The healthy eating habit of including fish in one's diet is growing increasingly expensive for older adults in Japan.

The nation’s food inflation surged to a 47-year high in May, with the price of fish increasing by 14.8% compared with the year before, while gains in the price of meat remained at a more modest 8.6%, according to data released by the Statistics Bureau of Japan.

That means those age 70 and above, who spent on average more than ¥7,000 ($48.73) on fish per month, according to the latest household spending data, are feeling a much larger inflationary hit than younger people. Those between the ages of 20 and 29 only spent less than a third of that amount on fish.

Fish remains a major source of protein in Japan, and is particularly important for senior citizens to help reduce loss of muscles and brain cells.

The government announced an increase in monthly pension payments for the first time in 3 years this year, which would raise pensioners’ income by an amount between 1.9% and 2.2%.

But that’s not enough for the growing number of older people facing a higher cost of living, as overall inflation remains above 3%, and the number of workers contributing to the pension system is also shrinking.