New Risks of Trans Fatty Acids Discovered

One of the most tested controversies in nutrition over past few decades has been over the issue of butter versus margarine and the potential detrimental effects of the types of fat each contain. A recent study published in the American Journal of Clinical Nutrition gives new light on the controversy: implicating trans fatty acids as a major risk factor for type 2 diabetes.

Butter is high in saturated fat: known for its role in increasing risks of hypercholesterolaemia and cardiovascular disease. Margarine, on the other hand, endures a commercial process called hydrogenation to avoid spoilage and increase shelf-life. And the byproducts of this process are trans fatty acids: fats which are identified by their unusual chemical configuration and are found rarely in nature.

Risks of cardiovascular disease have been associated, in previous studies, both with saturated fats and trans fatty acids. The controversy, so it goes, involves the argument over which one is worse. Studies funded by the margarine industry have declared trans fats safer than saturated fats, studies funded by the butter industry show the opposite.

In this study, researchers from the Harvard School of Public Health evaluated the correlation of fat with type 2 diabetes incidence. Looking, retrospectively, at over 84,000 women – the authors concluded that saturated fats (found in animal foods, including butter) and monounsaturated fats (found in nuts and vegetables) were not associated with risk of type 2 diabetes. On the other hand, trans fatty acid intake increased risks of developing diabetes significantly. The only fats associated with a decreased risk of diabetes were polyunsaturated fats, like those found in fish oils.

The authors of the study concluded that “Substituting non hydrogenated polyunsaturated fatty acids for trans fatty acids would likely reduce the risk of type 2 diabetes substantially.” Similar recommendations have been previously made regarding cardiovascular disease.

Confounding the controversy is the lack of food labeling requirement for foods containing trans fatty acids. Currently, the FDA does not mandate trans fats to be listed on standard labels. The problem with food labeling, according to Harvard researcher Walter Willet, is that the current regulations actually encourage manufacturers to increase trans fats to reduce the amount of saturated fats that are required to be listed on the label. If the amount of trans fatty acids were required on food labels, consumers could make more informed decisions.

Foods which are a significant source of trans fatty acids include: margarine, cakes, cookies, doughnuts, crackers, chips, peanut butter and shortening. Foods with ‘hydrogenated oils’ or ‘partially hydrogenated oils’ listed on the ingredient list contain trans fatty acids.