The U.S. Food and Drug Administration's proposal to ban trans fats from the food supply will trigger some scrambling by manufacturers and restaurant chains, but ultimately it will be a boon to the nation's health, dietitians say.
In fact, food manufacturers had been pivoting away from trans fats before the FDA announced its proposal Thursday, searching for useful substitutes.
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"The lion's share of the added trans fats have been removed from our food supply. But this is a good step toward eliminating the remaining amount that continues to pose heart disease risk for many people," said Kim Larson, a registered dietitian nutritionist and spokeswoman for the Academy of Nutrition & Dietetics.
Even so, the FDA estimates that totally eliminating trans fats could prevent 20,000 heart attacks and 7,000 deaths due to heart disease each year.
Food makers first adopted partially hydrogenated vegetable oils -- the source of trans fats -- as a substitute for butter, due to health concerns over the saturated fats contained in butter, explained Cleveland Clinic dietitian Kristin Kirkpatrick.
Using trans fats to make a cracker gives it flakiness and "adds a buttery taste without putting butter in it," Kirkpatrick said. Trans fats also can be used to add a creamy taste, she said, noting that non-dairy creamers are loaded with the artificial fats.
Other foods that contain trans fats include margarine, prepared desserts, canned cake frosting, microwave popcorn, frozen pizzas and boxed cookies, nutritionists noted.
But the food industry has progressed to the point where trans fats can be replaced with healthier options, with no effect on food's taste or texture, Kirkpatrick said.
"I think this is an opportunity to look at some of those healthier oils, like canola oil or other vegetable oils, and how they can be incorporated into foods that traditionally used trans fats," Kirkpatrick said. "I think we can do that without affecting taste."
Trans fats are created in an industrial process that adds hydrogen to liquid vegetable oils. These partially hydrogenated vegetable oils are solid at room temperature.
Trans fats became popular because of their versatility in food production. They make processed foods "shelf-stable," able to stay on supermarket shelves for months without going bad. Fast food restaurants loved trans fats because they could be used repeatedly in commercial deep fryers without having to be replaced, according to the American Heart Association.
But, trans fats gained a notorious reputation because they literally do everything wrong in the human body when it comes to cholesterol.
They also cause inflammation, said Penny Kris-Etherton, a registered dietitian and professor of nutrition at Penn State University. "Inflammation is not only a root cause of heart disease, but other chronic diseases as well," she said.
Trans fats, which are man-made, shouldn't be confused saturated fats or unsaturated fats.
Saturated fats are considered "bad" fats because they increase your "bad" cholesterol levels, which can cause artery-blocking plaques. Unsaturated fats are considered "good" fats because they increase your levels of "good" cholesterol, a type of cholesterol that actually helps carry away the "bad" cholesterol and prevent plaques.
The use of trans fats has decreased as public knowledge of their health risks increased. New York City banned trans fats in restaurants in 2006. And studies have found that fast-food chains like McDonald's, Burger King and Wendy's have significantly decreased the amount of trans fats used in their french fries.
Food manufacturers also have been limiting the use of trans fats, most notably since the FDA required in 2006 that trans fats be listed on the Nutrition Facts labels placed on nearly all food products.
"As a result of that decision, we have greatly reduced trans fats in the food supply," said Kris-Etherton. "Consumers have become more health- conscious and that has not worked well for the trans fats industry."
The move away from trans fats already has been reflected in the diet of the average American. Trans fat intake has declined per person from 4.6 grams per day in 2006 to about one gram a day in 2012. Levels of trans fatty acids in the blood of white adults in the United States declined 58 percent between 2000 and 2009, according to the U.S. Centers for Disease Control and Prevention.
There are some concerns moving forward, mostly related to what food manufacturers will use as a substitute for trans fats.
"What I wouldn't want the food industry to do is go back to butter, because saturated fats have health risks as well," Kirkpatrick said.
People also shouldn't assume that a trans fat-free food automatically will be good for them.
"If you remove the trans fats from a cookie loaded with sugar, you still have a cookie loaded with sugar," Kirkpatrick said.