What Are Onions Good For?

Botanical name: Allium cepa

Whether white, yellow, or red, onions are one of the world’s most popular and versatile vegetables, delivering an unmistakable, pungent heat – some more than others. They’re in demand for cold salads and hot soups, sliced in rings or solid disks on burgers, and chopped in relish. The delicious caramelization that takes place when onions are sautéed is due to their high sugar content.
(Try them sautéed with bell peppers for a tasty fajita ingredient.) Spanish red onions are generally milder than white or yellow. The Vidalia variety is one of the sweetest.

The sharp fragrance and flavor emitted by onions is due to the sulfur compound allyl propyl disulphide; it’s allyl sulphide that brings you to tears when peeling one, serving the good purpose of washing the thin epithelial layer of the eyes. Holding peeled onions under cold water for several seconds before slicing minimizes this effect.

Health Benefits of Eating Onions

Onions are loaded with numerous health benefits, and scientists are still discovering how beneficial this vegetable really is. They’re a very good source of vitamin C and B6, iron, folate, and potassium. The manganese content in onions provides cold and flu relief with its anti-inflammatory abilities.

Two phytochemical (plant-derived nutrient) compounds in onions – allium and allyl disulphide – convert to allicin when the bulb is cut or crushed due to enzyme activation.

Studies show these compounds to have cancer- and diabetes-fighting properties, while decreasing blood vessel stiffness by releasing nitric oxide. This can reduce blood pressure, inhibit platelet clot formation, and help decrease the risk of coronary artery disease, peripheral vascular diseases, and stroke.

Significant amounts of polyphenols (another phytochemical in onions) and an antioxidant flavonoid called quercetin (which has proven anti-cancer, anti-inflammatory, and anti-diabetic functions) account for the reputation onions have for disease prevention. 

Luckily, cooking onions in soup doesn’t diminish their quercetin value – it simply transfers to the broth. The flavonoids in onions are more concentrated in the outer layers, so discard as little as possible.

Studies Done on Onions

Studies showed strong evidence that eating onions may considerably reduce the risk of stomach cancer1. In another study, beneficial effects of red, yellow, and white onion extracts were noted for their antioxidant and anti-mutagenic (cell mutation prohibitive) activity2 – better than Butylated hydroxytoluene (BHT), a synthetic chemical added to foods as a preservative, and ascorbic acid. Free-radical scavenging activity increased, depending on the concentration.

Rainbow Chard with Red Onions


  •     1 medium red onion, sliced into half moons
  •     1 tablespoon olive oil
  •     1 bunch chard or spinach, chopped finely
  •     1 tablespoon tamari soy sauce
  •     1 teaspoon lemon juice


  1. Place chopped onion into skillet with olive oil. Cook for about 3 minutes.
  2. Add the chard, cook for another 2 minutes, then add the tamari soy sauce and lemon juice. Cook for another 2 minutes.
  3. Place into a medium-sized bowl and serve. Makes 4 servings.

(From Healthy Recipes for Your Nutritional Type by Dr. Mercola)

Onion Fun Facts

Egyptian mummies have been found with onions tucked into their pelvic regions, flattened against their ears, and attached to their feet and legs. Flowering onions were sometimes placed on their chests. King Ramses IV, who died in 1160 B.C., was found with onions inserted into his eye sockets.


Since the dawn of time, onions have been used to liven up food recipes and added to ancient concoctions for medicinal purposes.

Modern medicine has found onions to be highly beneficial in almost every area of the body, from maintaining cell health to preventing inflammation to purifying the blood.

Onions also add a kick in kitchens all over the world, providing a savory goodness that blends well with other foods.

Sources and Resources:

1 Gastroenterology, “Consumption of Onions and a Reduced Risk of Stomach Carcinoma,” (1996), Aug. 2012

2 Antimutagenic, antioxidant and free radical scavenging activity of ethyl acetate extracts from white, yellow and red onions, Aug. 2012