• Published on: Apr 17, 2020
  • 4 minute read
  • By: Dr Rajan Choudhary

Vitamin D In Reducing The Risk Of COVID 19

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Why Vitamin D is the only supplement we will recommend for you.

Most of our blogs have looked at theories posted on social media, and shown how they are usually not true, or have no factual basis behind them. But here we will show some evidence that supports something truly interesting, especially during the time of this pandemic.

For a number of years research has shown a possible link between vitamin D and illnesses, specifically respiratory infections. In our previous blogs we have shown that vitamin supplementation is unnecessary, except for vitamin D. Here we will show why supplementation may be in your best interest for reducing the risk of COVID.

Now I’ll be honest. Vitamin D and immunity was not something we were taught at medical school, or in medical practice. The fact that such a large amount of research exists on this topic is certainly interesting, and whilst researching this topic I have certainly learnt a lot myself, enough to change my own medical practice. And it is because of the high quality of evidence present that I feel confident in supporting the claims below.

SUMMARY

  • Many people are low in Vitamin D due to various risk factors (see our blog on vitamin D)
  • Vitamin D appears to have a role in modulating immune function
  • Low Vitamin D levels appear to increase the severity of autoimmune disorders
  • Low Vitamin D levels appear to increase the risk of getting respiratory infections
  • Vitamin D supplementation appears to reduce the risk of getting respiratory infections
  • Those who are at risk of having low vitamin D should take low dose supplementations.

If you want the good stuff, skip to the section on SUPPLEMENTATION

IMMUNE FUNCTIONS

As we’ve discussed, vitamin D is key in maintaining the right balance of calcium, ensuring the right amount is taken up from the food we eat, integrated into our bones, and removed in our urine if not required. We know that there are some people who are at risk of vitamin D deficiency, and this is more common in countries closer to the poles and with cloudy weather.

But there also appears to be a role for vitamin D in modulating the immune system. We have found many more cells in our body other than bone, intestine and kidney that possess the vitamin D receptor. These include immune cells, and one role may be to promote proliferation of these cells as well as promote their protective immunity.

AUTOIMMUNE

Due to its role in immune function, studies have been performed to see whether there is a link between autoimmune diseases and vitamin D. Common autoimmune disorders (and the organs the affect) include multiple sclerosis (nerves), rheumatoid arthritis (joints), diabetes mellitus (pancreas), inflammatory bowel disease (bowels) and systemic lupus erythematous (the entire body). All of these diseases lead to loss in function of an organ or system as the immune system recognises the organ as an “invader” and begins to destroy it.

One study looked at 161 patients with early forms of autoimmune diseases over 2 years. Out of them, 35 went on to develop full blown autoimmune disorders (like rheumatoid and lupus). Whilst the two groups of patients were mostly similar, vitamin D was noticeably lower in the group that progressed to disease. But this is one study, with a small number of patients.

Other studies have looked at vitamin D levels in patients across the globe, and the majority of them have shown there to be a correlation between low vitamin D or severe deficiency, and the severity of autoimmune disorder they have. We will not go into them in detail because this is beyond the scope of this blog, but it certainly is interesting and supports this new role for vitamin D.

RESPIRATORY INFECTIONS

We have unknowingly tried to use Vitamin D to treat infections prior to the advent of antibiotics. A common treatment for tuberculosis was to send patients to sanatoriums, where treatments included exposure to sunlight, and provision of cod liver oil, a rich source of vitamin D.

Large population studies done in the 1980s and 1990s involving 19,000 people showed that those with low vitamin D levels were more likely to self report recent upper respiratory tract infections than those with normal levels. This was true even if age, gender, season and race were accounted for. Similar studies have shown similar results when looking at rates of influenza, bacterial vaginosis and HIV.

Normally we are very skeptical with such studies, and look for weaknesses in their methodology and conclusions. After all, we could just cherry pick the studies that show a benefit. Furthermore, just because there is a trend with vitamin D levels and infection, this does not imply a direct link. More evidence is required. However, the fact 19,000 people were surveyed provides this study with good statistical power, and lends it validity. But lets look for more.

SUPPLEMENTATION

Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data – Martineau 2017, British Medical Journal

A systematic review and meta analysis is the highest level of evidence in the realm of medical research. It is the absolute pinnacle of thorough research, looking and comparing other studies with very close scrutiny to see whether we have conducted enough research worldwide to support a theory. In this case this systematic review was published in the British Medical Journal, a highly reputable source that again scrutinises any study submitted thoroughly before accepting it for publication. In my eyes, this is some of the best evidence we will have on this topic. And it is a far sight better than any WhatsApp forwards.

So what does this say?

Vitamin D supplementation was safe and it protected against acute respiratory tract infection overall. Patients who were very vitamin D deficient and those not receiving bolus doses experienced the most benefit.

I don’t think I could have summarised it better myself. If you wish to read the study yourself you can use this link: https://www.bmj.com/content/356/bmj.i6583 Vitamin D supplementation to prevent acute respiratory tract infections

WHAT DOES THIS MEAN FOR ME?

