Probiotics, omega-3 fatty acids, multivitamin or vitamin D supplements are associated with the reduced risk of coronavirus infection in women but not men, while vitamin C, garlic and zinc show no clear benefit, according to the latest findings of users of the App COVID-19 Symptom Study.
The study is the largest observational study of SARS-CoV-2 infection and the use of nutritional supplements to date, based on data from more than 400,000 app users from 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 microbiome and metabolomics at the Department of Twin Research and Genetic Epidemiology, King’s College London, and is leading the study. “We had a very large sample size to look at the correlation between the supplements and COVID-19, and found that vitamin D, probiotics, multivitamins and omega-3 show a modest reduction in the chance of COVID-19 uptake. catch, “she said. Medscape News UK in an interview.
“We can not make a recommendation on this basis, but it does lay the groundwork for a larger randomized controlled trial.”
Dr. Menni adjusted the results for the diet, which of course can affect the outcome. However, it seems that the effect of multivitamins, vitamin D, omega-3 is completely independent of the diet. The connection with probiotics after adjustment remains, but the effect is smaller, “she explained.
The risk reduction remains in women of all ages and the body mass index (BMI) groups for probiotics, omega-3 fatty acids, multivitamins and vitamin D. For probiotics, the odds ratio (OR) ranged from 0.73 (95% AI): 0.63 to 0.85) in women younger than 40 years; to OR 0.91 (95% AI 0.86 to 0.96) for vitamin D in women aged 40-60 years.
“We have found that women have higher protection,” Dr Menni reported. “But it’s usually women who buy supplements for the family, and usually those who take them.”
Increase in sales of multivitamins, vitamin C and zinc since pandemic
The sales records show an increase in the intake of vitamin supplements with the UK market share of vitamin C increasing by 110% and that of multivitamins by 93% in the period up to the first exclusion (March 2020).
In the US, zinc supplements rose 415% in the first week of March, at the height of COVID-19 fears there. Due to the increase in the use of supplements, the researchers wanted to determine if these high sales were justified by the effect of testing positive for SARS-CoV-2 infection.
“Based on these results, however, we do not suggest that people run to the pharmacy,” said Dr. Menni said.
The finding on vitamin C, which shows no effect on infection rates, could possibly be related to behavioral patterns of consumption, said dr. Menni added. “Maybe people start taking vitamin C when they are sick, rather than regularly, every day. The pattern of vitamin C is different from using vitamin D or multivitamins.”
Behavioral factors, especially health-related factors, can also have an impact on the findings. ‘It’s true that we have found that vitamin D, multivitamins, probiotics and omega-3 reduce the chances of catching COVID-19, but there may be a healthy user benefit as people reporting on the app become more health conscious is. “
COVID-19 symptom study information provides data
Data were obtained from the COVID-19 symptom study app that collects self-reported information regarding SARS-CoV-2 infection, including location, age, core risk factors for health, daily updating of symptoms, visits to healthcare, SARS-CoV-2- test results, self-guarantee, and any health care you seek. Asymptomatic individuals also used the app. A total of 372,720 users in the UK, 45,757 from the US and 27,373 from Sweden contributed their data to the app.
Information analyzed in this study relates to app users, between the ages of 16 and 90, who regularly (> three times a week for at least 3 months) used nutritional supplements during May, June and July 2020 (the first wave of the pandemic), as well as data on any coronavirus swab test results (confirmed by PCR test). Users were asked to complete a questionnaire themselves 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 consists of users who do not take 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 (IMD), smoking, ethnicity, health worker / caregiver status and dietary quality.
Moderate protective effect
Dr Menni and colleagues found that 175,652 UK subscribers regularly took nutritional supplements during the first wave, and 197,068 did not. In total, 67% of the people who used supplements were women and more than half were overweight (average BMI of 27). A total of 23,521 people tested positive for SARS-CoV-2 and 349,199 tested negative during the three months.
In the UK, those using probiotics, omega-3 fatty acids, multivitamins or vitamin D have a 14% lower risk of SARS-CoV-2 infection (95% AI (8% to 19%)), 12 % (95% CI (8% to 16%)), 13% (95% CI (10% to 16%)) and 9% (95% CI (6% to 12%)), after adjusting for potential confusion.
The risk reduction of the positive test for SARS-CoV-2 with the use of omega-3 fatty acids was 21% in the US group and 16% in the Swedish group. Probiotics are modestly protected against infections with a risk reduction of 18% in the US group and 37% in the Swedish data.
With multivitamins, the risk for SARS-CoV-2 was reduced by 12% in the US group and by 22% in the Swedish group. With vitamin D, the risk reduction was 24% and 19%, respectively.
Probiotics improve the intestinal microbiome and increase immunity
In commenting on the modest effect of probiotics on risk reduction, dr. Menni said a healthy diet could have a confusing effect on the association.
“A recent study linked the gut microbiome to the immune response in COVID-19 and we also know that the severity of COVID-19 is associated with the gut microbiome.”
In terms of probiotics, it improves the diversity of the microbiome, which is good for the immune system, and as a result, an individual is less likely to get sick, she added.
“The finding on probiotics opens up many potential research pathways and supports a clinical trial of probiotics.”
Professor Sumantra Ray, executive director of NNEdPro Global Center for Nutrition and Health, who co-owns the journal, commented on the findings. “To date, there is little convincing evidence that the intake of nutritional supplements has any therapeutic value other than maintaining the body’s normal immune response.
“In addition, this study was not primarily designed to answer questions about the role of nutritional supplements in COVID-19.”
The researchers acknowledge that this is an emerging area of research and warrant further rigorous research, including RCTs, which investigate the possible protective effects on infection and severity of diseases, as well as adverse effects, before drawing firm conclusions about the role of nutritional supplements around infection to prevent. with SARS-CoV2. They also note that the study is based on self-reported data and a self-selected group. No information was collected on supplemental doses or ingredients.
COI: Dr Menni declares no conflicts of interest. Other authors mention a variety of interests on the paper.
Published in the 19th issue of the journal BMJ Nutrition Prevention and Health