The sunshine vitamin — vitamin D — is the latest target for researchers investigating treatment options for the coronavirus. Previous re...
The sunshine vitamin — vitamin D — is the latest target for researchers investigating treatment options for the coronavirus.
Previous research has shown that the vitamin, which mainly comes from exposure to the sun and is essential for a healthy immune system, can help protect against other respiratory infections.
Now, Spanish researchers have started a ten-week trial to see if vitamin D can also help with Covid-19. So should we all be taking a daily supplement to reduce our chances of getting the coronavirus or to help our bodies fight it?
Vitamin D could help your body fight off coronavirus. It is collected by spending time outdoors
What does the new trial hope to find?
The researchers at the University of Granada are carrying out a trial to investigate whether high doses of vitamin D can treat mild symptoms of Covid-19, such as headache, fever and fatigue, and prevent patients from deteriorating and needing hospital care and ventilation.
Two hundred patients aged 40 to 70 will receive either 625 mcg (micrograms) of vitamin D daily, or just their usual medication. This is far higher than the 10 mcg recommended daily dose in the UK.
If the trial suggests vitamin D does prevent the coronavirus from progressing, it could potentially be used as a treatment in the community and hospitals. However, more studies will be needed to confirm the findings and the dose required to have an effect.
Dr Alison Tedstone, chief nutritionist at Public Health England, says: ‘There is not sufficient evidence to support recommending vitamin D for reducing the risk of Covid-19.’
Why are scientists investigating vitamin D?
The new study is based on the finding that reduced levels of vitamin D in calves was the main cause of bovine coronavirus infection in the past. Previous studies have also shown that vitamin D can help both prevent and treat other respiratory infections.
‘Vitamin D has an anti-inflammatory action, particularly when given at higher doses,’ says Professor Adrian Martineau, a clinical professor of respiratory infection and immunity at Queen Mary University of London. ‘Previous trials have looked at using it as a treatment for TB.
‘It is the overactive inflammatory response in patients with Covid-19 that seems to be implicated with poor prognosis. The idea is to see if it can reduce this response.’
A study, published in the BMJ in 2017, which reviewed data from 25 trials, showed the vitamin can also help prevent acute respiratory infections, particularly in those with a vitamin D deficiency.
Professor Martineau, who was the lead author of the review, says: ‘When vitamin D is made in the skin, it gets converted in the liver to a form that circulates around the body. This creates a natural antibiotic-like substance in the lining of the airway that can bash viruses and bacteria, killing them.
‘It is a generic effect: we don’t know yet whether that would work against Covid-19.’
A study by Trinity College Dublin found that adults who took vitamin D supplements saw a 50 per cent fall in chest infections.
However, Professor Martineau adds: ‘These results cannot automatically be extrapolated to the coronavirus.’
Is it worth stocking up in case I get sick?
Having adequate levels of vitamin D is important for general health — it is needed for healthy bones, too, for example — and will help prevent you getting sick.
One in five people in the UK, under normal circumstances, has a vitamin D deficiency. Now, with the coronavirus lockdown meaning little time outside in sunlight, our levels could be even lower. Since 2016, the Government has recommended a daily supplement of 10mcg to ensure we have healthy levels. Experts argue that just adhering to this advice would in itself make a big difference.
Dr Tedstone says: ‘To protect their bone and muscle health, people should consider taking a daily supplement containing 10mcg of vitamin D.’
Professor Martineau adds. ‘There is little or no downside to following this advice — and, who knows, it may have a benefit in reducing the susceptibility to coronavirus.’
Vitamin D can also be found in oily fish such as salmon, sardines and herring. Daily exercise even during lockdown will help, says Martin Hewison, a professor of molecular endocrinology at the University of Birmingham.
‘For people with pale skin, ten minutes of skin exposure on their arms and face a day may be enough, while others may need around 25 minutes.’
Who could benefit most from a supplement?
People who are at higher risk of vitamin D deficiency also appear to be at higher risk of coronavirus.
‘People who are obese, elderly and have darker skin are at high risk of vitamin D deficiency and appear to be potentially at higher risk of more severe Covid-19 symptoms,’ says Professor Hewison.
‘If vitamin D has benefits with the coronavirus — and there is no evidence of this yet — it is likely to be better at preventing the severe effects of the virus, rather than treating it.’
What’s the best one to buy?
Vitamin D supplements are available in supermarkets and pharmacies and should cost only a few pounds, says Aisling Pigott, of the British Dietetic Association. The main type is called D3 and is made from animal products. If you are vegetarian, there is a plant alternative called D2.
Professor Hewison says: ‘The minimum dose is 10mcg daily, but the evidence shows that you can take up to 100mcg a day with no adverse effects. It may take several weeks to build up your vitamin D levels.’
Do I need to take it year round?
Public Health England advises that in spring and summer, the majority of the population gets enough vitamin D through sunlight on the skin and a healthy, balanced diet.
People whose skin gets little or no exposure to the sun, such as those in care homes or those who cover their skin when outside, need to take a supplement throughout the year.
Ethnic minority groups with dark skin should also consider taking a year-round supplement.
Research from the University of Birmingham has shown that having a vitamin D deficiency trebles the length of time patients stay in hospital.
Those with the lowest levels are also frailer and more likely to die in hospital than those with the highest levels.
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