💪 IMMUNE RESILIENCE #19: VITAMIN D (aka Vitamin Sunshine)

Vitamin D Sunshine Calendar

Immune resilience #19: Vitamin D (aka Vitamin Sunshine). In light of COVID-19, health experts across the globe are advising us to pay attention to and bolster our vitamin D levels. Every single cell in our body – including our immune cells – contains receptors for vitamin D. Indeed, as early as 2010 scientists at the University of Copenhagen found that without sufficient vitamin D our immune defences cannot be activated, meaning that the killer T cells of the immune system will not be able to react to and fight off serious infections in the body.

Science Daily reported that the Danish research team found:

… T cells first search for vitamin D in order to activate and if they cannot find enough of it will not complete the activation process… [these] T cells rely on vitamin D in order to activate and they would remain dormant, naive to the possibility of threat if vitamin D is lacking in the blood.

In addition to viruses like COVID and less serious common colds and the flu, vitamin D helps with healthy cell replication and may play a role in protecting against the development of autoimmune conditions. We also know that vitamin D can prevent prolonged or excessive inflammatory responses.

Adrian Martineau, a professor of respiratory infection and immunity at Queen Mary University of London, said deaths among BAME NHS staff had brought the question of vitamin D deficiency to the fore.

“Vitamin D could almost be thought of as a designer drug for helping the body to handle viral respiratory infections,” he said. “It boosts the ability of cells to kill and resist viruses and simultaneously dampens down harmful inflammation, which is one of the big problems with Covid.” – Guardian 17 June 2020

We know that those of us with darker skins need longer sun exposure to make optimum levels of Vitamin D.

Darker-skinned people have more melanin, a compound that protects against skin damage by reducing the amount of UVB light absorbed. Darker-skinned people need more time in sunlight to make the same amount of vitamin D as lighter-skinned people. Studies estimate that darker-skinned people may need anywhere from 30 minutes to three hours longer to get sufficient vitamin D, compared to lighter-skinned people. This is a major reason why darker-skinned people have a higher risk of deficiency. – Healthline 2018

Why Vitamin Sunshine is King

Vitamin D helps with healthy cell replication and may play a role in protecting against the development of autoimmune conditions, in addition to less serious common colds and the flu. Now health experts across the globe are advising us to pay attention to and bolster our vitamin D levels…

Getting enough vitamin D, but even taking higher doses of vitamin D for short periods of time, like 10,000 to 50,000 units a day for one or two weeks to bolster your immune system, can be helpful. Again, don’t do this long-term because vitamin D can be toxic at high doses over an extended period. (Chris Kresser – How to be prepared for Covid-19)

Without question, getting outside into Vitamin Sunshine should absolutely be our priority – especially in Covid-19 ‘lockdown’ conditions. For a comprehensive understanding of why Vitamin Sunshine matters, I highly recommend reading the posts I’ve linked below.

Vitamin D (aka Vitamin Sunshine) – effects on immune resilience

Scientists at the University of Copenhagen have found that vitamin D is crucial to activating our immune defenses and that without sufficient intake of the vitamin – the killer cells of the immune system — T cells — will not be able to react to and fight off serious infections in the body. The research team found that T cells first search for vitamin D in order to activate and if they cannot find enough of it will not complete the activation process. The researchers found that the T cells rely on vitamin D in order to activate and they would remain dormant, ‘naïve’ to the possibility of threat if vitamin D is lacking in the blood.

Healthline’s Covid-19 Updates and Resources say this:

Vitamin D is necessary for the proper functioning of your immune system, which is your body’s first line of defense against infection and disease.

This vitamin plays a critical role in promoting immune response. It has both anti-inflammatory and immunoregulatory properties and is crucial for the activation of immune system defenses.

Vitamin D is known to enhance the function of immune cells, including T-cells and macrophages, that protect your body against pathogens.

In fact, the vitamin is so important for immune function that low levels of vitamin D have been associated with increased susceptibility to infection, disease, and immune-related disorders.

For example, low vitamin D levels are associated with an increased risk of respiratory diseases, including tuberculosis, asthma, and chronic obstructive pulmonary disease (COPD), as well as viral and bacterial respiratory infections.

What’s more, vitamin D deficiency has been linked to decreased lung function, which may affect your body’s ability to fight respiratory infections.

Studies also indicate that inflammation is often at the root of many modern, chronic diseases and autoimmune disorders.

Vitamin D is somewhat misunderstood as a ‘vitamin’ because it isn’t like most other vitamins. Our body makes its own vitamin D when we expose our skin to sunlight. But our body can’t make other vitamins – we need to get these from the foods we eat. For example, you need to get vitamin C from fruits and vegetables.

Importantly, our body turns vitamin D into a complex and potent hormone – sometimes called activated vitamin D, or ‘calcitriol’ and it’s this status that is key to understanding D’s importance to our health. Although it’s generally associated with calcium metabolism (for instance brain cell signalling, bone and tooth health) it’s a big player: nearly every tissue and cell in the body has a vitamin D receptor. This alone alerts us to D’s importance; the only other hormone to have receptors at every cell is thyroid hormone (responsible for directing energy to every cell in the body).

What’s the problem?

