Trans fatty acids: effects on cardiometabolic health and implications for policy

Abstract

In both developed and developing countries, trans fatty acids (TFA) are largely consumed from partially hydrogenated vegetable oils. This article focuses on TFA as a modifiable dietary risk factor for cardiovascular disease, reviewing the evidence for lipid and non-lipid effects; the relations of trans fat intake with clinical endpoints; and current policy and legislative issues. In both observational cohort studies and randomized clinical trials, TFA adversely affect lipid profiles (including raising LDL and triglyceride levels, and reducing HDL levels), systemic inflammation, and endothelial function. More limited but growing evidence suggests that TFA also exacerbate visceral adiposity and insulin resistance. These potent effects of TFA on a multitude of cardiovascular risk factors are consistent with the strong associations seen in prospective cohort studies between TFA consumption and risk of myocardial infarction and coronary heart disease (CHD) death. The documented harmful effects of TFA along with the feasibility of substituting partially hydrogenated vegetable oils with healthy alternatives indicate little reason for continued presence of industrially produced TFA in food preparation and manufacturing or in home cooking fats/oils. A comprehensive strategy to eliminate the use of industrial TFA in both developed and developing countries, including education, food labeling, and policy and legislative initiatives, would likely prevent tens of thousands of CHD events worldwide each year.

Figure 1

Changes in LDL and HDL cholesterol levels, when cis unsaturated (a) or saturated (b) fatty acids are isocalorically replaced with TFA, based on a meta-analysis of 12 randomized controlled trials in humans [19]. LDL, high density lipoprotein; HDL, high density lipoprotein; TFA, trans fatty acids.

Figure 1

Changes in LDL and HDL cholesterol levels, when cis unsaturated (a) or saturated (b) fatty acids are isocalorically replaced with TFA, based on a meta-analysis of 12 randomized controlled trials in humans [19]. LDL, high density lipoprotein; HDL, high density lipoprotein; TFA, trans fatty acids.

Figure 2

Circulating markers of endothelial dysfunction, including soluble vascular adhesion molecules (ICAM 1 and VCAM 1) (a) and E-selectin (b) according to quintiles of habitual TFA consumption, after adjustment for other risk factors and lifestyle habits, among 730 overweight but otherwise generally healthy women [28].

Figure 2

Circulating markers of endothelial dysfunction, including soluble vascular adhesion molecules (ICAM 1 and VCAM 1) (a) and E-selectin (b) according to quintiles of habitual TFA consumption, after adjustment for other risk factors and lifestyle habits, among 730 overweight but otherwise generally healthy women [28].