News & Perspectives

Trans Fatty Acids: What they are and why you should care

Trans fatty acids are making headlines. Effective January 1st 2006, the Food and Drug Administration requires food manufacturers to list trans fat separately on all packaged foods. You have also probably seen trans fatty acids in the news. In 2003, a group of activists sued McDonalds for not implementing a new kind of cooking oil that would reduce the amounts of trans fats found in McDonalds food. The group lost their case because the judge determined that McDonalds was indeed researching alternative cooking oils, but what is all the fuss about? What are trans fats and why is there a sudden media uproar about their inclusion in our diets?


If you examine a food label at your local grocery store you will find three types of fat listed, and they are not alike. Unsaturated fats include monounsaturated, polyunsaturated, and omega-3 fatty acids. Nutritionists consider these healthy fats that the body uses for repair and cell membranes, and as part of energy production in various kinds of cells. These fats are found in nuts, fish, vegetable oils, and some vegetables like avocados. Unsaturated fats do not raise your low density lipoprotein (LDL) or “bad” cholesterol. Saturated fats are the kind found in meat, chicken, butter, and palm or coconut oils. These fats raise your “bad” LDL cholesterol and nutritionists have been advocating limiting their intake for years. The newest fats listed are trans fats. Trans fats occur in small amounts in red meat and dairy products but, more substantially in products manufactured with partially hydrogenated oil. These products typically include shortenings, margarines, cookies, crackers, fried foods such as french fries, chicken, or doughnuts, and many other baked goods and snack foods. These foods are manufactured with partially hydrogenated oils in order to extend shelf life, and improve the foods taste, shape and texture. Unfortunately, while benefiting these measures trans fat has also been shown to increase levels of “bad” LDL cholesterol and actually lower levels of high density lipoprotein (HDL) or “good” cholesterol (1, 2).


Researchers are quickly trying to assess the extent of damage trans fats inflict on our health. The American Heart Association (AHA) suggests that Americans’ intake of trans and saturated fats be as low as possible while consuming an nutritionally adequate diet. Researchers at the Harvard Medical School have found positive correlations between trans fat intake and risk of heart attack (3). Other studies tracking people’s trans fat intake and subsequent risk of cardiovascular disease also support this link (4, 5). Other studies though, have not found the same results (6). Research efforts on trans fatty acids is rapidly expanding and future studies will be needed in order to determine how trans fatty acid intake influences rates of heart disease in the U.S. Until that time however, a viable solution for protecting you and your family is to eat a balanced diet of whole grains, fiber, vegetables, fruits and lean meats. Try to eliminate or reduce your intake of processed and fast foods which are cooked in partially hydrogenated oils. Look for products such as trans-free margarines, which are also often low in saturated fats (7). Remember a good rule of thumb: the farther a food is from its natural state than the more chemical additives it will contain – and the less likely it is to contribute to your health and overall wellbeing.





  1. Mensink RPM, Katan MB. Effect of dietary trans fatty acids on high-density and lowdensity lipoprotein cholesterol levels in healthy subjects. N Engl J Med 1990; 323:439-45.
  2. Judd JT, Clevidence BA, Muesing RA, Wittes J, Sunkin ME, Podczasy JJ. Dietary trans fatty acids: effects of plasma lipids and lipoproteins on healthy men and women. Am J Clin Nutr 1994; 59:861-868.
  3. Ascherio A, Hennekens CH, Buring JE, Master C, Stampfer MJ, Willett WC. Trans fatty acids intake and risk of myocardial infarction. Circulation 1994; 89:94-101.
  4. Willett WC, Stampfer MJ, Manson JE, Colditz GA, Speizer FE, Rosner BA, Sampson LA, Hennekens CH. Intake of trans fatty acids and risk of coronary heart disease among women. Lancet. 1993;341:581-585.
  5. Kromhout D, Menotti A, Bloemberg B, Arauanis C, Blackburn H, Buzina R, Dontas AS, Fidanza F, Giampaoli S, Jansen A, et al. Dietary saturated and trans fatty acids and cholesterol and 25-year mortality from coronary heart disease: the seven countries study. Prev Med. 1995;24:308-315.
  6. Aro A, Kardinaal AFM, Salminen I, Kark JD, Riemersma RA, Delgado-Rodriguez M, Gomez-Aracena J, Huttunen JK, Kohlmeier L, Marin BC, Marin-Moreno JM, Mazaev VP, Ringstad J, Thamm M, van’t Veer P, Kok FJ. Adipose tissue isomeric trans fatty acids and risk of myocardial infarction in nine countries: the EURAMIC study. Lancet. 1995;345:273-278.
  7. Katan MB. Exit trans fatty acids (Invited Commentary). Lancet 1995; 346:1245-1246.

Date Published: 04/19/2006
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