For more than a decade, the Food and Drug Administration has been mulling the question of trans fats: what to do about the partially hydrogenated oils increasingly linked to heart disease?
The FDA provided an answer in dramatic fashion Thursday, saying that it was considering a determination that trans fats are not "generally recognized as safe" for use in food, banning them almost entirely.
"One of the FDA's core regulatory functions is ensuring that food, including all substances added to food, is safe," said Michael Taylor, deputy commissioner for foods and veterinary medicine. "Food manufacturers have voluntarily decreased trans-fat levels in many foods in recent years, but a substantial number of food products still contain partially hydrogenated oils, which are the major source of trans fat in processed food."
Trans fats are a common ingredient in foods such as frozen pizzas, margarine, frosting and microwave popcorn. They are manufactured by adding hydrogen to vegetable oils and used primarily for their low cost and ability to extend shelf life.
Trans fats that occur naturally in small amounts in some meat and dairy products would not be affected by the proposed FDA ban.
The FDA opened up a 60-day comment period on its proposed new rule, which would classify artificial trans fats as a food additive not generally recognized as safe. Manufacturers wishing to use trans fats in their foods would have to apply with the agency to show that the products are not a threat to public health.
The Institute of Medicine in 2002 determined that trans fats provide no known health benefit and that there is no safe level for consumption of them.
"There's pretty good evidence to suggest that getting rid of it would save lots of lives," said Karen Hacker, director of the Allegheny County Health Department, noting that trans fats can boost the levels of LDL, or "bad cholesterol" and suppress levels of HDL, or "good cholesterol."
Research has also linked trans fats to diabetes and macular degeneration, which causes a loss of vision, said Leslie Bonci, director of sports nutrition at the UPMC Center for Sports Medicine. "Literally, it's from head to toe," she said. "This has some very adverse health consequences."
The FDA in 2006 started requiring that trans fat information be included on nutrition labels. Intake among Americans has declined from 4.6 grams per day in 2003 to about 1 gram per day in 2012, according to the agency.
Major chains such McDonald's and Dunkin Donuts have eliminated trans fats from their menus in recent years, spurred in part by a 2007 New York City ban on the fats.
Other chains, such as Popeyes and Hardee's, still use them, however, and the fats are still present in processed foods such as frozen desserts and coffee creamer.
Dr. Hacker applauded the FDA's decision to ban the fats nationwide, saying that local control can be problematic in this area. Other governments, such as Philadelphia and California, have also banned them.
"I just think the nice thing for us is that this takes it out of the responsibility of a local organization," she said. "If you just do this on a community-by-community basis, we worry that the cost of food could go up, put restaurants out of business."
While the cost of oil without trans fats was once prohibitively expensive, costs have come down considerably in recent years as demand for trans fat-free oil has risen, she said.
Local bans can also become political hot potatoes. A nationwide survey conducted in the past week by the Pew Research Center found 44 percent of those polled in favor of prohibiting restaurants from using trans fats in foods and 52 percent opposed, with opposition highest among Republicans.
Though the elimination of trans fats is certainly a positive health step, Ms. Bonci said that consumers should not think that a product is healthy just because it doesn't have trans fats.
"It's certainly a step in the right direction, but let's think about the entire plate," she said. "Just because they take the trans fat out and replace it with something doesn't make it a healthier product -- it's still a doughnut, still a french fry. You don't see trans fat in grapes."
Anya Sostek: email@example.com or 412-263-1308.