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.’
The vitamin was previously investigated as a possible treatment for tuberculosis (stock image)
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.’
Is THIS finally proof Vitamin C will help too?
Vitamin C supplements have been flying off the shelves in the belief that the nutrient may help protect us from the coronavirus — and early results from a trial in China may add to the demand.
Doctors in Wuhan ran a small trial to see if high-dose vitamin C can help treat severely ill Covid-19 patients.
Dr Peng Zhiyong, director of the intensive care unit at Zhongnan Hospital, part of the University of Wuhan, gave 50 patients either 12g of vitamin C or a water placebo via an intravenous drip, twice a day for a week. Both groups also received standard treatment — in this case, an anti-clotting drug to make oxygen more available to the lungs.
The patients’ progress was monitored for a further three weeks, during which time 35 per cent of those who got the placebo died, compared with a quarter of those who had the vitamin C drip.
According to Dr Peng, the sickest patients showed the most benefit from the treatment. ‘They had less inflammation in their lungs and spent less time on ventilation,’ he says.
The dose used in the trial was far higher than the 40mg daily intake advised by the NHS. And vitamin C cannot be stored in the body — any excess is removed in urine and high doses can cause diarrhoea.
‘That’s true when you are well,’ says Dr Peng, ‘but vitamin C is a key part of the body’s immune response to infection and gets used up very quickly as the virus takes hold,’ he says. ‘No patients suffered bowel problems in the trial.’
Dr Peng decided to investigate high-dose vitamin C as a potential treatment for Covid-19 because of previous research. ‘It had been used in patients during the SARS epidemic 17 years ago and they showed signs of improvement,’ he says.
A report published at the time said: ‘The possibility that vitamin C affects severe viral respiratory tract infections would seem to warrant further study.’
David Smith, an emeritus professor of pharmacology at the University of Oxford, adds: ‘This latest trial from China does make the case for more studies using high-dose vitamin C in intensive care. But we will have to wait until the full report to see the complete figures.’
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.’
Public Health England says you can get all the vitamin D you need by spending time outdoors
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.