Vitamin D was first characterised as a fat soluble vitamin, which was needed to prevent the bone disease rickets in children.  However over the last 15 years our understanding has changed, we now know it is also a hormone. 

Vitamin D has many functions; it helps to regulate our bone development, our muscle function, our immune function, our insulin activity, our calcium and phosphorus balance.  Research over the last 15 years has shown us that there are Vitamin D receptors (VDRs) on the cell membranes of most cell types in the body, therefore its functions are no longer believed to be limited to bone metabolism.

Vitamin D and Bone Health

Bone is composed of many substances, including collagen proteins, keratin proteins, a variety of minerals including silicon, boron and magnesium and the important – calcium and phosphorus, this is not without two bone health regulators; parathyroid hormone and Vitamin D.  Vitamin D helps the intestines absorb more calcium from our food, and helps our kidneys retain calcium.

Vitamin D and Immune Function

Our understanding of Vitamin D’s role in immune regulation has changed significantly in recent years.  The link between Vitamin D and auto-immune diseases are now seen as inter-linked.  The discovery of VDRs on the immune system’s cells has been significant. These cells, triggered by Vitamin D are capable of releasing anti-bacterial peptides; these antibacterial peptides play a critical role in the immune system’s prevention of infection.

Vitamin D and Blood Pressure

Vitamin D plays a direct role in regulating blood pressure by inhibiting the rennin-angiotensin system, whose job is to raise blood pressure when it gets too low.  Vitamin D prevents this system raising our blood pressure under inappropriate circumstances.

Vitamin D and Blood Sugar Regulation

Vitamin D deficiency is clearly a risk factor for developing Type II diabetes, and Vitamin D deficiency has been associated with insulin secretion by the pancreas’ beta cells, as well as insulin activity once released into the bloodstream.

Vitamin D and Muscle Composition

Vitamin D deficiency has been associated with too much accumulation of fat throughout muscle tissue, in such a way that muscle strength is decreased and physical performance is compromised.

Vitamin D and Cancer

The role of Vitamin D in cancer prevention is currently under much media attention.  Research has shown a clear role for Vitamin D in prevention of bladder, breast, colon, ovarian, prostate and rectal cancers.

Other Functions of Vitamin D

There is considerable research in the area of Vitamin D deficiency and cognitive function, especially in aging persons, particularly senile dementia and Alzheimer’s disease.

Food Sources of Vitamin D including: Salmon, Sardines, Cod, Eggs and Butter but it is nearly impossible to get adequate amounts of Vitamin D from diet alone.  Sunlight exposure is the only reliable way to generate Vitamin D within the body.  Vitamin D is produced by your skin in response to exposure to ultraviolet radiation from natural sunlight.  Even weak sunscreens (SPF-8) block your body’s ability to generate vitamin D by 95%.  You cannot generate too much vitamin D in your body from sunlight exposure, your body will self-regulate, only generating what it needs. We would recommend having 15 minutes every day of exposure to the sun without sunscreen in order to get your daily requirement. Vitamin D is activated by your kidneys and liver before it can be used.  Having kidney disease or liver damage can impair the body’s ability to activate circulating Vitamin D.

If you don’t get regular sun exposure without SPF, we would recommend having 15 minutes every day of exposure to the sun without sunscreen either before 11am or after 3pm in order to get your daily requirement, or if your need for Vitamin D is higher, then follow the link to a Nutrition Mission recommended Vitamin D supplement -

http://www.nutritionmission.co.uk/shop/product.asp?strParents=0&CAT_ID=0&P_ID=604

At Nutrition Mission we would always recommend having a consultation with one of our qualified nutritional therapists before buying a dietary supplement so that you know which supplements you require rather than waste your money on supplements you may not need.