11 May 2017 --- Restaurant foods and commercially processed foods sold in stores accounted for about 70 percent of dietary sodium intake in a study in three US regions, according to new research in the American Heart Association’s journal Circulation. Sodium is an important contributor to high blood pressure, one of the leading causes of heart attack and stroke. The American Heart Association recommends a maximum of 2,300 milligrams (mg) of sodium a day, which is equivalent to 1 teaspoon of salt.