There’s been a lot of interest about Vitamin D and the possible protecting effect it has against the coronavirus, or COVID-19. While scientists aren’t yet 100% sure what the exact mechanism is, many doctors are strongly advising supplementing with Vitamin D as a precaution. In this article, we’ll look at how Vitamin D may protect against the coronavirus and other upper respiratory infections.

A Note from Elaine: I ’ve hesitated to add to the sea of information about COVID available online. I feel the media are generating more panic than reassurance, and I don’t want to add to it. But this time of year I would be giving advice about immune protection through the flu and cold season anyway, and Vitamin D deserves an in-depth look. And if it allays some of the worry for you: so much the better.

Vitamin D

Vitamin D is fat-soluble, and production is triggered on the skin’s surface when exposed to sunlight in the summer. The UV-B rays activate chemicals on the skin, which are then absorbed into the body and converted into the vitamin. It takes just 10-15 minutes in a short-sleeved T shirt in the mid-day sun, a few times a week for the body to synthesise it's own Vitamin D.

Historically, deficiency was common in urban areas of the UK during and after the Industrial Revolution, when people living in big towns and cities spent less time outdoors. Pollution from coal fires and factories prevented sunlight getting through and many people became ill with respiratory problems, tuberculosis, or the disease Rickets which causes bones to soften and bend. In adults it is called osteomalacia. My father had Rickets as a boy in smoky 1930s London. He was prescribed milk by his doctor as it was (by that time) fortified with Vitamin D, and had to wear heavy splints to straighten his legs until the bones became stronger.

Do you need Vitamin D?

If you spend a lot of time outdoors in the summer your body may have enough Vitamin D to get through the winter. If you regularly eat a selection of dairy products, fortified cereals, oily fish, sun-dried mushrooms or eggs, you’re also likely to get adequate Vitamin D. But if your diet doesn’t include these food sources and your skin hasn't seen much sun; consider supplementing, especially if you tick any of the following:

  • Wear sunscreen or sun cream: Sun protection prevents the UV rays from reaching the skin where Vitamin D is produced.
  • Spend a lot of time indoors: UV doesn’t penetrate through glass. Given that many of us have been indoors more during the summer due to lockdown, deficiency could be more of a risk than it might be usually.
  • Live where there are high levels of pollution and the UV rays are blocked
  • Over 50? - skin isn’t as efficient at making its’ own Vitamin D
  • Live in the Northern Hemisphere: winter sunlight isn’t strong enough for skin to make the vitamin. So that means you may need to take Vitamin D in the winter if you live in the UK, and if you live in Scotland, the spring and autumn too.
  • Are vegan or vegetarian: you may lack adequate Vitamin D if you don't replace dairy with other sources of Vitamin D, such as products like Engevita, a nutritional yeast.
  • Wear concealed clothes: skin has to be directly exposed to the sun to synthesise Vitamin D
  • Have darker skin: darker pigmentation provides more of a barrier to UV rays that activate chemicals on the surface of the skin.

Asian and ethnic people who live in the northern Hemisphere are particularly at risk of Vitamin D deficiency. There is no proof or hypothesis that Vitamin D deficiency could be a factor, but as we know in the UK, BAME groups do seem to be higher-risk for contracting the coronavirus

How much Vitamin D should you take?

10mcg of Vitamin D a day in relation to Coronavirus is the current advice from the NHS. (2)

10-15mcg per day for the over 50s: aging skin produces less of the vitamin (3)

It's not necessary to take more than the above recommendations of Vitamin D. If you have a medical condition, or are on any other medication, check with your GP before taking any vitamins to make sure they are safe for you. Since most vitamins require other co-factors and vitamins to work well, my advice is to take a broad spectrum multi-vitamin that includes Vitamin D. Also look for high vitamin B, Vitamin C and zinc - these all keep the immune system strong. Good quality supplements like Biocare or Lamberts are a little pricier, but they really are worth it. The cheaper brands often use forms of vitamins the body can't assimilate properly.

Contra-indications for Vitamin D - Thiazide diuretics: taking Vitamin D may cause excess or toxic levels of calcium in the body.

Vitamin D: The Science

Scientists are hesitant to give official backing for Vitamin D as there are few official studies in relation to immunity. There have been many studies of Vitamin D in relation to tuberculosis, skeletal disease, heart disease and cancer. Evidence indicates that both innate and adaptive immunity link bacterial and viral infection to Vitamin D deficiency, but the subject is complex. It is perhaps telling that colds, ‘flu, respiratory and gastrointestinal viruses all peak in winter when Vitamin D levels are low.

Here's a helpful video from Dr. JoAnn Manson, MD DrPH Does Vitamin D protect against Coronavirus?

In her 2011 paper: The Role of Vitamin D in Human Health: A Paradigm Shift, Joan M. Lappe says: ‘A wealth of clinical evidence supports the effect of vitamin D on decreasing the risk of infectious diseases’. She cites Sabetta et al, who found that when Vitamin D was present in blood serum, it was associated with a significant reduction in the risk of developing acute respiratory infections, plus a marked reduction in the percentages of days ill.

Ginde AA, et. al. discovered a clear link between Vitamin D and upper respiratory tract infection during a 6 year US survey with 18,883 participants.(5) Their research of recent studies suggested a role for vitamin D in innate immunity, including the prevention of respiratory tract infections.

Read more about Vitamin D

As we go through this pandemic it's important to be careful, but also to live as normally as possible.Stay in touch with friends and family by phone or online if you cannot see them in person.If you feel anxious or depressed, be brave and reach out for help - we're all in this together and we'll get through by helping each other.

Stay well! Elaine x

Sources

(1) https://www.medscape.com/viewarticle/930152 Does Vitamin D Protect Against COVID-19?. JoAnn E. Manson, MD, DrPH

(2) https://www.nhs.uk/conditions/vitamins-and-mineral...

(3) Lamberts Practitioner’s Guide to Supplements

(4) Vitamin D, innate immunity and upper respiratory tract infection. J. Bartley https://www.cambridge.org/core/journals/journal-of...

(5) Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey. Adit A Ginde 1, Jonathan M Mansbach, Carlos A Camargo Jr https://pubmed.ncbi.nlm.nih.gov/19237723/

(6) Human Nutrition, A Health Pespective. M.E. Barasi. Hodder Arnold. ISBN: 978-0-340810255