Vitamin D deficiency
Sun produces UV rays which are divided into 3 different types of UV rays which are UVA, UVB and UVC.
UVB radiation produces vitamin D in the skin which is important for healthy bones. In the UK we get most of our vitamin D from sunlight exposure from around late March/early April to the end of September.
We need 10 to 30 minutes in a day several times a day. Exposure to sunlight for too long can cause sunburn.
Calcium and phosphate are important minerals for healthy bones, teeth and muscles and vitamin D helps us absorb these minerals from our diet.
Vitamin D deficiency (lack of vitamin D) can cause bones to become soft and weak, which can lead to bone deformities. For example, in children a lack of vitamin D can lead to rickets. In adults, it can lead to osteomalacia, which causes bone pain and tenderness.
Your body can’t make vitamin D if you’re sitting indoors by a sunny window because UVB rays can’t get through the glass also Using sunbeds isn’t a recommended way of making vitamin D.
Sources of vitamin D other than sunlight:
- Oily fish like salmon, mackerel, herring and sardines
- Red meat, beef liver
- Eggs (egg yolk)
- Infant formula milk
- Some breakfast cereals
- dietary supplements
- Some dairy products, orange juice, soy milk, cow’s milk and cereals
- Shrimp, oysters.
There are 2 types of vitamin D, vitamin D2 and vitamin D3.
Vitamin D2 (ergocalciferol) – is synthesized by plants and is not produced by the human body
Vitamin D3 (cholecalciferol) – which is made in large quantities in the skin when sunlight strikes bare skin. It can also be ingested from animal sources. It’s lipid soluble, stored by adipocyte cells and has half-life of up to two months.
Factors to consider:
- You make the most vitamin D when you expose a large area of your skin, such as your back, rather than a small area such as your face or arms.
- How old you are. As you get older, your skin has a harder time producing vitamin D.
- Whether you’re wearing sunscreen. Sunscreen blocks a lot of vitamin D production.
- The altitude you’re at. The sun is more intense on top of a mountain than at the beach. This means you make more vitamin D the higher up you are (at higher altitudes).
- Whether it is cloudy. Less UVB reaches your skin on a cloudy day and your skin makes less vitamin D.
- Air pollution. Polluted air soaks up UVB or reflects it back into space. This means that if you live somewhere where there is lots of pollution, your skin makes less vitamin D.
After you have exposed your skin for half the time it takes for you to begin to burn, cover up with clothing and go into the shade. Using sunscreen is not as recommended as using shade and clothing to protect your skin, because it hasn’t consistently been shown to prevent all types of skin cancers.
If you want to you can use a sunscreen that blocks both UVA light and UVB light.
Amount Vitamin D for:
- Age 1-70: 600 IU
- Age 71 and older: 800 IU