Trans fatty acids (TFA) are unsaturated fatty acids that have at least one double bond in the trans configuration. There is ample evidence suggesting a link between industrially produced TFA intake and the risk of coronary heart disease (CHD): First, TFA negatively influence blood lipids. Second, they promote inflammation, an important risk factor of atherosclerosis. Third, TFA seem to impair the function of the endothelial cells (the inside surface of blood vessels). Fourth, the increase in the energy intake from TFA is associated with increased incidence of CHD.

Katrin Kuhnt and co-workers, Friedrich Schiller University, Jena, Germany, analyzed 339 German foods of six categories — semi-solid fats, deep-fried potato products, bakery products, confectioneries and chocolate, instant products and butter — to characterize their TFA profiles including the important t9/t11 index indicating the origin of TFA (industrial vs ruminant, respectively). It is important to distinguish between industrial TFA and between TFA produced by fermentation in the rumen, as ruminant TFA are not implicated in CHD.

Sources of ruminant TFA are milk, dairy products and meat, which have a low t9/t11 index, while the highest index was observed in shortenings and deep-fried potato products indicating the use of industrially hydrogenated fats.

To learn about the trans fats in your favorite foods, check out the paper — it is freely accessible:

• Trans fatty acid isomers and t9/t11 index in German foods
  K. Kuhnt, M. Baehr, C. Rohrer, G. Jahreis,
  Eur. J. Lipid Sci. Technol. 2011, 113, 1281–1292.
  DOI: 10.1002/ejlt.201100037