VITAMIN D supplements may enhance resistance to respiratory infections such as Covid-19, or limit the severity of the illness for those that do become infected, according to new research from two Dublin-based academics.
Dr Daniel McCartney of Technological University Dublin (TU Dublin) and Dr Declan Byrne of St. James’s Hospital and School of Medicine, Trinity, recommend that adults living in Ireland take 20-50 micrograms of vitamin D per day.
Existing health guidelines already advise that older adults should supplement their diet with vitamin D, but they say the that all hospital patients, nursing home residents, older adults as well as the broader adult population, particularly frontline healthcare workers, should now be taking it.
The report, A Healthcare Professional summary of - Optimisation of Vitamin D Status for Enhanced Immuno-protection against Covid-19, by Dr Daniel McCartney of TU Dublin and Dr Declan Byrne of St James’s Hospital and School of Medicine, Trinity, has been published in the Irish Medical Journal.
The findings have been adopted by the Irish Nutrition and Dietetic Institute and the Irish Society for Parenteral and Enteral Nutrition while the Irish Pharmacy Union is publishing them to its 2,300 members in 1,800 plus pharmacies.
Supplementation at the recommended 20-50 micrograms of vitamin D per day is a short-term measure to specifically address the risk of Covid-19 infection over the coming three to six months.
It is one of two reports published by Dublin researchers this week highlighting the potential importance of Vitamin D in protecting against Covid-19. The other was from the team at The Irish Longitudinal Study on Ageing (Tilda) at Trinity College.
Dr McCartney, a lecturer in Human Nutrition & Dietetics, said vitamin D deficiency was prevalent in Ireland, especially in older people, nursing home residents and hospital inpatients, and may significantly increase the risk and severity of viral respiratory infections, including Covid-19.
He said supplementing a healthy diet with 20-50 micrograms per day of vitamin D represented a cheap, safe and potentially very effective protection for Irish adults against Covid-19.
Dr Declan Byrne, a clinical senior lecturer, says the recommendations were important while the development of a vaccine and trial evidence of effective drug treatment for Covid-19 were awaited
“Our findings call for the immediate supplementation of all hospital inpatients, nursing home residents and older Irish adults with vitamin D. Our findings also suggest that vitamin D supplementation in the broader adult population, and particularly in frontline healthcare workers, may further help to limit infection and flatten the Covid-19 curve.
They also recommend that the guidance should be prioritised in vulnerable groups including those with diabetes mellitus or compromised immune function, individuals with limited habitual sun exposure, those with darker skin, vegans, vegetarians, smokers and those who are overweight or obese. It
Their article notes that people with low vitamin D levels have a higher risk of acute respiratory tract infection and community-acquired pneumonia and that taking it as a supplement may reduce the likelihood of acute respiratory tract infection, and decrease its severity.
“These respiratory tract infections may include Covid-19” it states, adding that vitamin D supplementation “has been shown to suppress CD26, a cell surface receptor which is thought to facilitate entry of the Covid-19 virus into the host cell.”
Historically, humans received most of their vitamin D from sunshine during the summer months, with diet contributing only very modest amounts in relation to overall needs. In recent decades, sun exposure has decreased, and many people in Ireland may consequently have low blood levels of vitamin D, with older adults, especially likely to be vitamin D deficient.