By Andrea Bartels CNP NNCP RNT
Registered Nutritional Therapist

06 Aug 2020

Even those of us who are not part of this vulnerable group need to pay attention to our vitamin D status over the summer. Wearing sunscreen and sun-proof clothing unfortunately reduces our capacity to make vitamin D because this vitamin is made in the skin and depends on sun exposure. Since protecting our skin from the damaging effects of excessive UV ray exposure interferes with vitamin D production, it makes sense to take a vitamin D3 supplement through the summer-especially as we prepare for a potential 'second wave' of infections as the weather cools off. But is there really an immuno-protective benefit to optimizing vitamin D status? Check out these facts:

Earlier this year, vitamin D status in a sample of 235 COVID-19-positive patients at Sina Hospital in Tehran, Iran was linked to the severity of their illness. That is to say that those with levels of vitamin D more than 30 ng/liter (75 nmol/liter) had milder symptoms and a death rate of just 9.7 percent, while 20 percent of those with levels than 30 ng/liter (75 nmol/liter) succumbed to the virus's complications. Researchers also found lower levels of the inflammatory biomarker C-reactive protein, higher levels of lymphocytes and higher oxygen levels in those with higher blood levels of vitamin D. Is this just a coincidence? Or does it make sense?

ARDS (acute respiratory distress syndrome) is the dreaded complication that kills many of those with severe cases of COVID-19. Could we reduce the risk of developing and dying from ARDS by keeping our vitamin D levels up? A 2015 study published in the journal Thorax on ARDS-at-risk and ARDS-diagnosed patients post-surgery suggests a reason to think so. Researchers there found that vitamin D deficiency was associated with increased extravascular fluid in the lungs-a phenomenon that is associated pneumonia. What's more, 96 percent of those at risk were found to be vitamin D-deficient (lower than 50 nmol/liter). Those study participants who were extremely deficient---with vitamin D levels below 20 nmol/liter-- had a 4.2 fold higher risk of developing ARDS than patients with levels at or above this value (after adjusting for other potential factors). The results of this interesting study suggests that vitamin D status can influence the severity of symptoms experienced by those with lung infections.

How Much To Take and How to Monitor Your Levels

Testing for vitamin D status by measuring 25-OH-Cholecalciferol in the blood is a good way to check if you're absorbing it, and, will determine what level of supplementation is needed. First, obtain a set of multiple requisition forms from your primary health care provider-one for each of the several blood draws you will obtain over the coming year. Then, take 1,000 i.u. of vitamin D3 daily, being consistent in taking it each day. After 3 weeks, go get your vitamin D levels checked. If it is below the optimal range of 75 - 100 nmol/liter it makes sense to increase the dosage you take each day. After 3 weeks on the new dosage your levels can be checked once again. If you are now in the ideal range, stick with the dose; if not, increasing your intake should increase blood levels. This cycle can be repeated until the desired range is reached. It is especially important to test near the beginning of 'flu season', and again in early winter, to see if increased indoor time is reducing your levels.

Will a "second wave" of COVID-19 infections occur this Autumn? The arrival of the Fall season historically sees an increased incidence of cold and flu. The best way to prepare for the possibility is to make sure your nutritional status is optimized. Don't let hot weather keep you in a deficit situation. Support your immune system with PureLab Vitamin D. At 1000 i.u. per capsule, it's a safe and simple way to help strengthen your defences.


Andersen R, Brot C, Jakobsen J, et al. Seasonal changes in vitamin D status among Danish adolescent girls and elderly women: the influence of sun exposure and vitamin D intake. Eur J Clin Nutr. 2013;67(3):270-274.

Dancer RCA, Parekh D, Lax S, et al. Vitamin D deficiency contributes directly to the acute respiratory distress syndrome (ARDS). Thorax 2015;70:617-624.

Maghbooli, Zhila et al. Vitamin D Sufficiency Reduced Risk for Morbidity and Mortality in COVID-19 Patients. (Manuscript draft). 05/27/20

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