Two important new studies by researchers in Ireland highlight vitamin D’s potentially important role in priming the body’s defences against the Covid-19 virus.
Optimisation of Vitamin D Status for Enhanced Immuno-protection Against Covid-19, published this month in the Irish Medical Journal, notes that a growing body of research documents the effectiveness of vitamin D supplementation in reducing the risk of respiratory infection.
Examining the potential for vitamin D supplementation to support natural defences to Covid-19, the authors highlight a mechanism by which correcting vitamin D deficiency is thought to suppress CD26, a molecule for Covid-19 host cell invasion. They write: “Vitamin D may also attenuate interferon gamma and interleukin-6 inflammatory responses, both potent predictors of poorer outcome in critically-ill ventilated patients including those with Covid-19.”
“Vitamin D may also attenuate interferon gamma and interleukin-6 inflammatory responses, both potent predictors of poorer outcome in critically-ill ventilated patients including those with Covid-19”
Noting that vitamin D deficiency is common in Ireland (and northern countries generally) and may contribute to increased risk of complications from Covid-19, the researchers from Technological University Dublin and Trinity College Dublin, call for “prioritised supplementation of all hospital inpatients, nursing home residents and community-dwelling older adults with vitamin D at a minimum daily dose of 20 micrograms per day.” They add that “in absence of a vaccine or any effective anti-viral drug therapy” a similar regime should then be extended to the general population “in order to mitigate the grave public health risks associated with Covid-19 infection”.
Another report, from the Irish Longitudinal Study on Ageing (TILDA), emphasises the importance of increasing vitamin D by older people who are staying at home or cocooning.
The TILDA team describe vitamin D “as a potent immune modifying micronutrient” and suggest that, at sufficient levels, it could play an important role in protecting vulnerable adults, particularly those who are obese and those with pre-existing lung conditions, both of which are more susceptible to complications from Covid-19.
The authors highlight a recent large meta-analysis (looking at 10,933 people in 25 trials), which showed that vitamin D supplementation reduced the risk of cold and flu patients developing acute respiratory infections (ARIs) from 60% to 32%.
They also report on trials showing how vitamin D can alter the immune system response through its influence on the production of immune molecules known as cytokines. They write: “Vitamin D has been shown to help signal the increased production of ant-inflammatory molecules and decrease the production of pro-inflammatory molecules. This switch in immune response, in theory, may have some potential benefit in cases of ‘cytokine storm’ – a massive release of pro-inflammation (which has been observed in those infected with COVID) which can cause acute respiratory distress syndrome”.