Since COVID-19 emerged, discussions have been ongoing regarding the potential benefits of taking supplementary vitamin D to prevent or treat the virus.

The vitamin, often referred to as the sunshine vitamin due to its production in our bodies when exposed to light, holds particular significance in autumn and winter when outdoor activities decrease.

During the winter months, individuals are commonly advised to take vitamin D supplements to maintain bone and muscle health and support overall well-being. However, regarding COVID-19, health experts exercise caution in establishing a definitive link.

In June 2020, Paul Chrisp, director of the Centre for Guidelines at the National Institute for Health and Care Excellence in the UK, stated, "While there are health benefits associated with vitamin D, our rapid evidence summary did not identify sufficient evidence to support the use of vitamin D supplements for the treatment or prevention of COVID-19."

This conclusion followed a meticulous analysis of five studies investigating the relationship between coronavirus and vitamin D. Chrisp emphasized the ongoing nature of research, with continuous monitoring of newly published evidence.

An observational study by the UK’s Covid Symptom Study app suggested that vitamin D supplements might play a small role in reducing the risk of COVID-19 in women, though not in men. However, researchers highlighted the need for additional clinical trials.

Early in the pandemic, 1.4 million app users contributed data to the COVID Symptom Study app, detailing their supplement use. Among them, over 445,000 were diagnosed with COVID-19, while 126,000 were presumed to have the disease based on symptoms.

Upon analyzing the data of those with and without COVID-19, researchers concluded that multivitamins, vitamin D, omega-3, and probiotic supplements exhibited a very small but statistically significant protective effect. Vitamin C, zinc, or garlic supplements showed no detectable impact.