New research suggests that dark red onions, which are known as the richest source of dietary flavonoids may help fight off cancer of the colon and the breast. “We found that onions are excellent at killing cancer cells,” said Abdulmonem Murayyan, a doctoral student at the University of Guelph in Ontario, Canada. The findings, published in the journal, ‘Food Research International’, showed that red onions contain high levels of quercetin which has benefits such as lowering inflammation and fighting allergies and is also believed to have the power of stealing iron from cancer cells, which they use to grow. Quercetin has the power to shrink cancer cells.
The team tested five onion types and discovered that the Ruby Ring variety of onion – tall globe-shaped bulbs of dark red colour was the best. The red onion is said to be full of powerful compounds that help to kill tumours. Red onions also have high amounts of anthocyanin which boosts the scavenging properties of quercetin molecules and is also responsible for its dark red colour. When cells of colon and breast cancer were placed in direct contact with the quercetin extracted from the five different onion varieties, the team found them effective at killing cancer cells. “Onions activate pathways that encourage cancer cells to undergo cell death. They promote an unfavourable environment for cancer cells and disrupt communication between cancer cells and inhibits growth” according to Abdulmonem Murayyan.
Hence any type of onion, regardless of its colour, may help to destroy cancer, though the red ones may be the most potent. Some are wary of the findings as there have been no human trials and it may be different when tried on humans as the human body is more complex.
Abdulmonem I. Murayyan et al. 2017. Antiproliferative activity of Ontario grown onions against colorectal adenocarcinoma cells. Food Research International 96: 12-18; doi: 10.1016/j.foodres.2017.03.017