Despite years of public health campaigns, salt consumption in Japan has not decreased as expected, recent research shows.
Experts are reviewing their anti-sodium pushes to better address the situation.
High salt intake can lead to a range of health problems, including high blood pressure and hardening of the arteries, which could eventually cause strokes or heart attacks.
The Japanese diet has changed over the years, and traditional foods containing high levels of salt, such as miso soup and tsukemono (pickles), are no longer the sole culprits, experts say. They also say people in different age groups should be advised distinctly.
According to the annual National Health and Nutrition Survey by the Health, Labor and Welfare Ministry, the average sodium intake in Japan was 10 grams a day in 2014.
Although that is down from 11.2 grams 2004, the anti-sodium campaign has not been a big success, given that total daily calories consumed have decreased by more than 15 percent over the past 40 years.
Experts acknowledge that their research has not been thorough enough.
“Japan has lagged behind others in grasping the amount of salt people take from different foods,” said Satoshi Sasaki, a nutrition professor at the University of Tokyo.
To determine what food contributes to sodium intake and by how much, Sasaki, worked with nutritionists nationwide in 2013 to measure the precise amount of sodium discharged by 760 healthy people who agreed to undergo urine tests.
In addition, he asked the participants to log their diet history as rigorously as possible, down to the volume of soy sauce dropped on a tiny plate.
The results showed that average salt intake per day was 14 grams for men and 11.8 grams for women. The figures were far above the government’s goal of reducing intake to less than 8 grams for men and 7 grams for women. The World Health Organization recommends an intake of 5 grams.
According to a 2013 survey published in the BMJ Open, an open-access journal run by BMJ Publishing Group, Japan ranked 15th in the world in daily salt consumption in 2010 at 12.4 grams, with the highest sodium consumers in Kazakhstan, at 15.2 grams a day. As a whole, Asian countries ranked high on the list of 187 nations surveyed.
By category, Japanese consumed salt from seasonings, bread, noodles and other processed foods. In particular, soy sauce, salt and miso were major culprits, meaning that it’s not the food itself but the way it is cooked or seasoned that ultimately influences levels in the body, experts say.
A separate survey by the Niigata Prefectural Government underscored the trend.
The prefecture found that a public health campaign it started in 2009 to cut salt consumption by residents has shown little progress so far.
During the campaign, the prefectural staff offered nutrition and lifestyle advice on how to reduce salt intake. They also urged residents to eat more vegetables and fruits, because they contain potassium that helps discharge sodium. Few people, however, followed this advice.
Nobuko Murayama, a professor of public health nutrition at the University of Niigata Prefecture, said her research found that people in different age groups have completely different dietary habits.
Among people between 20 and 50, those who often consumed one-plate dinners such as ramen, soba and udon (wheat flour noodles) and curry rice, were found to consume more salt.
Many people in these age groups also ate a combination of high-sodium foods per meal, such as bento and instant noodles, or fried rice with ramen. While the amount of salt contained often varies among restaurants and food providers, a bowl of ramen typically contains 6 or 7 grams of salt, while a bowl of curry rice contains 2 to 4 grams.
Among people 60 and over, the number of stewed and salted dishes they ate affected their sodium intake.
Based on the results of the survey, the Niigata Prefectural Government recently compiled a leaflet on “10 eating habits that make Niigata residents overconsume salt,” urging people not to have one-plate dinners too often and reduce the number of salty stewed dishes and pickles.
The prefecture also urged company cafeterias and businesses selling bento to reduce the amount of salt they use and increase the amount of vegetables and fruits on their menus instead. The prefecture even called on food manufacturers to make their products less salty.
“High blood pressure has a huge impact on people’s health,” Sasaki said. “To reduce salt consumption, we need to understand the sources of their intake and take a long-term approach.”