of energy from PUFAs replacing SFAs reduces the occurrence of CHD events by 2%-3% (Mozaffarian et al 2010;Li et al 2015;Givens 2017), with little evidence available to conclude on the relative effect of replacement with n-6 PUFAs versus n-3 PUFAs.…”