What is Vitamin D3 and What Does It Do?

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Vitamin D3 is an important vitamin for strengthening bones and muscles, helping to boost immunity and even improving heart function. Discover more here.

Vitamin D3 is a supplement that is often prescribed to people to help their bodies absorb calcium. It is a form of the “sunshine vitamin” vitamin D. The supplement will only be prescribed if you have a vitamin D deficiency, or an order related to such a deficiency such as rickets or osteomalacia. But what is vitamin D3 and why do we need it? Find out all you need to know in this article.

What is Vitamin D3?Vitamin D3

Vitamin D3, or also known as cholecalciferol, is a fat-soluble vitamin which allows your body to better its absorption of calcium and phosphorus. This is essential in maintaining healthy growth and development of bones and muscles. It may also be used on top of other medications or supplements to help minimise the risk of other conditions.

How does vitamin D3 work?

There are various benefits to taking vitamin D3 supplements, especially if you feel as though you are lacking in vitamin D or have been diagnosed with a vitamin D deficiency.

A few of the many benefits associated with vitamin D3 include:

  • The strengthening of bones and muscles
  • Immunity boosting abilities
  • Ability to improve and boost mood
  • Improves the function of the heart
  • Works to reduce inflammation.

Bones and muscles

It is not surprise that bones need calcium to grow to their optimal potential and to maintain it too. Vitamin D and calcium work together to maintain the functioning of the bones and muscles. So, when someone is suffering from a vitamin D deficiency, the bones and muscles can weaken, which poses the risk of fractures and osteoporosis.

The way in which vitamin D3 can help is by improving peak bone density, which is the maximum amount of bone tissue a human reach during adulthood.


Vitamin D3 can help to support the immune system in fighting off viruses and bacterial infections, such as pneumonia and respiratory infections. There have also been studies to show that lower levels of vitamin D can put you at higher risk of catching COVID-19. Which is why taking vitamin D3 supplements can help to boost those vitamin levels, and thus help your immune system to stay strong.


There have been studies to suggest that those who have low vitamin D levels may suffer from clinical depression, however the link is yet to be detailed. There has been evidence to show that taking a vitamin D3 supplement can help boost your mood and help with symptoms of depression.

Anti-inflammatory Properties

Vitamin D can affect medical conditions that are caused by that of inflammation. These include Asthma, Eczema and other allergies. There have been studies to suggest that taking vitamin D3 supplements can lower your risk of suffering from such anti-inflammatory diseases, or minimise the symptoms.

There have also been studies that suggest the supplement be taken by pregnant women to minimise the risk of the baby suffering from such anti-inflammatory issues once born.

Heart health

There has been research linked with vitamin D3 supplements and heart health to show that it can help to decrease the chances of heart disease, stroke, high blood pressure and heart attacks.

It is believed to reduce the risk of heart failure and helps to improve heart function in people with weak hearts.

What are good sources of vitamin D3?

The recommended dietary allowance for vitamin D is:

  • 600 international units for adults up to 70
  • 800 international unit for adults over 70.


Vitamin D3 foods

There are many different food sources that are great choices when wanting to incorporate more vitamin D3 in your diet. The following foods are all great options for vitamin D3.

  • Beef liver
  • Cheese
  • Butter
  • Cod Liver Oil
  • Mackerel
  • Tuna
  • Fresh Salmon

However, if you live a strict vegan lifestyle, it may be harder to consume enough vitamin D3 through your diet alone. So, supplements will be much more important for your diet. However, there are a few food sources in a vegan diet that contain good amounts of the vitamin:

  • Almond, Oat or Soy Milk
  • Portabella Mushrooms

What happens if I take too much vitamin D3

The supplement itself is usually considered safe to consume, but to the recommended amount. As with any vitamin, taking too much can be toxic.

If you do consume too much vitamin D3, you may be at risk of absorbing too much calcium, which can lead to a condition known as hypercalcemia, this can lead to all sorts of side effects such as:

  • Weakening of the bones
  • Interreference with brain and heart development and function
  • Kidney stones.

Other symptoms of taking too much vitamin D3 can include:

  • Vomiting
  • Mood swings
  • ConfusionWoman taking tablet
  • Muscle weakness
  • Loss of appetite.

An overdose of vitamin D3 can only come from taking too much of the supplement. It is not common to ingest too much vitamin D3 through foods alone. If you do suspect you have consumed too much vitamin D3, then you should contact your doctor immediately, and cease taking any form of supplement.

Vitamin D3 is important for the healthy function and maintenance of bone and muscle matter. And may help to minimise the symptoms and signs of depression, anti-inflammatory diseases and heart failure. Always seek medical advice before taking any kind of supplements, as they may not be advised depending on other medical factors.

That is the end to our vitamin D3 guide, want to find out more about vitamin D and what foods you can get it from? Take a look at our article, best foods for vitamin D, next.






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