Researchers from the Kumamoto University in Japan have discovered that a compound found in onions, known as Onionin A (ONA), can significantly lower the risk of developing ovarian cancer.
According to statistics from the American Cancer Society, ovarian cancer affects more than 35000 or 3% of women and causes more than 15000 deaths in the US per year. It is the eighth most common cancer in the world and the fifth leading cause of cancer-related death in women.
The average age of death from ovarian cancer is 70, with survival rates much lower than other cancers that affect women.
The World Health Organization (WHO) rates epithelial ovarian cancer (EOC) as the most common and deadly type of ovarian cancer, with 80% of patients relapsing and only 46% surviving for 5 years following treatment.
How do onions fight cancer?
Food scientists at Cornell University conducted a study on onions and found that a specific type of flavonoid, known as quercetin, is effective at reducing the risk of developing multiple types of cancer.
Out of 28 types of vegetables and 9 types of fruits, onions have been found to contain the highest amount of quercetin, which to neutralizes cancer cells and restores a healthy cellular environment.
Professor Rui Hai Liu said: “Onions are one of the richest sources of flavonoids in the human diet and flavonoid consumption has been associated with a reduced risk of cancer, heart disease, and diabetes. Flavonoids are not only anti-cancer but are also known to be antibacterial, antiviral, anti-allergenic, and anti-inflammatory.”
What does ONA do?
While studying the effects of Onionin A (ONA) on a preclinical model of epithelial ovarian cancer in both vivo and in-vitro cases, researchers from Kumamoto University discovered that ONA had the ability to not only slow the growth of ovarian cancer cells but also to inhibit pro-tumor activities.
“By suppressing the growth of myeloid-derived suppressor cells (MDSC), an immune response is triggered, which was additionally found to enhance the effects of anti-cancer drugs by elevating their anti-proliferation properties,” they said.
Further experiments were conducted on mice, which proved that even oral doses of ONA could stop ovarian cancer tumor development and increase life span significantly. Because ONA is an organic compound, it was also found to have no side effects, which means that an oral ONA supplement could greatly benefit ovarian cancer patients.
“We found that ONA reduced the extent of ovarian cancer cell proliferation induced by co-culture with human macrophages. In addition, we found that ONA directly suppressed cancer cell proliferation, thus, ONA is considered useful for the additional treatment of patients with ovarian cancer owing to its suppression of pro-tumor activation and its direct cytotoxicity against cancer cells,” said the team.
Which onions are the best?
Professor Liu says: “Although milder onions are becoming more popular, the bitter and more pungent onions seem to have more flavonoid compounds and appear to be more healthful.”
Shallots, Western Yellow, pungent yellow, and Northern Red onions were found to contain the most concentrated anti-cancer properties, proven to reduce the risk of developing colon, liver, ovarian and many other types of cancer.