[Dietary trans-fatty acids: a risk factor for coronary disease]

Unsaturated fatty acids with their double bond in trans configuration raise serum low-density lipoprotein (LDL) cholesterol and lipoprotein(a) levels, and lower high-density lipoprotein (HDL) cholesterol in humans when substituted for cis unsaturated fatty acids in the diet. These effects should increase the risk of coronary heart disease, which is confirmed by epidemiological studies. Trans fatty acids are formed from cis unsaturated fatty acids during hydrogenation of vegetable oils in food industries. Until recently, major dietary sources of trans fatty acids in the Netherlands were frying fats, shortenings, and margarines, which in the past contained up to 50% of trans fatty acids. Nowadays, most shortenings and margarines sold in the Netherlands have a low trans fatty acid content due to manufacturing changes in the recent past. However, frying fats used in fast-food outlets still contain over 30% of trans fatty acids. French fries sold in these outlets provide 7-8 g of trans fatty acids per portion. Producers of frying fats for fast-food outlets therefore should also reduce the trans fatty acid content of their products as much as possible.