What does vitamin D do?
Vitamin D has several important roles – for example, it helps control the amount of calcium and phosphate in your body, which are needed to keep your bones and teeth healthy.
Having too little vitamin D (a deficiency) can damage the way your body absorbs calcium and phosphorus. In children, this can lead to rickets – a condition that can cause bone deformities, such as bowed legs. In adults, vitamin D deficiency can cause rickets (otherwise known as osteomalacia or weak bones), which can make bones painful and tender.
Where do I get vitamin D?
You get most of your vitamin D from sunlight on your skin. This is because the vitamin forms under your skin in reaction to sunlight. Vitamin D is also found in a small number of foods, including:
- Oily fish
- Fortified foods that have had vitamin D added to them – such as breakfast cereals and powdered milk
Who is at risk of vitamin D deficiency?
Most people can get all the vitamin D they need by eating a healthy, balanced diet and getting a little sunlight. However, the Department of Health recommends a daily vitamin D supplement for the following people:
- All children aged six months to four years (see below)
- All pregnant and breastfeeding women
- All people aged 65 and over
- people who aren’t exposed to much sun – for example, people who cover up their skin for cultural reasons, or people who are housebound (stay indoors) for long periods of time
Vitamin D for babies and children
The Department of Health and the Chief Medical Officers recommend a dose of 7-8.5 micrograms (approximately 300 units) for all children aged six months to five years.
If you are exclusively breastfeeding your baby, you should give your baby a daily vitamin D supplement from the age of six months.
If your baby is fed with infant formula, you should give them a daily vitamin D supplement if they are drinking less than 500ml (one pint) of formula a day.
If you are breastfeeding your baby and giving them infant formula as well, they will need a daily vitamin D supplement from the age of six months, or if they are drinking less than 500ml (one pint) of formula a day.
You should continue to give your child a vitamin D supplement until they are five years old.
For more information about vitamin D supplements for children, read our page on vitamins for children. If you qualify, you can get free vitamin drops containing vitamin D from Healthy Start vitamins.
The rays of natural sunlight that produce vitamin D in your skin cannot penetrate glass. This means you cannot get vitamin D inside a car or at home.
- A person would have to drink ten tall glasses of vitamin D fortified milk each day just to get minimum levels of vitamin D into their diet.
- The further you live from the equator, the longer exposure you need to the sun in order to generate vitamin D. Canada, the UK and most U.S. states are far from the equator.
- Weak sunscreens (such as SPF 8) can block Vitamin D by up to 95%. This can cause vitamin d deficiency problems and disease if used commonly.
- 40% of the U.S. population is vitamin D deficient.
- People who are tan require more time in the sun to get vitamin D, because the darker skin pigment blocks the effects of the sun.
Vitamin D Facts
Vitamin D, also known as the sunshine vitamin, is a very important vitamin. It helps us absorb calcium and phosphorus, so we can have strong bones. Vitamin D was discovered due to some people having too little of it in their diets, causing a disease called rickets. In our body, sunlight can help produce vitamin D, beginning with our skin, being changed by our liver, and finally becoming the vitamin we can use when our kidney processes it. The vitamin D pills you can get at the store usually need a working liver and kidney to make them useable by the body. Read on for more fun facts about this very important vitamin!
Interesting Vitamin D Facts:
Vitamin D, although extremely important for the health of your bones, also affects other things. It can be important for the immune system, your heart, and may be helpful in fighting certain cancers. It also plays a role in helping muscles move, and helping nerves carry messages throughout the body.
Vitamin D is a fat soluble vitamin, this means that it sticks around in our bodies for a while. So getting enough vitamin D is important, but taking too much can make people sick.
Some foods naturally have vitamin D. These include fatty fish (tuna, salmon), beef liver, cheese, egg yolks, and mushrooms.
There are lots of foods that are fortified with vitamin D (means they have vitamin D added). These include milk, breakfast cereals, some orange juice, yogurt, margarine, and some soy drinks.
Low vitamin D levels can be bad for you. Some things low levels of this vitamin can cause include high blood pressure and diabetes. If they are really low, you can get a condition called rickets.
Rickets (the big medical name for this is osteomalacia when it occurs in adults) is a softening of the bones in kids, and leads to bowing out of the legs. It can also cause tender bones, some weakness, easily broken bones, muscle spasms, and if it happens in babies can cause a soft skull.
One of the ways that food is fortified with vitamin D is to shine ultraviolet light on it, which changes some of the chemicals into vitamin D.
Low vitamin D levels are becoming a problem in the United States, and is thought to be due to kids spending more time indoors playing games or watching TV, instead of being outside in the sunshine.
A popular remedy many years ago for rickets was cod liver oil, which is a very good source of both vitamin D and vitamin A.
Being indoors and having the sun shine through windows does not help your body make vitamin D. The glass doesn’t allow the type of light, called ultraviolet B light, to go through.
Sunscreen with an SPF (sun protection factor) of 8 or more will block the ultraviolet B light needed for the skin to make vitamin D.
Vitamin D supplements come in two different forms – vitamin D2 and vitamin D3.
How long should we spend in the sun?
There isn’t one recommendation for everyone. 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 factors. These include your skin type (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 of time in the sun means just a few minutes – evidence suggests that about 10 to 15 minutes is enough for most lighter-skinned people – and is less than the time it takes you to start going red or burn.
The larger the area of 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 your risk of skin cancer. Remember to cover up or protect your skin before the time it takes you to start turning red or burn. Stay covered up for most of the time you spend outside and use sunscreen with a sun protection factor (SPF) of at least 15.
Can you have too much vitamin D?
People who take supplements are advised not to take more than 25 micrograms (µg) of vitamin D a day, as intakes from supplements above this amount could be harmful, according to the UK Expert Group on Vitamins and Minerals.
The amount of vitamin D contained in supplements is sometimes expressed in international units (IU), where 40 IU equals 1µg of vitamin D.
Your body doesn’t make too much vitamin D from sun exposure, but always cover up or protect your skin before the time it takes you to start turning red or burn.