vitd 1260
12 Feb 2024

What is Vitamin D’s role in supporting the immune system?

4 mins to read
There is increasing attention and evidence emerging about the immune-supporting properties of vitamin D. Explore how you can use it to improve your immunity.

Vitamin D is well known for its benefits for bone development, building, and strength. It also aids in the absorption of calcium and phosphorus, which is important for bone health. 

Lack of vitamin D also means that the body doesn’t absorb calcium from food. Instead, the body then uses calcium from the bones, leading to weak bones.

According to Columbia University Irving Medical Centre, Vitamin D also maintains the calcium levels in our bones.

There is increasing attention and evidence emerging about the immune-supporting properties of vitamin D. According to the Science Museum of Virginia, vitamin D may increase immune cell production.

Sources of vitamin D

Vitamin D is a hormone the body can make when exposed to the sun. This is why Vitamin D is sometimes also known as the ‘sunshine vitamin.’ Most of the vitamin D in our body comes from the sun. However, it’s important to protect yourself from the sun, such as with a hat and sunscreen.


According to the University of New South Wales (UNSW), during Australia's summer, you only need a few minutes mid-morning or mid-afternoon for your skin to produce enough vitamin D. During winter in the more southern parts of Australia, you may need two to three hours per week.

However, during winter, getting this sunshine is difficult. Indoor work environments and the need to protect ourselves from high UV levels mean we are getting less sun exposure.

A Curtin University study in 2022 has found 95 per cent of Australians have low vitamin D intakes. According to Australian Eggs, the prevalence of vitamin D deficiency increases to 36% in winter.

The diet is another way of getting more vitamin D into your body.

How to include Vitamin D in your diet

The challenge of getting vitamin D through diet is there isn’t a big variety of foods that contain Vitamin D unless it’s been fortified.

It’s best to get nutrients through natural sources, and eggs are one of these. According to Australian Eggs, an average serving of two eggs provides 82%. New peer-reviewed research commissioned by Australian Eggs and undertaken by Deakin University has found there is a positive link between eggs and vitamin D. This research found that weekly consumption of at least 7 eggs can help to prevent a drop in vitamin D levels in the cooler months. On average, Australians are consuming four eggs per week, which falls short of the seven required to help maintain vitamin D levels through the colder season.

These are some other food sources that naturally contain vitamin D:

  • Milk
  • Cheese
  • Fatty fish, especially wild-caught salmon and mackerel
  • Canned tuna in water
  • Sardines
  • Beef or calf liver

Interestingly, the UNSW reports that mushrooms produce more vitamin D when exposed to the sun and it only takes 15 minutes of mushroom “sunbathing”.

Vitamin D-fortified products include certain cereals, bread, orange juice, yogurt, and soy milk

Fish, especially fatty, oily fish like salmon are a natural source of vitamin D. Wild fish may have a higher content than farmed fish. A study showed farmed salmon only had approximately 25% of the vitamin D content as wild salmon. Fish liver oils are also a great source of vitamin D. 

How much vitamin D do you need?

The Australian Dietary Guidelines state that babies, children, teenagers, and adults aged 19–50 years should have 5μg (micrograms) of vitamin D per day. Adults aged 51-70 years should have 10μg of vitamin D per day. Adults aged over 70 years should have 15μg of vitamin D per day.

Supplement support

It is very difficult to get enough vitamin D from diet alone, with the main dietary sources being fortified margarine, oily fish, and eggs. You may need vitamin D supplements, particularly during the winter months. If you become concerned about your vitamin D levels, consult with your GP.  

Australian Therapeutic Guidelines advise that vitamin D supplementation is only recommended for those with confirmed deficiency.

Columbia University Irving Medical Centre reports there are two forms of vitamin D available in supplements: vitamin D3 and vitamin D2. Vitamin D3 is naturally produced by animals, including humans, while Vitamin D2 is the plant form. They can both help treat vitamin D deficiency, but most doctors recommend D3 as it is the form made in our bodies. 










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