Background:There is an important concern about the intake of foods which contains trans fatty acids due to their harmful effects on human health. Although adverse affects of trans fatty acids on the cardiovascular system were established, but a few data are available on the trans fatty acids contents of Iranian foods, including fast foods. In this study we quantify the amounts of the common fatty acids exist in several Iranian fast foods, with specific focus on trans fatty acids.
Methods:Seven samples of the most common consumed fast foods in Iran, sausage, calbas, hamburger and pizza, were randomly selected from products which available in the supermarkets and restaurants. Each time 10 g sample was drawn and prepared for fatty acid analysis. Total and individual fatty acids were quantified by gas chromatography (GC) with 60 meter capillary column and flame ionization detector.
Findings:The most common saturated fatty acid (SFA) in Iranian fast foods was stearic acid (C18:0) with range of 14.0% to 20.9%. SFAs in calbas were significantly higher than other groups. Trans fatty acids constitute almost 23.6% to 30.6% in these products. The most common trans fatty acids in these fast foods were elaidic acid (C18:1 9t). Total cis unsaturated fatty acid content of tested fast foods was varied from 25.3 %( in sausage) to 46.8% (in calbas) with oleic acid (C18:1 9c) followed by linoleic acid (C18:2) being the most common fatty acids in these products.
Conclusion:This study showed higher contents of trans fatty acids in Iranian commercially available fast foods compared to the amounts recommended by dietary guidelines (maximum 2%). Because of the adverse effects of trans fatty acids on health, it is recommended that the amount and type of the fatty acids, especially trans fatty acids, declare in the nutrition label of all foods.

Key words:Fatty acids, Trans fatty acids, Fast food, Gas chromatography.