In women, the use of probiotics, omega-3 fatty acid, multivitamin or vitamin D supplements is associated with a lower risk of testing positive for the novel coronavirus, a recent study suggests.

There were no clear benefits for men and overall no effects were found for vitamin C, zinc or garlic supplements, even though many of these supplements had been rumored early on in the pandemic to help prevent coronavirus infections, being promoted as such across television and social media.
In the UK in particular, the supplement market rose by 19.5% in March 2020 amid the panic-buying craze as everyone prepared for the long road of solitude ahead. Vitamin C and multivitamin supplements in particular rose by 110% and 93% respectively. Zinc went up by 415%.
"In 372,720 UK participants (175,652 supplement users and 197068 non-users), those taking probiotics, omega-3 fatty acids, multivitamins or vitamin D had a lower risk of SARS-CoV-2 infection by 14%," the study authors wrote, with 14% being an overall figure for both men and women across the board.
"On stratification by sex, age and body mass index (BMI), the protective associations in individuals taking probiotics, omega-3 fatty acids, multivitamins and vitamin D were observed in females across all ages and BMI groups, but were not seen in men," the researchers added.
The study worked off of self-reported personal information regarding the health of participants amid the coronavirus pandemic, which were submitted via the COVID-19 symptom study app launched in the US, UK and Sweden in March.
The study noted that similar results were also observed by teams performing parallel studies in Sweden and the United States.
With the UK study being made up of predominately female participants (66.8%), they intended to firm their results by replicating the samples within the cohorts working out of the US and Sweden.
While the overall findings were similar in both of the external studies - the association that the use of probiotics, omega-3, multivitamin or vitamin D corresponds with a lower risk of getting coronavirus - the evidence that this method is more effective in women was only replicated in the US study but not within the Swedish one.
In the Swedish study, males taking the aforementioned beneficial supplements had a decreased risk of infection, same as women. Separately, in the US study, men taking probiotics or vitamin D supplements were associated with a lower risk of infection.
"Here we provide evidence to support a protective effect in omega-3 fatty  acid  supplements users with a 12% reduction in risk of testing positive for SARS-CoV-2 in the overall UK cohort, 21% in the US cohort and 16% in the SE cohort," the researchers wrote. "Although, in the UK, stratified  analysis shows this effect is largely driven by females, and only significant in one male stratum."
The study did note its limitations, however.
While many of these supplements "plausibly" lead to enhanced immune function and response, the researchers noted that there needs to be large randomized trials on each individual supplement to know with certainty "before any evidence-based recommendations can be made," as this study was merely observational.
Additionally, regarding the evidence that the use of the listed supplements have a "modest but significant association" with a lower risk of contracting coronavirus in women, the researchers noted gender differences when it comes to hygiene and health.
"Polling reveals that a greater percentage of females versus males are anxious for the health of them-selves or their family and therefore are more precautionary, cancelling plans and staying home more often," the researchers said. "Females who purchase vitamins may also be more health conscious than males, such as having  greater use of wearing face masks and hand-washing."
Along that notion, males who take these supplements are also likely to be more health conscious than those who do not, which could add the overall benefits being inflated.
The supplements are not a one-stop solution to preventing coronavirus as this study has made clear and many other studies have proven, although they may assist in fighting or contracting infections.
In the case of vitamin D, which has long been understood to impact immune response, low levels of it have been linked to higher risk for severe COVID-19, but high vitamin D levels do not fix the problem.
Doctors in Brazil found that boosting vitamin D levels in critically ill patients ineffective in shortening their hospital stay or lowering their chances of being moved to the intensive care unit, being put on a ventilator or dying.
And while the year of the coronavirus pandemic has been riddled with misinformation - from claims by former US President Donald Trump that hydroxychloroquine, an antimalarial drug, can cure coronavirus to information on how the virus spreads, what caused the coronavirus pandemic, etc. - many thoroughly researched studies are beginning to come to surface, given hope to eventually building a full understanding of COVID-19, it's mutations and how to best combat it's effect and spread in the future.
The researchers noted that they are currently awaiting the results of ongoing studies that are specifically looking at the use of vitamin D and omega-3 fatty acids in reference to risks of developing a COVID-19 infection.