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I'm confused about the fats in butter and margarine. I know butter has cholesterol, but I've heard margarine has trans fats that are just as bad. Can you help me understand this? — Ginger, OR
Rachel Johnson


Many people are confused about the best kind of fats to enjoy in their diets. Butter is very high in saturated fats (62% of the fat in butter is saturated). Margarine is lower in saturated fats (14% of the fat in most margarine is saturated), but, you are correct that margarine is often high in trans fatty acids which are which have been proven to raise LDL cholesterol levels (LDL is the "bad" cholesterol). Trans fats have been in Foods in the News recently because the FDA is looking at adding them to the Nutrition Facts panel.

A process called hydrogenation is used to make margarine firm at room temperature. Hydrogenation changes polyunsaturated fats, which are liquid at room temperature, to the harder trans fats which
give desirable qualities to food.
For example, hydrogenating the oil in peanut butter gives it a creamy consistency and the oil stays mixed in and doesn't rise to the top.

In order to limit your intake of trans fatty acids, choose a soft margarine, preferably those sold in tubs or in squeeze bottles. An even better choice is to use liquid vegetable oils. Olive oil is high in monounsaturated fatty acids and does not raise LDL cholesterol levels. Instead of butter or margarine, try mixing a little minced garlic in with olive oil and dip your bread in this. Liquid vegetable oils (like canola or olive) can also be used in cooking.

About Rachel Johnson

Rachel Johnson, RD, MPH, PhD is Associate Dean of Research for the College of Agriculture and Life Sciences and Associate Professor in the Department of Nutrition and Food Sciences at the University of Vermont. Dr. Johnson earned a Ph.D. in Nutrition from The Pennsylvania State University, and a Master of Public Health degree from the University of Hawaii.

She's a member of the USDA/USDHHS Dietary Guidelines Scientific Advisory Committee, American Dietetic Association (elected member, Commission on Dietetic Registration), and the American Dietetic Association Pediatric Nutrition Practice Group. Dr. Johnson has served as the chair of the sugars subcommittee of the Dietary Guidelines Advisory Committee (2000 edition). Her research expertise is national nutrition policy, nutrition and young children, dietary intake methodology, and energy metabolism.

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