How does the body convert sunlight to vitamin D?

Published by Charlie Davidson on

How does the body convert sunlight to vitamin D?

When your skin is exposed to sunlight, it manufactures vitamin D. The sun’s ultraviolet B (UVB) rays interact with a protein called 7-DHC in the skin, converting it into vitamin D3, the active form of vitamin D.

How is vitamin D converted to active form?

Vitamin D obtained from sun exposure, foods, and supplements is biologically inert and must undergo two hydroxylations in the body for activation. The first hydroxylation, which occurs in the liver, converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as “calcidiol.”

What is the difference in vitamin D and D3?

Vitamin D is less expensive to produce and therefore is the form most commonly found in fortified food products. Vitamin D3 mainly comes from animal sources such as fish oil, fatty fish, liver, and egg yolks. When your skin is exposed to sunlight, it produces vitamin D3.

Can I get vitamin D from the sun?

Our body creates vitamin D from direct sunlight on our skin when we’re outdoors. From about late March/early April to the end of September, most people should be able to get all the vitamin D we need from sunlight.

Where can I find preformed vitamin A in my diet?

Two forms of vitamin A are available in the human diet: preformed vitamin A (retinol and its esterified form, retinyl ester) and provitamin A carotenoids [1-5]. Preformed vitamin A is found in foods from animal sources, including dairy products, fish, and meat (especially liver).

Where does the majority of provitamin A come from?

Data from NHANES III, conducted in 1988–1994, found that approximately 26% of the vitamin A in RAEs consumed by men and 34% of that consumed by women in the United States comes from provitamin A carotenoids, with the remainder coming from preformed vitamin A, mostly in the form of retinyl esters [5].

Where are provitamin A carotenoids oxidized in the body?

The various forms of vitamin A are solubilized into micelles in the intestinal lumen and absorbed by duodenal mucosal cells [5]. Both retinyl esters and provitamin A carotenoids are converted to retinol, which is oxidized to retinal and then to retinoic acid [2].

Is there vitamin A in a multivitamin supplement?

Vitamin A is available in multivitamins and as a stand-alone supplement, often in the form of retinyl acetate or retinyl palmitate [2]. A portion of the vitamin A in some supplements is in the form of beta-carotene and the remainder is preformed vitamin A; others contain only preformed vitamin A or only beta-carotene.

Categories: Trending