There is no good evidence that Vitamin D protects against coronavirus, the National Institute of Health and Care Excellence has ruled.
In April, health officials urged everyone to take a Vitamin D supplement in order to boost bone health, amid concern that lockdown was depriving most people of enough sunshine.
A number of studies have suggested that those lacking the “sunshine” nutrient are more likely to develop Covid-19.
But today Nice said the evidence in such research was “low quality” and failed to adjust for other factors – such as excess weight, or underlying health conditions, which were also found.
However, health officials stressed that taking a daily supplement is still advised – in order to protect bone and muscle health.
They are particularly concerned that those who have been “shielding” may have been deprived of the nutrient, after months stuck indoors.
Public Health England commissioned Nice to do a rapid evidence summary evaluating emerging evidence on vitamin-D in relation to Covid-19.
It examined five studies, all of which were found to have a high risk of evidence, because of the low quality of evidence involved.
Paul Chrisp, director for the centre for guidelines at Nice said: “While there are health benefits associated with vitamin D, our rapid evidence summary did not identify sufficient evidence to support the use of vitamin D supplements for the treatment or prevention of Covid-19.
“We know that the research on this subject is ongoing, and Nice is continuing to monitor new published evidence.”
Sunlight is the primary source of Vitamin D, which is essential for the absorption of calcium to maintain healthy bones and teeth.
For some years, PHE has said everyone should consider taking a supplement during autumn and winter months, when sunshine is limited.
Children, the elderly and those with some health conditions are already advised to consider doing so all year round.
But after lockdown began, the advice was changed, with officials saying everyone should think about taking a daily supplement to ensure they have enough levels of the “sunshine supplement”.
Dr Alison Tedstone, PHE chief nutritionist said: “With many people spending more time indoors, particularly the more vulnerable groups and those ‘shielding’, there is a risk that some people may not be getting all the vitamin D they need from sunlight. It’s important they consider taking a daily 10 micrograms vitamin D supplement to help protect bone and muscle health.”
On Monday, scientists urged the Government to give stronger messages about the importance of following such advice.
A Royal Society review concluded that low levels of the vitamin may be a factor in poor Covid-19 outcomes in some groups, but said more data was needed.
Vitamin D is known to play an important role in the immune system and has been shown to help limit infections from some respiratory viruses, they said.
“Although the direct evidence on Vitamin D in Covid-19 is lacking, it is quite plausible that the same will hold for this virus,” said Professor Charles Bangham, Chair of Immunology at Imperial College London.
“It is possible that higher rates of Vitamin D deficiency could be one reason why people with darker skin are affected more seriously by the disease – but there are a lot of other factors as well so we need to collect this data”.