Vitamin D is made in the skin after the skin is exposed to sunlight. In the summer months in the UK, most people are able to make enough vitamin D if they have adequate exposure to sunlight. However, in the winter when the sun is too low in the sky, it is not possible to make enough vitamin D from sunlight alone. That is why it is recommended to take a 10 microgram (400 unit) vitamin D supplement between October and March every year. An easy way to remember this is when your shadow is longer than your height, you make no vitamin D from the sun.
Vitamin D is also found in food, for example:
- Oily fish like salmon, sardines, herring, mackerel
- Red meat, liver
- Egg yolks
- Fortified foods such as breakfast cereals and margarines
It is difficult to obtain your full daily requirement of vitamin D from food alone, but it is still recommended to include foods that provide vitamin D in your diet. It is important to maintain a varied and balanced healthy diet to make sure you have a good intake of other nutrients like other vitamins, minerals, and fibre. See the Eatwell Guide for further details.