Britons aren't getting enough sun, and now doctors want all of them - even the healthy ones - to start taking vitamin D supplements.
Public Health England (PHE) yesterday said while most people get enough in summer, during the isles' notoriously gloomy autumn and winter months "everyone will need to rely on dietary sources of vitamin D".
"A healthy, balanced diet and short bursts of sunshine will mean most people get all the vitamin D they need in spring and summer," says Dr Louis Nevy, PHE head of nutrition science.
"However, everyone will need to consider taking a supplement in the autumn and winter if you don’t eat enough foods that naturally contain vitamin D or are fortified with it. And those who don't get out in the sun or always cover their skin when they do, should take a vitamin D supplement throughout the year."
A lack of vitamin D causes bone disease rickets, which was common in Victorian times but largely eradicated in the middle of last century.
It's made a comeback in recent years though, with annual cases in the UK doubling since 2006. Its resurgence has been blamed on computer games keeping kids indoors and diets low in fish, eggs and liver.
PHE says people of African, Afro-Caribbean and south Asian descent are particularly at risk due to their darker skin, and should consider taking vitamin D supplements all-year round.
The recommended dose is 10mcg a day.
Even babies need to be topped up if they're being breast-fed - infant formula already has enough, but mothers' milk might not.
Only 5 percent of Kiwi adults are deficient in vitamin D, says the Ministry of Health. New Zealand gets a lot more sun than the UK, but it recommends people living south of Nelson to consider taking supplements between May and August if they don't get out much.