Vitamin D is essential for healthy bones, and we get most of our vitamin D from exposure to sunlight. Find out how to make sure you get enough without risking sun damage.
Everyone needs vitamin D to absorb calcium and phosphorus from their diet. These minerals are important for healthy bones. A lack of vitamin D (known as vitamin D deficiency) can cause softening and weakening of bones and lead to bone deformities. In children, for example, lack of vitamin D can lead to rickets. In adults, lack of vitamin D can lead to osteomalacia, which causes bone pain and tenderness.
How do we get vitamin D?
Our body creates most of our vitamin D from direct sunlight on our skin.
We also get vitamin D from some foods, such as oily fish (for example salmon, mackerel and sardines), eggs and meat.
Vitamin D is also added to all margarine and infant formula milk, and to some breakfast cereals, soya products, dairy products, powdered milks and low-fat spreads.
How long should we spend in the sun?
There isn't one recommendation to suit everybody. This is because the amount of time you need to spend in the sun for your skin to make enough vitamin D depends on a number of things.
These include your skin type (for example, how dark your skin is or how easily you get sunburnt), the time of year and what time of day it is.
Short daily periods of sun exposure without sunscreen during the summer months (April to October) are enough for most people to make enough vitamin D. Evidence suggests that the most effective time of day for vitamin D production is between 11am and 3pm.
A short period in the sun means a matter of minutes – about 10 to 15 minutes for most people – and is less than the time it takes you to start going red or to burn. The larger the area of your skin that is exposed to sunlight, the more chance there is of making enough vitamin D before you start to burn.
People with darker skin will need to spend longer in the sun to produce the same amount of vitamin D.
In the UK, our skin isn't able to make vitamin D from winter sunlight (November to March) as the sunlight hasn't got enough UVB (ultraviolet B) radiation. During the winter, we get vitamin D from our body's stores and from food sources.
The longer you stay in the sun, especially for prolonged periods without sun protection, the greater the risk of skin cancer. So remember to cover up or protect your skin before the amount of time it takes you to start to turn red or burn later on. For most of the time you spend outside, stay covered up and use sunscreen with a sun protection factor (SPF) of at least 15. Find out more about keeping skin safe in the sun.
Who is at risk of vitamin D deficiency?
Some groups of the population are at risk of vitamin D deficiency, and the Department of Health advises that they take daily vitamin D supplements. These groups are:
- all pregnant and breastfeeding women
- all babies and young children from six months to five years old
- older people aged 65 years and over
- people who are not exposed to much sun, for example those who cover their skin, or who are housebound or confined indoors for long periods
- people who have darker skin, for example those of African Caribbean and South Asian origin
It is important that pregnant and breastfeeding women take a vitamin D supplement to make sure their own needs for vitamin D are met, and so that their baby is born with enough stores of vitamin D for the first few months of its life.
Pregnant women and children aged five or under,who qualify for the Healthy Start scheme can get free supplements containing vitamin D.
Can you have too much vitamin D?
People who take supplements are advised not to take more than 25 micrograms of vitamin D a day, as intakes from supplements above this amount could be harmful.
The amount of vitamin D contained in supplements is sometimes expressed in International Units (IU), where 40 IU equals one microgram of vitamin D.
Your body doesn't make too much vitamin D from sun exposure, but always remember to cover up or protect your skin before the time it takes you to start turning red or to burn later on.
Further information
The Department of Health's recommendations on taking vitamin D supplements are based on advice from the Scientific Advisory Committee on Nutrition (SACN). SACN produced a report in 2007 that summarised the scientific evidence on vitamin D and health. SACN is now reviewing the latest evidence on vitamin D and health and will report on this when it is complete.
Watch an animation on Cancer Research UK's SunSmart website to see how sunburn damages your skin.
In 2010, seven British health organisations produced a joint statement of their views of vitamin D. Read the joint statement on vitamin D.
Find out more about healthy diet in pregnancy.
