Onions are an underappreciated vegetable. In addition to adding flavor, onions provide valuable nutrients and health-promoting bioactive compounds. Here are some of the nutritional benefits of onions:
High protein quality (ratio of mg amino acid/gram protein).
A good source of fiber and folic acid, raw onions are high in vitamin C.
Provide two vital minerals: calcium and iron.
One of the richest sources of the antioxidant, quercetin.
The pungent aroma is a sign that onions contain organosulfur compounds.
More information about these health-promoting properties.As a member of the Allium plant family, onions are closely related to chives, garlic, shallots, and leeks. Onions can be consumed raw, cooked, pickled, or powdered. Production numbers estimate that the average American consumes 20 pounds of onions yearly. The varieties of onions include yellow, red, white, purple, Spanish, Vidalia onions, and young green onions (scallions).
Onions are rich in a non-digestible fiber needed to maintain gut health. Although we can’t digest prebiotic fiber, the bacteria in our gut use it as fuel to help increase their numbers and produce by-products called short-chain fatty acids (SCFAs). Research shows that these SCFAs are essential for maintaining the health and integrity of the gut and supporting our immunity and digestion.
Quercetin is an antioxidant that prohibits the activity or creation of cancer-causing elements. A quercetin-rich diet has been associated with a lower risk of developing lung cancer, and studies indicate that quercetin helps to eliminate free radicals in the body, inhibit low-density lipoprotein oxidation (a reaction in the development of atherosclerosis and coronary heart disease), protect and regenerate vitamin E (a powerful antioxidant). Quercetin also supports the immune system by transporting zinc into our cells. Darker-colored onions, like red and chartreuse onions, contain the highest amounts of quercetin.
Other antioxidants in onions also reduce oxidative stress and appear to reduce bone loss. A study examining the effect on peri- and post-menopausal women reported that frequent onion consumption decreased the risk of hip fracture. Remember that antioxidant concentrations are higher in the onion’s outer layers, so peel off as few as possible during preparation.
It’s not only quercetin that helps support heart health. Organic sulfur compounds help reduce the level of cholesterol in your body and may also help break down blood clots, lowering your risk for heart disease and stroke. Eating onions raw provides the highest amounts of sulfur compounds.
The quercetin and organic sulfur compounds in onions promote insulin production, making them a positive vegetable choice for those with diabetes.
Though onions are nutritional powerhouses, they don’t agree with everyone. Onions—especially when eaten raw—may increase gas and bloating for those with irritable bowel syndrome (IBS). Onion consumption should be limited in those cases.
How to Enjoy More OnionsRaw yellow onions are the sweetest variety, making them an excellent salsa addition. Cooked yellow onions make a savory base for soups, stews, and sauces. Onions are also delicious, roasted, grilled or sautéed.
Check out the accompanying recipe for caramelized red onion dip. Here are some other ways to use the zesty onion:
Top sandwiches and burgers with grilled or raw onions to increase your zesty vegetable intake.
Add pickled red onions to grain bowls, fish or pork tacos, or alongside any meaty main dish for a tangy burst of flavor- and beautiful color.
Add caramelized onions to savory baked goods.
Combine cooked onions with other vegetables for a healthy side dish.
Add cooked onions to egg dishes, such as omelets, frittatas, or quiches.
Top meat, chicken, or tofu with sautéed onions.
Add thinly sliced red or green onions to a vegetable salad.
Make a fiber-rich salad with chickpeas, chopped onions, and red peppers.
Top tacos, fajitas, and other Mexican dishes with chopped raw onions.
Make a homemade salsa with onions, garlic, tomatoes, chilies, and fresh cilantro.
Prepare a hearty onion and vegetable soup.
Caramelized Onion Dip
1 tablespoon extra-virgin olive oil
2 ½ lbs. red onions, chopped (about 6 cups)
1 teaspoon kosher salt
¼ cup steak sauce
1 ¼ cups Greek yogurt
1 teaspoon black pepper, plus more for garnish
1 Tablespoon thinly sliced fresh green onion tops (save the bottoms for another use)
Fresh vegetables for dipping
- Heat oil in a large, heavy skillet over medium-low. Add onions and salt; cook, often stirring, until deeply browned, 40 to 45 minutes. (The low heat and frequent stirring are the key to properly caramelized onions, so resist the urge to crank up the heat.)
Add steak sauce; cook, stirring occasionally) until liquid evaporates, about four to five minutes. Let cool completely, about 10 minutes.
Reserve 2-tablespoons of onion mixture for garnish.
Combine the remaining cooked onion, sour cream, and pepper in a bowl. Top with reserved onion mixture. Sprinkle with green onion slices and several grinds of black pepper. Serve with crunchy vegetables.