Probiotics, omega-3 fatty acids, multivitamin or vitamin D supplements are associated with a reduced risk of coronavirus infection in women, but not in men, while vitamin C, garlic and zinc they show no clear benefit in either, according to the latest findings from users of the COVID-19 Symptom Study Application.
The study is the largest observational study of SARS-CoV-2 infection and the use of dietary supplements to date, based on data from more than 400,000 application users in the UK, US and Sweden. Similar results were found in all three countries and are published today in the journal BMJ Nutrition Prevention and Health.
Cristina Menni, PhD, specializes in intestinal microbiomes and metabolomics in the Department of Twin Research and Genetic Epidemiology, King’s College London, and led the study. “We had a very large sample size looking at the correlation between supplements and COVID-19, and we found that vitamin D, probiotics, multivitamins, and omega-3s show a modest reduction in the chances of capturing COVID-19. “, he said. Medscape News UK in an interview.
“We can’t make a recommendation based on that alone, but it nevertheless lays the groundwork for a larger randomized controlled trial.”
Dr. Menni adjusted the results of the diet, which could naturally affect the result. However, “it seems that the effect of multivitamins, vitamin D, omega-3 is completely independent of the diet. The association with probiotics after adjustment is maintained, but the effect is less.” , explained.
Risk reduction was maintained in women of all ages and body mass index (BMI) groups of probiotics, omega-3 fatty acids, multivitamins, and vitamin D. For probiotics, the probability (OR) fluctuates. lava between 0.73 (95% CI: 0.63 to 0.85) in women under 40; at OR 0.91 (95% CI: 0.86 to 0.96) for vitamin D in women aged 40 to 60 years.
“We found that women had more protection,” Dr. Menni reported. “But women are usually the ones who buy supplements for the family and generally take them.”
Increased sales of multivitamins, vitamin C and zinc since the pandemic
Sales records show an increase in the uptake of vitamin supplements, with a UK market share of vitamin C increasing by 110% and of multivitamins by 93% in the period before the first blockade (March 2020).
In the United States, sales of zinc supplements rose 415% in the first week of March, on par with fears of COVID-19. Faced with such a high increase in the use of supplements, the researchers wanted to find out whether these high sales were justified by their effect in testing positive for SARS-CoV-2 infection.
However, “based on these results, we do not suggest that people go to the pharmacy,” Dr. Menni said.
The finding on vitamin C, which shows no effect on infection rates, could be related to behavioral consumption patterns, Dr. Menni added. “Possibly people start taking vitamin C when they are already sick and not routinely, on a daily basis. The pattern of taking vitamin C is different from taking vitamin D or multivitamins.”
Behavioral factors, specifically related to health, can also have an impact on outcomes. “It is true that we have found that vitamin D, multivitamins, probiotics and omega-3s reduce the chances of capturing COVID-19, but there may be a healthy user bias in the sense that people who report ‘application are more health conscious. “
Data provided by the COVID-19 symptom study application
Data were extracted from the COVID-19 Symptom Study application that collects self-reported information related to SARS-CoV-2 infection, including location, age, basic health risk factors, updates daily symptoms, medical visits, SARS-CoV-2 test results. , self-quarantine and any health care sought. Asymptomatic individuals also used the app. A total of 372,720 users in the UK, 45,757 in the US and 27,373 in Sweden contributed their data to the app.
The information analyzed in this study referred to users of applications, aged 16 to 90 years, who regularly used (> three times a week for at least 3 months) dietary supplements during the months of May, June and July 2020 (the first wave of pandemic) as well as data on any coronavirus swab test result (confirmed by PCR test). Users were asked to fill out a questionnaire about their use of probiotics, garlic, omega-3 fatty acids, multivitamins, vitamin D, vitamin C and zinc, or if they were not taking supplements. The control group included users who were not taking any supplements.
Data were adjusted for age, sex, BMI, and health status at enrollment, comorbidities (including type 2 diabetes, cancer, asthma, heart disease, eczema, hay fever, kidney disease, and lung disease), index of multiple deprivation (DMI), smoking, ethnicity, health / caregiver, and quality of diet.
Modest protective effect in general
Dr Menni and his colleagues found that during the first wave, 175,652 subscribers in the UK regularly took dietary supplements and 197,068 did not. In total, 67% of people taking supplements were women and more than half were overweight (mean BMI of 27). In total, 23,521 people tested positive for SARS-CoV-2 and 349,199 tested negative for the 3 months.
In UK users specifically, those taking probiotics, omega-3 fatty acids, multivitamins or vitamin D had a 14% lower risk of SARS-CoV-2 infection (95% CI). 19%)), 12% (95). % CI (8% to 16%)), 13% (95% CI (10% to 16%)) and 9% (95% CI (6% to 12%)) respectively, after adjusting to possible confusing.
The reduction in risk by testing positive for SARS-CoV-2 with the use of omega-3 fatty acids was 21% in the US cohort and 16% in the Swedish cohort. Probiotics were modestly protected from infection with a 18% reduction in risk in the US cohort and 37% in Swedish data.
With multivitamins, the risk of SARS-CoV-2 was reduced by 12% in the American cohort and 22% in the Swedish cohort. With vitamin D, the risk reduction was 24% and 19%, respectively.
Probiotics improve the intestinal microbiome and increase immunity
Commenting on the modest effect of probiotics on risk reduction, Dr. Menni said a healthy diet could have had a confusing effect on the association found.
“A recent study related the intestinal microbiome to the immune response of COVID-19 and we also know that the severity of COVID-19 is associated with the intestinal microbiome.”
As for probiotics, they enhance the diversity of the microbiome, which is good for the immune system and therefore less likely for a person to get sick, he added.
“The finding on probiotics opens up many possibilities for research and supports a clinical trial of probiotics.”
Professor Sumantra Ray, executive director of the NNEdPro World Center for Nutrition and Health, who co-owns the journal, commented on the results. “So far, there is little convincing evidence that taking nutritional supplements has any therapeutic value beyond maintaining the body’s normal immune response.
“Furthermore, this study was not primarily designed to answer questions about the role of nutritional supplements in COVID-19.”
Researchers recognize that it is an emerging area of research and warrant a more rigorous study, including RCTs, that investigates possible protective effects on infection and disease severity, as well as adverse effects, before firm conclusions can be drawn. on the role of nutritional supplements in infection prevention. with SARS-CoV2. They also point out that the study was based on self-reported data and a self-selected group. No information was collected on the doses or ingredients of the supplements.
IOC: Dr. Menni does not declare any conflict of interest. Other authors list a number of interests in the paper.
Published in the April 19 issue of BMJ Nutrition Prevention and Health magazine