See Stier on CBS's Early Show 10/31/06 on trans fats.
See Stier on CNBC's Power Lunch 12/05/06 on trans fats
Executive Summary
• Most of the trans fatty acids (TFAs) in the U.S. food supply are derived from partially hydrogenated vegetable oils. TFAs also occur naturally in beef, lamb, and dairy products. TFAs accounted for about 2.5 percent of the energy (calorie) content of the U.S. diet prior to any changes prompted by the 2006 requirement for the inclusion of trans fat in nutrition labeling.
• TFAs are one of several dietary factors that affect blood lipid levels, and blood lipid levels are one of several factors that influence the risk of heart disease.
• Until the early 1990s, scientists generally believed that the impact of TFAs on blood lipid levels was minimal, and that fats that contain TFAs were a desirable replacement for saturated fats. More recent research indicates, however, that TFAs raise blood levels of undesirable low-density lipoprotein (LDL) cholesterol to an extent comparable to that produced by saturated fatty acids and that TFAs, particularly at high levels of intake, may also lower levels of desirable high-density lipoprotein (HDL) cholesterol, an effect that saturated fatty acids do not share.
• Based on the effects of TFAs on lipid levels, it has been estimated that replacing all of the TFAs from partially hydrogenated vegetable oils in the U.S. diet with cis unsaturated fatty acids could lead to as much as a 3 to 6 percent reduction in heart disease risk. This value should be regarded only as a rough estimate because there are multiple sources of uncertainty in the data used to calculate it. Moreover, the reduction achievable in practice is likely to be substantially lower than calculated estimates because cis unsaturated fatty acids cannot replace TFAs in some food applications for reasons related to texture or stability.
• Much higher estimates of the benefit that could be achieved by removing TFAs from the diet have occasionally appeared in the scientific literature and the news media. These estimates are based on epidemiological data that may not reflect a cause-and-effect relationship.
• Contrary to some reports in the news media, the calorie counts of fats containing TFAs are no higher than those of other fats. The scientific rationale for limiting the consumption of TFAs is related to effects on blood cholesterol levels, not effects on obesity. All types of fat are equally high in calories.
• As part of an overall effort to reduce risk factors for heart disease, advice to the public to limit consumption of both saturated fatty acids and TFAs by substituting polyunsaturated or monounsaturated fats whenever possible is justified by the scientific evidence. Scare tactics, including claims that there should be zero tolerance for TFAs in the food supply, are not justified.
• Overstating the health effects of TFAs is harmful to public health because it promotes an overemphasis on this single dietary factor as opposed to other aspects of diet, other risk factors for coronary heart disease, and other public health priorities. By drawing attention away from other, more significant health risks, the current exaggerated focus on TFAs may actually cause more problems than it solves.
Introduction
The recent addition of trans fat information to the Nutrition Facts labels on food products, combined with news media reports and activists’ warnings, have brought these fats to the forefront of public concern. In a national survey conducted in November 2005, 81 percent of a representative sample of U.S. consumers reported being aware of trans fats, and 54 percent indicated that they were trying to decrease their trans fat consumption (IFIC Foundation, 2006).
Putting the role of trans fatty acids (TFAs) into perspective can be difficult, both because of the intensity of the rhetoric surrounding them and because of widely varying claims about the extent of the health risk they pose. Should American consumers believe the Food and Drug Administration’s claim that between 600 and 1,200 heart attacks per year will be averted by trans fat labeling on food products? Or should they believe the predictions by some scientists that removal of TFAs from the food supply could prevent more than 200,000 heart attacks per year? Is some number between these two extremes more realistic? Or are the data insufficient to justify confidence in any numerical estimates at all?
In this report, the American Council on Science and Health (ACSH) reviews the scientific evidence on the health effects of TFAs in foods, explaining the origins of the widely divergent estimates of the health impact of TFAs and providing perspective on the relative importance of TFA intake in comparison with other aspects of diet and other risk factors for coronary heart disease.
BELOW IS A TABLE OF CONTENTS FOR THE FULL REPORT, WHICH CAN BE ORDERED -- OR DOWNLOADED FOR FREE -- AT THE RIGHT MARGIN.
