The diet change could also ward off nearly 9 million cases of stroke and heart disease.
A 1 gram reduction in daily salt consumption might prevent over 9 million occurrences of heart disease and strokes and save 4 million lives by 2030, according to estimations published in the open access journal BMJ Nutrition Prevention & Health.
China has one of the highest salt intakes in the world, averaging 11 g/day—more than double the level advised by the Chinese government. High salt consumption raises blood pressure, increasing the risk of cardiovascular disease, which accounts for 40% of all fatalities in China each year.
The researchers set out to assess the health benefits of lowering salt consumption throughout the country in order to help guide the establishment of a feasible salt reduction program.
They gathered the most recent and reliable statistics on population size, salt consumption, blood pressure, and disease rates by location and age, and then assessed the effect on cardiovascular health for three different approaches.
The first of them was to reduce daily salt consumption by 1 gram within a year. The second was the WHO’s interim aim of a 30% reduction by 2025, which equated to a 3.2 gram/day decrease over the period.
The third goal was to reduce salt consumption to less than 5 g per day by 2030, the aim established by the Chinese government in its health and development action plan, ‘Healthy China 2030.’
They then estimated the falls in systolic blood pressure—the higher number in a blood pressure reading that indicates the force at which the heart pumps blood around the body—and the subsequent risk of heart attacks/stroke and cardiovascular disease deaths.
Given that, on average, adults in China consume 11 g/day of salt, reducing this by 1 g/day should lower average systolic blood pressure by about 1.2 mmHg. And if this reduction were achieved in a year and sustained, some 9 million cases of heart disease and stroke could be prevented by 2030—4 million of them fatal.
Keeping this up for another 10 years could add up to around 13 million cases of heart attack and strokes avoided—6 million of them fatal.
Achieving the WHO’s interim target by 2025 would require a 3.2 g/day fall in salt intake. Were this to be maintained for another 5 years, a cumulative total of about 14 million cases of heart disease and strokes could be prevented by 2030—6 million of them fatal.
And if kept up until 2040, the cumulative total could reach around 27 million cases, 12 million of them fatal.
Achieving the ‘Healthy China 2030’ target would require a 6 g/day reduction in salt intake, reducing average systolic blood pressure by just over 7 mmHg, adding up to 17 million cases of heart disease and strokes prevented—8 million of them fatal.
The benefits of a reduction in dietary salt intake would apply to men and women of all ages across China, say the researchers.
There might also be additional health benefits, which the lack of relevant data didn’t allow the researchers to estimate: these include secondary prevention of cardiovascular disease and reductions in cases of chronic kidney disease and stomach cancer, rates of which are already high or rising in China, they suggest.
“The Chinese government’s action plan ‘Healthy China 2030’ includes nutritional recommendations to reduce the intake of salt, sugar, and oil. This modeling study shows that salt reduction alone could bring enormous health benefits to the entire population of China,” say the researchers, adding that a 1 g daily reduction in intake “would be easily achievable.”
But they highlight: “Our estimates rely on salt reductions to not only be achieved but also sustained over time, which may be a great challenge given the fast-changing dietary patterns seen in China given its rapid urbanization.”
They conclude: “The evidence for the substantial benefits of salt reduction in China is consistent and compelling. Achieving and sustaining population salt reduction in China could prevent millions of unnecessary cardiovascular events and deaths. Given the sheer size of the Chinese population, this would also bring major benefits to global health.”
“Modelling studies like this one provide an indicator of how specific dietary changes have the potential to alter the course of diet-related disease,” comments Shane McAuliffe, Science and Digital Communications Lead at the NNEdPro Global Centre for Nutrition and Health, which co-owns the journal.
“Given the established dose-response relationship between salt intake, systolic blood pressure, and cardiovascular disease, reducing the intake of one of the highest global consumers would have a significant impact on population health—something that has already been achieved in other countries worldwide,” he adds.
Reference: “Reducing daily salt intake in China by 1 g could prevent almost 9 million cardiovascular events by 2030: a modelling study” by Monique Tan, Feng He, Joan K Morris and Graham MacGregor, 16 August 2022, BMJ Nutrition Prevention & Health.
The study was funded by the National Institute of Health and Care Research.