As a lack of vitamin D is linked to various diseases including the return of rickets, cancer, heart disease, tuberculosis and diabetes.
Since it is produced in the skin on exposure to sunlight, those living in Scotland and the North of England are more likely to suffer deficiency.
Experts recommend between five and 25 micrograms per day, however, 90 per cent of adults in the UK make less than three.
The situation is worst for those north of Birmingham where the sun is too weak in winter for the vitamin to be produced.
A recent report in the US journal Proceedings of the National Academy of Sciences revealed that people with higher levels were more likely to survive colon, breast and lung cancer. This follows last year’s University of San Diego review of 40 years of research, which revealed that a daily dose could halve the risk of breast and bowel cancer.
Other claims are that it reduces the risk of heart disease (a study of 10,000 women in California found that those who took supplements had a 31 per cent lower risk of dying from it), diabetes (in a Finnish study of 12,000 children, it cut their chance of developing Type A diabetes by 80 per cent), even colds and flu (New Yorkers who took vitamin D had flu 70 per cent less often).
Yet despite this increasingly compelling evidence, too many of us are not getting enough. The result: a resurgence in rickets, which stunts growth and deforms the skeleton, causing bowed legs.
Vitamin D Fact File
90 per cent of the body’s supply of vitamin D is generated by reaction to sunlight on the skin.
Vitamin D is found in oily fish like sardines, salmon, mackerel and tuna, cod liver oil, and in milk, cheese, eggs and liver.
“Healthy Start” supplements for children up to the age of four are given free to those on benefits but can also be bought for £1.70 at pharmacies or health clinics.
The first mention of rickets is credited to Daniel Whistler, an English doctor who wrote a paper in 1645 on the subject.
Vitamin D was named in 1922 by the American biochemist Elmer McCollum, who performed experiments to find the nutrients within cod liver oil. It was so called because it was the fourth substance he identified.
One in 100 children from ethnic minorities in this country is thought to be deficient in vitamin D; darker skin requires more sun to produce the vitamin.
In 2003 a New York couple were convicted of endangering the life of their 15-month-old baby after subjecting her to a strict vegan diet which left her suffering from rickets. Silva and Joseph Swinton were sentenced to six and five years in jail.
The classic signs of rickets are bow legs caused by softening of the bones; if not detected early surgery is needed to correct it.
Most people can make enough vitamin D in the summer to last them through the winter