Nutrition notes:Trans Fat Traps

NUTRITION NOTES 

September 7, 2009     Contact: Alice Bender, (202) 328-7744 

Trans Fat Traps 

Karen Collins, MS, RD, CDN

American Institute for Cancer Research 

      The latest World Health Organization’s Scientific Update on trans fat shows that companies are gradually removing them from many popular foods. But even so, it's easy to think you eat less trans fat than you do by falling into some common traps.

      Most trans fat forms when liquid fats are subjected to a process called hydrogenation. Partial hydrogenation makes the oils spreadable or more shelf-stable. Natural trans fats are found in meats and dairy products but are a small proportion of our total intake and do not seem to pose the same health risks as the industrial (partially hydrogenated) trans fats.

      Industrial trans fats account for about 2 to 3 percent of the average adult’s calories. Studies show that an increase of just 2 percent of our calories from trans fats is linked with at least 23 percent increase in heart disease. They increase LDL (“bad”) and decrease HDL (“good”) cholesterol and damage blood vessels. Now, studies suggest trans fat also promotes inflammation, which may raise the risk of cancer as well as heart disease. Current recommendations call for less than 1 percent of calories from trans fats, meaning less than two grams per day for the average adult.

Trap #1: You get trans fat more places than you think   

      Some people assume that trans fat is only in margarine or fast food. Yet research reveals 40 percent of U.S. trans fat comes from foods like cookies, crackers, cakes, pies and muffins. Margarine and shortening account for almost a quarter of trans fat, although margarines and spreads vary widely in fat content. French fries and packaged snacks like chips and microwave popcorn provide about 13 percent of trans fat.

      Trans fat can be just as concentrated in many deep-fried foods, such as chicken nuggets and breaded fish. Even if a restaurant fries food in zero-trans fat oil, if the product is pre-cooked it may have already accumulated trans fat in processing.

Trap #2: “Zero trans fat” doesn’t mean zero

      In the United States, a food with less than 0.5 grams of trans fat per serving is labeled as 0 trans fat. Unfortunately, foods that contain trans fat are often eaten in portions larger than the standard serving listed. So if you have two “0 trans fat” snack cakes that contain 0.4 grams of trans fat per serving, you’ve had more than a third of your recommended limit.

Trap #3: The effect of removing trans fat depends on what replaces it

      Experts say the most common substitutes for partially hydrogenated oils are tropical oils, especially palm oil. At least half of their fat is saturated fat so they’re better, but not ideal. Other substitutes include interesterified oils, customized blends of a liquid oil with a highly saturated fat (like palm oil or a fully hydrogenated oil). Some can be relatively low in saturated fat, but others, especially those for bakery, often contain substantial saturated fat.

      Bottom line: Use oils like olive and canola oil when possible, and choose a soft zero-trans spread with low saturated fat. Limit commercial bakery goods (cookies, pies, donuts); chips; crackers; and processed foods, including commercial sauces and dressings, breaded entrees and vegetables, and cake or muffin mixes. As side benefits, you’ll also reduce sugar, sodium, calories and have a chance to eat more unrefined, high-nutrient foods.

      When you do buy pre-cooked or processed foods, check the Nutrition Facts panel and the ingredients list. Top picks are those that don’t list partially hydrogenated oil and still have a comparatively low total of saturated plus trans fat.  

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The American Institute for Cancer Research (AICR) is the cancer charity that fosters research on the relationship of nutrition, physical activity and weight management to cancer risk, interprets the scientific literature and educates the public about the results. It has contributed more than $87 million for innovative research conducted at universities, hospitals and research centers across the country. AICR has published two landmark reports that interpret the accumulated research in the field and is committed to a process of continuous review. AICR also provides a wide range of educational programs to help millions of Americans learn to make dietary changes for lower cancer risk. Its award-winning New American Plate program is presented in brochures, seminars and on its Web site, www.aicr.org. AICR is a member of the World Cancer Research Fund International.