Vitamin D sources
RDA is only 5 micrograms.
Vitamin D is produced when our skin is exposed to ultra-violet light from the sun.
Where do you get it?
It is available in fatty fish, eggs, milk, butter and cheese, and cod liver oil. Small amounts are found in green, leafy vegetables and mushrooms.
Actions
Vitamin D, the "sunshine vitamin" controls the amount of calcium and phosphorus in your body. It is a fat-soluble vitamin and it is stored all around the body.
It keeps your bones, muscles and teeth healthy, along with your heart and nerves.
Too much
Because we can store vitamin D, we don’t need to take very much on a daily basis.
Too much vitamin D can have toxic effects due to increased blood levels of calcium.
Too little
You might lack vitamin D if you rarely get any sunshine, if you are elderly, especially in winter or if you are a vegan.
Lack of vitamin D can cause muscle weakness, constipation and irritability and ultimately bone pain and deformities, and deafness.
If you want to get more vitamin D it is best to adjust your diet and take cod liver oil in winter and fish oil in the summer.
Supplement
Supplements should be in combination with calcium.