Action Points

With the growing focus on the ill effects of trans-fatty acids, the majority of food companies have lowered levels of the ingredient in their products — but only about half completely eliminated use of the processed fat, researchers found.

In an analysis of 270 food products, 66% had reduced their trans fat content between 2007 and 2011, Dariush Mozaffarian, MD, DrPH, of the Harvard School of Public Health, and colleagues reported online in Preventing Chronic Disease.

The majority (82%) listed 0 grams of trans fat on their nutrition labels (anything below 0.5 grams qualifies as trans-fat-free per FDA standards), but only half had completely eliminated the use of partially hydrogenated vegetable oil, the main trans fat used in industrially produced foods.

”Manufacturers are at times reducing, but not eliminating, trans fat,” David Katz, MD, director of the Yale-Griffin Prevention Research Center, told MedPage Today. ”A dose of less than 0.5 grams per serving allows for a ’0 g trans fat’ banner on the package per FDA rules, even though there’s still partially hydrogenated oil in the product, and the ingredient list.”

”I am glad to see the progress in this report, but frankly more than a little surprised it has not been greater,” Katz continued. ”Of course, we could all fix that by refusing to buy products containing partially hydrogenated oil.”

Most trans fat in the modern diet is the result of industrially produced partially hydrogenated vegetable oils (PHVO), the researchers said. Partial hydrogenation converts vegetable oils into semi-solid fats that have attractive commercial properties for cooking, baking, and frying.

Use of PHVO rose during the 20th century, but recent evidence has since shown the fats to have cardiovascular and metabolic risks, spurring some companies to reformulate their products to reduce trans fats. New York City banned the use of trans fats in restaurants in 2006.

To assess changes in levels of trans fats in food products, Mozaffarian and colleagues looked at 270 products from prominent brands — including General Mills, Kellogg Company, Heinz, ConAgra, Safeway, Giant, Campbell Soup, Sara Lee, and Walmart — that were selected from certain large supermarkets and sold between 2007 and 2011.

They found that by 2011, 66% of those products had reduced levels of trans fats, with a mean decline of 1.5 grams per serving and a mean 78% drop in trans fat content in that group.

Most of these reformulated products (82%) reduced trans fat content to less than 0.5 grams per serving, but half of them still contained partially hydrogenated vegetable oils in the ingredients list, the researchers found.

”This finding suggests that consumers can view a ’0 grams trans fat’ listing on a reformulated product with cautious optimism, as a substantial proportion of trans fat content has been eliminated,” the researchers wrote. ”Nonetheless, when consumed across multiple servings and different products, these remaining amounts of PHVO pose a health risk and should be eliminated.”

”Given the very strong association between trans fat and adverse health effects, any reduction in prevailing exposure is a good thing,” Katz said. ”But on the other hand … with all of the attention to harmful effects of trans fat, and the availability of alternatives, how is it that manufacturers can still sell, and the public will still buy, products ’contaminated’ with this substance?”

Taking into account all 270 products — including those that didn’t significantly reduce trans fat — the mean trans fat content fell 49% between 2007 and 2011, from 1.9 grams per serving to 0.9 grams per serving (P<0.001). That drop was predominantly due to reformulations that reduced trans-fatty acid to less than 0.5 grams per serving, they noted.

Yet mean trans-fat reduction slowed over time, from 30.3% between 2007 and 2008 to 12.1% between 2008 and 2010 and finally to 3.4% between 2010 and 2011, they reported (P<0.001 for trend) -- largely due to fewer reformulations among products containing trans fats at the start of each period, and smaller reductions in trans fats among reformulated products.

Mozaffarian and colleagues also found that reformulations varied substantially by both food category and manufacturer, with some eliminating or nearly eliminating trans fats and others showing no significant changes.

Differences in reformulation could reflect technical challenges of reformulating certain foods, they noted. French fries, ice cream, and doughnuts were reformulated to meet trans fat goals, they wrote, but popcorn, pies, margarines, and rolls still averaged more than 1.5 grams of trans fats per serving.

However, in each of those latter categories, individual products managed to reduce or eliminate trans fats, suggesting that ”it is possible to produce marketable forms of these products with reduced or eliminated trans fat,” they wrote.

”Because trans fat consumption is harmful even at low levels, our results emphasize the need for continued major efforts and commitment toward reformulating (or discontinuing) foods to eliminate PHVO,” they concluded, ”with particular focus on certain food categories and companies.”