The D is for Deficiency
Recent research has shown that upwards of 60% of the population living in Northern climates have a Vitamin D deficiency. This unique vitamin has been implicated in protecting people from 17 varieties of cancer, heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects and periodontal disease.
It is very important to note that all the information in this article pertains specifically to the form of Vitamin D called Cholecalciferol (Vitamin D3). This is the naturally occurring form of Vitamin D produced by your body from sun exposure. Ergocalciferol is produced by irritating fungus and is not naturally found in humans. Although it is less potent than its natural counterpart, Ergocalciferol has been shown to be potentially more toxic.
Using the skin, the liver and the kidneys, our body's can make vitamin D from exposure to ultraviolet radiation from the sun. In order for this process to occur we must have adequate exposure to ample sunlight in the absence of sunscreen. However, due to rising rates of skin cancer direct sun exposure for more than 10-15 minutes without sunscreen is not advised. The problem is compounded by the fact that most people do not spend ample time outdoors in the sun as most of the population spends the day inside at work or school.
The widespread occurrence of Vitamin D deficiency seen more recently in our population may be related to the fact that our ancestors spent much more time outside.
Food is another source of vitamin D but usually occurs at low levels. Fortified foods represent a higher source but are rarely enough to overcome deficiency.
Vitamin D is unique from other vitamins in several ways. For starters, most vitamins are not produced in substantial quantities by the body. The skin's ability to produce Vitamin D from sunlight is unique from all other vitamins. Additionally, every cell in the body has a receptor site specifically for vitamin D. The only other substances in the body that have receptors on every cell are hormones! Due to this fact and the fact that Vitamin D is substantially made within the body implies it would be better classified as a hormone instead of a vitamin.
The RDA values for vitamin D are between 200-600IU's/day depending on your age group (older individuals require higher doses). For a long time many scientists and doctors believed that vitamin D had the potential to be toxic. However extensive research in the last 10 years has failed to find any substantial Vitamin D toxicity even at doses 100x what the RDA considered safe. The Vitamin D counsel http://www.vitamindcouncil.com/ documents and explains the latest research that clearly demonstrates the safety and importance of vitamin D.
The best way to assess your Vitamin D needs is to have your doctor check your levels with a blood test. The only blood test worth getting is referred to as the 25-hydroxy vitamin D test. This is the best test as it is the only one that will measure your Cholecalciferol (D3) levels.
A great example which demonstrates the safety of Vitamin D can be observed by asking mother nature how much we were intended to get. Within 20 minutes of full sun exposure you body makes an excess of 10,000IU of Vitamin D. Consuming the RDA recommended 400IU daily during a significant portion of the year when sun exposure is limited is surely enough to explain why 60% of northern populations are deficient.
Vitamin D is closely associated with autoimmune disease and immune dysfunction in general. This well demonstrated by the clear correlation between the auto-immune condition multiple sclerosis increasing in numbers the farther north of the equator one travels.