Margarine is made through the process of hydrogenating vegetable oils in order to make a more solid or spreadable fat. Liquid vegetable oils, such as soybean, corn and cottonseed oils are bombarded with hydrogen gas, which produces a solid and spreadable, instead of liquid, consistency. Margarine has been marketed as "heart-healthy" due to its lower saturated fat content as compared to butter. Further research has revealed the flaws in this logic. For example, the hydrogenation process produces trans fats, which may increase heart disease risk by promoting inflammation and increasing cholesterol levels.
Inflammation
According to the Linus Pauling Institute, diets high in trans fats can promote inflammation in the body. Chronic inflammation is associated with a number of health conditions, including diabetes, obesity and heart disease.
Cholesterol
Trans fats increase total cholesterol and LDL, or bad cholesterol, levels while actually decreasing HDL, or good cholesterol, levels, according to Gropper's "Advanced Nutrition and Human Metabolism."
Trans Fat Intake Recommendation
The 2010 "Dietary Guidelines for Americans," released by the U.S. Department of Agriculture and Department of Health and Human Services, recommends that Americans should keep their intake of trans fats as low as possible. This should entail eliminating any margarine that lists "hydrogenated oil" on the label.
Labeling Loophole
Starting in January of 2006, foods with a nutrition facts label are required to list the amount of trans fats per serving of that food. The purpose of this labeling law was to allow you, the consumer, to see which foods have trans fats, so you could make an informed decision about which foods to eat. Unfortunately, the regulations regarding the labeling of trans fat content in foods are somewhat misleading. Food manufacturers can list a food as having 0 g of trans fat per serving on the label if the food has less than 0.5 g of trans fat per serving. Trans fat content from multiple sources in the diet like margarine, shortening and baked goods could add up to a significant amount of trans fats in the diet daily, though the label may you lead to believe you aren't consuming any trans fat at all.
Trans fats aren't the only problem with margarine. The other oils in margarine are often soybean, corn and cottonseed oils. These oils are high in omega-6 fatty acids, which promote inflammation in the body, according to the Linus Pauling Institute. Many non-hydrogenated margarines contain significant amounts of pro-inflammatory omega-6 fatty acids. While the trans fat problem has been eliminated from non-hydrogenated margarines, the omega-6 fatty acids still present a heart disease risk.
References
- Linus Pauling Institute at Oregon State University: Inflammation
- "Advanced Nutrition and Human Metabolism"; Sareen Gropper, Jack Smith, James Groff; 2005
- Dietary Guidelines for Americans 2010
