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 have no clear benefits, according to the latest discoveries of 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 over 400,000 application users in the UK, US and Sweden. Similar results were found in all three countries and are published in the journal today BMJ Nutrition Prevention and Health.
Cristina Menni, PhD, specializes in the intestinal microbiome and metabolomics at the Department of Twin Research and Genetic Epidemiology, King’s College London, and led the study. “We had a very large sample size, analyzing the correlation between supplements and COVID-19 and found that vitamin D, probiotics, multivitamins and omega-3 show a modest reduction in the chances of catching COVID-19,” she said. Medscape News United Kingdom in an interview.
“We can’t make a recommendation on this basis alone, but it does lay the groundwork for a larger randomized controlled trial.”
Dr. Menni adjusted the results for the diet, which could naturally affect the result. However, “it appears that the effect of multivitamins, vitamin D, omega-3 is completely independent of diet. The association with probiotics after adjustment remains, but the effect is smaller,” she explained.
The risk reduction remained in women of all ages and groups with body mass index (BMI) for probiotics, omega-3 fatty acids, multivitamins and vitamin D. For probiotics, the probability ratio (OR) ranged from 0.73 (95). % CI: 0.63 to 0.85) in women under 40 years; up to OR 0.91 (95% CI 0.86 to 0.96) for vitamin D in women aged 40 to 60 years.
“We have found that women have greater protection,” Dr. Menni said. “But women are usually the ones who buy family supplements and usually the ones who take them.”
Increased sales of multivitamins, vitamin C and zinc since the pandemic
Sales records show an increase in the consumption of vitamin supplements, with the UK market share of vitamin C increasing by 110% and that of multivitamins by 93% in the period preceding the first blockade (March 2020).
In the US, sales of zinc supplements rose 415% in the first week of March, at the height of COVID-19 fears. Given such an increase in the use of supplements, the researchers wanted to know if these high sales were justified by their effect on testing positive for SARS-CoV-2 infection.
However, “based on these results, we do not suggest that people run to the pharmacy,” said Dr. Menni.
The finding of vitamin C, which has no effect on infection rates, could possibly be related to behavioral patterns of consumption, Dr. Menni added. “Possibly, people start taking vitamin C when they are already sick, rather than usual, every day. The pattern of taking vitamin C is different from taking vitamin D or multivitamins.”
Behavioral factors, especially those related to health, could also have an impact on the findings. “It is true that we have found that vitamin D, multivitamins, probiotics and omega-3 reduce the chances of catching COVID-19, but there could be a bias of healthy users by the fact that people who report in the 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 on SARS-CoV-2 infection, including location, age, health risk factors, daily symptom updates, medical visits, SARS-test results. CoV-2, self-quarantine and any medical care required. Asymptomatic people also used the application. A total of 372,720 users in the UK, 45,757 in the US and 27,373 in Sweden contributed data to the app.
The information analyzed in this study targeted application users, aged 16 to 90, who used food supplements regularly (> three times a week for at least 3 months) in May, June, and July. 2020 (the first wave of the pandemic) as well as data on the results of any coronavirus tamponade test (confirmed by PCR test). Users were asked to automatically complete a questionnaire asking about their use of probiotics, garlic, omega-3 fatty acids, multivitamins, vitamin D, vitamin C and zinc, or if they did not take supplements. The control group included users who were not taking supplements.
Data were adjusted for age, sex, BMI and enrollment health, comorbidities (including type 2 diabetes, cancer, asthma, heart disease, eczema, hay fever, kidney disease and lung disease), multiple deprivation index (IMD), smoking, ethnicity, medical / caregiver status and quality of diet.
Modest protective effect in general
Dr. Menni and 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 over half were overweight (average BMI of 27). In total, 23,521 people gave positive results for SARS-CoV-2 and 349,199 gave negative results during 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 (8% to at 19%)), 12% (95% CI (8% to 16%)), 13% (95% CI (10% to 16%)) and 9% (95% CI (6% to 12%)), after adjusting for potential confounders.
The risk reduction in 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 are modestly protected from infections, with a 18% reduction in risk in the US cohort and 37% in Swedish data.
With multivitamins, the risk for SARS-CoV-2 was reduced by 12% in the US 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 a confusing effect on the association found.
A recent study linked the intestinal microbiome to the immune response in COVID-19 and we also know that the severity of COVID-19 is associated with the intestinal microbiome.
As for probiotics, they improve the diversity of the microbiome, which is good for the immune system and, as such, is less likely for an individual to get sick, she added.
The finding on probiotics opens up a lot of potential research avenues and supports a clinical trial of probiotics.
Professor Sumantra Ray, executive director, NNEdPro Global Center for Nutrition and Health, who is the co-owner of the journal, commented on the findings. “To date, there is little convincing evidence that the administration of nutritional supplements has any therapeutic value beyond maintaining the body’s normal immune response.
Moreover, this study was not primarily designed to answer questions about the role of nutritional supplements in COVID-19.
Researchers acknowledge that this is an emerging field of research and warrant further rigorous study, including RCTs, investigating possible protective effects on infection and disease severity, as well as adverse effects, before firm conclusions can be drawn about the role of nutritional supplements in preventing infection. with SARS-CoV2. He also notes that the study was based on self-reported data and a self-selected group. No information was collected on additional doses or ingredients.
IOC: Dr. Menni does not declare conflicts of interest. Other authors list a number of interests in the paper.
Published in the April 19 issue of BMJ Nutrition Prevention and Health