Published Aug 1, 2020

Vitamin D isn’t usually the first vitamin we think of when we think of our immune health. It’s usually vitamin C, which is found in citrus fruits, berries and kiwi fruits. Vitamin C is crucial for a healthy immune system, but it’s not the only vitamin that supports our immunity.

Vitamin D is also crucial for good immune health. We normally think of the benefits of vitamin D to our teeth and bones, and we’d be right for thinking that, but the immune system also relies on vitamin D to help defend us against illness and disease.


How vitamin D supports a healthy immune system

The immune system is a complex system of cells, molecules, tissue and organs, all with an essential role. It helps to defend us against disease with a smart two pronged attack – a system of ‘seek and destroy’ which seeks out invading pathogens in order to destroy them (carried out by a branch of the immune system called the innate immune system) and a memory bank (carried out by the adaptive immune system) that helps to remember pathogens so that we’re fully equipped to fight them should we come across them again.

Vitamin D helps to modulate our immune response by playing a role in the switching on and off of some of the cells of the immune system called the B cells and the T cells. In doing so, during an immune response, these cells are able to both deal with the threat, and communicate to other cells and molecules that there’s a threat to conquer.


Where do we get our vitamin D from?

We can see that without enough vitamin D, we run the risk of developing an impaired immune system. So, we just eat enough vitamin D rich foods, right?

Not quite.

Unlike all other vitamins, we don’t get much of our daily recommended amount of vitamin D from food. Vitamin D fortified dairy products and cereals, egg yolks, mushrooms (to a certain extent) and fish with edible bones (such as pilchards and whitebait) are good sources of vitamin D, but we’d have to eat an awful lot of these foods to get enough.

Instead, the body manufactures vitamin D after sunlight hits the skin. That’s why it’s commonly called the sunshine vitamin. During the summer, when sunlight levels are high and we cover up less of our skin, we’re generally thought to get enough vitamin D.

But during the colder, darker months from October to March, we’re all thought to be at risk of a vitamin D deficiency. That’s why it’s recommended that those of us living in the Northern hemisphere take a 10mcg daily supplement of vitamin D to make sure we’re not deficient.


Vitamin D and mental health

Vitamin D also plays a role in supporting our mental health too. It’s now thought that Seasonal Affective Disorder, or SAD is linked to low levels of vitamin D, not just low levels of mood boosting sunlight. SAD leads to a low mood, lethargy, poor concentration and other poor mental health symptoms and is often referred to as winter depression.

Feeling stressed and anxious can mean that the immune system becomes compromised, so it’s important to take your vitamin D supplement in the autumn and winter months.

The NHS are now advising that we continue to take 10mcg of vitamin D daily at the moment, since due to the coronavirus pandemic, we’re all staying inside for much longer, so make sure you’re topping up your levels of this immune supporting essential nutrient.



Written by Hannah De Gruchy

Health, Wellness & Environmental Writer | Human Biology BSc (Hons)

I have an extensive knowledge of diet, health and wellbeing topics and consistently produce high quality, fully researched content for blogs, features and articles.

I’ve always loved to write, and after spending the first ten years of my career laboratory based, embarked on a career change in 2009 by joining an innovative and first to market online doctor. I was responsible for managing all online and printed content including articles, product descriptions and marketing materials, and now have extensive knowledge of what it takes to write engaging, imaginative pieces.

In 2013 I had a major role in setting up and have had overall responsibility for all content (including the blog and product descriptions), social media and printed materials. Emmbie is an online health, diet, fitness and lifestyle company selling natural, organic, vegan health food supplements.

I also have experience in proofreading and editing content written by doctors, making sure it reads well as a non-doctor and am fully versed in being consistent with editorial guidelines.

I’m motivated and well organised for freelance working, my desk shares a space with a running machine, which often comes in handy when I’m told by my watch I’ve been sitting down too long or need some inspiration away from the screen!

I try to live a simple life, always conscious of my impact on the environment and have recently taken a keen interest in Buddhism. I choose natural beauty and household products and eat local, organic produce when I can. Staying true to both my way of life and my scientific background, I have a passion for writing on these subjects that is evident in my work.

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