Cultural practices that protect the Japanese

sir – Having lived and worked in Japan for 17 years, I agree that lower levels of obesity have contributed to Japan’s relative success in combating Covid-19 (Leading Article, May 22) – eating with chopsticks will always limit food consumption.

More important, however, are the cultural practice of regular handwashing, the wearing of masks when suffering from a cold and the respecting of individual space at all times – combined with the traditional greeting of bowing, rather than a handshake or a hug.

Malcolm Thompson

Crewkerne, Somerset

sir – Japan has a lower death rate from Covid-19 than Britain, in spite of its older population. This fact should be considered in light of correlations that have been reported between vitamin D levels and the incidence or severity of Covid-19 cases. Is it the fish? You can, of course, get adequate vitamin D from sunlight without eating fish, but you generally cannot be deficient in vitamin D if your diet includes a lot of fish.

Of the 10 countries in the world reported by the Helgi Library data provider to have annual per-capita consumption of fish above 50kg, the deaths per reported Covid case currently vary from nil to 4.3 per cent. The British consume 20kg of fish and seem to have a higher ratio of Covid deaths to reported cases.

Included in the top 10 fish-eaters are Japan, Portugal, Iceland, Hong Kong, Norway and South Korea, all of which have populations with a sizeable proportion of over-65s (much as in Britain, where 18 per cent of the population is 65 or over).

Peter Hardy

Norwich