Health Effects of Trans Fatty Acids Intake

Testimony submitted at October 30, 2006 hearing before the New York City Board of Health by Walter Willett, M.D., M.P.H., Dr. P.H., Departments of Epidemiology and Nutrition, Harvard School of Public Health

First, I want to thank the New York City Department of Health for providing this opportunity to comment on the proposed restriction of trans fatty acids in food served in public eating places.

Our research group at the Harvard School of Public Health has been investigating the health effects of trans fatty acids since the late 1970s, when their potential for harm came to our attention. This concern was based on the fact that trans fatty acids are similar to, and thus may compete with, essential fatty acids that play critical roles in cell structure and function, that they are by far the most abundant artificial chemical in our food supply, and that the increase in trans fatty acid consumption during the last century has correlated with the rise of coronary heart disease and other major illnesses.

Since 1980, we have examined intake of trans fatty acids in relation to incidence of major health outcomes, including coronary heart disease, in several large populations that include over 200,000 men and women. We have found that persons who consume greater amounts of trans fatty acids have higher risks of coronary heart disease, a finding that has been confirmed by other investigators elsewhere. We and others have provided what is now firm evidence that trans fatty acids have adverse effects on blood cholesterol fractions and inflammatory factors, and that they had adverse effects on the lining of arteries. Together, these findings have provided compelling evidence that trans fatty acids contribute importantly to the development of coronary heart disease in the U.S.; my colleague Dr. Dariush Mozaffarian will describe in detail the number of cases of coronary heart disease that can be prevented by reducing intake of trans fatty acids. In addition to their effects on coronary heart disease, we have found that higher intake of trans fatty acids predicts greater risks of type 2 diabetes, and my colleague Dr. Martha-Claire Morris has found that those who consume more trans fatty acids have a higher risk of Alzheimer’s disease; these findings are probably related to the pro-inflammatory effects of trans fatty acids. Also, we have seen in several studies that intake of trans fatty acids is related to weight gain more strongly than any other dietary factor; this has been confirmed in a recent 5-year study in monkeys.

In summary, the restrictions on the use of trans fatty acids by restaurants proposed by the New York City Department of Health will have major multiple benefits for the residents of New York City and those of us who visit here. Because this is an issue of food safety, this restriction is absolutely appropriate for a Department of Health, just in the same way that the department would restrict the addition of arsenic to food it if was knowingly being adulterated in this way. My colleagues and I applaud the Department for taking this important step forward.

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