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Let The Sun Shine: Why Vitamin D Could Be Your Best Natural Protection Against Respiratory Illness

Updated: Oct 28, 2020

Let's face it, we just feel much better when we are in the sunshine. We flock towards balmy holiday destinations and love to find those little sunny afternoon spots to bask in. Animals love it too. Its in our nature. And its not just about the brightness and the warmth...our bodies crave the sunshine so that we can make more Vitamin D. The hormone-like sunshine vitamin keeps surprising us with a growing list of health benefits from cancer prevention, to osteoporosis prevention, to gut health and even mental health. With the growing focus on the new invisible enemy, Covid 19, the role that vitamin D plays in immunity and particularly in respiratory immunity has been the focal point of new studies. Since Covid 19 is a novel virus, we don't have solid research on it to make firm statements on the use of Vitamin D, but so far the data is looking promising and has fuelled a lot of interest in the medical and scientific communities, which should result in more research. Like with anything, there is no one cure-all for a viral infection and we can only look at the data coming in and make recommendations based on improving outcomes in a theoretical way. Vitamin D is not an alternative to medical interventions and its not a miracle cure by any means, but its seems to make a considerable difference, and that's a good start.

A recent and very large population study done in Isreal, looked at data for over 4 million people in the National Health Services. Researchers also matched 52,405 infected patients with 524,050 control individuals to assess the relationship between Vitamin D levels, aquisition of supplenents and positive Covid 19. Resuklts showed a highly significant correleation between vitamin D deficiency and covid 19 infection.

Not only does Vitamin D status help to prevent infection, but it has also shown promise in reducing ICU admissions in people with active Covid. One study out of Italy on 103 patients with severe covid, 52 mild cases and 206 controls showed that Vitamin D deficiency was positively associated with more severe cases requiring ICU admissions.

Another new study conducted at Northwestern University looked at data from hospitals and clinics across China, France, Germany, Italy, Iran, South Korea, Spain, Switzerland, the UK and the US and noted that countries with the highest Covid 19 mortality rates also had lower levels of Vitamin D in comparison to countries with higher mortality rates. The authors of this study concluded that a good vitamin D status might not prevent you from contracting the virus but could prevent you from having a severe course of or dying from the virus. This comes after another small study, conducted in the Phillipines, which looked at a group of 212 patients diagnosed with COVID-19 and found that patients with the most adequate Vitamin D status had the most favourable outcomes.

Vitamin D status was also found to have favourable outcomes during the SARS pandemic. In 2009, a meta-analysis study and Vitamin D and immunity concluded that the strongest evidence supports further research into adjunctive vitamin D therapy for tuberculosis, influenza, and viral upper respiratory tract illnesses and that serious adverse events attributable to vitamin D supplementation were rare across all studies.

Since then there have been many more studies linking low vitamin D status to worsening outcomes in respiratory diseases and a 2017 review study looked at 25 studies including 11321 participants and concluded that 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.

This is exceptionally promising research! So where to from here? A good start is if you do have access to it, get your Vitamin D levels checked and aim to keep them above the recommended levels but below the levels of toxicity.

Vitamin D Sources

Our main source of vitamin D is good old sunshine, which is not in a very good supply for many in winter and also with the current world-wide lockdown laws in place. Also, many people have genetic mutations or other confounding factors that increase their likelihood of deficiency, making supplements another viable source of Vitamin D.

Less than 10% of vitamin D is derived from dietary sources in the absence of food fortification or use of supplements. Both the D2 and D3 forms are used for food fortification. The primary natural (unfortified) dietary sources of vitamin D are oily fish (salmon, mackerel, sardines, pilchards), cod liver oil, liver and organ meats, and egg yolk.

