ABSTRACT
The purpose of this report is to clarify what constitutes best practice on vitamin D supplement use, particularly among older adults, who are at highest risk of Covid-19. On Friday 3rd April, three reports were published on how vitamin D may protect against Covid-19. Two reports are aligned with national and international guidelines on vitamin intake requirements for health: one looked at the importance of vitamin D adequacy in protecting children from respiratory illness but included important advice cautioning against high dose vitamin D;the other is from The Irish Longitudinal Study on Ageing (TILDA) that looked at specific ’at risk’ groups for vitamin D deficiency in those over 50 years in a representative sample from the 26 counties. TILDA provides a strong evidence base for intervening in older adults with supplemental vitamin D (10 µg to 20 µg daily). A third report advises that every adult should take high doses of vitamin D (20 µg to 50 µg daily) in order to protect against Covid-19. The authors make no mention about other sources of vitamin D in adults. This creates confusion at a time when there is widespread fear and anxiety about the Covid-19 pandemic. The following provides a review of the evidence and summarises best practice regarding vitamin D nutrition to protect against Covid-19.