Vitamin D, as you probably know, is a fat-soluble steroid hormone precursor that furthers to the support of essential levels of phosphorus and calcium in the bloodstream. In other words, vitamin D is not a vitamin because of the fact that our skin can produce it, but it is concerned to one for several historical reasons. Also if you hear the word "calciferol" know that it is the second name of vitamin D.

Vitamin D has several forms: vitamin D1, vitamin D2, vitamin D3, vitamin D4 and vitamin D5. Vitamin D1 consists of lumisterol and ergocalciferol in 1:1 ratio. Vitamin D2 is called ergocalciferol. Vitamin D3 is made of 7-dehydrocholesterol and it is called cholecalciferol. Vitamin D4 is called dihydroergocalciferol. Vitamin D5 is called sitocalciferol.

Vitamin D3, which second name is cholecalciferol, is the vitamin D natural human form. It is produced in the human skin while via 7-dehydrocholesterol cholesterol reacts with skin ultraviolet light. Do you know that vitamin D and sun are interconnected conceptions? Ultraviolet light, which is found in sunlight while the sun is at the peak of its way for ultraviolet light penetrates the Earth atmosphere, UVB is liable for the cholecalciferol maintenance.

Until the human skin just starts to turn pink under sunlight or after one exposure minimal dose it is possible to produce up to 20,000 IU in our skin; this fact is very interesting about vitamin D and sun. Ergocalciferol is produced by irradiating fungi to create vitamin D2. Ergocalciferol doesn't occur naturally in the human body only if it is added by appendix.

Let's review some interesting facts about vitamin D and sun there are some parts of the globe, specifically at higher latitudes, aggregate vitamin D intake is often not adequate, generally in the winter time, that's why the recent anxiety about vitamin D deficiency is widespread. To assist stave off this possibility, special food such as fortified milk with ergocalciferol or cholecalciferol, but there is one weakness of milk - it contains only 100 IU per one glass, those number of IU can be made after sunbathing during fifteen minutes at solar noon at hot summer.

A strict vitamin D deficiency results in such children disease as rickets, during which the bones become softer and affect mineralization, old people get similar disease which is called osteomalacia. Modern medical investigations associate vitamin D shortage with every disease starting from main cancer forms to heart stroke, diabetes, depression, autoimmune diseases, hypertension, obesity and even periodontal disease.

Vitamin D3 is moved to the liver where cholecalciferol is hydroxylated to 25-hydroxy-vitamin D or calcidiol, the depot of the vitamin form. A blood level of calcidiol is the one and single method to determine deficiency of vitamin D; those levels must be within 40 and 60 ng/ml for optimum human health state.

Calcitriol is the most vitamin active form, a steroid hormone potent. The result of synthesis is calcitriol, it is produced by calcidiol in the kidneys to execute its special endocrine function of supporting the economy of calcium. Gene expression is regulated by transcription factor and Calcitriol binds to it. The result is the support of levels of phosphorus and calcium in the blood and bone with the help of calcitonin and parathyroid hormone.

Thus, now you a general idea about vitamin D and sun, and you know that vitamin D and sunlight are interconnected, because sunlight produces some forms of vitamin D in skin.