Benefits are possible but evidence is sparse, indirect, and inconclusive
One high profile controversy has been the role of vitamin D in the prevention and management of covid-19.
The joint guidance concludes that there is little good evidence on vitamin D and covid-19, highlights the need for further research, and supports existing government advice that adults and children in the UK should take 10 μg (400 IU) a day between October and March, to optimise musculoskeletal health. It also recommends that certain populations such as minority ethnic groups, consider taking vitamin D throughout the year.
What’s the evidence?
Vitamin D supplementation of 10-25 μg a day has a modest protective effect against acute respiratory infections,4 but research on a direct effect in covid-19 is sparse.
Implications for guidance
Although the recommended 10 μg daily seems justifiable to maintain serum concentrations of 25-hydroxyvitamin D above 25 nmol/L, whether this is enough to gain any immunomodulatory benefits for patients with covid-19 remains unclear. UK guidance recommending 10 μg a day of vitamin D has been in existence for a while, but adherence is not guaranteed. Raising awareness of the relevance of vitamin D to musculoskeletal health is therefore appropriate, particularly during pandemic restrictions on movement. Evidence for a role in covid-19 remains suggestive only, but people may choose to take the recommended dose on the precautionary principle that it does no harm, may be beneficial, and improves bone health.
It’s important that people are not falsely reassured by vitamin D supplements, and guidance must stress the importance of hand hygiene, face coverings, physical distancing, and vaccination against covid-19 in culturally and linguistically appropriate campaigns through local community groups.