Having sufficient levels of Vitamin D in the body is linked to reduced risk of severe Covid19, according to a Boston University study published inPLOS One. Vitamin D is an organic micronutrient that’s obtained via sun exposure and certain foods (fatty fish, egg yolks, cheese), but can also be taken via supplement.

This study adds to previous research strengthening Vitamin D’s role in the immune system’s fight against Covid19. Previous research proved that Vitamin D deficiencies were linked to a higher likelihood of testing positive for Covid19 and that sufficient Vitamin D levels were linked to a reduced risk of catching Covid19 by 54%.

Scientists used blood samples to monitor the Vitamin D levels of 235 hospitalized Covid19 patients. Around 74% had severe COVID-19 infection and 32.8% were vitamin D sufficient. They checked infection severity, breathing difficulties, C reactive protein and lymphocyte levels, and their ability to overcome the disease. Then, scientists compared these parameters in patients who were Vitamin D sufficient and Vitamin D deficient. After adjusting for confounding factors, researchers saw a clear link between healthy Vitamin D levels and a reduction in severe Covid19 and mortality. Plus, scientists also observed an increased presence of lymphocytes (white blood cells) and a decrease in serum CRP (an inflammatory marker), both related to sufficient Vitamin D levels.

“This study provides direct evidence that vitamin D sufficiency can reduce complications, including the cytokine storm (release of too many proteins into the blood too quickly) and ultimately death from Covid19,” Michael F. Holick, Ph.D., MD, study author and professor of medicine at Boston University, said in a statement.

Related on The Swaddle:

No Link Between Vitamin D Levels and Late‑Life Clinical Depression: Study

According to The Lancet, interest in Vitamin D as a means to prevent/treat respiratory illnesses dates back to the 1930s, when scientists looked into cod liver oil as a means to drop common cold rates. “From a mechanistic angle, there are good reasons to postulate that vitamin D favorably modulates host responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), both in the early viraemic and later hyperinflammatory phases of COVID-19. Vitamin D metabolites have long been known to support innate antiviral effector mechanisms, including induction of antimicrobial peptides and autophagy,” Adrian R Martineau and Nita G Forouhi write in the Lancet.

“There is great concern that the combination of an influenza infection and a coronal viral infection could substantially increase hospitalizations and death due to complications from these viral infections,” Dr. Holick said in a statement, adding, “Because vitamin D deficiency and insufficiency is so widespread in children and adults in the United States and worldwide, especially in the winter months, it is prudent for everyone to take a vitamin D supplement to reduce risk of being infected and having complications from Covid19.”