Other issues of Nutrition Advisor

The truth about trans fats

Saturated fat has certainly been in the news, but have you heard the latest about the next fat to appear on the food label—trans fatty acids?

What are trans fats?
It may sound complicated, but trans refers to the chemical makeup of the fatty acid. During a process called "hydrogenation," hydrogen atoms are added to the fat, making it more stable at room temperature. Although small amounts occur naturally in some animal and dairy foods, most of the trans fat in the foods we eat is made from this process.

Trans fatty acids add desirable effects to foods, like making peanut butter creamier and extending the shelf life of packaged products. That's why you are likely to find trans fat in packaged snacks, such as cookies and crackers and stick margarines.

While other heart healthy fats like mono and polyunsaturated types are an important part of a balanced diet, trans fatty acids are not required for normal health. Instead, trans fatty acids are guilty of increasing the risk for coronary heart disease, decreasing "good" cholesterol and increasing "bad" cholesterol, even more so than saturated fats (1-4).

How much is too much?
When it comes to the amount of trans fat in your diet, it's wise to keep your overall intake to a minimum. A good guideline is to follow the American Heart Association's recommendation for Americans over the age of two, which is no more than 30% of total calories from fat, with a maximum of 7-10% from saturated fat, up to 10% from polyunsaturated fat and 10-15% monounsaturated fat. If you don't exceed a total fat intake of 5-8 teaspoons a day, you're likely to stay within your fat guidelines.

The Yale-New Haven Nutrition Advisor is created by registered dietitians and dietetic interns who staff the Nutrition Clinic at Yale-New Haven Hospital. For information, contact the Nutrition InfoLine at (203) 688-2422.

For more information on this topic, you could visit:

• Press release: Trans fat on food labels: A big help for consumers in watching their cholesterol and staying healthy, says American Dietetic Association, American Dietetic Association, July 8, 2003
• Food labeling: Trans fatty acids in nutrition labeling, nutrient content claims, and health claims, Center for Food Safety and Applied Nutrition, U.S. Food & Drug Administration, August 20, 2003
• Cell membrane trans-fatty acids and the risk of primary cardiac arrest, Circulation, v. 105, no. 6, February 12, 2002
• Press release: Trans fat harder on arteries than saturated fat, American Heart Association, July 13, 2001
• Replacement of dietary saturated fatty acids by trans fatty acids lower serum HDL cholesterol and impairs endothelial function in healthy men and women, Arteriosclerosis, Thrombosis and Vascular Biology, v. 21, no. 7, July 1, 2001
• Trans fatty acids and cholesterol metabolism: mechanistic studies in rats and rabbits fed semipurified diets, International Journal of Food Sciences and Nutrition, v. 52, no. 5, September 2001
• Association between trans fatty acid intake and 10-year risk of coronary heart disease in the Zutphen Elderly Study: a prospective population-based study, The Lancet, v. 357, March 10, 2001

Other issues addressed by Yale-New Haven Nutrition Advisor:

• Understanding yogurt
• Thinking about going low-carb?
• What's to drink?
• Obesity—it's not just for grown-ups anymore
• Fruits and vegetables: Always in season
• Calcium: Not just for bones anymore!
• Mercury Rising
• A powerful B vitamin: Folate
• Vegging out
• Manic for organic
• Beta carotene
• Shellfish & cholesterol
• Archive

Last revised: March 10, 2005 (jj)

Home page URL: http://www.ynhh.org

All information is intended for your general knowledge and is not a substitute for medical advice or treatment for specific medical conditions. You should seek prompt medical care for any specific health issues and consult your physician before starting a new fitness regimen.