Manabu "Mani" Nakamura, a professor of biochemical and molecular nutrition, earned his doctor of veterinary medicine degree at the University of Tokyo. After practicing in veterinary medicine for several years, he began graduate study in nutrition at the University of California at Davis, where he earned his doctorate. He joined the faculty at Illinois in 2000. His research interests include metabolism and the function of polyunsaturated fatty acids; the molecular mechanisms of dietary induced obesity and insulin resistance; dietary fat and cardiovascular health; and nutrition education.
The KFC restaurant company recently announced it was eliminating trans fats in many of the foods it offers. How important a step is this for consumers, and do you think it will start a trend among fast-food restaurants?
This is a welcome move. Although frying oil is not the only source of trans fats, this is certainly a positive step toward reducing trans fats in our diet. I believe that other fast-food restaurants will follow KFC's example because it will make their products healthier, and because alternatives to trans fat oil are becoming more economically feasible.
What are trans fats?
Trans fats are unsaturated fats that have a slightly different chemical structure from common unsaturated fats in foods. A very small amount of trans fat is present in natural foods. However, a large amount of trans fat is generated when oils are treated with a process called partial hydrogenation, which reduces the amount of polyunsaturated fats in vegetable oils such as corn oil and soybean oil. The food industry uses this process to improve the stability of frying oil. Partial hydrogenation is also used to create shortening and margarine from vegetable oil.
Why are trans fats bad for us?
Trans fats raise blood cholesterol, and thus increase the risk of heart disease, the No. 1 killer in the U.S. By elevating blood cholesterol, trans fats act more like saturated fats than unsaturated fats.
Are there substitutes for trans fats that are healthier alternatives and that don't adversely affect the taste of food?
Yes, there are. One is to develop breeds of corn and soy that naturally have desirable fat composition for frying oil or shortening. Another is to use new and different processing methods besides partial hydrogenation in order to create the creamy texture for margarine. The agriculture and food industries are already moving in this direction. Healthy foods will become more available and affordable in the future.
The FDA recently mandated that the amount of trans fats must be shown on food labels. So, you can compare and choose trans fat-free or low trans fat products when you shop for baked goods, margarine and shortening. Most of the cooking and salad oils for household use do not contain trans fats.