People who take high doses of folic acid, a dietary supplement given for a variety of conditions, face an increased risk of contracting Covid-19 but also an increased risk of dying from the infection, a study in a large sample of participants shows.
Folate is a synthetic form of vitamin B9, a deficiency of which is linked to birth defects and an increased risk of heart disease and stroke.
It is given in large doses for diseases such as sickle cell disease, in high-risk pregnancies and in people taking anti-epileptic drugs. It is prescribed to offset the side effects of methotrexate, a drug used to treat certain cancers and autoimmune diseases, which blocks the action of folic acid.
“We looked at whether Covid-19 diagnosis and death from the disease are associated with high doses of folic acid – five times the safe upper limit – prescribed to patients with a variety of medical indications. We found that the risk of infection and death was significantly higher,” said Ralph Green of the University of California, Davis, an expert on B vitamins.
The coronavirus uses folate
His team’s study, published in the journal BMJ Open, found that patients prescribed folic acid were 1.5 times more likely to contract the coronavirus and 2.6 times more likely to die from the disease.
The researchers decided to look into the matter because of a previous study published last year in Nature Communications showing that SARS-CoV uses folate to replicate.
To see if the supplement increased the risk, they looked at data on 380,000 people registered between 2019 and 2021 in the UK Biobank.
The analysis led to the expected result that folic acid favors Covid-19, at least when taken in large doses.
“Our findings could have implications for patients taking folic acid as a dietary supplement to prevent complications of other drug interventions,” said Angelo Gaffo of the University of Alabama, a member of the research team.
“However, our results will need confirmation,” he clarified.
As Dr. Green added, “the established upper safe limit for folate is one milligram. Until we gather more information, it would be prudent to avoid extremely large doses of folic acid unless medically indicated.”
“High doses of folic acid would be of greater concern to vaccinated individuals.”