Onions are a heart-healthy vegetable that have numerous health benefits and are considered to be a nutritional superfood. Onions are commonly used in cooking and contain compounds that are beneficial in preventing some types of cancer, heart disease, type 2 diabetes and other common diseases.
Onions have an antibiotic quality and are known to help reduce food contamination. The protective sulphur compounds in onions give the vegetable its pungent tear-inducing quality, but this aspect of onions helps to reduce cholesterol. Onions also contain phytochemicals that promote immune function, help to protect nerves, and inhibit the growth of some types of tumors. Chromium, a metal that helps to maintain blood sugar levels, is also found in onions. Because the outer layers of onions contain the highest concentration of antioxidant flavonoids, the least amount of the onion's exterior as possible should be removed when chopping the vegetable.
For over 3,500 years, onions have been used in cooking and to fight infections and inflammation. Onions are a culinary staple and have been promoted by well-known chefs, such as Julia Child. They can be eaten raw in salads or sautéed in butter or olive oil and cooked with vegetables, fish, meat or other protein foods. Onions are found in numerous recipes and add a sweet and pungent flavor to food.