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The Sunshine Vitamin: Lesser-Known Facts About Vitamin D You Should Know to Boost Your Immune Defences

Sunshine vitamin


It absolutely astounds me to learn about 1 billion people worldwide have Vitamin D “deficiency”, while 50% of the global population has vitamin D “insufficiency”.

Vitamin D plays a vital role in our overall health, yet many of us are unaware of how much we need of it or whether we’re getting enough.

As a health coach focused on chronic disease prevention, I consider Vitamin D a priority to boost immune defences and resilience, in order to prevent a host of chronic diseases.

For me, Vitamin D is a “no-brainer” supplement I take all-year round and give to my children for better immunity and healthy bone development.

Let’s dive into the lesser-known facts about Vitamin D, why it is so important for boosting your immune defences, and how you can make sure you’re getting enough of "the sunshine vitamin".


Lesser Known Facts About Vitamin D


Vitamin D is essential for maintaining overall health. It plays a key role in keeping our immune system functioning properly, helping us fend off infections.

It is unique because our bodies produce it, only when exposed to sunlight. We can also get some from foods like oily fish, mushrooms, and eggs, but to a much lesser degree.

Here are the lesser known facts about Vitamin D:

  • Vitamin D is on par with Calcium for healthy bones: Vitamin D helps our bodies absorb calcium, essential for strong bones and teeth. So even if you consume enough calcium, if Vitamin D is insufficient, then calcium absorption is compromised.

  • Vitamin D modulates gene function: Vitamin D affects the expression of genes, meaning how and when genes turn on and off. Even if you are genetically predisposed in one way or another, having enough vitamin D will help keep the negative pre-dispositions from being expressed in real life.


  • Vitamin D supports a healthy gut function: It helps maintain the integrity of the gut lining and promotes the growth of “good bacteria”, because it acts as a prebiotic.

  • Vitamin D inhibits the development of chronic diseases like cancer: Because of its impact on immunity, gut health and gene expression, Vitamin D is a potent inhibitor of diseases like cancer.

In one study, 87% of cancer patients were found to be Vitamin D deficient. According to a meta-analysis published in the BMJ in 2019, Vitamin D supplementation was associated with a 15% reduction in cancer mortality. That beats the promised efficacy rates of many approved medications.


The Takeaway: Ensuring Vitamin D levels are optimal can be a proactive step towards reducing risk of cancer and other serious health conditions.

What Might Be Driving The Prevalence of Vitamin D Deficiency

too much sunscreen?

A few modern lifestyle changes might surprisingly be driving the rise in Vitamin D deficiencies:

  • Time spent indoors: Modern lifestyles often keep us inside, reducing our exposure to sunlight, the primary source of Vitamin D. Interestingly, glass windows absorb all the rays that are needed to produce Vitamin D. So even if you are sitting in a sunny indoor spot, you won't get any benefit.

  • Sunscreen use: While protecting our skin from harmful cancer-causing UV rays, sunscreen also blocks out 97% of the Vitamin D we could be synthesizing. Not to mention that many standard sunscreens contain known human toxins, so you really need to choose wisely. For more on this, check out my blog: The Truth About Common Household Toxins

  • Genetic pre-dispositions: Some of us, like me, have a pre-disposition for inefficient Vitamin D absorption and/or transport, thus requiring more regular or higher dose supplementation. Knowing your predispositions can help you supplement adequately. As part of my programmes, you can now request a nutrigenomic test analysis to learn about your pre-dispositions across a number of health functions.

  • Some health conditions: Conditions like Crohn's and Celiac disease can affect how the intestines absorb nutrients, including Vitamin D.

  • Skin colour: The darker the skin, the less Vitamin D your body can make, as melanin, skin’s pigmentation agent, reduces the ability to produce Vitamin D from sunlight.


Reference ranges on a blood test

Forget About "Reference" Ranges: Know the "Optimal" Vitamin D Ranges


As a health coach and mother of young kids, I believe it is essential to know your Vitamin D levels. You can find out using a standard blood test. Depending on the results, you can take steps to ensure you're within the optimal range in order to boost your immune defences.

While a standard blood test would indicate 30ng/ml as the lower reference range, the reality is that 30ng/ml is the level below which one would have a serious deficiency.

A more insightful scale to consider when optimising your Vitamin D levels is:

  • Deficient: <30 ng/ml

  • Insufficient: 30 ng/ml to 50 ng/ml

  • Adequate: 50 ng/ml to 75 ng/ml

  • Optimal: 75 ng/ml to 125 ng/ml


sunshine vitamin

Small Tweaks to Increase Your Vitamin D Levels


  • Get Direct Sunlight: Spend more time outdoors to naturally boost your Vitamin D levels. Even 10-30 minutes of sunlight is sufficient for your daily needs. For skin protection reasons, I would avoid extended sun exposure from noon to about 3pm.

  • Consider Supplementation: Consider taking Vitamin D3 supplements, especially during the winter months or all year round if you have risk factors for deficiency. Vitamin D3 is the type that more closely mimics what your body produces. You will see Vitamin D2 supplements on the market; these are synthetic and far less effective.

  • Top-up on Vitamin D with Diet: Incorporate Vitamin D-rich foods like mushrooms, oily fish, and egg yolks into your diet, but do not solely rely on food for your daily requirements.



Vitamin D is more than just a vitamin; it's a vital component of our overall health. By understanding its importance and taking proactive steps to maintain optimal levels, you reduce the risk of various chronic diseases, including cancer.

Don't wait for a deficiency to make changes—start today and reap the benefits of this essential nutrient.

Curious about your current level of vitamins or your pre-dispositions?

Take a look at The Health Audit, which is a data-driven, one-stop health deep-dive session, that helps you create a clear picture of your health starting point to minimise your long-term chronic disease risk.


certified health coach in London nada soubra

More About Nada


I am a Certified Resilience & Metabolic Health Coach.

I empower busy parents to take more control of their health, get stronger, and prevent chronic disease using realistic approaches that create consistency, without overwhelm.


My approach is rooted in tried-and-tested nutrition and lifestyle methodology rooted in metabolic health.

I want to make early mid-life a chapter in which parents can feel reassured about their health and thrive in all aspects of their life.


Previously, a Partner in a top-tier strategy consulting firm, I pivoted into health coaching and founded The Healthy Chain, after a personal experience with ovarian cancer, which prompted me to make health my top priority.


I am a mum of three and I know how hard it can be to prioritise health when you are juggling a career and family. I focus on realistic tweaks and swaps that slot easily into busy schedules.

You can now schedule a free "Discovery Call" with me to explore how you can start on your journey towards better health. Use this link to book.

Get in touch – I love hearing from you!

Thank you,

Nada Soubra

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