Taking Vitamin D to prevent COVID-19
This week’s expert:
Prof Peter Ebeling, Endocrinologist and Head of the Department of Medicine, Monash University
Drawn from Dr David Lim’s interview with Prof Peter Ebeling on the Healthed Podcast, ‘Going Viral’.
• Previous research (from 2006 published in Science) has shown the active form of Vitamin D produces an antimicrobial agent within leucocytes
• A meta-analysis (published in 2017) showed that Vitamin D supplementation reduced the risk of acute respiratory tract infections by 20 percent. Supplementation was most effective in those people who were Vitamin D deficient at baseline
• There is evidence that Vitamin D can influence the ACE2 receptor, which is also the receptor utilised by the SARS-CoV-2 virus. It is thought Vitamin D can act as an antagonist against SARS-CoV-2.
• It is known COVID-19 mortality increases with latitude. Greater latitudes are associated with lower UV levels and, as a consequence, lower levels of Vitamin D in the population.
• Previous research has suggested as many as 50% of Melburnians have low Vitamin D levels in winter. People in aged care homes and those with dark skin are most at risk and it appears these are the populations that are currently getting the most severely affected by COVID-19 in the Victorian outbreak.
• To avoid the musculoskeletal effects of Vitamin D deficiency it is recommended that people have serum levels of at least 75 nmol/L which would require an intake of approximately 1000 IU per day (more in those who are overweight or obese). However, it is estimated that to prevent respiratory tract infections (and COVID-19 in particular) serum levels need to be in the order of 90-100 nmol/L. This requires a daily intake of between 2000-4000 IU. (In the UK there is a COVID-19 prevention trial currently underway that involves 10,000 people who have been randomised to receive either 3000 IU/day or 400-1000 IU/day.)
• Supplementation of Vitamin D at 4000 IU/day is known to be safe. The Institute of Medicine in the US has determined that 10,000 IU/day is the upper tolerable level.
• In Australia it is not possible to get sufficient Vitamin D from diet alone. It is estimated we only receive 110 IU/day from food. Most of our Vitamin D comes from UV exposure.
• Vitamin D3 is the most commonly available and most preferable form of supplementation in Australia
• A number of randomised controlled trials are currently underway to determine the effectiveness of Vitamin D in the prevention and treatment of COVID-19. A number of these studies will also be looking at the role of cofactors (used along with Vitamin D) such as the antioxidants – zinc and Vitamin C.
• Until the results of these RCTs are published, the evidence for Vitamin D to prevent or treat COVID-19 is largely theoretical. However, given the scientific logic behind this theory and the known safety of Vitamin D supplementation it would be worthwhile for people in Melbourne, particularly the elderly to consider taking at least 3000 IU/daily of Vitamin D3.