This site is intended for health professionals only

Study: Salt intake drop leads to 40% fewer CVD deaths

Lower salt intake has had a "key role" in plummeting cardiovascular disease deaths over the past ten years, a study published BMJ Open has claimed. 

Average salt intake fell by 15% in 2003/11 in England, while deaths from heart disease and stroke fell by around 40%. 

However, the authors have warned that average intake is "far too high" across the country. 

Dietary salt is known to increase blood pressure, which is a major risk for heart disease and stroke. 

Researchers from Queen Mary University looked at more than 31,500 people taking part in the Health Survey for England in 2003, 2006, 2008 and 2011. 

Initiatives to curb population salt intake began in 2003. 

The average population salt intake was calculated from urine collected over a 24 hour period in almost 3,000 people who were part of the National Diet and Nutrition Survey between 2003 and 2011. This survey involves random samples of the population.

During this period, nationally collated figures show that stroke deaths fell by 42% while deaths from coronary heart disease dropped by 40% in England.

Similarly, the prevalence of several risk factors for cardiovascular disease also fell, including average cholesterol, blood pressure (3/1.4 mm Hg), and smoking, although average weight (Body Mass Index) rose. And fruit and vegetable consumption rose slightly.

With the exception of increasing weight gain, all these trends, along with better treatment of cardiovascular disease and its risk factors would have probably contributed to the dramatic falls in stroke and heart disease deaths, explain the authors.

But daily salt intake fell by an average of 1.4 g during this period, amounting to a drop of 15%. And among those not taking blood pressure lowering drugs, average blood pressure still fell by 2.7/1.1 mm Hg, even after taking into account other influential factors.

The authors used several sets of data, involving different people, so were not able to track changes at the individual level, nor were they able to account for physical activity levels.

Nevertheless, they wrote: “The reduction in salt intake is likely to be an important contributor to the falls in blood pressure in England from 2003 to 2011. As a result, the decrease in salt intake would have played an important role in the reduction in stroke and ischaemic heart disease mortality during this period.”

Despite considerable progress, 70% of the adult population is still eating more than the recommended 6g/day, with 80% of intake coming from processed foods, the authors wrote.

“Therefore, continuing and much greater efforts are needed to achieve further reductions in salt intake to prevent the maximum number of stroke and heart disease deaths."

The full paper is available to view on the BMJ Open website