In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it (as vitamin D3) when sun exposure is adequate (hence its nickname, the "sunshine vitamin"). Several forms of vitamin D exist however the two major forms are vitamin D2 or ergocalciferol, and vitamin D3 or cholecalciferol known collectively as calciferol. Vitamin D is a group of fat-soluble secosteroids (steroids in which one of the bonds in the steroid rings is broken).
When synthesized in the kidneys, calcitriol circulates as a hormone, regulating the concentration of calcium and phosphate in the bloodstream and promoting the healthy growth and remodelling of bone. Vitamin D prevents rickets in children and osteomalacia in adults, and, together with calcium, helps to protect older adults from osteoporosis. Vitamin D also affects neuromuscular function, inflammation, and influences the action of many genes that regulate the proliferation, differentiation and apoptosis of cells.
Serum levels (from a vitamin D3 blood test) reflect endogenous synthesis from exposure to sunlight as well as intake from the diet, and it is believed that synthesis may contribute generally to the maintenance of adequate serum concentrations. Evidence indicates that the synthesis of vitamin D from sun exposure works in a feedback loop that prevents toxicity but, because of uncertainty about the cancer risk from sunlight, no recommendations are issued by the Institute of Medicine, USA, for the amount of sun exposure required to meet vitamin D requirements. Accordingly, the Dietary Reference Intakes for vitamin D assume that no synthesis occurs and that all of a person's vitamin D is from their diet.
The relationship between latitude and UVB penetration is however complicated by factors such as atmosphere height (50% higher at the equator), cloud cover (denser at the equator) and ozone layer density, and latitude does not consistently predict the average serum vitamin D level of a population. UVB penetrating to the earth's surface over 24 hours during the summer months in northern Canada (where summer days are longer) equals or exceeds UVB penetration at the equator, allowing sufficient opportunity during the spring, summer, and fall at high latitude to form and store vitamin D3.
It is important to take magnesium with vitamin D. Many people today in the West do not have adequate magnesium levels. It has been shown that showering after sunbathing can wash off the Vitamin D on the skin.
Supplemental vitamin D3 appears to decrease mortality, with the best evidence of a benefit in elderly women. Low serum vitamin D levels are associated with rickets, falls, and low bone mineral density. One of the most important roles of vitamin D is to maintain skeletal calcium balance by promoting calcium absorption in the intestines, promoting bone reabsorption by increasing osteoclast number, maintaining calcium and phosphate levels for bone formation, and allowing proper functioning of parathyroid hormone to maintain serum calcium levels. Vitamin D deficiency can result in lower bone mineral density and an increased risk of bone loss (osteoporosis) or bone fracture because a lack of vitamin D alters mineral metabolism in the body.
Vitamin D appears to have a protective effect against multiple sclerosis. Rickets, a childhood disease characterized by impeded growth and deformity of the long bones, can be caused by calcium or phosphorus deficiency as well as a lack of vitamin D. Osteomalacia, a bone-thinning disorder that occurs exclusively in adults and is characterized by proximal muscle weakness and bone fragility.
Inadequate vitamin D (low 25(OH D) has also been associated with hair follicle growth, peripheral vascular disease, certain cancers, rheumatoid arthritis, juvenile diabetes, Parkinson's and Alzheimer's disease.
1 capsule per day or as suggested by your health professional
|Product||Caps||Each cap contains||Dosage|
|Vitamin D-3||120||Vitamin D-3||800 I.U.|