Vitamin D is an essential fat-soluble vitamin required to perform many body functions. It is required for absorption of calcium and phosphorus and to facilitate normal immune system function. It is also needed for bone health and without sufficient vitamin D bones can become thin, brittle or misshapen. Vitamin D sufficiency prevents rickets in children and osteomalacia in adults. Vitamin D and calcium also helps protect older adults from osteoporosis. Deficiency of vitamin D has been associated with increased autoimmunity as well as an increased susceptibility to infections notably, upper respiratory tract infections.
Vitamin D is found naturally in oily fish such as salmon, herring, mackerel and sardines, red meat, liver, eggs, some fortified foods such as breakfast cereals. However, you don’t get enough vitamin D form the food sources and sunlight is the best source for Vitamin D.
Public Health England is recommending the use of Vitamin D supplements since people are mainly staying indoors during the lockdown which puts them at a high risk of vitamin D deficiency.
The Department of Health and Social Care recommends taking a daily supplement containing 10 micrograms of vitamin D throughout the year for people who are dark skinned, housebound, in care homes and usually cover up their skin when they are outdoors.
A recent study reported a strong connection between Vitamin D levels and COVID-19 complications. The authors suggested that “Vitamin D is most likely to reduce serious COVID-19 complications since vitamin D is important in regulation and suppression of the inflammatory cytokine response, which causes the severe consequences of COVID-19 and ‘acute respiratory distress syndrome’ associated with ventilation and death”.
Another research is recommending a dose of 10,000 IU/d of vitamin D3 for a few weeks to rapidly raise 25(OH)D concentrations, followed by 5000 IU/d for the people at risk of influenza and/or COVID-19 with an intention to raise 25(OH)D concentrations above 40-60 ng/mL (100-150 nmol/L).
NHS states there have been some reports about vitamin D reducing the risk of coronavirus. However, there is currently no clinical evidence on vitamin D in COVID-19. More clinical trials are underway to study whether Vitamin D is beneficial in this context.
However, we still need to make sure we are taking enough vitamin D rich foods in our diet and Vitamin D supplements, as recommended by PHE, to reduce the risks of Vitamin D insufficiency or deficiency, especially for older people as they are at high risk of poor outcome from COVID-19 and of vitamin D deficiency.
What is the advice for children, babies and pregnant women?
The advice is:
- breastfed babies from birth to one year of age should be given a daily supplement of 8.5 to 10 micrograms of vitamin D to make sure they get enough
- formula-fed babies should not be given a supplement until they are having less than 500ml (about a pint) of infant formula a day because formula contains vitamin D
- children aged one to four should be given a daily supplement of 10 micrograms
- The dose for adults (10 micrograms a day) applies to pregnant and breastfeeding women.
Laird, J. Rhodes, R.A. Kenny.Vitamin D and Inflammation: Potential Implications for Severity of Covid-19.Irish Medical Journal, 2020; 113 (5): P81
Grant, W.B.; Lahore, H.; McDonnell, S.L.; Baggerly, C.A.; French, C.B.; Aliano, J.L.; Bhattoa, H.P. Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths. Nutrients 2020, 12, 988.