This Vitamin Is Essential For...
healthy bones and teeth.
normal muscle contraction.
Fatty fish such as herring, salmon, and tuna, dairy products, eggs, summer sun, breakfast cereals, and infant formulas are fortified with vitamin D.
The vitamin D we receive from food or supplements is not active until it is converted by the liver and kidneys. Therefore if you have problems with these organs, you may not be absorbing enough Vitamin D. If you sit out in the sun for a short while your reserves will be replenished.
If you are going to take vitamin D supplements, do not take them without calcium and beware of how much you are taking. Always seek professional advice.