Scientific evidence indicates vitamin D reduces infections & deaths
Research shows low vitamin D levels almost certainly promote COVID-19 infections, hospitalizations, and deaths. Given its safety, we call for immediate widespread increased vitamin D intakes.
Vitamin D modulates thousands of genes and many aspects of immune function, both innate and adaptive. The scientific evidence1 shows that:
Higher vitamin D blood levels are associated with lower rates of SARS-CoV-2 infection.
Higher D levels are associated with lower risk of a severe case (hospitalization, ICU, or death).
Intervention studies (including RCTs) indicate that vitamin D can be a very effective treatment.
Many papers reveal several biological mechanisms by which vitamin D influences COVID-19.
Causal inference modelling, Hill’s criteria, the intervention studies & the biological mechanisms indicate that vitamin D’s influence on COVID-19 is very likely causal, not just correlation.
Vitamin D is well known to be essential, but most people do not get enough. Two common definitions of inadequacy are deficiency < 20ng/ml (50nmol/L), the target of most governmental organizations, and insufficiency < 30ng/ml (75nmol/L), the target of several medical societies & experts.2
Too many people have levels below these targets. Rates of vitamin D deficiency <20ng/ml exceed 33% of the population in most of the world, and most estimates of insufficiency <30ng/ml are well over 50% (but much higher in many countries).3 Rates are even higher in winter, and several groups have notably worse deficiency: the overweight, those with dark skin (especially far from the equator), and care home residents. These same groups face increased COVID-19 risk.
It has been shown that 3875 IU (97mcg) daily is required for 97.5% of people to reach 20ng/ml, and 6200 IU (155mcg) for 30ng/ml,4 intakes far above all national guidelines. Unfortunately, the report that set the US RDA included an admitted statistical error in which required intake was calculated to be ~10x too low.4
Numerous calls in the academic literature to raise official recommended intakes had not yet resulted in increases by the time SARS-CoV-2 arrived. Now, many papers indicate that vitamin D affects COVID-19 more strongly than most other health conditions, with increased risk at levels < 30ng/ml (75nmol/L) and severely greater risk < 20ng/ml (50nmol/L).1
https://vitamindforall.org/letter.html