There is currently not enough evidence to support taking vitamin D to prevent and treat Covid-19, according to a new rapid evidence review from NICE.

The expert panel still supports current government advice for everyone to take the supplement throughout the autumn and winter, but recommends that more research be conducted on the subject, stressing the use of high-quality randomised controlled trials in future studies.

Dr Paul Chrisp, director of the Centre for Guidelines at NICE, said: “While there is insufficient evidence to recommend vitamin D for the prevention or treatment of Covid-19 at this time, we encourage people to follow government advice on taking the supplement throughout the autumn and winter period.

“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.”

The review was conducted in collaboration with Public Health England (PHE), and the Scientific Advisory Committee on Nutrition (SACN) and found that it was not possible to determine a direct relationship between vitamin D and Covid-19 based on the available evidence.

Pandemic has meant more time indoors and less sunlight exposure

Professor Ian Young, Chair of the Scientific Advisory Committee on Nutrition, which advises PHE and other UK government organisations on nutrition and related health matters, said: “SACN has worked closely with NICE and PHE to consider the available evidence from recent studies on vitamin D in relation to Covid-19. This evidence review confirms that currently there is not enough available evidence to determine that there is a causal relationship between vitamin D and Covid-19.”

It is recommended that everyone should take a daily 10 microgram (400 international units) vitamin D supplement from October to early March. This dose is safe and effective at maintaining healthy vitamin D blood levels.

Vitamin D is required for the maintenance of healthy bone and muscle. Although sunlight exposure is the major source of vitamin D for most people during summer months, it can also be obtained from the diet or supplements.

Many people have been indoors more than usual this spring and summer, which means we might not have been making enough vitamin D from sunlight. So, it’s even more important this year to take a vitamin D supplement as we go into the winter months.

Some people are more at risk of not having enough vitamin D even in spring and summer, including those with dark skin (such as those with African, African-Caribbean or south Asian backgrounds), those who are not outdoors often, those in care homes, and those who cover up most of the skin when outdoors. 

NICE advise these people to take a vitamin D supplement all year round. Clinically vulnerable groups will also be eligible for free vitamin D supplements throughout the winter period, starting in January.