Researchers at Cooper University Health Care Find that Vitamin D Supplements May Reduce Incidence of Influenza-Like Illness

In a new study published recently in Nutrients, a peer-reviewed journal of human nutrition, researchers at Cooper University Health Care found that Vitamin D supplementation can reduce the incidence of influenza-like illness in populations at risk.

The study, funded by the Won Sook Chung Foundation, was conceived during the COVID-19 pandemic  to help prevent viral infections in health care workers. Because of repeated exposure to sick patients, health care workers have a higher risk than the general population of acquiring respiratory illnesses, including COVID-19. In addition to possibly spreading illness to patients, widespread illness among health care workers lead to critical staffing shortages during the pandemic.

Personal protective gear (masks, gloves, gowns) and practicing good hand hygiene offer some protection against the spread of respiratory illnesses. However, researchers wanted to assess the hypothesis that vitamin D3 supplementation at 5,000 IU daily could reduce influenza-like illness, including COVID-19, in health care workers, according to Noud van Helmond, MD, PhD, Director of Research at the Department of Anesthesiology at Cooper.

The researchers conducted the prospective, controlled trial among health care employees at Cooper who voluntarily participated. A random group of health care workers was invited to receive 5,000 IU daily vitamin D3 supplementation for nine months, while other random health care system workers served as controls. Between October 2020 and November 2021, 255 health care workers completed at least two months of vitamin D3 supplementation. The control group consisted of 2,827 workers.

All employees were required to self-monitor and report to the employee health department for COVID-19 testing if they experienced symptoms of influenza-like illnesses. The primary analysis between the vitamin D and control groups compared the incidence rate of all influenza-like illnesses, while secondary analyses examined incidence rates of COVID-19 and non-COVID-19 influenza-like illnesses.

Over the course of the study, the researchers found that those workers who had received the vitamin D3 supplementation experienced a lower rate of influenza-like illnesses.

“We found the results to be promising, but this is just a first step,” said Dr. van Helmond. “Additional large-scale studies will help determine the efficacy of daily Vitamin D therapy as an effective and inexpensive method to prevent respiratory illnesses.”

Read the complete study here: Vitamin D3 Supplementation at 5000 IU Daily for the Prevention of Influenza-like Illness in Healthcare Workers: A Pragmatic Randomized Clinical Trial

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