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Vitamin D & COVID-19: What you need to know

Vitamin D & COVID-19: What you need to know

In the last few weeks there has been so much emerging research and talk in the media surrounding how Vitamin D could help with ensuring better outcomes in patients who contract COVID-19. There appears to be a correlation in those who have low vitamin D levels and severe COVID-19 symptoms. There has been significant research carried out by Cambridge University Hospital and by Trinity College Dublin to name but a few to suggest that it may be of benefit.

The Irish Longitudinal Study on Ageing (TILDA) have released information on how their research has highlighted the key role that Vitamin D plays in the body’s immune response when fighting off infection. Their research has highlighted the role that the vitamin plays in preventing respiratory infection, reducing the need for antibiotics and generally boosting the immune system. It also stressed the importance of taking a Vitamin D supplement while at home or cocooning as it was estimated that 27% of Irish adults over the age of 70 who are ‘cocooning’ are deficient.

See the findings of the research study here:

Vitamin D deficiency is common in the adult population in Ireland, particularly among the elderly, hospital patients, nursing home residents and vulnerable patient groups such as those with diabetes and compromised immune functions. Deficiency is also common in those with darker skin, vegans and vegetarians, those who are overweight and smokers. Although it is not known for sure how those taking Vitamin D have better outcomes when they contract COVID-19 then those who don’t, it is a supplement worth taking which will benefit you in many positive ways as well as giving you the best chance at having a good outcome in the case of contracting COVID-19.

It is recommended that the wider general adult population, as well as those at risk, take a Vitamin D supplement to ensure their immune system is as strong as it can be and that they have better outcomes if they contract COVID-19.  However, it is important to note that taking Vitamin D it is not a treatment for COVID-19 nor does it protect you from catching COVID-19 in the first instance.

Read more on Vitamin D, its benefits and how to choose the right one for you below:

What is Vitamin D?

Vitamin D is a steroid hormone and one of many fat-soluble vitamins that the body requires to function correctly. The two most important forms of Vitamin D are Vitamin D2 and D3. D2 is produced by plants whilst D3 is made by the skin and in supplements. Vitamin D3 is generally better absorbed by the body over D2. Vitamin D3 is suitable for vegetarians but not vegans whereas D2 is suitable for both.

What does Vitamin D do?

Vitamin D is responsible for a number of functions within the body. It helps regulate Calcium and Phosphate in the body ensuring it enters the bone to maintain healthy bones and teeth. In serious deficiencies patients can get rickets which is a condition where the bones become softer and deform.

The density of our bones decreases after the age of 30. Therefore, it is important to build up Vitamin D levels to try and maintain bone density. Vitamin D supports a healthy immune system, protecting the body from illnesses such as the common cold and viruses and it plays a fundamental role in ensuring normal muscle function.

Vitamin D deficiency is associated with increased risk of acute viral respiratory infections and community acquired pneumonia. Taking Vitamin D supplements has been shown to reduce the risk of getting respiratory infections.

In a study carried out by Cambridge University Hospital in relation to COVID-19 specifically:

  • Vitamin D deficiency correction is thought to suppress CD26. This an adhesive molecule for COVID-19 host cell invasion, therefore its suppression can help decrease COVID-19 uptake in the body.
  • Vitamin D is also shown to attenuate (slow down) 2 inflammatory responses in the body. These immunological responses are thought to elicit poorer clinical outcomes in COVID-19 infection and so decreasing those responses helps those patients in their recovery.

Why do we need to take a Vitamin D supplement?

There is an increasing need for us to supplement with Vitamin D in order to maintain a healthy level of Vitamin D in our bodies. Reasons for this are that we are living in Ireland, a country that does not get as much sunlight as we need. From late March to late September we have the opportunity to make Vitamin D from the sun in Ireland however, this can be dependent on many factors such as weather and lifestyle. Processed diets and specialist diets that cut out certain food groups that contain Vitamin D mean we are not getting it from our food.  We are living a more sedentary lifestyle now that we are staying at home for work and possibly cocooning. We are educated on the risk associated with sun damage and wear high factor when we are exposed.

Where can we get it from?

We make this essential vitamin from the skin's unprotected exposure to sunlight and this is why it is known as the sunshine vitamin. It takes approximately 10-15 minutes of unprotected sun exposure to get the necessary amount we need daily.

It can also be found naturally in certain foods such as red meat, eggs, cheese and fatty fish. Other foods are fortified and have vitamin D added to them like cereal, Supermilk and bread. We can also take a Vitamin D supplement to ensure we get the amount we need every day.

Did you know... To achieve the minimum recommended daily amount of 400 IU you would need to eat: 8 eggs, 3kg of cheddar cheese or 2 cans of tuna - everyday!

