Salt substitution prevents cardiovascular disease in China, modelling study finds

A nationwide intervention to replace regular household salt with potassium-enriched salt substitutes in China could prevent nearly half a million cardiovascular deaths per year, according to a new modelling study published in the British Medical Journal.

According to Jason Wu, MSc, PhD, senior co-author of the study and program head of nutrition science at The George Institute in Sydney, Australia, replacing regular salt with potassium-enriched salt substitutes combines the blood pressure lowering effects of reduced sodium and increased potassium intake.

The study found that, overall, the blood pressure-lowering effects of salt substitution could prevent more than 460,000 cardiovascular disease (CVD) deaths each year, including 208,000 from stroke and 175,000 from heart disease. They were also estimated to prevent nearly 743,000 non-fatal CVD events each year, including 365,000 strokes and 147,000 heart attacks, and decrease rates of chronic kidney disease (CKD) by around 120,000 each year, or almost 7 percent of new cases.

An important part of this study was to look at the potential benefits of blood pressure reduction at the same time as the possible risk to people with CKD from increased potassium intakes. Among an estimated 17.2 million people with CKD, the blood pressure lowering effects of the intervention could prevent around 32,000 CVD deaths, but the increased potassium intake and higher blood potassium levels could potentially cause some 11,000 additional CVD deaths, resulting in an estimated 21,000 deaths avoided overall.

Eating too much salt increases blood pressure, which is one of the biggest contributors to premature death from stroke or heart disease. Worldwide, excess salt intake is estimated to cause about three million deaths each year.

In China, sodium intake is more than double the World Health Organization-recommended limit, and nearly half of Chinese people ages 35 to 75 years old have high blood pressure. Almost 30 percent of fatal strokes in Chinese people aged under 70 are attributable to high sodium consumption. In contrast to most Western countries, the largest contributor of dietary sodium in China is discretionary salt, or salt added in the home during cooking or at the table, contributing to about two thirds of sodium intake.

“While potassium intake in China is low, intake of sodium is well above recommended levels, mainly coming from salt used at home, in cooking or at the table,” said Wu in a statement. “Salt substitution is therefore a promising strategy to reduce blood pressure and related diseases like CVD and CKD in China, where over two million deaths were attributed to elevated blood pressure in 2015. Our findings suggest that a nationwide intervention to encourage use of potassium-enriched salt substitutes could prevent nearly one in nine CVD deaths in China.”