On July 9, 2003, the FDA released a statement that it will require food products to start listing the amount of trans fats on the Nutrition Facts panel. The FDA has given food companies until January 1, 2006 to comply with this new requirement. However, it is likely the new rule will result in a reduction in the amount of trans fat in at least some food products long before 2006.

Currently food labels do not reveal the amount of trans fat to be listed. Back in 1993 when the current food labeling requirements went into effect, the FDA still did not regard trans fats as being particularly dangerous. This is because most studies up until that time had shown that hydrogenated fats have a more modest impact on cholesterol levels than do saturated fats. However, in 1990 Drs. Mesink and Katan published a study clearly showing that the more modest cholesterol level raising impact of trans fats compared to saturated fats was due to the fact that while trans fats raised LDL (or ?bad cholesterol?) nearly as much as saturated fats they also lowered HDL (or ?good? cholesterol) levels.1 This troubling finding suggested that trans fats might increase the risk of heart disease at least as much as saturated fats. Still there was no direct evidence linking trans fat intake with more heart attacks. By the time a prospective study of nurses found a strong association between increasing trans fat intake and a greater risk of coronary heart disease,2 the food labeling rules were already going into effect.Research is beginning to show other harmful effects when trans fats replace even saturated fats in the diet. The impairment of the cell function in artery walls (endothelials cells) as well as a reduction in HDL (by 21%) was shown to occur in healthy subjects who were fed trans fat in place of saturated fats.3 Impaired endothelial function is associated with an increased risk of having a heart attack.Another study found that when trans fats displace natural polyunsaturated fats from cell membranes this can increase the risk of cardiac arrythmia (irregular heartbeat) and sudden cardiac death.4 Trans fat also increases lipoprotein(a).5 An increase in lipoprotein(a) greatly increases the risk of dying of a heart attack.It needs to be mentioned that the trans fatty acids found in the meat and milk of ruminant animals (cows, goats, sheep and deer) will NOT require labelling as will the man made trans fats. As pointed out in the CLA article on the back page, these naturally produced trans fats act very differently in the body than those produced by partially hydrogenating vegetable oils. If anything they are beneficial. However, more research is needed to know what benefits (and possibly long-term risks) they have and what would be an approriate amount to use as a supplement.

Bottom line:There is no longer any doubt that trans fats, produced when vegetable oils are partially hydrogenated, increase the risk of heart disease by a variety of mechanisms. While the new food labeling rules should help reduce the trans fat content of packaged foods they will do little to reduce a growing source of trans fat for Americans. Trans fats are found in their highest concentration in frying oils and shortenings. Foods bought at fast food restaurants, bakeries, and donut shops are loaded with heart disease promoting trans fats. Hydrogenation of vegetable oils makes them chemically more stable. They save money for the food industry because they can be used longer in frying and they also increase the shelf life of donuts, chips, cakes, cookies, and other baked goods. However, a conservative estimate is that they kill about 30,000 Americans each year from heart disease.6By James J. Kenney, PhD, RD, LD, FACN.References:1. N Eng J Med 1990;323:439-452. Lancet 1993:341:581-53. Arterioscler Thromb Vasc Biol 2001;21:1233-74. Circulation 2002;105:697-7015. J Lipid Res 1992;33:1493-15016. Am J Clin Nutr 1997;66(suppl):1006S-10S