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 didn't.

A study published Thursday in 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 percent of people who had sufficient levels of the vitamin in their blood.

We know vitamin D is vital for bone health, but its role in protecting against severe COVID-19 is less-well established.

The latest research was the first to examine vitamin D levels in individuals 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," per the Times of Israel.

The findings come from 253 people admitted to Galilee Medical Center in Nahariya, Israel between 7 April 2020 and 4 February 2021 – a period before the highly-infectious Omicron variant emerged.

Dror said the findings suggested vitamin D helped bolster the immune system to deal with viruses that attack the respiratory system.

"This is equally relevant for Omicron as it was for previous variants," Dror said.

The research doesn't prove vitamin D protects against COVID-19 and isn't a green light to avoid vaccines and take vitamins instead. Vaccines cut the risk of Omicron hospitalization, particularly after a booster, by up to 90 percent, according to the UK Health Security Agency.

Most vitamin D comes from direct sunlight on the skin. It's also found in foods such as fatty fish, mushrooms, and egg yolks as well as supplements.

Vitamin D levels of more than 20 nanograms per milliliter are considered sufficient for most people, according to the Centers for Disease Control and Prevention – which is the benchmark used by the researchers from Bar-Ilan University and Galilee Medical Center.

Research compiled before the emergence of COVID-19 and published in The Lancet, found vitamin D cut the risk of other respiratory infections, compared with dummy drugs.

But for COVID-19, early findings have been inconsistentsome studies have found a link between low vitamin D levels and severe COVID-19, whilst others concluded the vitamin wasn't protective.

It wasn't clear – even from those studies with results showing a positive correlation between low vitamin D levels and severe COVID-19 – if depleted vitamin D came before or after people got sick, the Israeli researchers said.

Despite the new Israel data, we still don't know if low vitamin D levels cause people with COVID-19 to develop serious disease.

Underlying conditions that reduce vitamin D can also make people more vulnerable to severe COVID-19, for example.

The Israeli researchers cautioned 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.

This article was originally published by Business Insider.

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