The idea that vitamin D supplements can reduce the susceptibility to and severity of Covid-19 is tempting – it provides a simple, elegant solution to a very complex and deadly problem. But analyzes containing large European data sets suggest that the enthusiasm for the sunshine vitamin could be misplaced.
Two more peer-reviewed articles looked at the link between vitamin D levels and Covid-19 and both came to the same conclusion: evidence for a direct link between vitamin D deficiency and Covid outcomes is lacking.
Can a short workout increase your protection against Covid-19? Although many immunologists have studied the role of stress in vaccine responses, some researchers have turned their attention to exercise, with some interesting results.
Consider the following experiment by Prof Kate Edwards at the University of Sydney, who asked a group of young adults to perform 25-minute bicep curls and lateral raises, about six hours before receiving a flu vaccine. As hoped, these people showed an increased immune response to the injection over the next 20 weeks, compared to participants who rested on the day of the shot. Confirming these beneficial effects, Edwards later found that exercise could also improve vaccination responses to pneumonia.
In addition to the increased effectiveness, a short workout can soothe the side effects of a vaccine. 15 minutes of upper body exercise – before or after the injection – has been shown to reduce the swelling and fever sometimes caused by the HPV vaccine.
How can this be? One possibility is that the slight wear and tear of our muscles, while we exercise, can itself cause a mild reaction in the immune system. Thus, when the vaccine is administered, the body is well prepared to handle the antigen more effectively within the injection, which increases the benefits of the vaccine and reduces the potential discomfort.
One set of researchers exploited a database of hundreds of thousands of mostly white participants to understand whether administering vitamin D could reduce their chances of symptomatic or severe Covid.
Researchers looked at the records of people with certain genetic markers that make them prone to vitamin D deficiencies, something that is not affected by factors such as age and other underlying conditions. They found no evidence for the idea that supplements protect against Covid.
Another study compared the incidence of vitamin D deficiency in 24 European countries with data on Covid infections, recovery and deaths.
Lead author Dr Michael Chourdakis of Aristotle University of Greece said the analysis avoided the methodological limitations of previous studies using only recent data on vitamin D, and did not include only subgroups of the population, such as people in nursing homes. .
In addition, they specifically looked at levels of deficiency instead of using average vitamin D levels, which can be distorted by certain sections of the population with very high or very low concentrations.
“There’s an overload of information on vitamin D benefits … vitamin D has been priced for too many things,” he said, “even though we have very limited data for it.”
He added that the study was methodologically solid and that the data showed no significant association between vitamin D and Covid infections, recovery or mortality.
Those who traditionally show vitamin D deficiency – older adults and ethnic populations of minorities – are the same groups affected disproportionately by Covid-19. Prolonged closures and subdivisions of the population protection also improved the time inside away from vitamin D-rich sunlight. And in general, vitamin D has been implicated in helping the immune response to respiratory infections – so supplements feel like the intuitive answer.
But the evidence about Covid so far – although some of it is positive – is ambiguous. Some researchers argue that it is not strong enough to give a policy of giving supplements to the entire population, especially given the impact it can have on individual behavior and possible negative physical side effects of too much intake.
In a recent review, the National Institute of Excellence in Health and Care (Nice) agrees, to find evidence of vitamin D supplementation with the aim of preventing or treating Covid, and that further research is needed.
“We are scientists – we believe in data. We believe that data today suggests that vitamin D will not protect against Covid outcomes. We welcome the data that suggests otherwise, ” said Dr Brent Richards, a McGill University clinical scientist, focusing on endocrinology, epidemiology and biostatistics, one of the authors of the genetic study.
‘But it’s important to remember that there is a familiarity with vitamins in the field of vitamin studies and a high degree of confidence that we do not see with other types of interventions. So people really want this solution to be a vitamin-based solution – and sometimes it’s not always the case. ‘
A recent example of this is a study by scientists from the University of Barcelona who suggested that high doses of vitamin D in coronavirus patients when they are admitted to hospital could reduce mortality by 60%, which the former Brexit secretary and LP David Davis for the therapy in hospitals.
But some scientists pointed out that although the data are presented as a randomized trial of vitamin D supplementation, it appears that individuals were not randomized, the wards in the hospital were. Depending on their level of illness and risk, different wards take different patients.
Eventually, the study – which has not yet been reviewed by the peer – was removed from the server of the medical journal The Lancet due to concerns that an investigation into the newspaper had begun.
Meanwhile, randomized controlled trials are being designed to definitively answer whether vitamin D status plays a direct role in Covid infections and the outcomes are ongoing. “What we are currently lacking is actually a definitive trial showing a cause and effect relationship,” said Adrian Martineau, a professor of respiratory infection and immunity at Queen Mary University of London, who is leading such a study. said.
‘You can not reject the circumstantial evidence …[but] this is not the highest evidence. I think there is a philosophical question: if you have an intervention that has a good chance of working and is completely safe, why not implement it while you wait to find out given the public health emergency ? ‘