• 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

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Excessive

Heat Exhaustion Warning Signs: Symptoms You Should Never Ignore

Heat-related illnesses are common during hot weather, particularly in tropical countries like India where summer temperatures can become extreme. Heat exhaustion is a serious condition that occurs when the body overheats due to prolonged exposure to high temperatures and inadequate hydration.

Recognizing heat exhaustion warning signs early can prevent life-threatening complications such as heatstroke.

 

What Is Heat Exhaustion?

Heat exhaustion is a heat-related illness caused by:

  • Excessive heat exposure
     

  • Dehydration
     

  • Loss of electrolytes through sweating
     

It often occurs during outdoor work, exercise or travel in hot environments.

If untreated, it may progress to heatstroke — a medical emergency.

 

Common Heat Exhaustion Warning Signs

1. Heavy Sweating

Excessive sweating is one of the earliest signs.

The body attempts to cool itself through perspiration, leading to fluid loss.

2. Dizziness or Lightheadedness

Low blood pressure due to dehydration may cause:

  • Feeling faint
     

  • Blurred vision
     

  • Weakness
     

 

3. Fatigue and Weakness

Muscle weakness and exhaustion occur as the body struggles to regulate temperature.

 

4. Nausea and Vomiting

Digestive discomfort is common in heat-related illnesses.

 

5. Headache

Dehydration and heat stress can trigger throbbing headaches.

 

6. Muscle Cramps

Electrolyte imbalance may cause painful muscle cramps, especially in legs.

 

7. Rapid Heartbeat

Increased heart rate helps circulate blood for cooling but may indicate strain.

 

8. Cool, Clammy Skin

Despite hot weather, skin may feel cool and moist due to heavy sweating.

 

Who Is at Higher Risk?

Certain groups are more vulnerable:

  • Outdoor laborers
     

  • Athletes
     

  • Elderly individuals
     

  • Children
     

  • People with chronic illnesses
     

  • Individuals on certain medications
     

Urban heat exposure increases risk during peak summer months in India.

 

Heat Exhaustion vs Heatstroke

Heat exhaustion is serious but manageable if treated promptly.

Heatstroke symptoms include:

  • High body temperature (above 40°C)
     

  • Confusion or disorientation
     

  • Dry, hot skin
     

  • Seizures
     

  • Loss of consciousness
     

Heatstroke requires immediate emergency medical attention.

 

Immediate Steps to Take

If heat exhaustion is suspected:

  1. Move to a cool, shaded area
     

  2. Loosen tight clothing
     

  3. Drink water or oral rehydration solution
     

  4. Apply cool cloths to body
     

  5. Rest until symptoms improve
     

Seek medical care if symptoms persist beyond one hour.

 

Prevention Tips

Stay Hydrated

Drink water regularly, even if not thirsty.

 

Avoid Peak Sun Hours

Limit outdoor activity between 12 PM and 4 PM.

 

Wear Light Clothing

Choose loose, breathable fabrics.

 

Use Sun Protection

Wear hats and sunglasses when outdoors.

 

Take Frequent Breaks

Rest in shaded or air-conditioned areas.

 

Maintain Electrolyte Balance

Use oral rehydration solutions if sweating heavily.

 

Heat Illness in the Indian Context

India frequently experiences heatwaves, especially in northern and central regions. Public awareness about hydration and heat safety is essential to reduce hospitalizations and fatalities.

Community-level education can significantly improve prevention.

 

When to Seek Medical Help

Immediate medical attention is required if:

  • Symptoms worsen
     

  • Body temperature rises significantly
     

  • Confusion develops
     

  • Fainting occurs
     

  • Vomiting persists
     

Early treatment prevents severe complications.

 

Conclusion

Heat exhaustion is a preventable but potentially dangerous condition. Recognizing warning signs such as heavy sweating, dizziness, nausea and muscle cramps allows timely intervention.

With rising summer temperatures, especially in India, proactive hydration and heat safety measures are essential. Preventive care and awareness can protect vulnerable individuals and reduce health risks.

Staying cool and hydrated is the simplest way to safeguard your health during hot weather.

 

References

  • Indian Meteorological Department – Heatwave Reports

  • World Health Organization – Heat-Related Illness Guidelines

  • Indian Council of Medical Research – Public Health Advisory

  • National Disaster Management Authority (India) – Heatwave Action Plan

  • Lancet Planetary Health – Climate and Health Research

 

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