A pair of studies released Wednesday suggest that diet soda drinkers face a higher risk of heart attack and stroke than people who do not drink any soda, and that salty food boosts stroke risks, too.
The soda study examined 2,564 people in Manhattan and found that those who reported consuming diet fizzy drinks daily had a 61 percent higher risk of vascular events than people who said they did not drink any soda at all.
When researchers factored in allowances for metabolic syndrome, peripheral vascular disease and heart disease history, the risk was 48 percent higher, said the research presented at the American Stroke Association's International Stroke Conference.
"If our results are confirmed with future studies, then it would suggest that diet soda may not be the optimal substitute for sugar-sweetened beverages," said lead study author Hannah Gardener at the University of Miami Miller School of Medicine.
A second study looked at 2,657 participants in the same area and found that high salt intake was linked to a dramatically increased risk of ischemic strokes, in which a blockage cuts blood flow to the brain.
People who reported eating more than 4,000 milligrams of sodium daily - the amount contained in four large orders of french fries in the United States - faced twice the risk of stroke as people who consumed less than 1,500 milligrams per day.
The average American consumes about 3,000 milligrams of salt per day, according to the study, though previous research has said it could be as high as 4,000 milligrams per day.
"Stroke risk, independent of hypertension, increased 16 percent for every 500 milligrams of sodium consumed a day," allowing for adjustments for age, sex, ethnicity, education, alcohol use, exercise, daily caloric intake, smoking status, diabetes, high cholesterol, high blood pressure and previous heart disease, it said.
Current dietary guidelines in the United States urge people to consume less that 2,300 milligrams of sodium per day, or about a teaspoon of salt. The American Heart Association recommends less than 1,500 milligrams per day.