Why Is Vitamin D Known As The Sunshine Vitamin?

The reason vitamin D is known as the sunshine vitamin is because it is produced in the body from cholesterol when the skin is exposed to sunlight. Vitamin D is important for bone health and for the function of the immune system.

We mostly get all of the nutrition we need from the food we eat. There is one important component of our bodies, however, that we derive in a different way. The nutrient we want to “shine some light on” is Vitamin D and the source that kicks off the production of this vitamin in our bodies is the Sun!

Smiling Sun

Credits:Marharyta Kovalenko/Shutterstock

Let’s have a look at exactly how this process is carried out, along with the health benefits of this self-manufactured vitamin.

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How It Works

Let’s start with the crucial element already stored just under your skin: Cholesterol. We get cholesterol from the foods we eat, mainly from meat and dairy products.

When we go frolicking outside and sunlight hits our skin, the ultraviolet B rays in the sunlight convert the cholesterol under our skin (which, to be specific, is in the form of 7-dehydrocholesterol) into Vitamin D3 (its chemical name is cholecalciferol).

vitamin d3

Manufacture of Vitamin D3 in the Skin

From there, the Vit. D3 travels through the bloodstream to one of the most vital organs in the body where most metabolic conversions take place: the liver. At that point, the Vit. D3 is converted again to give us Calcidiol, which goes on another journey through the body to reach the kidney. Here, calcidiol is finally converted into the active form of the vitamin, which is known as Calcitriol.

Drunk Man on Bench Meme

Credits:Oleg Mikhaylov/Shutterstock

Also Read: What Do Fat-Soluble Vitamins Do In Our Body?

What It Does

Calcitriol travels to target cells and binds to a special receptor known as Vitamin D receptor (VDR). This binding of calcitriol to VDRs results in increased absorption of calcium from our food. Naturally, this calcium will then be used to strengthen our bones.

Funny how the Sun eventually ends up making us stronger!

What Would Happen Without Vitamin D

Since the main function of vitamin D is to eventually strengthen our bones, a lack of vitamin D either in our diet (vitamin D can also obtained from foods like fish, mushrooms, cheese and egg yolks) or from exposure to sunlight will result in diseases and disorders related to our bones. The most common disease that this deficiency of vitamin D results in is osteoporosis, which is a reduction in mineralization (calcium deposition) of our bones and, in turn, reduced bone density. This leads to brittle bones, which is one of the biggest health risks for elderly populations.


Children with vitamin D deficiencies end up having soft bones (rickets) and adults can also develop similarly fragile bones (osteomalacia).

In addition to deterioration in the quality of bones, vitamin D deficiency may lead to a decrease in the function of our immune system. Turns out, there’s evidence that vitamin D even helps to prevent cancer and heart disease. Therefore, a lack of vitamin D in our bodies could lead to a greater risk for these diseases.

Strangely enough, there’s also evidence suggesting that vitamin D can help prevent depression! This actually makes sense, as it’s well known that people living in colder countries that rarely receive any sunlight are more prone to depression.

What we’re saying is go out into the bright sunshine (perhaps applying sunscreen would be wise if the sun is shining particularly strong that day) and enjoy the vitamin D that your body produces by utilizing that glorious sunlight.

Also Read: Know Your Vitamins: What Do Water-Soluble Vitamins Do In The Body?

Taking Sunshine


Your bones will thank you later.

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About the Author

Brendan has a Bachelors of Science degree in Biotechnology from Mumbai University (India). He likes superheroes, and swears loyalty to members of the Justice League. He likes to take part in discussions regarding the human body, and when he is not doing that, he is generally reading superhero trivia.