Hello and welcome to the Zero to Finals podcast.

My name is Tom and in this episode I'm going to be going through Vitamin D.

And you can find written notes on this topic at zero to finals.com slash vitamin D

or in the endocrinology section of the second edition of the

zero to finals medicine book. And you can find flashcards and questions to train your knowledge on this

content and help you remember the information for longer at members.0tofinals.com. So let's get straight into it.

Vitamin D is a hormone that the skin creates in response to sunlight. It's also obtained

in limited amounts from food, although a standard diet on its own does not contain enough

vitamin D to cover the entire

body's requirements. So sunlight or vitamin D supplements is needed in addition to a standard diet.

Vitamin D is a fat soluble vitamin, meaning that it dissolves in fats and oils rather than water. The other fat soluble

vitamins are A, E, and K. Vitamin D helps regulate bone mineralization, hormone secretion and immune

function, and we're going to talk about all of these in more detail.

Let's start by talking about vitamin D metabolism.

Vitamin D originates in three potential places.

Created in the skin from cholesterol in response to ultraviolet B or UVB radiation from sunlight,

ergo-calciferal, which is vitamin D2 in the diet, which is primarily found in plant sources,

fortified foods or supplements, and colicalciferal, or vitamin D3, in the diet,

primarily from animal sources, fortified foods or supplements.

Some clinical relevance for you, the standard treatment for vitamin D deficiency is giving

oral colicalciferal, or vitamin D3.

In the skin, a photochemical reaction in response to ultraviolet B radiation from the sun

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