Do vitamin D tablets protect you against the coronavirus? Various studies indicate that they are good for health, but the effect on COVID-19 is still unclear.
If you can believe some headlines, there is an easy way to oppose it coronavirus to protect: take a vitamin D tablet every day. In fact, according to some, the benefits are so great that people should take huge doses. But there is not enough scientific evidence for such claims.
Adrian Martineau from Queen Mary University London and Nita Forouhi from Cambridge University now have a comprehensive meta-analysis conducted several studies on vitamin D and COVID-19. What is right and what is wrong?
Daily supplement
Vitamin D is a fat-soluble substance that is produced in the skin under the influence of sunlight. It is also in food, for example in fatty fish. Vitamin D is known for strengthening bones. It also plays a role in the immune system: it helps to kill, among other things, cells infected by a virus.
Some previous studies have already indicated that taking vitamin D tablets increases resistance to respiratory infections such as colds. In June the British concluded Scientific Advisory Committee on Nutrition (SACN), however, that there is insufficient evidence for such an effect.
Despite this, the committee, like many other health authorities, recommends taking a daily supplement to protect the bones. Also the Dutch Nutrition Center recommends many people to take extra vitamin D..
Possibly misleading
What about the corona virus? Several researchers say vitamin D can protect people from COVID-19 contamination. They also believe it can help weaken the disease in infected people. Evidence for those claims is slowly starting to pile up.
Most of that evidence, however, comes in the form of observational research. This can be misleading, as such research does not conclusively establish that a vitamin D deficiency causes infections. It just shows that there is some connection between the two.
Take a research that made headlines in late September. It found that people hospitalized with COVID-19 were twice as likely to die of the disease if they were vitamin D deficient.
However, that shortage does not necessarily have to be the cause of the higher risk of death. There may be a third factor that causes both vitamin D deficiency and increased susceptibility to the virus. Obesity for example, because vitamin D is stored in adipose tissue. The more fat someone has, the more vitamin D they need to take to maintain their levels.
Big effect
The best way to assess the benefits of vitamin D supplements is through clinical trials. In addition, you give people with COVID-19 the supplements and see if they help with their treatment. Recent research in a Spanish hospital has found that COVID-19 patients who received high doses of vitamin D ended up in intensive care much less often than patients who did not receive these doses.
However, the study included only 76 patients. In addition, there happened to be more people with high blood pressure in the group that didn’t get vitamin D, so their prognosis was worse anyway. But even when you include that difference in the results, there is a big effect, says José Manuel Quesada Gómez of the University Medical Center Reina Sofia in Córdoba, one of the researchers.
Another side note is that the research only shows that vitamin D appears to help in the treatment of hospital patients. It says nothing about the possible preventive effect of supplements. Overall, the results are promising, but larger follow-up research is needed, says Susan Lanham-New, SACN employee.
Double dose
Whether or not vitamin D helps against the coronavirus, all experts seem to agree on one thing: most people who live in a moderate climate, for example in the Low Countries, have to contend with a vitamin D deficiency in winter. than too little sunlight to trigger the production of the vitamin in the skin. That’s why most people should take a vitamin D supplement every day from October onwards, if only to strengthen the bones.
If people want to double the recommended daily dose for fear of the coronavirus, it probably won’t hurt, Lanham-New says. “The most important thing is to prevent a vitamin D deficiency.”
The analysis of the various vitamin D studies is published in The Lancet Diabetes & Endocrinology.
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