Vitamin D is needed by the body to regulate the amount of calcium and phosphate in the body.
Calcium and phosphate are nutrients which help keep the bones, teeth and muscles healthy, without which bone deformities and pain can develop.
During the spring and summer in the UK, most people get enough vitamin D from the sun while outdoors, but in the autumn and winter there isn’t enough sunlight to provide adequate amounts.
As the skin doesn’t absorb enough vitamin D from sunlight during the autumn and winter, it’s necessary for people to get the daily dose through their diet.
The best five food sources of vitamin D are oily fish, red meat, liver, egg yolks and foods fortified with vitamin D.
Oily fish includes salmon, sardines, herring and mackerel. Red meat includes pork, beef and lamb
Foods fortified with vitamin D include most fat spreads and some breakfast cereals.
However, as it’s not that easy to get the recommended daily amount of vitamin D through food alone, UK health officials advise taking a vitamin D supplement during the autumn and winter months.
“During the autumn and winter, you need to get vitamin D from your diet because the sun isn’t strong enough for the body to make vitamin D,” said the NHS.
“But since it’s difficult for people to get enough vitamin D from food alone, everyone should consider taking a daily supplement containing 10 micrograms of vitamin D during the autumn and winter.”
Some people who aren’t exposed to the sun much during spring and summer are advised to take vitamin D supplements all year round.
This includes people who aren’t often outdoors, for example those who are frail or housebound, or are in an institution like a care home.
People who usually wear clothes that cover up most of their skin when outdoors are also at risk of becoming deficient in vitamin D during the warmer months.
In addition, people with dark skin from African, African-Caribbean and south Asian backgrounds are too at a higher risk, according to the NHS.
It’s important not to take too much vitamin D as this can weaken the bones and damage the kidneys and heart.
“Taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body,” said the NHS.
“If you choose to take vitamin D supplements, 10 micrograms a day will be enough for most people. Don’t take more than 100 micrograms of vitamin D a day as it could be harmful.”
Children aged one to 10 years shouldn’t have more than 50 micrograms a day, while infants under 12 months shouldn’t have more than 25 micrograms a day.
“If your doctor has recommended you take a different amount of vitamin D, you should follow their advice,” said the NHS.