There is currently insufficient evidence to support taking vitamin D solely to prevent or treat COVID-19, according to new guidance, according to a rapid evidence review by the UK's National Institute for Health and Care Excellence (NICE), in conjunction with Public Health England, and the Scientific Advisory Committee on Nutrition (SACN), reports MedicalBrief.
The evidence review was in response to a small number of studies that had suggested it might play a role in the body's immune response to respiratory viruses. that vitamin D might help in the prevention or treatment of COVID-19 because of its role in the body's immune response to respiratory viruses. Data included the best available scientific evidence published so far, including both observational studies and randomised controlled trials.
NICE said more research was needed but advised those in the Northern Hemisphere winter to take a daily supplement to keep bones and muscles healthy.The review agreed that low vitamin D status was associated with more severe outcomes from COVID-19 but it was not possible to confirm causality because many of the risk factors for severe COVID-19 outcomes are the same as the risk factors for low vitamin D status.
Other problems with the available evidence were cited as inconsistencies between studies, and differences between supplementation doses, settings, populations, durations of trials, and definitions of outcomes. NICE said there should be a particular focus on subgroup analyses, including among older people and people from Black, Asian and Minority Ethnic groups where poorer outcomes are seen in people with COVID-19.
Dr Paul Chrisp, director of the Centre for Guidelines at NICE, said: “As research continues on the impact of vitamin D on COVID-19, we are continuing to monitor evidence as it is published and will review and update the guidance if necessary."
Taking vitamin D is particularly important this winter because of the amount of time people have spent indoors isolating and shielding from coronavirus. This means they may not be making enough vitamin D from sunlight – a key source. Vitamin D can also be obtained from certain foods, such as oily fish and cereals, and supplements.
Some people are at risk of not having enough vitamin D even in spring and summer, including:
those with dark skin (such as people with African, African-Caribbean or south Asian backgrounds)
those in care homes; those who don't go outside often; and those who cover up most of their skin when outdoors. These groups are advised to take a vitamin D supplement all year round.
Dr Alison Tedstone, chief nutritionist at Public Health England, said: "We advise that everyone – particularly the elderly, those who don't get outside and those with dark skin – takes a vitamin D supplement containing 10 micrograms (400IU) every day," she said. "This year, the advice is more important than ever with more people spending more time inside."
Full NICE Guideline on Vitamin D and COVID-19