Vitamin D is an important vitamin that helps regulate the amount of calcium and phosphate in the body.
Calcium and phosphate are needed to keep bones, teeth and muscles healthy.
A lack of vitamin D can cause bones to become soft and weak.
This can lead to bone deformities such as rickets in children, and bone pain in adults.
During the spring and summer months, from about late March to late September, most people get all the vitamin D they need from sunlight.
This is because the body creates vitamin D from direct sunlight on the skin.
However, during the autumn and winter months in the UK, from October to March, sunlight doesn’t contain enough UVB radiation in winter for skin to be able to make vitamin D.
In order to avoid a deficiency, the UK Department of Health recommends everyone take a daily supplement of vitamin D during these months.
Daily supplements should contain 10mcg of vitamin D.
It’s important not to take too many vitamin D supplements over a long period of time, as this can cause too much calcium to build up in the body.
This condition is known as hypercalcaemia, and can weaken the bones and damage the kidneys and heart.
The NHS warns not to take more than 100mcg of vitamin D a day, as this could be harmful.
Children between the ages of one and 10 should have no more of 50mcg a day, and infants under 12 months should have a maximum of 25mcg.
“If you choose to take vitamin D supplements, 10mcg a day will be enough for most people,” said the NHS.
It’s also possible to get vitamin D from some foods, such as oily fish, red meat, liver, egg yolks and fortified foods.
Oily fish includes salmon, sardines, herring and mackerel.
Fortified foods include most fat spreads and some breakfast cereals.
While sunlight provides enough vitamin D for most people during the spring and summer, some people may still be at risk of becoming deficient at this time.
Those still at risk during the summer include people who aren’t often outdoors, people who live in care homes, and people who usually wear clothes that cover up most of the skin when outdoors.
People with dark skin from African, African-Caribbean and south Asian backgrounds may also not get enough vitamin D from sunlight.
As a result, people in those categories may wish to take vitamin D supplements all year round.