Studies focusing on vitamin D and COVID-19 suggest that sunshine vitamins are unlikely to prevent COVID-19 and respiratory infections such as colds and flu.
clinical trials published in british medical journalwas part of COVIDENCE UK, a national study aimed at investigating risk factors for developing COVID-19. Researchers enrolled her 6,200 participants aged 16 and older.
British studies
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 vitamin D levels were randomly assigned to two groups of 1,550 people and assigned to take 3,200 IU or 800 IU vitamin D supplements daily for six months.
In the United States, the recommended daily dose of vitamin D for ages 1 to 70 is 600 International Units (UI) per day, and 800 IU per day for those 70 and older. In the UK, the recommended daily dose is 400 IU. Day.
Over the six months of the trial, the study suggests that neither high nor low doses of vitamin D were effective in preventing respiratory tract infections or identifying COVID-19 cases compared to controls. increase.
norwegian studies
A second double-blind, randomized clinical trial, also conducted during the pandemic, tested more than 34,000 Norwegians on cod liver oil with low doses of vitamin D or the effect of vitamin D on preventing COVID and respiratory disease. was given a placebo to test
The study divided 34,601 people between the ages of 18 and 75 into two groups. Each group took 1 teaspoon of cod liver oil or 1 teaspoon of corn oil (used as a placebo) daily for 6 months during winter.
A teaspoon of cod liver oil contained approximately 400 IU of vitamin D. A little over 75% of his participants did not use vitamin D supplements prior to enrollment.
Unlike the British study, where many of the participants were vitamin D deficient, the Norwegian study found that 90% of the cod liver oil group and 72% of the placebo group had adequate levels at study entry. “However, we did not find that this measurement affected the likelihood of contracting COVID-19 or other acute respiratory infections.”said the authors.
The authors found that cod liver oil had no effect on any outcome, including that the polymerase chain reaction confirmed COVID-19.
Notes
Luke Huber, naturopathic physician, vice president of scientific and regulatory affairs at the Council for Responsible Nutrition (CRN), said despite the oversimplification of early media coverage, the study should be read with caution. Said there was. “Reports on this study suggesting that vitamin D levels are not associated with COVID-19 outcomes ignore large-scale studies of this association and downplay the serious limitations of these studies. ”na
One notable limitation was that the UK study was not blinded or placebo-controlled and recognized that participants were taking vitamin D supplements.
“While the research study was reasonable in some respects, the way it has been interpreted in the media as ‘showing no benefit to vitamin D in Covid’ is not. Bestselling author and board-certified internist Jacob Teitelbaum, M.D.
“As to whether vitamin D intake reduces Covid risk, research suggests that it may not be the case in people with healthy vitamin D levels. This study was not blinded, so people on active vitamin D treatment knew they were on active treatment. Had it been shown, the detractors of nutritional medicine would have quickly invalidated the study because it was not blinded. However, this is a powerful confounding variable: in fact, 68 unvaccinated people who received high doses of vitamin D, 3200 units per day, tested Covid positive during the study. Also, what was almost shocking was that half of the control subjects were taking vitamin D alone. I’m not insane up there.”na
Teitelbaum added that the study’s conclusions were highly questionable, as there was no blinded placebo control and half of the participants in the inactive “control” group took their own vitamin D.
David Meltzer, MD, PhD, director of hospital medicine at the University of Chicago School of Medicine, also took note of the open-label work. “People who do not take vitamin D or who know they are taking low doses are more likely to take extra precautions to avoid risks or seek vitamin D supplementation outside of research. This may lead to biased results.” na
“The study population was a highly recently vaccinated group. Along these lines, it was very notable in unvaccinated patients: 0/68 covid+ in the 3200 IU treatment group versus 0/68 in the control group. It was 9/191 (4.7%).”na
Study population
Another limitation Meltzer pointed out is that there are not enough people of color to assess the effect within the group, where vitamin D benefits may be much greater.
Black Americans are nearly three times as likely to be infected with COVID-19 as white Americans, according to a National Urban League report. The report also shows that black Americans are twice as likely to die from the virus.
Additionally, Teitelbaum noted that 86% of the people in the second study that looked at the results had normal vitamin D levels, and most were fairly young and healthy. “This is not a group with normal severe outcomes. In fact, less than 1% of people had severe infections. So the study was done in the wrong population. unhealthy young people with normal vitamin D levels, so it does not contradict studies showing the importance of vitamin D in COVID.”na
The last word?none
The BMJ editorial that accompanied the study said two new trials found no effect, but concluded without final words:The invalid results of the studies should be interpreted in the context of the highly effective vaccines deployed in both studies. ”na
While Meltzer believes these studies are valuable and add to our understanding of whether vitamin D may reduce the risk of developing COVID-19, the study is an important one. He also said the issue was left unresolved.
“The bottom line? I still highly recommend a multivitamin with vitamin D and zinc for overall immune health during COVID-19.”Teitelbaum said.
sauce: british medical journalna
2022; 378 doi.org/10.1136/bmj-2022-071230
“Effects of a test-and-treatment approach to vitamin D supplementation on the risk of all-cause acute respiratory infections and covid-19: a phase 3 randomized controlled trial (CORONAVIT)”na
Author: D. Jolliffe et al.
british medical journalna
2022; 378 doi.org/10.1136/bmj-2022-071245
“Prevention of covid-19 and other acute respiratory infections with cod liver oil supplementation and low-dose vitamin D supplementation: a quadruple-blind, randomized, placebo-controlled trial”na
Author: S. Brunvoll et al.
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