London, Apr 21 (IANS): Women who take multivitamins, omega-3, probiotics or vitamin D supplements may be at less risk of testing positive for SARS-CoV-2, the virus responsible for Covid-19 infection, according to a large population study.

Women taking probiotics showed a 14 per cent lower risk of infections, while omega-3 fatty acids reduced risk by 12 per cent. Multivits and vitamin D were associated with a 13 per cent and 9 per cent lower risk of SARS-CoV-2 infection, respectively. However, no such clear associations were seen in men, said the research team, including Cristina Menni, from the Department of Twin Research and Genetic Epidemiology at King's College London, UK.

Moreover, the intake of much-publicised vitamin C, zinc, or garlic supplements did not lower the risk of testing positive for the virus, showed the findings published online in the journal BMJ Nutrition Prevention & Health.

Since the start of the pandemic, there has been plenty of celebrity endorsement of the use of dietary supplements to both ward off and treat Covid-19 infection. In the UK alone, market share rose by 19.5 per cent in the period leading up to the first national 'lockdown' on March 23 last year, with sales of vitamin C rising by 110 per cent and those of multivits by 93 per cent. Similarly, zinc supplement sales rose by 415 per cent in the first week of March, at the height of Covid-19 fears in the US.

Dietary supplements can help to support a healthy immune system, but whether specific supplements might be associated with a lower risk of catching SARS-CoV-2 isn't known, the researchers said.

To understand, the team analysed information supplied by 372,720 UK people on the Covid-19 Symptom Study app, to see if regular supplement users were less likely to test positive for SARS-CoV-2.

"This is an observational study, and as such, can't establish cause," the team noted.

But although the observed effects were modest, they were significant, note the researchers, who call for large clinical trials to inform evidence-based therapeutic recommendations.