Study Suggests Average Sodium Consumption Safe for Heart Health

New research shows that, for the vast majority of individuals, sodium consumption doesn't increase health risks except in those who eat more than 5 g per day, the equivalent of 2.5 tsp of salt.

Less than 5% of individuals in developed countries exceed that level.

The large, international study also shows that even for those individuals there is good news. Any health risk of sodium intake is virtually eliminated if people improve their diet quality by adding fruits, vegetables, dairy foods, potatoes, and other potassium-rich foods.

The research, published in The Lancet, is by scientists of the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences, along with their research colleagues from 21 countries.

The study followed 94,000 people, aged 35 to 70, for an average of eight years in communities from 18 countries around the world and found there was an associated risk of CVD and strokes only where the average intake is greater than 5 g sodium a day.

China is the only country in their study where 80% of communities have a sodium intake of more than 5 g per day. In the other countries, the majority of the communities had an average sodium consumption of 3 to 5 g per day (equivalent to 1.5 to 2.5 tsp of salt).

"The World Health Organization recommends consumption of less than 2 g of sodium—that's 1 tsp of salt—a day as a preventive measure against cardiovascular disease, but there is little evidence in terms of improved health outcomes that individuals ever achieve at such a low level," says Andrew Mente, PhD, MA, first author of the study, a PHRI researcher, and an associate professor of the department of health research methods, evidence, and impact at McMaster University.

He adds that the American Heart Association recommends even less—1.5 g sodium per day for individuals at risk of heart disease.

"Only in the communities with the most sodium intake—those over 5 g a day of sodium—which is mainly in China, did we find a direct link between sodium intake and major cardiovascular events like heart attack and stroke.

"In communities that consumed less than 5 g of sodium a day, the opposite was the case. Sodium consumption was inversely associated with myocardial infarction or heart attacks and total mortality, and no increase in stroke."

Mente adds, "We found all major cardiovascular problems, including death, decreased in communities and countries where there is an increased consumption of potassium, which is found in foods such as fruits, vegetables, dairy foods, potatoes, and nuts and beans."

The information for the research article came from the ongoing, international Prospective Urban Rural Epidemiology study run by the PHRI.

Most previous studies relating sodium intake to heart disease and stroke were based on individual-level information, says Martin O'Donnell, MB, MRCPI, coauthor of the report, a PHRI researcher, and an associate clinical professor of medicine at McMaster.

"Public health strategies should be based on best evidence. Our findings demonstrate that community-level interventions to reduce sodium intake should target communities with high sodium consumption, and should be embedded within approaches to improve overall dietary quality.

"There is no convincing evidence that people with moderate or average sodium intake need to reduce their sodium intake for prevention of heart disease and stroke," O'Donnell says.

— Source: McMaster University