BOSTON — Major brand-name reformulations generally have reduced the trans fat content substantially without making equivalent increases in saturated fat content, according to a scientific analysis appearing in the May 27 issue of the New England Journal of Medicine. In most restaurant and supermarket foods, reductions took place in the total combined levels of saturated fat and trans fat. Levels of saturated fat were reduced in most restaurant foods.

Dariush Mozaffarian, a doctor of medicine at Harvard Medical School in Boston, and Michael F. Jacobson, Ph.D., and Julie S. Greenstein, both of the Center for Science in the Public Interest, Washington, presented the research in a letter to the magazine. The Searle Scholar Award from the Searle Funds at the Chicago Community Trust and the Helena Rubenstein Foundation supported the study.

Researchers investigated 83 products, including 58 supermarket foods and 25 restaurant foods, that were reformulated to reduce trans fatty acid content from 1993 through 2006, the first evaluation, and from 2008 through 2009, the second evaluation. They assessed the products based on information from consumer magazines, health newsletters, a non-profit organization database and food composition databases at the Food and Drug Administration.

Reformulations reduced trans fat content to less than 0.5 grams per serving in 95% of the supermarket products and 80% of the restaurant products. Mean absolute reductions were 1.8 grams per serving in supermarket products and 3.3 grams per serving in restaurant products.

After reformulation, saturated fat levels were lower, unchanged or only slightly higher (less than 0.5 grams per serving) in 65% of supermarket products and 90% of restaurant products. Reduction levels in trans fat nearly always exceeded any increase in levels of saturated fat.

The combined levels of trans fat and saturated fat fell in 90% of the supermarket products and 96% of the restaurant products.