What is it?
Vitamin D is a fat soluble vitamin. We can make Vitamin D in our bodies by a process which starts with the action of sunlight on our skin. Interestingly the UV spectrum in the UK is only sufficient to stimulate the production of vitamin D between April and October. However it is generally considered that with sufficient exposure to sunlight during these months the body makes enough to put into storage (in the liver) to see us through the other five months of the year.
What does it do?
- Vitamin D helps our body to absorb and use minerals including Calcium & Phosphorus. These minerals are crucial for the health of our bones, teeth and muscles.
- Tooth decay
- Joint pain, backache
- Muscle cramps
- Severe deficiency can cause rickets in children and osteomalcia in adults.
People may become deficient in Vitamin D if they either do not have sufficient levels in their diets e.g. some vegan diets, or who do not get enough sunlight e.g. elderly people in nursing homes and also those with high natural levels of sunlight-blocking melatonin in their skin. As the liver is involved in converting vitamin D to its active form people with liver problems may also suffer from deficiency as their livers are not healthy enough to convert or store vitamin D.
Recommended Daily Amount (RDA)
Therapeutic amounts are generally considered to be slightly higher than RDAs however there are toxicity issues associated with higher doses of vitamin D. Higher doses should be considered in conjunction with a healthcare practitioner.
Cod liver oil, oily fish, including salmon, mackerel, herrings etc, oysters, butter and egg yolks.
Vitamin D has the greatest tendency of all vitamins to be toxic in large quantities. Doses of more than 1000 ius are not recommended (Ref Murray).