#1: Lifestyle

Although we’ve evolved to spend our time outdoors (actively!) over generations we’ve done the opposite of what Mother Nature intended for us and developed sedentary indoor lifestyles.  Our fear of sun exposure, obsessive use of sunscreens and not least, our cholesterol phobia has scored big hits on our health in widespread vitamin D deficiency.

#2: Location, location, location

And if that wasn’t enough – as we can see from the chart, where we live in the world determines how much vitamin D is even available to us at any time of year…. so this alone is how most of us end up not getting anywhere near enough vitamin D.

#3. Age

Add this into the mix: As we age, our ability to actually make vitamin D at all is reduced by a whopping 75%. And, although we store vitamin D in fatty tissues, it can get trapped in body fat – so if we carry a lot of fat we can expect a 55% reduction in blood levels of vitamin D!  Who knew?!

All this is hurting us – and especially so at this time of year.  And it’s even worse for those of us with darker skin (a very effective filter) who live in northern time zones with limited sunlight.

Health impacts of Vitamin D deficiency

For a FULL DISCUSSION on all aspects of vitamin D (health impact, co-dependencies, supplementation, safe sunbathing), I highly recommend my cornerstone post: Why Women Should Track Their Vitamin D.  Although the post focuses on some specifics of women’s health, the principles are the same for men too. Here’s the short story…

# Is associated with heart disease: the leading cause of death for women, as well as for men. D deficiency is a risk factor in heart attacks, congestive heart failure, peripheral arterial disease, strokes and the conditions associated with cardiovascular diseases, such as high blood pressure and diabetes.

# Is associated with thyroid disorders, specifically with autoimmune thyroid disease (AITD) and autoimmune-mediated thyroid dysfunction.

# Is implicated in insulin resistance & diabetes: D regulates insulin secretion, sensitivity and balances blood sugar.

# Is implicated in a low-fat diet: vitamin D is a fat-soluble vitamin and needs fat in the diet to be absorbed.

# Is related to leaky gut syndrome: a leaky or inflamed gut reduces D absorption. In common with other medications (anti-inflammatories, antibiotics), oral contraceptives may alter our gut microbes and pave the way for dysbiosis, inflammation and a compromised gut lining.

# Is associated with high cortisol levels: cortisol is released under stress – consider the stress levels of women juggling careers, finances, relationships and family commitments?

# Is associated with depression, anxiety and mood changes: research has found that women with low D are 11 times more at risk.

# Is related to sleep disorders: low D causes insomnia, sleep apnoea, REM related apnoea and their associated disorders, all of which disrupt or prevent the process of healing during sleep.

# Depletes our daily dose of B vitamins: low D changes our intestinal bacteria, which produce the B vitamins which convert our food to fuel to keep our bodies running like well-oiled machines.

# Increases our risk of multiple sclerosis (MS) an immune-mediated disease of the central nervous system which disrupts the flow of nerve signals between the brain and spinal cord to the rest of the body. Symptoms may include fatigue, weakness, numbness or tingling, cognitive impairment, pain, vision loss, depression.

But remember: vitamin D doesn’t play solo…

A more detailed discussion on the complex co-dependencies between vitamin D levels, vitamin K2,  calcium, magnesium and supplementation and sun exposure can be found in my cornerstone post: Why Women Should Track Their Vitamin D.

Beware Effective, safe sunbathing is a MUST

As with anything in this life, there is a ‘Goldilocks’ factor for sun exposure – it has to be ‘just right’!

Too much and we will burn, risk sunstroke and provoke skin damage. Too little and we will be vitamin D deficient with increased risk to every aspect of our health. In this post, I talk about the many benefits of sunbathing (over and above vitamin D) and this post highlights the specific ways that use of sunscreens can harm rather than support your health.



Once again, for a comprehensive understanding of why sunshine matters, I highly recommend reading the posts I’ve linked to in this article.



Resilient health is holistic health…

Our health is in our hands … WE make the decision to create the lifestyle changes that bring energy, vitality and resilient health… so let’s take the first step, however small, and walk purposefully and consistently towards those goals.

This post is part of my Immune Resilience Series – with this series, I’m making a commitment to my subscribers to provide helpful, evidence-based information and insights into what we can do with nutrition and lifestyle medicine to build immune resilience – the capacity of our immune system to respond to external challenges (such as the Covid-19 pandemic) and return to a healthy state of wellbeing.



Izabella Natrins

I'm here to inspire and support women at midlife and beyond to re-ignite purpose and meaning to take back control of their health and create the radical, resilient heath they want and deserve. As a whole-health expert with over 30 years experience in the field, a qualified Health and Wellness Coach and Ballymaloe-trained nutritional chef, my real food nutrition and lifestyle medicine programmes support women fighting fatigue, struggling with overwhelm, weight gain, sleep, energy and niggling or multiple diagnosed health issues. As an advocate for real food nutrition, regenerative agriculture and whole-health, my book 'The Real Food Solution' is an evidence-based treasury wisdom for energy, vitality and better health for people and planet and a call to action to change the way we grown, source and cook our food. As the CEO at The UK Health Coaches Association, I'm proud to continue the task of leading the first professional association for Health and Wellness Coaches in the world and the gold standard for the UK and Ireland.

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1 Response

  1. June 22, 2020

    […] Women Should Track Their Vitamin D. With COVID-19, Vitamin D is quite literally, on the tip of everyone’s tongue these days and research is giving us plenty […]

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