COVID-19 Update: Vitamin D3 New Research

by Denise Tam, Holistic Nutritionist

Hong Kong is in its third wave and we can all agree that it’s not looking good with daily highs and deaths. The government has put into place ‘shelter and place’ suggestions, enforcements on masks and restrictions on public gatherings, however there lacks guidance on nutrition and lifestyle factors which is just as an important aspect of keeping infections low and minimising the impact on the front line.

nutrition and lifestyle

I’ve spoken a lot about the core nutrients to support our immune system during the flu season and an epidemic like COVID-19. The core nutrients for immunity mainly being Vitamin C, A, D, Zinc and other herbals like echinacea and elderberry.

In this article, I’ll be highlighting Vitamin D with new research that has been recently published on July 15 that specifically looks at Vitamin D3 levels in COVID-19 patients.

To recap, Vitamin D is a lipid soluble vitamin derived from cholesterol and requires ultraviolet rays (UVB) to convert this cholesterol derivative into Vitamin D3. There are two forms of Vitamin D, D2 and D3. Vitamin D3 is the form that is utilised in our body.

Nutrients Open Access Journal

A large study published in Nutrients of over 365,000 patients studied over 10 years recorded many benefits of having optimal Vitamin D3 levels for a variety of health concerns including IBS, Chrons, multiple sclerosis, psoriasis and osteoporosis. Though there is no official agreement to a suggested reference range of Vitamin D the optimal level suggested in this study is 100-150 nmol/L, concluding that it is,

advisable to increase vitamin D intake and have sensible sunlight exposure to maintain serum 25-hydroxyvitamin D at least 75 nmol/L, and preferably at 100–150 nmol/L to achieve the optimal overall health benefits of vitamin D.

In comparison, the US Institute of Medicine suggests a minimal concentration of 52 nmol/L while the Endocrine Society suggests 78 nmol/L. These reference ranges however are typically to avoid deficiency rather than optimal overall health. In Hong Kong, Vitamin D deficiency in past studies have typically been defined as less than 50 nmol/L, half of the optimal range suggested in the large cohort study. 

According to a Vitamin D status report published by International Osteoporosis Foundation, more than 90% of young women in Beijing and Hong Kong had Vitamin D3 levels lower than 50 nmol/L, with those in the north (Beijing) having as low as 9nmol/L and in the south (Hong Kong), 34 nmol/L. 

Why is this interesting for us in this COVID-19 season?

The study on Vitamin D recently published in Nutrients, looked into the effects of Vitamin D on respiratory viral infections and COVID-19. It remarks that there are peaks in influenza infections in the winter time in higher altitude places while tropical areas (like Hong Kong), are more sporadic in their infections. The research proposes to explain that the seasonal outbreaks correlate to the seasonal variations in levels of Vitamin D3 which is typically lowest in the winter months.

Vitamin D concentrations in the blood however can vary throughout the year depending on your genetics like your skin pigmentation as well as other factors like sunlight exposure, dietary choices and of course supplementation. The journal quotes a cohort study in healthy adults living in New England who showed a “two fold reduction in the risk of developing acute respiratory tract infection”, which is exactly what we are dealing with in COVID. 

Furthermore , a recent meta-analysis of 25 randomised clinical trials showed that supplementation of Vitamin D can protect against the development of acute respite tract infections compared with placebos. 

The study in Nutrients explains that Vitamin D has antiviral activities that can regulate the body’s inflammatory response to a viral infection. The authors conclude that a supplementation of Vitamin D to maintain adequate Vitamin D  serum levels of 100-150 nmol/L is advisable in order to minimize the risk and severity of COVID-19 infections’. The authors go further in suggesting a standard of care “to give at least one single dose of 50,000 of Vitamin D to all COVID-19 patients as soon as possible after being hospitalised.”

Having said that, we would not be administering this ourselves at home even with COVID-19 symptoms but this should be interesting to all of us to use Vitamin D3, along with other core nutrients, as a preventative measure along with wearing masks, physical distancing and keeping good hygiene. 

If you ask me, the nutritional factors are a larger player in minimizing infection and severity. Because this epidemic seems uncontrollable and here to stay, it’s all the more reason to guard yourself inwardly not just outwardly. 

People at Risk of Vitamin D Deficiency

  • Premature babies
  • Babies born to mothers who are vitamin D deficient 
  • Exclusively breastfed babies who have little sun exposure
    Prince of Wales study in Hong Kong found that 97.4% of exclusively breastfed infants were Vitamin D deficient
  • People with a genetic SNPs that inhibit the conversion of Vitamin D2 to D3
    Most extensively studied are the rs4588 and rs7041 genetic polymorphisms (SNPS) which are associated with increased risk of vitamin D deficiency particularly in East Asian populations
  • Vegans
    Vitamin D is predominantly found in animal products. For those who are strict vegans, Pure Encapsulations has a vegan friendly Vitamin D3 drop that is derived from naturally occurring, sustainably harvested lichen, the same molecular structure and conformation as cholecalciferol derived from lanolin or fish. It is the only plant-derived source of vitamin D3 that has been accepted by the UK Vegan Society.
  • People who spend most of their times indoors 
  • People who keep all skin covered up by clothing
  • People who have limited outdoor activity 
  • People living in highly polluted areas where the sun cannot 
  • People with renal diseases, liver diseases and other chronic illnesses.

Supplementing with Vitamin D3

If you haven’t been recently tested, I would recommend getting your vitamin D3 levels tested.  If you have been tested in the past 3-4 months it is likely your doctor has told you you are in ‘normal’ ranges, but it's advisable to go back to your reports to check what your level is at. 

You may want to consider taking 2000-5000IU of Vitamin D3 depending if you are on the lower or higher end of the spectrum of the optimal range of Vitamin D3 status (100-150 nmol/L) . If your results show that you are deficient the Endocrine Society has a recommended dosage for vitamin D intake in individuals who are at risk for vitamin D deficiency and dosage of vitamin therapy treatment for patients with vitamin D deficiency in the table below.

dosage of vitamin therapy treatment for patients with vitamin D deficiency

Lastly, if you don’t have any blood work and are not planning on getting tested, a safe daily dosage for adults is 2000 IU, for children around 800IU and infants 400IU. In my previous article, I mentioned a BMJ study that showed consistent, daily supplementation of Vitamin D3 is more effective than a one off dose at cutting the risk of respiratory tract infections. So you can see that consistency is key.

This is just one of many things we can do to support ourselves and our community around us. With the rate of spread and mutations of this virus, it is better that you guard yourself inwardly as well as outwardly. Remember the other nutrients, like Vitamin C and zinc and healthy lifestyle habits like sleeping well, exercising and eating fresh foods.

Stay well, Stay happy, Stay healthy.

Written by: Denise Tam, Holistic Nutritionist


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