Although vaccine rollouts are in full swing in some countries, many of us are still living in the midst of the risks of the COVID-19 pandemic without protection and need all the help we can get.
An interesting study by an international team of researchers has now found a small association with supplement use, indicating that there are fewer COVID-19 infections in women taking certain types of vitamins. But don’t rush to the pharmacy just yet.
First, it’s important to remember that the potential benefits of multivitamins are extremely limited. Doctors generally recommend that most people get enough micronutrients in their diet to stay healthy, and in the past, studies of the health benefits of vitamin supplements without a diagnosed deficiency have been a real mixed bag.
Despite this, in the early days of the pandemic, vitamins were one of the many items to fly off pharmacy shelves.
“The UK supplement market rose 19.5 percent in the period leading up to the national lockdown in early March 2020, with sales of vitamin C up 110 percent and sales of multi-vitamin supplements up 93 percent,” wrote the team.
“Similarly, zinc supplement sales increased 415 percent over the 7-day period ending March 8, at the height of US COVID-19 concerns.”
Supplements can play a role in supporting our health. Zinc is one of the few micronutrients associated with shortening the disease course of the common cold; people on a vegan diet are advised to take B12 vitamins to combat deficiency. But preventing infections is where it gets tricky.
The researchers pulled data from an app launched in early 2020 by health science company Zoe called the ‘COVID-19 Symptom Study App’, which asked participants a wide variety of questions, including whether they were taking vitamins such as probiotics, garlic, fish oil. , multivitamins, vitamin D, vitamin C or zinc. They also asked if they had been tested for SARS-CoV-2 and what the results were.
In total, 445,850 subscribers from the UK, US and Sweden had answered the questionnaire by July 31, 2020, giving the team enough data to analyze.
In the UK, where the vast majority of those surveyed were based, just under half took some type of supplement. About 6 percent of those who took supplements tested positive for SARS-CoV-2, while 6.6 percent of those who did not take supplements tested positive. That is a difference of about 2,500 people.
In the British cohort, users who regularly supplement their diet with multivitamins had a lower risk of testing positive for SARS-CoV-2 by 13 percent, with vitamin D a lower risk by 9 percent, with probiotics a lower risk by 14 percent and with omega-3 fatty acids lower risk by 12 percent, ”the researchers wrote.
“There were no significant associations in those taking zinc, vitamin C or garlic.”
There are plenty of caveats to watch out for here. First, this is an observational study based on self-reports, meaning there is no causal evidence that vitamins led to fewer COVID-19 diagnoses.
The team adjusted for age, gender, BMI and a number of other factors, trying to account for “ healthy user bias, ” which is the idea that those taking vitamins are likely to be healthier in other ways as well, whatever the results.
Even after all that, the results were still there, but interestingly enough, when the team split the results by gender, there was no difference related to supplements for men, while for women the results were present in all ages and BMI groups .
The results were also slightly different between the US and Sweden, finding that omega-3 supplements did not seem to help Swedish women, and probiotics and vitamin D appeared to help American men.
“In the largest observational study on SARS-CoV-2 infection and dietary supplement use to date in more than 400,000 app users from three different countries, we show a significant association between users of omega-3 fatty acids, probiotics , multivitamin or vitamin D supplements, and a lower risk of testing positive for infection with SARS-CoV-2, ”the team wrote.
“Women who buy vitamins may also be more health conscious than men, such as wearing face masks and washing hands more often. Indeed, in our data we found that women wore masks more often than men.”
After all, the results show a very modest difference; for example, taking vitamins only lowered the absolute risk of getting COVID-19 by less than 1 percent in the UK study participants.
But at the population level, even small percentage points can save lives, so it’s imperative that we find out if it’s really the vitamins that make a difference.
The researchers have called for a large clinical trial to test its possible effects in a more controlled environment. For now, if you’re not getting a vaccine yet, masks, good hygiene, and social distance will probably still keep you much safer than any vitamin.
“This study was not primarily intended to answer questions about the role of dietary supplements in COVID-19,” said Sumantra Ray, a Cambridge nutritionist who was not involved in the study.
“This is still an emerging area of research that requires further rigorous study before firm conclusions can be drawn as to whether specific dietary supplements can reduce the risk of COVID-19 infection.”
The research is published in BMJ Nutrition Prevention & Health.