A June 2017 study by Engineering professor Suresh Neethirajan and PhD student Abdulmonem Murayyan at the University of Guelph concluded that, “the red onion not only has high levels of quercetin, but also high amounts of anthocyanin, which enriches the scavenging properties of quercetin molecules … We found onions are excellent at killing cancer cells …”

“Onions activate pathways that encourage cancer cells to undergo cell death. They promote an unfavourable environment for cancer cells and they disrupt communication between cancer cells, which inhibits growth."

"Anthocyanin is instrumental in providing colour to fruits and vegetables so it makes sense that the red onions, which are darkest in colour, would have the most cancer-fighting power."

The researchers determined, in an earlier study, that, “onions are effective at killing breast cancer cells.”

"The next step will be to test the vegetable's cancer-fighting powers in human trials," said the researchers.