A 15 percent reduction in salt consumption was likely “an important contributor” to a 40 percent reduction in stroke and heart disease deaths in the last decade in England, researchers said Monday.

The “single largest” contribution to the decline in deaths was a decrease in blood pressure, they said.

Smoking and blood cholesterol also declined over the period, 2003-11; produce consumption and body mass index rose. At the same time, there were improvements in treatment for high blood pressure and heart disease, they said in the online British Medical Journal Open.

The English government in 2003 began a program to get companies gradually to reduce the salt levels in processed foods. It led to a 15 percent decrease by 2011, the researchers wrote. Since the start of that program, salt intake fell by 1.4 grams a day. (In the United States, health authorities recommend people consume a limit of around 2 grams a day, depending on several factors such as age; the average intake is 3.4 to 4 grams.)

Because processed foods account for about 80 percent of total salt intake, and the industry undertook a gradual reduction in salt added to all such foods, the researchers said, it’s likely that the salt reduction occurred across the population. Analysis of the data around the disease and deaths show it had a “significant role.”

The salt researchers, from Queen Mary University of London, looked at data from several sources, including the Health Survey for England from 2003 to 2011 that tallies information on diet and health from 31,500 people. Average salt intake was measured through urine samples from nearly 3,000 people who took part in the National Diet and Nutrition Survey.

Salt intake needs to drop further in the U.K., the researchers said. Salt consumption increases blood pressure – a risk factor for stroke and heart disease.