The authors documented exciting associations between the consumption of omega-3, probiotics, multivitamins, and vitamin D supplements on the one side, and a reduced chance of positive tests for SARS-CoV-2 infection on the other.
More than 445,000 people from three countries (UK, US, and Sweden) were included in the study last year. These individuals had to answer various questions related to their hygiene, lifestyle, etc., using the COVID-19 Symptom Study application in early 2020.
Interestingly, the study’s main purpose wasn’t to assess the role of nutritional supplements in COVID-19. However, the study established correlations showing that women who take certain vitamins get infected less frequently.
Indeed, in the UK, where the vast majority of surveyed people were located, less than half of respondents used supplements. Of those taking supplements, roughly 6% tested positive for SARS-CoV-2, while 6.6% did not use supplements and tested positive. This came down to a difference of about 2,500 people.
Yet, we have to take all these results with a pinch of salt.
In the British cohort, consumers who supplemented their diets daily with multivitamins or vitamin D had a 13% and 9% lower risk of SARS-CoV-2 positivity, respectively. Probiotics reduced the risk of getting COVID-19 by 14% and omega-3 fatty acids by 12%.
It is noteworthy that after the adjustments for sex, body mass index (BMI), and other factors, significant differences were seen between males and females. Men had no benefits with supplementation, while the benefits for women seemed consistent regardless of their age and BMI.
Additionally, the findings significantly differ between the US and Sweden. For example, omega-3 supplements did not appear to benefit Swedish women, while probiotics and vitamin D seemed to help the US men.
Some limitations of the study were mentioned—there were no significant correlations for using zinc, vitamin C, or garlic supplements. Also, this was a self-reported discovery analysis, meaning that there was no causal evidence that vitamins are actually what led to decreased COVID-19 rates.
After all, the results showed a very modest difference; taking vitamins only lowered the absolute risk of getting COVID-19 by less than 1% in the UK study participants. Thus, the possible merits of multivitamins seem to be rather small.
Nevertheless, doctors commonly prescribe supplements to their patients to help them maintain the adequate micronutrient status. Besides, previous findings have demonstrated truly mixed health effects of vitamin supplementation in COVID-19 management.
However, even a low reduction in the risk of infection can save lives on population levels, so it is reasonable to consider vitamin use during the pandemic. Undeniably, vitamins were one of the many products that were flying off the store shelves in the early days of the world COVID-19 crisis.
During the UK lockdown in March 2020, the supplements industry grew by 19.5%, vitamin C sales were up 110%, and multivitamin supplements 93%. Similarly, the sales of zinc supplements rose 415% during the same period in the US.
Even though vitamins make a difference in SARS-CoV-2 infection rates, there is a call for large clinical trials to test the potential effects in a more controlled setting. Currently, if you’ve yet to receive a vaccine, masks, good hygiene, and social distancing are still likely to keep you much safer than any vitamin could.