How is vitamin D metabolized?

How is vitamin D metabolized?

For most vitamin D-mediated actions, vitamin D must first be metabolized to 25-hydroxyvitamin D (25OHD), a process that occurs primarily, but not exclusively, in the liver8. 25OHD is the major circulating metabolite of vitamin D9.

What is vitamin D synthesis?

In the presence of sunlight, a form of vitamin D3 called cholecalciferol is synthesized from a derivative of the steroid cholesterol in the skin. The liver converts cholecalciferol to calcidiol, which is then converted to calcitriol (the active chemical form of the vitamin) in the kidneys.

Why is vitamin D not being recommended?

Traditionally, vitamin D deficiency has been associated with rickets, a disease in which the bone tissue doesn’t properly mineralize, leading to soft bones and skeletal deformities.

What causes vitamin D malabsorption?

Vitamin D deficiency can result from Inadequate exposure to sunlight,[3] malabsorption (people who have undergone resection of the small intestine are at risk for this condition; diseases associated with vitamin D malabsorption include celiac sprue, short bowel syndrome[4] and cystic fibrosis[5]), medications (drugs …

Does vitamin D affect the kidneys?

Vitamin D has been reported to have a wide range of benefits. However, a recent case study indicates that excessive use of vitamin D can cause kidney damage in people who are not deficient in the vitamin.

Is vitamin D hard on liver?

While hepatocytes, cholangiocytes, stellate cells and resident immune cells in the liver have vitamin D receptors, there is no evidence that vitamin D causes injury to the liver.

What organs does vitamin D affect?

Most organs, including the gut, brain, heart, pancreas, skin, kidneys, and immune system have receptors for 1,25 (OH)vitamin D. Furthermore, all of these organs have the capacity to synthesize 1,25 (OH)vitamin D from vitamin D.

What happens if vitamin D is left untreated?

If left untreated over time, vitamin D deficiency can lead to serious bone disorders. For example, severe and long-term vitamin D deficiency may result in rickets or osteomalacia.

What are the biological effects of vitamin D?

Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and multiple other biological effects.

Where does vitamin D come from in the body?

Vitamin D from the diet or skin synthesis is biologically inactive; enzymatic conversion (hydroxylation) in the liver and kidney is required for activation.

What are the different forms of vitamin D?

Several forms (vitamers) of vitamin D exist. The two major forms are vitamin D2 or ergocalciferol, and vitamin D3 or cholecalciferol; vitamin D without a subscript refers to either D2 or D3 or both. These are known collectively as calciferol. Vitamin D2 was chemically characterized in 1931.

What does it mean if you have vitamin D deficiency?

Vitamin D deficiency. Vitamin D deficiency, or hypovitaminosis D, most commonly results from inadequate sunlight exposure (in particular sunlight with adequate ultraviolet B rays).