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Diet and Nutrition

Trans Fat: One of the Bad Guys?

 What's all this talk about trans fats? What are they? Where do you find them?  Can they harm me?

 

What are trans fats?

Trans fats are oils formed during food processing when hydrogen is added to “unsaturated” vegetable oil to make it more solid, such as in stick or tub margarines.  This process is called “hydrogenation.”   The oils formed are known as “partially hydrogenated oils” (PHOs) and are the main source of trans fat in the U.S. food supply.

Small quantities of naturally occurring trans fat can be found in animal-based foods such as:

 

Are trans fats unhealthy?

The health benefits of unsaturated oils are lost when they are hydrogenated.  This process adds hydrogen to the oils, resulting in more saturated, less healthy trans fats.  

It is well accepted that trans fat in the diet contributes to heart disease, the leading cause of death in the U.S.  The FDA agrees with expert groups, such as the Institute of Medicine and the American Heart Association, that trans fats have a stronger effect on the risk of coronary heart disease than other types of fats.  Research has shown that trans fat:

Therefore, the 2010 Dietary Guidelines for Americans recommend  that we should eat as little trans fat as possible.  Replacing both saturated fats and trans fats with monounsaturated and polyunsaturated fats may be the best dietary approach for fighting heart disease.

 

What types of foods are more likely to contain trans fat and partially hydrogenated oils (PHOs)?

Food manufacturers use trans fats to improve the texture, shelf life, and flavor stability of foods.  PHOs, and therefore trans fat, can be found in:

By limiting how much of these processed foods you eat, you will control your intake of trans fat.

 

How can I tell if a food is trans fat-free?

All food labels must list the number of grams of trans fat in one serving of the food item. Therefore, many food manufacturers have removed trans fats from their products to increase sales.  So, it is important to read labels to decide if a product is "trans fat-free" or not.

Also check the ingredient list on the product.  Even products listed as “0 g trans fat” on the food label may contain very small amounts of trans fat - less than 0.5 g/serving. The ingredient list will provide information on whether the product contains partially hydrogenated oils.

If a food is already prepared, you may not know if it contains trans fat. To ensure that food eaten away from home is trans fat-free, some states and cities have passed laws to eliminate trans fat from foods sold in:

If you are unsure of your local laws, you can ask the server or manager if the foods prepared in that establishment are trans fat-free.

 

Points to Remember:

 

Sources:

Trans Fat (CDC)

Questions and Answers Regarding Trans Fat (FDA)

 

For more information:

Go to the Diet and Nutrition health topic, where you can:

Last Reviewed: Jul 29, 2014

Bonnie J Brehm, PhD, RD Bonnie J Brehm, PhD, RD
Professor of Nursing
College of Nursing
University of Cincinnati