If you are someone who may be at risk of vitamin D deficiency, then low dose supplements (NOT treatment dose) may be beneficial in reducing the risk of getting a respiratory infection. Since COVID is caused by a respiratory virus, we can extrapolate that Vitamin D supplementations may reduce your risk of getting COVID. This is not a cure, and it is not a guaranteed protection. If you already have a balanced diet and are not low in Vit D, it may be less beneficial.

Dr Rajan Choudhary, UK, Chief Product Officer, Second Medic Inc

www.secondmedic.com

Read Blog
Hormone Balance Diet: Eat Smart, Feel Better with SecondMedic

Hormone Balance Diet: Eat Smart, Feel Better with SecondMedic

Your hormones are the body’s messengers - regulating everything from energy and digestion to mood and fertility. But today’s stressful lifestyles, processed foods, and erratic sleep can easily disrupt this delicate balance. The result? Fatigue, acne, mood swings, weight gain, and irregular cycles.

Thankfully, you can start restoring balance right at your dining table - with the Hormone Balance Diet, supported by SecondMedic’s personalized health guidance.

 

The Science Behind Hormone Balance

Hormones are chemical messengers produced by glands like the thyroid, pancreas, and ovaries/testes.
When they’re balanced, your metabolism, sleep, and mood remain stable. But when disrupted - due to stress, poor diet, or toxins - it leads to inflammation and chronic symptoms.

Major hormones influenced by diet include:

  • Insulin: controls blood sugar and fat storage

  • Thyroid (T3, T4): regulates metabolism

  • Cortisol: the stress hormone

  • Estrogen & Progesterone: reproductive health and mood
     

According to the ICMR 2024 study, 1 in 3 Indian adults shows early signs of hormonal imbalance - most linked to poor diet and stress.

 

Foods That Help Restore Hormonal Harmony

1. Eat Real, Whole Foods

Whole grains (brown rice, millets, oats) and vegetables stabilize insulin. Avoid refined flour, sugar, and processed foods - they cause spikes that disrupt hormones.

2. Include Protein in Every Meal

Proteins provide amino acids needed for hormone synthesis. Add eggs, lentils, paneer, tofu, or fish.
Tip: 1 gram of protein per kg of body weight per day is ideal.

3. Healthy Fats = Healthy Hormones

Fats help build estrogen, testosterone, and progesterone. Choose:

  • Ghee (in moderation)

  • Avocado, olive oil

  • Nuts & seeds (flaxseed, chia, sunflower)
     

Avoid hydrogenated oils and fried foods.

4. Boost Gut Health

Your gut microbiome regulates estrogen and cortisol. Include fermented foods like curd, buttermilk, kimchi, or probiotic drinks daily.

5. Micronutrients Matter

  • Magnesium: helps cortisol control - found in spinach, almonds

  • Zinc: supports thyroid and testosterone - pumpkin seeds, lentils

  • Vitamin D: crucial for insulin and estrogen balance - sunlight + fortified milk
     

6. Hydrate and Sleep Well

Dehydration and poor sleep elevate stress hormones. Aim for 7–8 hours of rest and 2–3 liters of water daily.

 

Common Signs of Hormonal Imbalance

  • Constant fatigue

  • Unexplained weight gain/loss

  • Hair thinning or acne

  • Irregular menstrual cycles

  • Mood swings, irritability

  • Low libido
     

If you notice 2–3 of these symptoms consistently, it’s worth booking a Hormonal Health Check through SecondMedic.

 

How SecondMedic Helps Restore Balance

SecondMedic’s Hormonal Health Program includes:

  • At-home hormone testing (thyroid, insulin, estrogen, testosterone)

  • Expert doctor consultation online

  • Personalized diet & supplement plans

  • Progress tracking through your SecondMedic health dashboard
     

This integrated care model helps patients restore hormonal balance naturally - through nutrition, sleep, and stress management.

 

Conclusion

Your hormones thrive on balance - not extremes. A well-planned Indian diet rich in whole foods, good fats, and fiber can naturally reset your system. Add mindful habits like yoga, rest, and hydration, and your body will thank you with lasting energy, focus, and peace.

At SecondMedic, we make hormone health simple, data-driven, and personalized - right from your home.

Book your Hormonal Health Test and Nutrition Consultation now at SecondMedic.com - because balance begins with care.

 

Real Data & References

  • ICMR 2024: 1 in 3 Indians shows signs of hormonal imbalance.
    icmr.gov.in

     

  • NIN India (2024): Balanced macronutrient diets improve hormone stability.
    nin.res.in

     

  • WHO India 2023: Nutrition-based intervention reduces insulin resistance by 28%.
    who.int/india

     

  • SecondMedic Hormone Health Data (2025): 76% of patients report symptom improvement within 3 months of nutrition therapy.
    secondmedic.com

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