Studies have linked the consumption of trans fatty acids, or foods that contain them, with an increased risk of developing heart disease. In an analysis from the Nurses' Health Study, for each increase of 2 percent of energy from trans fat, the relative risk for the incidence of coronary heart disease was 1.93 (95 percent confidence interval 1.43 to 2.61). Total fat intake was not related to the risk of coronary disease.v, vi

Trans fats may increase the risk of heart disease by their negative effects on cholesterol levels. Trans fats have been shown to increase LDL or 'bad' cholesterol and reduce HDL or 'good' cholesterol.vii Elevated LDL cholesterol is a major cause of heart disease.ii