The study published in the journal Plos One, was the first to analyse vitamin D levels prior to Covid-19 infection, allowing for a more accurate assessment than during hospitalisation.
It examined the vitamin D levels of more than 1,176 patients from two weeks to two years prior to infection.
The study showed that patients with vitamin D levels less than 20ng/mL were 14 times more likely to have severe or critical Covid-19 than those with levels more than 40ng/mL, and mortality among patients with sufficient vitamin D levels was 2.3% compared to 25.6% in the vitamin D deficient group.
Lead author of the study, Dr Amiel Dror said: "Our results suggest maintaining normal levels of vitamin D is beneficial to those who contract the virus. There is a clear consensus for vitamin D supplementation on a regular basis as advised by local health authorities as well as global health organisations.
“What we’re seeing is that people with sufficient vitamin D are better equipped to fight Covid-19 infections as a result of its effectiveness in bolstering the immune systems to deal with viral pathogens that attack the respiratory system. This is equally relevant for Omicron as it was for previous variants,” he added.
Vitamin D is essential for healthy bones, a robust immune system and reducing inflammation. However it can be difficult to obtain through diet alone. With a lack of sunshine during winter, increased sedentary lifestyles and chronic diseases, supplementation is necessary.
Vitamin D deficiency is a global health problem with research suggesting that Africa may have the highest frequency of severe deficiency. In the UK, health officials have recommended vitamin D supplementation to everyone during autumn and winter, while a new review has been launched to promote the importance of vitamin D and improve intake.
Volumes of research have shown vitamin D’s powerful role in boosting immunity, reducing the risk of cancer death and protecting against illness such as colds, flu and respiratory infections.
Health expert, Vanessa Ascencao said a strong immune system and healthy levels of vitamin D are key to protecting the body from illness, especially during winter when many viruses are more active.
“Follow a healthy lifestyle which includes good sleep, regular exercise, stress management, daily exposure to the sun, eating as healthy as possible and using high quality Vitamin D supplements. Vitamin D oral sprays, in particular are rapidly absorbed by the mouth’s blood vessels and are proven to be far more effective than pills,” said Ascencao.