What are the symptoms of a Vitamin D deficiency?

Most people who are deficient in Vitamin D have no symptoms. Others will experience:

  • Fatigue
  • Bone and Joint pain
  • Back pain
  • Muscle pain/cramps
  • Mood changes (low mood)
  • Frequent coughs and colds

Low vitamin D levels have been associated with increased risk of death from cardiovascular disease, cognitive impairment, severe asthma in children and some cancers.  

If you suffer from any of the above symptoms regularly, it could be a sign that you’re lacking in vitamin D. The best way to determine if you have a deficiency in Vitamin D is to get a blood test conducted by your GP.

Who is deficient in Vitamin D and who is most at risk?

In Ireland, due to poor dietary intake, low supplementation rates and low sun-exposure the prevalence of Vitamin D deficiency is high – particularly amongst older adults, who are the most vulnerable to COVID-19.

Vitamin D deficiency is common in Ireland, especially amongst older adults, hospital patients and nursing home residents. A study showed that 35.7% of adults 50-64 years and 44% if adults 65-84 years had below optimal Vitamin D levels all year round and these figures rose to 48.1 % and 55.4% respectively in the winter months.

Other vulnerable categories to Vitamin D deficiency include:

  • Those who are housebound
  • Those with Diabetes Mellitus
  • Those with compromised immune function
  • Those with darker skin
  • Vegetarians and vegans
  • Those who are overweight or obese
  • Smokers
  • Healthcare workers

It is also safe to take while pregnant or breastfeeding but may already be in a pregnancy/breastfeeding multivitamin so check with your pharmacist if you are currently taking one.

How much Vitamin D do we need?

The Food safety Society of Ireland (FSAI) recommend older adults should supplement with 10mcg (400IU) of Vitamin D per day. However most European countries now recommend intakes of 15-20mcg (600IU-800IU) per day in older groups. Irish adults require 20-50mcg (800IU-2000IU) per day of Vitamin D3. This amount is not achievable by diet alone therefore supplementation is recommended.

To know how much Vitamin D to take can be difficult. If a Doctor has completed a blood test and this comes back as being low in Vitamin D, supplementation is necessary. If no prescription is given and the Doctor advises take some Vitamin D, then the recommended regimen is to take 75mcg-100mcg (3000IU-4000IU) once daily for two months then decrease down to a maintenance dose of 25mcg (1000IU) once per day.

If you have just started to read about Vitamin D and the many benefits that it has and would like to start taking some, then 25mcg (1000IU) a day is sufficient. 

Is it possible to take too much Vitamin D?

While there are documented cases of Vitamin D toxicity, these are very rare and normally relate to exceptionally high doses and for extended periods of time. There is no evidence that supplementation of Vitamin D3 at 20-50mcg (800IU-2000IU) per day has any adverse effects. High dose’s of more than 100mcg (4000IU) per day should not be taken on an ongoing basis unless under the care of a doctor.

Vitamin D supplements:

There are many different forms and brands of Vitamin D supplements available from handy capsules and tablets that you take once per day with food, to mouth sprays. With so many options it can be hard to know which one is right for you.   

The following are my top recommended tablets/capsules to take:

Another form is the Better You D-Lux sprays which are a very efficient method of administering Vitamin D. The spray can to be used by spraying it under the tongue where there is an excellent blood supply for absorption.  The mouth has a huge amount of blood vessels in it and using this form allows the Vitamin D to be absorbed in the mouth and straight into the blood stream, therefore avoiding the digestive system. 

Should children take a Vitamin D supplement?

The Food Safety Authority of Ireland recommend all babies between 0-12months should receive a Vitamin D3 supplement. It is essential for them to build and maintain strong bones and teeth as well as build strong and healthy immune systems. 0-12 months should have no more than 5mcg (200IU) per day. Be aware a lot of infant formulas already are fortified with 5mcg (200IU) of Vitamin D so babies taking more than 300mls of formula per day may not require a supplement 

Vitamin D drops are available and generally come in a container with a dropper. Please note, many are measured in drops i.e. one drop not one full dropper. They also come in pump form and two pumps will achieve the recommended dose of 5mcg (200IU).  

Children aged 1-4 years should be given a daily supplement of 10mcg (400IU) per day. If your child is already taking a multivitamin, they may be already getting their recommended daily dose. If not, there are supplements available such as the BetterYou Dlux Infant Daily Vitamin D Oral Spray and Pharma Nord BioActive D-Pearls Junior

Our team is always here for you in any way that we can be. If you have any questions about Vitamin D or how best to ensure that you are doing everything you can to protect yourself from COVID-19 please contact any of our stores to discuss this with one of our expert pharmacy teams or contact our helpline on 014853098 or email

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