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Vitamin D: why vitamin D is vital for a strong, healthy immune system

Posted by for Strength

  A new study suggests that women taking vitamin D, probiotics, omega-3 fatty acids and multivitamins have a lower risk of being infected with the virus that causes Covid-19. Stylist asks Dr Sarah Brewer how vitamin D could help us stay healthy during the pandemic. 

Many stereotypes about the UK are far from accurate – no, we don’t all like tea – but unfortunately our famously rubbish weather seems to be about right. Don’t let the recently sunny skies trick you: the UK tends to have low levels of sunlight, and this actually has a pretty negative impact on our health and wellbeing. 

Not only does sunshine help to boost our mood, but our bodies also absorb nutrients from the sunlight. Namely, vitamin D. 

“You can only make vitamin D when the UV index is greater than three,” explains Dr Sarah Brewer, registered nutritionist and medical advisor to Healthspan. “You can top up with food, but it is only found in useful amounts in oily fish, liver products, eggs, butter or fortified foods. As a result, vitamin D deficiency becomes common during autumn and winter for people living in northern latitudes such as the UK, and that’s why we are advised to supplement during the colder months.”

So despite how surprisingly lovely the weather has been over the past few months, Public Health England has extended the guidelines for supplementation and recommends that we all still continue to top up with vitamin D tablets or sprays to absorb enough of the sunshine vitamin. 

In fact, a new study from the BMJ Nutrition Prevention & Health supports the theory that vitamin D – as well as some other vitamins and probiotics – could help reduce a person’s risk of Covid-19. Among the 372,000 UK participants, researchers found that women taking probiotics, omega-3 fatty acids, multivitamins or vitamin D had a lower risk of being infected with the virus that causes Covid-19.

But can taking the vitamin really help?  We put our burning vitamin D questions to Dr Brewer. 


We should always pay attention our vitamin D level – pandemic or no pandemic – as the nutrient is essential for building a strong immune system, which, right now, is more important now than ever. Dr Brewer adds: “Vitamin D is needed to make antibodies that regulate how our bodies respond to infections.”

There have been a handful of misleading reports about vitamin D reducing the risk of coronavirus. However, there is no evidence that this is the case. Currently the NHS states we should consider taking 10 micrograms of vitamin D a day to keep bones and muscles healthy in lockdown.

There has been early research published in the Irish Medical Journal that suggests there could be connection between vitamin D and Covid-19 resistance rates – but it remains inconclusive. 

It is, however, important to consider a vitamin D supplement while observing the coronavirus lockdown measures. Scroll down for help with how much vitamin D to take and the official NHS guidelines. 


Vitamin D helps our body fight infection by increasing the production of natural antimicrobial agents that kill microorganisms associated with infections.

One study shows that people who are low in vitamin D (less than 10 nanograms per milliliter) are 55% more likely to develop respiratory infections including colds and flus than those with higher levels (30 ng/ml).

There’s several ways we can take vitamin D including pills, gummies and even a spray. 


The general recommendation from PHE is that we supplement with 10mcg of vitamin D per day during the winter months, which was then extended into Spring whilst we remained in lockdown.

A final word: taking supplements does not make you immune to catching colds or flu, it just boosts your chances of staying healthy. “It’s one of the many tools that we can arm ourselves with to help fight the pandemic,” agrees Dr Brewer. “Hygiene, social distancing and following the guidance that we’re being given by the government are also of paramount importance.”

It is always best to check with your doctor or a pharmacist if a supplement is right for you before taking it. 

Try these Vitamin D supplements to support your immune system

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Chloe Gray

Chloe Gray is the senior writer for's fitness brand Strong Women. When she's not writing or lifting weights, she's most likely found practicing handstands, sipping a gin and tonic or eating peanut butter straight out of the jar (not all at the same time).

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