Causes of Vitamin D Insufficiency

The following have been identified as high-risk groups for Vitamin D deficiency:

· People with chronic illnesses

· Dark skinned individuals (The Indian and Black communities)

· People on certain medications like corticosteroids, anti-convulsants and anti-retrovirals

· People who spend most of their time indoors

· People who are often covered up (e.g. in certain religious communities)

· People with genetic mutations in Vitamin D metabolism related genes

Vitamin D deficiency defined

There is some controversy as to what defines a Vitamin D insufficiency or deficiency. Because of the mounting evidence for Vitamin D’s benefits, many experts are calling for optimal Vitamin D ranges to be raised.

Currently the serum ranges for diagnosis of Vitamin D deficiency are:

· Vitamin D sufficiency: 25(OH)D >20 ng/mL (50 nmol/L)

· Vitamin D insufficiency: 25(OH)D between 15 and 20 ng/mL (37.5 - 50 nmol/L)

· Vitamin D deficiency: 25(OH)D <15 ng/mL (37.5 nmol/L).

· Safe Upper Limit <60 ng/mL

· Toxicity >150 ng/mL

Institutes of Medicine (IOM) Committee recommends that a serum concentration of 25-hydroxyvitamin D (25(OH)D) of 50 nmol/l is sufficient for bone and overall health in healthy individuals and many experts are calling for Vitamin D levels to be in the higher ranges for optimum health (as close to 50 ng/mL as possible).

Vitamin D deficiency is actually more common then most people might think. Even in a sunny country, like South Africa, the prevalence of Vitamin D deficiency has been shown to be close to 50% in some places. A 2020 report in The Lancet describes the vitamin D status of 21 474 individuals living in 23 African countries. Vitamin D deficiency (<30 nmol/L 25[OH]D) was found in about 18% of these individuals, suggesting that Africa could be the continent with one of the highest frequencies of vitamin D deficiency

Where To From Here?

The jury is pretty much out! Vitamin D is vital to good health and its looking very likely that it could protect you from Covid 19. The following guidelines could help you to protect yourself and get your Vitamin D status optimal. Or at least, this is what I do

  • Try and get 20 minutes direct sunlight per day (without sunscreen or clothing). A good idea is to just expose your arms or your back for a short time.

  • Check your Vitamin D levels and take a supplement if necessary. Mine used to be 20 nmol/l and I take a Vitamin D3 5000 IU a few times per week and keep my levels close to 40 nmol/l. If you're on a supplement, you should periodically check levels to ensure you dont go above 60 nmol/l.

  • Include some Vitamin D rich foods in your diet e.g. fatty fish, eggs yolks and mushrooms


Vitamin D appears to play role in COVID-19 mortality rates. Center for Physical Genomics and Engineering and the associate director for Research Technology and Infrastructure at the Robert H. Lurie Comprehensive Cancer Center at Northwestern University, 7 May 2020.

Green etc al. SAMJ. Vitamin D deficiency and insufficiency in Africa and the Middle East, despite year-round sunny days. 2015

Israel, et al. The link between vitamin D deficiency and covid 19 in a large population. BMJ, 2020.

P Chutterpal, et al. SAMJ, S. Afr. med. j. vol.105 n.7 Cape Town Jul. 2015), Prevalence of vitamin D deficiency in older South Africans with and without hip fractures and the effects of age, body weight, ethnicity and functional status. 13 Nov 2018

Naidoo, et al. South African Family Practice. Prevalence of Vitamin D deficiency in a multiracial female population in KwaZulu-Natal province, South Africa. 2018

Boillion, etc al. The Lancet. Vitamin D status in Africa is worse than in other continents.

Francisco, et al. Arch Biochem Biophys. Vitamin D Safety and Requirements. 2013

Alipilo. Enocr Pract. Vitamin D Supplementation Could Possibly Improve Clinical Outcomes of Patients Infected with Coronavirus-2019 (COVID-2019). 2020.

Alexandra, et al. Endocr Pract. Vitamin D for treatment and prevention of Infectious Diseases: A systematic review of Randomized Control Trials. 2009


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