Published on September 8, 2021

64% of moderate COVID-19 cases compared to 84% of severe cases had vitamin D levels below 20 ng/ml

Vitamin D is necessary for proper immune function. Multiple studies have shown greater protection against viral infections and upper respiratory diseases with higher vitamin D levels. It is also known that the demand for vitamin D can be increased during times of acute infection, making it even more important to ensure continued adequate intake for the maintenance of vitamin D levels during these times.

With this in mind, findings that higher vitamin D levels are related to greater protection and better outcomes from diseases such as COVID-19 should come as no surprise.

Another Study Shows Low Vitamin D Related to Worse Prognosis

A recent study by Karanova et al., and co-authored by GrassrootsHealth scientist panel member Dr. William Grant, found a significant relationship between low vitamin D levels and severity and death among patients hospitalized with COVID-19. This study included 133 patients whose vitamin D levels at hospital admission ranged from 3 ng/ml to 97 ng/ml. The patients were grouped according to vitamin D level, with 90 patients diagnosed with vitamin D deficiency (less than 20 ng/ml or 50 nmol/L), 37 of which had severe deficiency (less than 10 ng/ml or 25 nmol/L). Normal vitamin D levels were defined as at least 30 ng/ml (75 nmol/L) and were found among only 12 (9%) of the participants in this study. It is important to note that the GrassrootsHealth panel of vitamin D scientists recommends a level of 40-60 ng/ml (100-150 nmol/L).

A further grouping was done based on whether patients were suffering a moderate or severe course of COVID-19 disease. 81% of the patients had a moderate course of disease. Of those suffering a severe course of COVID-19, 35% were severely vitamin D deficient and 15% were mildly vitamin D deficient.

Only one of the 18 patients (6%) who died from COVID-19 had a vitamin D level greater than 20 ng/ml (50 nmol/L).

Click to Enlarge & Print

Of note, those with severe COVID-19 tended to be older and more often had obesity, diabetes mellitus, and cardiovascular disease (especially coronary artery disease). In fact, this study showed that obesity alone worsened disease prognosis by at least 6 times, and vitamin D deficiency was found to contribute to a greater increase in risk of severity and death than a concurrent diabetes diagnosis.

In Conclusion

Overall, this study concludes that COVID-19 disease severity and death due to COVID-19 were both associated with vitamin D deficiency (levels below 20 ng/ml or 50 nmol/L), with increased significance among those whose vitamin D level was severely deficient, below 10 ng/ml (25 nmol/L). Those with vitamin D levels less than 10 ng/ml had more than 4 times the risk of severe disease and almost 6 times the risk of dying from COVID-19 compared to those 10 ng/ml and higher, after adjusting for age, sex, and comorbidities.

These findings are consistent with previous findings on vitamin D and COVID-19 outcomes, including those from a meta-analysis of 43 studies on vitamin D and COVID-19 that found

  • overall risk of severe COVID-19, defined as the need for intensive care and/or mechanical ventilation, was 160% higher among those with vitamin D levels below 20 ng/ml (50 nmol/L) compared to those whose levels were 20 ng/ml or higher (P<.01).

Click to Enlarge & Print

  • overall risk of death due to COVID-19 was 22% higher among those with vitamin D levels below 20 ng/ml (50 nmol/L) compared to those whose levels were 20 ng/ml or higher (P<.01).

Click to Enlarge & Print

For a summary of studies on vitamin D, COVID-19, respiratory infections, and immune function, visit this page.

Are Your Vitamin D Levels OK?

Let us know what your daily vitamin D routine is while testing your levels. Contribute your data as a citizen scientistwhat other discoveries can we make together?

Having and maintaining healthy vitamin D levels and other nutrient levels can help improve your health now and for your future. Choose which to measure, such as your vitamin D, omega-3s, and essential minerals including magnesium and zinc, by creating your custom home test kit today. Take steps to improve the status of each of these measurements to benefit your overall health. You can also track your own intakes, symptoms and results to see what works best for YOU.

Enroll and test your levels today, learn what steps to take to improve your status of vitamin D (see below) and other nutrients and blood markers, and take action! By enrolling in the GrassrootsHealth projects, you are not only contributing valuable information to everyone, you are also gaining knowledge about how you could improve your own health through measuring and tracking your nutrient status, and educating yourself on how to improve it.

Help everyone Move Research into Practice with vitamin D and other nutrients! As a special birthday gift to everyone, in honor of the science, we have created a special scholarship fund for anyone to donate to that will go towards helping others participate. Your donation will allow anyone to get help with funding their participation when they need it.

Text-to-give: Text Daction to 44321 to add to our Scholarship Fund.

How Can You Use this Information for YOUR Health?

Having and maintaining healthy vitamin D and other nutrient levels can help improve your health now and for your future. Measuring is the only way to make sure you are getting enough!

STEP 1 Order your at-home blood spot test kit to measure vitamin D and other nutrients of concern to you, such as omega-3s, magnesium, essential and toxic elements (zinc, copper, selenium, lead, cadmium, mercury); include hsCRP as a marker of inflammation or HbA1c for blood sugar health

STEP 2 Answer the online questionnaire as part of the GrassrootsHealth study

STEP 3 Using our educational materials and tools (such as our dose calculators), assess your results to determine if you are in your desired target range or if actions should be taken to get there

STEP 4 After 3-6 months of implementing your changes, re-test to see if you have achieved your target level(s)

Enroll in D*action and Build Your Custom Test Kit!