High intakes of vitamins A, E and D are linked to fewer respiratory illnesses, according to a study, with experts calling for more research into their effect on COVID-19.
It comes soon after a separate study found 82% of 216 coronavirus patients in a Spanish hospital had a vitamin D deficiency.
UK Health Secretary Matt Hancock has ordered a review into vitamin D’s effect on the disease, after previously saying it appeared to have no effect.
The latest study involved 6,115 adults, with people self-reporting their vitamin intake and any respiratory problems.
Illnesses included chesty coughs, as well as long-term conditions such as asthma and pulmonary disease.
Overall, there were 33 cases of respiratory complaints, and researchers found vitamin A and E from both diet and supplements was associated with a lower likelihood of them being reported.
Vitamin A can be fund in food such as whole milk, cheese, carrots and dark leafy veg.
Vitamin E is found in nuts, seeds and vegetable oils.
Meanwhile, vitamin D intake from supplements was also associated with fewer respiratory complaints, the study found.
Most people’s bodies make enough of the vitamin from sunlight, but in the winter the NHS advises supplements for some groups.
It is also present in some foods such as salmon, mackerel, herring and sardines, red meat and eggs.
Sunshine provides enough vitamin D in the summer but some groups are advised to take a supplement in the winter
Vitamin D deficiency is more common in older people, overweight people, and in black and Asian people – all groups at increased risk of becoming seriously ill with coronavirus.
The researchers in the latest study, including from Imperial College London, said their work supported the hypothesis that supplementation is “critical” for some, and that diet alone is often not enough.
They recommended further work “to assess the implications of the current study in the context of the current coronavirus disease” pandemic.
Shane McAuliffe, from the NNEdPro Nutrition and Covid-19 Taskforce, which includes University of Cambridge experts, said: “While acknowledging the limitations of this data, it does add further to a growing body of interest and evidence for the role of vitamin D in respiratory health.
He said the low cost and low risk of adverse effects made it “sensible” to provide supplementation to people most likely to be deficient.
Experts from Queen Mary University of London are also studying whether correcting people’s vitamin D can reduce the risk and/or severity of COVID-19 and other infections.
Lead researcher Professor Adrian Martineau said: “There is mounting evidence that vitamin D might reduce the risk of respiratory infections, with some recent studies suggesting that people with lower vitamin D levels may be more susceptible to coronavirus.”
A study in Boston last month also found that people with sufficient vitamin D were less likely to experience complications and die from COVID-19.
However, in June, five studies on coronavirus and vitamin D were reviewed by the UK’s National Institute for Health and Care Excellence, which concluded there was currently no evidence to support supplementation reducing the risk or severity of the virus.