Author: Amy Cottrell (DipCNM, mBANT, rCNHC, mANP)

After some (hopefully) sunny summer vacations and adventures that help us recharge our batteries, school starts, and work begins again. If we remember that our human batteries contain vital vitamins and minerals, for example, the so-called “sunshine vitamin,” vitamin D, contributes to our health in many ways.

Vitamin D has been the buzzword for the past couple of years owing to its valuable links to our immune health. Did you know that vitamin D isn’t even a vitamin; it’s a hormone? Vitamin D is produced in the skin in response to sunlight exposure and is also available in small amounts in some food we eat (e.g., oily fish and mushrooms).

Vitamin D promotes calcium absorption in the gut and is involved in bone growth and remodelling [a]. Often people think it’s just calcium that is the answer to healthy bones, but the truth is that without vitamin D, bones can become brittle and even misshapen [b].

Vitamin D is also closely linked to maintaining a healthy immune system. Optimal vitamin D levels are more challenging to maintain from October to March due to the sun’s positioning, which is one of the reasons our vitamin D levels might drop to less than optimal during these months without supplementation.

Our immune systems are less resilient during winter, and more viruses and bugs also go around during these months. Bolstering our immunity, particularly after summer, is super important. Our bodies are more prepared as we head into those winter months, where we tend to find ourselves more susceptible to getting sick.

How does vitamin D play a role in our immune system health?

Our immune systems are super complicated and indeed not easy to sum up in a nutshell, but it’s worth knowing that there are two systems through which our body fights off infections. Firstly, there is something called the  “innate” immune system, our so-called first line of defence and usually non-specific. Secondly, we have an “adaptive” immune system which is slower to respond than the innate immune system but is far more specific in its activity [c]. Impressively, vitamin D can influence both of these systems [d]. Vitamin D deficiency has been linked to a higher susceptibility to infection and an increased incidence of autoimmunity [e] (where our immune system mistakenly recognises our tissues as foreign and attacks them).

Why is sunshine exposure not the only thing we need to think about?

There is a lot of attention on how much sunshine we’re getting regarding our vitamin D levels. Something else that influences our vitamin D status is our genes!

Let’s look at how our genetic makeup can influence our vitamin D status and potentially impact our immune health.

Firstly, a transcription factor (a molecule that can control a gene’s activity) called vitamin D receptor (VDR), which essentially provides instructions to make a protein called VDR. This protein is important because it regulates the body’s response to vitamin D, and since VDR is present in immune cells, it can ultimately affect our immune system function [f].  Over 30% of the population carries a VDR genetic variant, which may result in low vitamin D levels. Suppose you have this genetic variant in 30% of the population. In that case, it means you might have an increased need for vitamin D, and even if you are out in the sun regularly and take supplements, your levels might not be optimal and require additional support.

Another gene connected to our vitamin D status is the “GC” gene. This gene produces “vitamin D binding protein” (DBP), which is responsible for transporting vitamin D between the skin, liver and kidney and to various target cells [g]. Variants on the GC gene have been seen to influence vitamin D status and might result in decreased vitamin D levels [h].

If you discover that your genes predispose you to lower vitamin D levels, don’t worry; you are not destined for a life of low vitamin D levels or a less efficient immune system. It just means you might have to monitor your levels more closely and ensure that you’re sufficiently topping up your vitamin D levels.

Should we supplement? Hell yeah!

The reason why it’s worth considering increasing vitamin D from October to April at the very least is because of the sun’s position in the UK during these months when we won’t be able to produce vitamin D as efficiently from sunlight.

Here’s a little hack: if your shadow is shorter than you, you will be able to produce vitamin D from sunlight. However, if the shadow is longer than you, it likely means that you will not be able to make vitamin D via sunlight (because the sun is too far away).

The NHS recommends that from October to March, we should all be considering supplementing ten micrograms (or 400 IU) [i]. IU stands for “International Units” and measures fat-soluble vitamins, including vitamins A, D and E.

This recommended amount might not be enough for all individuals, so it’s best to test your vitamin D status before supplementing to check your levels to see if you need a bit extra, particularly during those winter months. As already mentioned, if you are genetically predisposed to an increased need for vitamin D, it will likely mean that a small dosage like 400 IU will not be sufficient to reach optimal vitamin D levels.

Vitamin D is vital for human health, and in particular, it plays a key role in ensuring that our immune systems are working optimally. Luckily, we can make informed choices around our vitamin D supplementation to ensure that it’s tailored to our own specific needs to support our health throughout the winter months and beyond!

It’s time to prepare your immune system for the winter. Order our DNApal test today to determine how your genes influence your vitamin D levels!

Feel free to leave us a comment if you have any further questions.

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