Onion-based flavonoids are best at triggering apoptosis in abnormally dividing cells, researchers found.
Researchers conducting a promising study in Canada predicted that red onion extract will eventually be added to food products and sold as a natural cancer preventative. According to the lead author Abdulmonem Murayyan, “We found onions are excellent at killing cancer cells.”
Our study confirmed that red onion varieties are more potent in inhibiting cancer cells than other onion varieties.
Scientists know that a high consumption of onions is associated with a reduced risk of several types of cancer. Moreover, as this vegetable is a part of the Mediterranean diet (MedDiet), it may be partially responsible for the low incidence of the disease in Southern Europe. Researchers Murayyan and Suresh Neethirajan at the University of Guelph wanted to ascertain which variety of onions has the most anticancer properties.
In the study published in the journal Food Research International, they tested the effects of five kinds of onions on human colon cancer cells and found Ruby Ring onions had the highest efficacy in fighting the disease.
“Our study confirmed that red onion varieties are more potent in inhibiting cancer cells than other onion varieties,” Suresh Neethirajan told Olive Oil Times. “They showed a 3.5- to 4‑fold increase in the number of cells undergoing apoptosis (cancer cell death), compared to the other types.”
What is so special about red onions? While all varieties of the vegetable contain a high quantity of an anticancer flavonoid called quercetin, red onions are also rich in anthocyanin, a compound that boosts the scavenging properties of quercetin, explained Murayyan.
“Anthocyanin is instrumental in providing color to fruits and vegetables, so it makes sense that the red onions, which are darkest in color, would have the most cancer-fighting power,” added Murayyan.
Neethirajan also shared how the healthful compound in onions fights cancer.
“Free radicals in the human system can lead to cancerous cells that could develop into tumors, and they increase the risk of diabetes or heart disease if left unheeded,” he said.
“The quercetin molecules in onions attract and neutralize the free radicals. A hallmark of cancer cells is their ability to avoid apoptosis. By triggering apoptosis in abnormally dividing cells, cancer cells and metastasis can be put in check. Onion-based flavonoids are best at triggering apoptosis. Out of 28 vegetables and nine fruits, onions lead in quercetin content.”
In addition to the current discovery, the researchers recently found onions were effective at eradicating breast cancer cells. Next, they plan to evaluate the vegetable’s anticancer effects in human clinical trials.
Although it can be beneficial to put red onions in salads and hamburgers, the team believes onion extract will be added to food products such as juice or baked goods in the future. They also anticipate that it will be sold in pill form as a nutritional supplement for fighting cancer.