Laws that restrict adding trans fats to foods have had immediate beneficial effects on heart health, new research has found.

The Food and Drug Administration plans to restrict the use of trans fats in foods nationwide in 2018, but between 2007 and 2011, some counties in New York State, but not others, banned trans fatty acids in restaurants, bakeries, soup kitchens, park concessions and other public places where food is served. In a natural experiment to test the effect of the ban, researchers compared nine counties with trans fat restrictions to eight that had none.

Cardiovascular disease has been declining nationwide in recent years, but the decline was even steeper in counties where trans fats were banned. Three years after restrictions were imposed, there was an additional 6.2 percent decline in hospital admissions for heart attacks and strokes in counties that banned trans fats compared with those that did not. The study, in JAMA Cardiology, accounted for age and other demographic factors.

“The most important message from these data is that they confirm what we predicted — benefit in the reduction of heart attacks and strokes,” said the lead author, Dr. Eric J. Brandt, a fellow in cardiovascular medicine at Yale. “This is a well-planned and well-executed public policy.”