Can we "eat our way out of this pandemic" by eating leeks? No, there's no evidence that's true: An author's claim relies on studies by other people, none of which say that eating leeks prevents COVID-19 infections. A spokesperson for the Food and Drug Administration (FDA) told Lead Stories that, at the time of writing, there was no evidence linking leeks to the prevention of COVID.
The claim appeared in a Medium post (archived here) entitled "Take A Leek Against SARS," published on December 14, 2021. The author, Kevin Lau, identifies as "Dad. Google. Product. Education. Pathfinder in complexity. Speaker of inconvenient truths." In the post, he asked and answered:
Are you suggesting we eat our way out of this pandemic?
Yes! The science clearly says eating a vegetable (leeks) would feed our immune system with a MBL that hunts down SARS-CoV-2 for dinner. Didn't your parents teach you to eat your vegetables because they're good for you?
Let's feast upon leeks so our immune system can feast upon the SARS coronavirus!
This is what the post looked like online at the time of writing:
MBL stands for mannose-binding lectin, a type of lectin that plays an important role in innate immunity. Lau cites a number of studies that talk about MBL, but none say that eating leeks prevents COVID infections.
Lead Stories reached out to several of the authors of the cited studies. We will update this story, as appropriate, if we hear back. Nearly all the papers were published before the COVID pandemic. One, which was published after the start of the pandemic, concludes:
Based on prior studies on coronaviruses, mannose-specific plant lectins offer potential applications to prevent SARS-CoV-2 infection in COVID-19.
Note that that conclusion falls well short of what Lau is claiming.
We also reached out to the FDA to ask about Lau's claims. In an email to Lead Stories, dated December 28, 2021, a spokesperson wrote:
Currently, there is no evidence of leeks being associated with the prevention of COVID-19 infections.
All that said, Lau is right about one thing: Vegetables are good for you. In particular, the leek is believed to have many health benefits and is a great source of fiber, iron and vitamins K, C and B6. Just don't count on it keeping you safe from COVID-19.