Vitamin D3 Explained

Vitamin D3, also known as the "sunshine vitamin," plays a crucial role in maintaining overall health and well-being. Generally, it is recommended that everyone considers supplementing with vitamin D. In this article, we will explain why. You will learn how the body makes vitamin d, why the body doesn't make enough of it, what it does for you, and how much you should consider taking.

Vitamin D - What Is It?

Vitamin D is a fat-soluble vitamin which means it dissolves and can be stored in fat. On the contrary, Vitamins like B and C are water-soluble and they can't be stored in our bodies. Any excess that we consume gets peed out while fat-soluble vitamins are stored in our bodies. This means that we can store any extra Vitamin D we make, consume or get from the sun.

Vitamin D - Production

Vitamin D can be made in our skin when we're exposed to sunlight, specifically ultraviolet B or UVB rays. The body uses cholesterol to form a substance called 7-dehydrocholesterol when the skin is exposed to sunlight. Just under the skin 7-dehydrocholesterol gets converted to Pre-Vitamin D3 which then gets converted to Cholecalciferol. This then gets converted to 25 (OH)D3 which is what scientists use to measure serum Vitamin D levels. finally, this gets converted to the active form of Calcitriol in the kidneys.

An important fact to know is that we can store so much of it that it can become toxic in our bodies. This is called hypervitaminosis D and it causes some serious issues. Nothing to worry though as the production of Vitamin D in our skin uses a feedback system that stops producing too much Vitamin D from sunlight which is why we never have to worry about producing too much. This is also the problem as we just can't get enough Vitamin D from sunlight alone. Not to mention, we all spend a lot of time indoors and when we do leave the house we're usually fully clothed and/or travel around in cars and the car’s glass filters out UVB rays. Also, you might live far from the equator like the UK, and only be able to get enough UVB rays to produce vitamin D in the summer.

Vitamin D - Food & Deficiencies

Unfortunately, there are very few good sources of Vitamin D in our diet. It's found in meat eggs or dairy but not in high amounts. To put it in perspective you'd need to eat 2kgs of steak just to get your daily amount of Vitamin D. Dairy products often have even less and that's why they are often fortified with Vitamin D to prevent deficiency. Egg yolks are a little better but you'd still need around 250 grams of pure egg yolk just to meet your daily dose. On the contrary animal, the liver can be a good source of Vitamin D as can some oily fish and fish liver.

This is why Vitamin D deficiency is so common. When serum levels of Vitamin D are below 50 nanomoles per liter you are considered insufficient. Now statistics show that 40% of Europeans have levels below that and 13% have levels below 30 nanomoles per litre. That's why Vitamin D deficiency is considered to be a global health problem.

Vitamin D - Role In The Body

There are many important functions through something called the Vitamin D receptor. Vitamin D binds with this nuclear receptor and then regulates the expression of specific genes. Vitamin D receptor is found in virtually every tissue in the body which means that vitamin D has a big role to play in our health.

One of Vitamin D's most popular roles is in bone health which is because it regulates the body's blood calcium levels. Vitamin D helps to increase the absorption of calcium from our gut and when blood calcium levels drop it helps to absorb more calcium from our kidneys. Furthermore, it can even take calcium from bones if it is needed as the level of calcium in the blood needs to be maintained at a specific level due to many essential processes in the body such as nerve transmission or muscle contraction. Moreover, due to its role in calcium metabolism Vitamin D is essential for building a strong skeleton. Lower Vitamin D levels are associated with lower bone mineral density and a greater risk of fractures in both younger and older people.

Vitamin D also plays an important role in insulin sensitivity, which is the way we process glucose. Additionally, Vitamin D is important for the health of the body's fat stores. Finally, Vitamin D has a massive role to play in the body's immune system helping to fight off disease. Low Vitamin D levels are associated with a greater risk of autoimmune disease as well as higher rates of cardiovascular disease, high blood pressure, diabetes, and other cardiometabolic conditions.

Vitamin D also has a major role to play in muscle growth as higher levels of Vitamin D are associated with higher levels of testosterone, greater muscle mass, strength, and physical function. Higher levels of Vitamin D are also associated with a lower risk of death as we age.

Vitamin D - Dosage

Generally, You need to aim to increase Vitamin D serum levels to above 50 nanomoles per litre in order to reap the benefits. However, this may take time especially if your serum levels were below 50 to start with which is usually the case.

As we can see above, Vitamin D is very important for our bodies, and because we don't get much from our diet or sunlight supplementing it seems to be a good idea. However, the current UK recommendation is 400 international units which is not going to increase your serum levels at all. Most multivitamins contain this amount which is why you might want to consider supplementing with Vitamin D itself. Now, to efficiently increase your Vitamin D serum level over time higher doses are recommended. The upper recommended dosage is 4,000 international units. If your serum levels are way below the standard of 50 nanomoles, the doctor may prescribe you an even higher dosage. It is a good idea to supplement yourself with the upper dosage of Vitamin D and test your levels in the meantime as it takes time for the serum levels to increase.

On the contrary, there is a negative side effect of consuming way more Vitamin D than we need and are able to store. It can become toxic in the body and have some serious negative health effects. Hypervitaminosis D is very real and Vitamin D3 should be consumed at more than the upper limit for a prolonged period of time.

Final Thought

Vitamin D is a fat-soluble vitamin that is vital to the body. Many important roles it has in the body start with bone health, insulin sensitivity, the health of fat storage, muscle growth, testosterone levels, and physical functions. It can be made in your skin when exposed to sunlight but not in great amounts. That’s why it is recommended to supplement it with an upper dose of 4000 IU. It should be taken a long period of time to increase its stores to get health benefits. It is safe to use however the upper dosage should be exceeded.