Customers will be able to buy low-sodium salt at 959 supermarkets in Beijing as part of the government's efforts to limit salt intake and curtail health problems, such as high blood pressure, that follow a high-salt diet.

Made from refined iodized salt, the low-sodium salt has been proven to be more healthy, especially for people with high blood pressure and senior citizens.

Sodium is known to strengthen the surface tension of blood vessels and cause blood to flow more quickly, eventually causing high blood pressure, the municipal commission of commerce said on Monday.

The promotion of low-sodium salt is being done by the Beijing government as a public service, the commission said. From the end of May, the centralized distribution of promotion-packaged salt will be delivered through the salt monopolies. Each 475 g package will include 75 g provided for free by the government and a 2 g spoon in each package will help people measure their salt use in cooking.

This year, the market share of low-sodium salt among small packaged salt should reach 10 percent, said Ding Xiangyang, the deputy mayor of Beijing, who spoke about the idea at the National People's Congress earlier this year.

"According to government rules, we are going to shift all current salts to low-sodium ones," said Wang Wenli, a saleswoman in charge of the condiment section of a Beijing Ito Yokado Supermarket.

Wang said they had purchased some packaged low sodium salt from the State-owned salt monopoly China Salt Company about six months ago.

"We put up a promotion board beyond the display shelves and it has been selling quite well," she said.

The percentage of sodium contained in the low-sodium salt is less than normal salt by between 35 and 40 percent.

However, the complicated purification process means the healthier type of salt sells for a relatively high price. The government has promised to bring that price down.

According to a 2005 study, the prevalence of high blood pressure among Beijing citizens was the highest among all Chinese cities. The research pointed out that the reasons for the high incidence included an unbalanced diet and static lifestyle.