On Jan. 17, the Expert Review of Anti-infective Therapy journal conclusively found that COVID-19 patients supplemented with vitamin D “demonstrate fewer rates of ICU [intensive care unit] admission, mortality events, and RT-PCR positivity.” Contributors to the study spanned multiple professional departments in India. They performed a systematic review and meta-analysis of six randomized controlled trials (RCTs) with 551 COVID-19 patients.
Immunity and COVID-19
According to the U.S. National Institutes of Health (NIH), Vitamin D is “critical for bone and mineral metabolism” and has the “potential to modulate innate and adaptive immune responses.” A receptor for vitamin D is expressed on B cells, T cells, and antigen-presenting cells, which are immune cells that can “synthesize active Vitamin D metabolite.”
Vitamin D deficiency is common in the United States, especially in Hispanic and black individuals, as well as the obese and those with high blood pressure. These same demographics also suffer worse outcomes with COVID-19.
The NIH states that there is “insufficient evidence to recommend either for or against the use of vitamin D for the prevention or treatment of COVID-19.” However, its guidance is only based on a handful of studies up through April 21, 2021. It does not include subsequent randomized controlled trials.
Emerging evidence shows vitamin D can “affect SARS-CoV-2 gene expression and alleviate infection upon binding to the vitamin D response element.” It may also regulate the renin-angiotensin system and angiotensin-converting enzyme 2 (ACE2), a receptor known to mediate SARS-CoV-2 viral infections.
Significant results
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The Indian authors conducted the systematic review and meta-analysis by reviewing 755 articles. All participants were aged 18 or older with a mean age between 36 and 56 years. The vitamin D treatment group was compared against a placebo group in two studies, a non-vitamin control group in three studies, and a “standard treatment comparator group” in one study.
Based on a meta-analysis of pooled data from all of the studies, COVID-19 patients supplemented with vitamin D were shown to have reduced overall risk for all outcomes. The “collective overall evidence on severity, ICU care, mortality, sero and RT-PCR positivity events reported in all trials indicated that COVID-19 patients treated with vitamin D showed lower rates of these outcomes relative to patients receiving no-vitamin D/standard/placebo.”
The authors of the Indian study implore other researchers to conduct larger RCTs with improved designs and larger sample sizes to better assess COVID-19 related outcomes. The analyzed studies were heterogeneous, with different doses of vitamin D, the timing of doses, and different control groups. Importantly, none of the studies “reported any adverse events due to vitamin supplementation.”
Recommended dosage
There is no clear consensus about how much vitamin D3 an individual should treat COVID-19. But recommendations for vitamin D3 dosing can be found on the “Prophylaxis & Early Outpatient Treatment Protocol for COVID-19” page on the Front Line COVID-19 Critical Care (FLCCC) Alliance website.
FLCCC is a non-profit organization “dedicated to developing highly effective treatment protocols to prevent the transmission of COVID-19 and to improve the outcomes for patients ill with the disease.” The group is composed of several accomplished physicians with thousands of peer-reviewed publications.
Recommended vitamin D3 doses for COVID-19 can either be based on known vitamin D levels in the blood or on body mass index (BMI), a measure of body fat based on height and weight. The doses can be given daily or once a week. For example, a non-obese person with a BMI between 20 and 29 can take 5,000 to 7,000 international units of vitamin D3 daily or 50,000 international units once a week.