Think taking vitamins protects you from dying of Covid-19? Think again

Researchers from University of Toledo in Ohio, United States, reviewed Covid-19 hospitalisation data from all over the globe and found that supplements that boost the immune system such as vitamin C, vitamin D and zinc do not lower your chances of dying from the novel coronavirus.

When the novel coronavirus first emerged, healthcare workers used a variety of micronutrients as possible treatments for the illness. More recently, supplements “have been promoted by some as an alternative to safe and proven vaccines.”

And yet, Dr Azizullah Beran says there is little evidence that supplements and micronutrients work to stave off the coronavirus, even though people showed persistent interest in them.

In the paper, the research team wrote that “Micronutrient supplements such as vitamin D, vitamin C, and zinc have been used in managing viral illnesses. However, the clinical significance of these individual micronutrients in patients with Coronavirus disease 2019 (Covid-19) remains unclear.”

The researchers say that they conducted a meta-analysis of multiple studies from around the world “to provide a quantitative assessment of the clinical significance of these individual micronutrients in Covid-19.”

“A lot of people have this misconception that if you load up on zinc, vitamin D or vitamin C, it can help the clinical outcome of Covid-19,” says Beran, an internal medicine resident at the University of Toledo College of Medicine and Life Sciences. “That hasn’t been shown to be true.”

Beran is the lead author on a new paper that greatly enhances the emerging medical consensus that micronutrient supplements are “not an effective treatment for Covid-19.”

The researchers write: “We identified 26 studies (10 randomised controlled trials and 16 observational studies) involving 5,633 Covid-19 patients that compared three individual micronutrient supplements (vitamin C, vitamin D, and zinc) with SOC [standard-of-care].”

Nine of the studies were on vitamin C in 1,488 patients (605 receiving vitamin C and 883 in SOC). The researchers found that “vitamin C supplementation had no significant effect on mortality, … intubation rate, or LOS [length of hospital stay].”

Fourteen of the studies were on vitamin D – whether it reduced mortality among 3,497 patients (927 receiving vitamin D and 2,570 in SOC). The researchers found that “vitamin D did not reduce mortality … but reduced intubation rate … and LOS.” Subgroup analysis, the researchers wrote, showed that vitamin D supplement was not associated with a mortality benefit in patients receiving vitamin D pre- or post-Covid-19 diagnosis.

Five of the studies were on zinc in 738 patients, comparing the supplement intake with standard-of-care (447 in zinc and 291 in SOC). The researchers found that “zinc supplementation was not associated with a significant reduction of mortality .”

To sum it up, the researchers’ analysis found no reduction in mortality for patients being treated with vitamin D, vitamin C or zinc compared to those who did not receive one of these three supplements.

The paper, published in Clinical Nutrition ESPEN, focused mainly on patients already infected and hospitalised with the coronavirus when receiving the supplements. Yet the researchers also analysed a small group of people who had been taking vitamin D before falling ill, and “found no significant difference in the mortality rate of that population either.”

“It’s important for people to understand that taking a lot of these supplements does not translate into better outcomes,” says Dr Ragheb Assaly, a UToledo professor of medicine and the paper’s senior author. “The other important message is that the answer to this disease is the vaccine. Micronutrient supplements will not offset the lack of vaccination or make you not need the vaccine.”

Researchers note that the study does not suggest that vitamin and mineral supplements are bad or should be avoided, but that they are ineffective against stopping coronavirus deaths.

The doctors say that while some patients who are malnourished or lacking micronutrients in their system may be helped by the additional boost from vitamin D, vitamin C and zinc, that does not mean that the nutrients work against the virus.

“What we’re saying is this: If you don’t medically need these supplements, don’t take them thinking they’re protective against COVID-19,” Beran explains. “They’re not going to prevent you from getting it and they’re not going to prevent you from dying.”