Subscribe to Dr. Meschino’s Free Newsletter

Subscribe Now

NMU 301 – Low Vitamin D Blood Levels Shown to Increase Risk of Long COVID Syndrome

Nutrition/Natural Medicine Update No 301 (August 30, 2023)

with Dr. James Meschino

Topic: Low Vitamin D Blood Levels Shown to Increase Risk of Long COVID Syndrome

Source: Journal of Clinical Endocrinology & Metabolism (April 2023)


Long COVID Syndrome affects 50-70% of all COVID-19 survivors, but doctors have been at a loss to predict who is susceptible to developing Long COVID.  The study published in the April 2023 issue of The Journal of Clinical Endocrinology & Metabolism suggests very strongly that low vitamin D levels may be an important risk factor for the development of Long COVID syndrome. So, this is what we have learned so far about Long COVID. Up to this point some evidence has suggested that being a woman as well as having diabetes, pulmonary disease and/or obesity, may increase risk of developing Long COVID Syndrome. Symptoms of Long COVID can involve neurocognitive issues (like brain fog) as well as disturbances of the cardiorespiratory and gastrointestinal systems, constitutional symptoms, and musculoskeletal involvement (muscle pain or myalgia), as well as taste and smell disorders. Previous studies have shown that low vitamin D levels were associated with worse outcomes for patients who contracted COVID-19 infections.  Lower vitamin D levels were associated with higher rates of death, more severe infections, increased likelihood of being admitted to the Intensive Care Unit of a hospital, longer stay in the ICU, and increased likelihood of requiring mechanical ventilation.

In April 2023 researchers published a groundbreaking study showing that those with Long COVID syndrome also tend to have lower blood vitamin D levels than COVID-19 survivors who did not develop Long COVID syndrome. The study involved 50 patients with Long COVID and 50 patients who contracted COVID-19 but did not develop Long COVID. The average age of the patients was 61 years old, with a mix of men and women. After controlling for a host confounding variables, the study showed a strong correlation between low vitamin D levels at the time of the 6-month follow-up post COVID-19 infection, in the patients who developed Long COVID syndrome. More specifically, the study showed that Long COVID syndrome patients had an average vitamin D level of 20.1 ng/ml whereas COVID-19 survivors who did not develop Long COVID had an average blood vitamin D level of 23.2 ng/ml. In Canada vitamin D levels are reported in umol/L. As such, Long COVID patients in this study had an average vitamin D blood level of 50.25 umol/L and COVID-19 survivors who did not develop Long COVID had an average blood level of 58 umol/L.

As the researchers pointed out vitamin D is well-known to support and regulate many aspects of immune system function, helping us fight off infections, including viral infections. Vitamin D also supports muscle health and muscle recovery and helps to improve muscle pain and arthralgia symptoms (painful joints), and it helps to prevent age-related muscle atrophy. Vitamin D also influences neurocognitive functions and disorders, and vitamin D supplementation has been shown to promote respiratory recovery after pneumonia. The researchers made some closing comments in their research paper and during the Medscape interview afterwards. Here are some quotes:

“In this study we have observed that COVID-19 survivors who reported persistent signs and symptoms 6 months after hospital discharge consistent with long COVID syndrome were characterized by lower 25(OH) vitamin D levels than those without the syndrome, and lower 25(OH) vitamin D levels were an independent risk factor for long COVID occurrence.

“Our data suggest that vitamin D levels should be evaluated in COVID-19 patients after hospital discharge,” write the researchers from San Raffaele Hospital, Milan, Italy.

“The highly controlled nature of our study helps us better understand the role of vitamin D deficiency in long COVID and establish that there is likely a link between vitamin D deficiency and long COVID,” senior author Andrea Giustina, MD, said in a press release from the ECE.

In my view, the evidence is very convincing that for optimal immune function it is best to have a blood vitamin D level above 75 umol/L (30 ng/ml) and no higher than 150 umol/L (60 ng/ml) unless otherwise indicated by your physician (for patients with autoimmune diseases higher vitamin D levels may be more beneficial).  I have provided this evidence in previous Lifestyle Medicine Updates. So, get your blood vitamin D level tested and take appropriate steps to get into the ideal range. It may help to prevent severe COVID infection and help guard against the development of Long COVID syndrome, which can really be life altering.

I have provided the references for this study in the text below.



di Fiippo et al. Low vitamin D levels are associated with long COVID Syndrome in COVID-19 survivors. Journal of Clinical Endocrinology & Metabolism. April 13, 2023.

Medscape: Could vitamin D supplementation help in long COVID?

Tuesday August 29, 2023 (Marlene Busko)


Eat Smart, Live Well, Look Great,
Dr. Meschino

Facebook Comments