Saturday Nov 9, 2013 (foodconsumer.org) -- A study published in the Lancet suggests that eating trans fat or trans fat containing foods may cause coronary heart disease.  It is a possibility but not a certainty because the study was observational and it did not establish a causal relation.

The study led by Prof Walter C. Willett from Department of Nutrition, Harvard School of Public Health in Boston, Massachusetts and colleagues women who had foods with high amounts of trans fat for more than 10 years were 67% more likely to suffer coronary heart disease.

This is not a surprising result considering that trans fat has been known for years if not decades to increase the ratio of serum low-density lipoprotein cholesterol (bad cholesterol) to high density lipoprotein cholesterol (good cholesterol).

For the study, the researchers analyzed data on intake of trans fatty acids from 85,095 participants, who did not have diagnosed coronary heart disease, stroke, diabetes or high cholesterol (hypercholesterolaemia) when enrolled in the Nurses' Health Study.  

They found 431 women diagnosed with coronary heart disease cases including non-fatal myocardial infarction or death from CHD during an eight-year follow-up.   After adjustment for age and total energy intake, intake of trans fat in the highest quintile was found associated with 50% increased risk of coronary heart disease compared with intake of trans fat in the lowest quintile.

The association was not modified substantially by other risk factors, use of multivitamins, saturated fat intake, intake of monounsaturated fat and linoleic acid, dietary cholesterol, vitamin E and C, carotene, and fiber.

Among women who had used margarine, which contains high amounts of trans fatty acids, for more than 10 years, the risk of coronary heart disease was 67% higher.

The major sources of trans fat including margarine, cookies, biscuits, cake, and white bread were each significantly correlated with higher risk of coronary heart disease.

The study concluded "These findings support the hypothesis that consumption of partially hydrogenated vegetable oils may contribute to occurrence of CHD (coronary heart disease)."

Trans fats or partially hydrogenated vegetable oils are commonly used to produce margarine and vegetable shortening.  Many processed foods contain trans fat. (David Liu, PHD)