- Low levels of vitamin D prior to catching COVID-19 were linked to worse illness
- Vitamin D helps help regulate the immune system to fight viruses
- Everyone should attempt to maintain a healthy vitamin D level to bolster immunity
Israeli scientists said they found striking differences in the chances of getting seriously ill from COVID-19 when they compared patients who had sufficient vitamin D levels prior to contracting the disease with those who were functionally deficient.
The study*, published on Thursday February, 3rd in the research journal PLOS One, found that about half of people who were vitamin D deficient before getting COVID-19 developed severe illness, compared to less than 10% of people who had sufficient active levels of the vitamin in their blood.
It is well established that vitamin D is vital for bone health but understanding its role in protecting against severe COVID-19 and supporting immune activity has only become established in recent years.
The latest research was the first to examine vitamin D levels in people prior to them contracting COVID-19, the study authors said.
Dr. Amiel Dror, a study author and physician at the Galilee Medical Center, said of the findings, "We found it remarkable, and striking, to see the difference in the chances of becoming a severe patient when you are lacking in vitamin D compared to when you're not".
The findings come from 253 people admitted to Galilee Medical Center in Nahariya, Israel, between April 7, 2020, and February 4, 2021 — a period before the highly infectious Omicron variant emerged.
Dror said the findings suggested that vitamin D helped bolster the immune system to deal with viruses that attack the respiratory system. It is now known that active vitamin D plays a critical role in creating a balanced and effective immune response.
"This is equally relevant for Omicron as it was for previous variants," Dror said.
Most vitamin D comes from direct sunlight on the skin. It's also found in foods such as fatty fish (cod liver oil, salmon, anchovies), mushrooms, egg yolks, and in supplements.
Research compiled before the emergence of COVID-19 and published in The Lancet found that vitamin D reduced the risk of other respiratory infections, compared with placebo.
The Israeli researchers cautioned that vitamin D was "one piece of the complex puzzle" underlying severe COVID-19, in addition to comorbidities, genetic predisposition, dietary habits, and geographic factors.
"Our study warrants further studies investigating if and when vitamin D supplementation among vitamin D deficient individuals in the community impacts the outcome of an eventual COVID-19 episode," they said.
*Pre-infection 25-hydroxyvitamin D3 levels and association with severity of COVID-19 illness
Amiel A. Dror et al, Published: February 3, 2022