In a laboratory experiment, researchers placed both colon cancer and breast cancer cells in contact with a plant pigment called quercetin extracted from five different types of onions. The onion extracts prompted cell death in the cancer cells, inhibited cancer growth, and created an inhospitable environment for cancer, according to the experiment, and red onions were a standout. Red onions are especially high in quercetin as well as another group of plant pigments called anthocyanins, which also have anti-cancer properties. Population studies also suggest that regularly eating onions and their “cousins” like leeks, garlic, and shallots may reduce your risk of several types of cancer. We don’t know exactly how many servings of onion might be ideal for prevention, but since onions impart delicious, savory flavor to dishes ranging from soups and salads to sandwiches, keep them on hand and use them liberally.
“… flavonoids are shown to have antioxidative activity, free-radical scavenging capacity, coronary heart disease prevention, and anticancer activity….” Mary Ann Lienhart-Cross, Purdue Extension Educator