Neither dose of vitamin D supplementation “was associated with a reduction in the risk of acute respiratory infections (ARIs) from all causes, nor did it lead to a reduction in the risk or severity of COVID-19 in particular,” study author Dr. . Adrian Martineau, Professor of Respiratory Infections and Immunity at the Institute for Population and Health Sciences at Queen Mary University of London, said by email.
The British Medical Journal published both studies on Wednesday.
“The main takeaway is that vitamin D supplements did not prevent COVID-19, severe COVID-19, or symptomatic acute respiratory infections in the general population,” study author Arne Søraas, Ph.D. By email from Oslo University Hospital, Norway.
Søraas said the UK study design “complemented ours in several ways, such as administering high doses of vitamin D to participants only after measuring their vitamin D status. Regardless, their results support our findings, which is also an important point.Neither study is significant.A protective effect was seen after vitamin D supplementation.”
Both authors point out that the study was done before vaccination was widely available. “We can be absolutely sure that vaccination is much more effective than vitamin D, which probably doesn’t prevent COVID-19 at all,” Søraas said.
Popularity of Vitamin D
The main function of vitamin D is to help the body absorb calcium and phosphate. This keeps your muscles and teeth healthy and your bones strong and less prone to fractures. However, vitamin D is also known to help the immune system fight off invading bacteria and viruses.
Early in the pandemic, frontline doctors began noticing that people with low vitamin D levels appeared to be at higher risk of dying from Covid-19. Suddenly, the internet was flooded with speculation that taking vitamin D supplements, even if they weren’t necessary, could prevent the coronavirus from taking hold.
However, unlike vitamin C, vitamin D is a fat-soluble vitamin that can “build up” in the system and cause toxicity if taken in very high doses over an extended period of time.
Studies suggest that long-term use of high levels of vitamin D increases all-cause mortality, increases the risk of cancer and cardiovascular events, and increases falls and fractures in older adults.
Studies in People with Low Vitamin D Levels
A randomized sample of participants was given a vitamin D blood test and 3,100 were found to have low vitamin D levels. The remaining 3,100 of her were assigned to controls.
Study participants with low levels of vitamin D were randomly assigned to two groups of 1,550 people and assigned to take a daily 3,200 IU or 800 IU vitamin D supplement for six months. However, this study was not blinded or placebo-controlled.Each person knew they were taking supplements provided by the two pharmaceutical companies that supported the study.
The study found that during the six months of the trial, high- or low-dose vitamin D was ineffective in preventing respiratory tract infections compared to controls, and no Covid-19 cases were identified.
low dose use
A Norwegian survey conducted between November 2020 and June 2021 divided 34,601 people between the ages of 18 and 75 into two groups. Each group received 1 teaspoon (5 milliliters) of cod liver oil or 1 teaspoon of corn oil (used as a placebo) daily during winter.
A teaspoon of cod liver oil contains about 400 IU (10 micrograms) of vitamin D, says Søraas. Cod liver oil is a staple food in Norway and has been used for centuries to add vitamin D and omega-3 fatty acids to the Norwegian diet. However, 75.5% of those who participated in this study did not use vitamin D supplements prior to enrollment.
Unlike the UK study, where many people were vitamin D deficient, tests in Norway showed adequate levels in 90% of people in the cod liver oil group and 72% of people in the placebo group. At the start of the study: “However, we did not find that this measure affected the likelihood of contracting COVID-19 or other acute respiratory infections,” Søraas said.
However, similar to British studies, a Norwegian study found that vitamin D in cod liver oil had no protective effect against respiratory infections and confirmed cases of Covid-19.
“The overall message is consistent. Two studies with different designs investigating related interventions in slightly different populations. But the results are the same. No effect seen.”
“As a physician, I see a lot of speculation that very high doses of vitamin D may have beneficial effects on a variety of ailments, but it is important to follow science-based government recommendations for all nutrients. I recommend it to people of
“Our results support existing recommendations that do not involve high doses.”