A unique aspect of vitamin D as a nutrient is that it can be synthesized by the human body through the action of sunlight. These dual sources of vitamin D make it challenging to develop dietary reference intake values. Vitamin D, also known as calciferol, comprises a group of fat-soluble seco-sterols.
Where does vitamin D get synthesized?
Vitamin D3 (cholecalciferol) is synthesized in the skin by the reaction of 7-dehydrocholesterol with UVB radiation, present in sunlight with an UV index of three or more.
How is vitamin D produced in the body?
When exposed to the sun, your skin can manufacture its own vitamin D. “We each have vitamin D receptor cells that, through a chain of reactions starting with conversion of cholesterol in the skin, produce vitamin D3 when they’re exposed to ultraviolet B (UVB) from the sun,” says Yale Medicine dermatologist David J.
What are the 3 ways for the body to obtain vitamin D?
You can get vitamin D in three ways: through your skin, from your diet, and from supplements. Your body forms vitamin D naturally after exposure to sunlight. However, too much sun exposure can lead to skin aging and skin cancer. So many people try to get their vitamin D from other sources.
What is a precursor to vitamin D?
Ergosterol, which occurs in plants, is a vitamin D precursor. The active form of vitamin D (1,25(OH)2D) is a steroid hormone. Renal activation of vitamin D is regulated by several endocrine factors. Liver and/or kidney disease can result in a 1,25(OH)2D deficiency.
What does vitamin D synthesis mean?
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.
How is synthetic vitamin D made?
We can also create synthetic vitamin D by mimicking the biological process of the sunlight hitting our skin. We do this by replacing the cholesterol found in our body with the cholesterol in lanolin, a waxy-grease like substance found in sheep wool.
Where does vitamin A originate?
Concentrations of preformed vitamin A are highest in liver and fish oils [2]. Other sources of preformed vitamin A are milk and eggs, which also include some provitamin A [2]. Most dietary provitamin A comes from leafy green vegetables, orange and yellow vegetables, tomato products, fruits, and some vegetable oils [2].
Which is responsible for the production of vitamin D in the human body visible light?
Excessive exposure to solar ultraviolet (UV) radiation has damaging effects on life on Earth. High-energy short-wavelength ultraviolet B (UVB) is biologically effective, influencing a range of dermal processes, including the potentially beneficial production of vitamin D.
What is main source of vitamin D?
Few foods are naturally rich in vitamin D3. The best sources are the flesh of fatty fish and fish liver oils. Smaller amounts are found in egg yolks, cheese, and beef liver.
What is the precursor that can make vitamin D in the skin derived from?
The natural type is produced in the skin from a universally present form of cholesterol, 7-dehydrocholesterol. Sunlight is the key: Its ultraviolet B (UVB) energy converts the precursor to vitamin D3.
What is artificial vitamin D?
What is this added synthetic Vitamin D3 used in just about every dog food and is the reason for the recalls? Vitamin D is not a real vitamin. It is just called a vitamin to make it easy to market. It is actually a synthetic hormone mainly produced from the product of sheep grease expressed from lamb wool.
How is vitamin D synthesized in the human body?
Vitamin D synthesis in the body. Vitamin D is produced when sunlight converts cholesterol on the skin into calciferol (Vitamin D3). Vitamin D3 is then converted into calcidiol (25-hydroxyVitamin D3) in the liver. The kidneys then convert calcidiol into the active form of Vitamin D, called calcitriol (1,25-hydroxyVitamin D3).
What is the source of vitamin D3?
Vitamin D 3 (cholecalciferol) is taken in the diet (from fortified dairy products and fish oils) or is synthesized in the skin from 7-dehydrocholesterol by ultraviolet irradiation. The vitamin D produced by 7-dehydrocholesterol depends on the intensity of UV irradiation which varies with season and latitude (1).
What is the difference between vitamin D and vitamins?
This is because the body is capable of producing its own Vitamin D through the action of sunlight on the skin, while Vitamins are nutrients that cannot be synthesized by the body and must be acquired through the diet or supplements. Role of Vitamin D : Vitamin D has multiple roles in the body, helping to:
Is vitamin D a pro-hormone or a vitamin?
In spite of the name, Vitamin D is considered a pro-hormone and not actually a Vitamin. This is because the body is capable of producing its own Vitamin D through the action of sunlight on the skin, while Vitamins are nutrients that cannot be synthesized by the body and must be acquired through the diet or supplements.
