Onions

Also indexed as: Bermuda Onions, Cipollini Onions, Green Onions, Maui Onions, Ramps, Red Onions, Shallots, Spanish Onions, Sweet Onions, Vidalia Onions, Walla Walla Onions, White Onions, Yellow Onions

If chopping onions brings tears to your eyes, invest in a pair of plastic goggles and wear them while chopping.

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With its characteristic flavor and aroma, the onion has become a staple in nearly every cuisine around the world. This underground bulb is related to the lily and has a wide and diverse family. There are more than 300 species in its genus (Allium), many of which are native to North America.

Varieties

Onions come in a variety of sizes, from the size of large marbles to softballs. Onion varieties include full-flavored and versatile yellow onions; cipollini; white onions, which have a higher water content and are slightly sweeter; Spanish onions, which are very large yellow onions; and red onions, also called Bermuda onions, which are sweeter and milder. Sweet onions, such as Vidalia, Maui, and Walla Walla onions, named after the locations in which they’re grown, are usually available only during spring and summer. Green onions are small, with their tender greens still attached, and have a fresh, bright flavor. Scallions are long and slender, with white roots fading into green tops, and a delicate flavor. Leeks look like larger scallions and have an earthier flavor. Ramps look like tiny leeks, but the greens are delicate and can be used with the white bulbs, and the flavor is more assertive and wild. Shallots are sold as firm, violet-tinged bulbs in golden skins; they have a more intense flavor, without the harshness of onions or garlic.

Buying and storing tips

Onions can be found in the produce section of health food stores and supermarkets. Look for firm, heavy onions, and avoid any with brown, soft, or translucent spots, or those that have begun to sprout. Green onions, scallions, leeks, and ramps should have crisp, bright greens with no signs of wilting. Use green onions, leeks, scallions, and ramps as soon as possible, or store in a plastic bag for up to two days. Bulb onions can be stored loose, in a paper or mesh bag, in a cool, dry location for up to two weeks.

Availability

Onions are available all year long. Green onions are available in the spring and summer. Sweet onions are available from April through July.

Preparation, uses, and tips

To avoid tearing, caused by sulfur compounds in onions, try holding onions under water to peel, then freeze them for 20 minutes before chopping. An inexpensive pair of plastic goggles from the hardware store is the best way to prevent tears. Onions can be sautéed, baked, roasted, or used in soups, stews, casseroles, and a variety of other dishes. Sweet onions, red onions, and green onions can be eaten raw, on sandwiches, or in salads.

Nutritional Highlights

Onions (raw, chopped), 1 cup (100g)
Calories: 61
Protein: 1.8g
Carbohydrate: 13.8g
Total Fat: 0.25g
Fiber: 2.9g
*Good source of: Vitamin C (10mg)

*Foods that are an “excellent source” of a particular nutrient provide 20% or more of the Recommended Daily Value. Foods that are a “good source” of a particular nutrient provide between 10 and 20% of the Recommended Daily Value.

Health benefits and concerns

Asthma

Vitamin C, present in fruits and vegetables, is a powerful antioxidant and anti-inflammatory. This anti-inflammatory activity may influence the development of asthma symptoms. A large preliminary study has shown that young children with asthma experience significantly less wheezing if they eat a diet high in fruits rich in vitamin C.

Bruising

Many Americans eat insufficient amounts of foods containing vitamin C; the disease caused by vitamin C deficiency, scurvy, causes easy bruising. While very few people actually have scurvy, even minor deficiencies of vitamin C can increase the incidence of bruising. People who experience easy bruising may want to try eating more fruits and vegetables—common dietary sources of vitamin C.

Capillary fragility

Eating plenty of flavonoid- and vitamin C-rich fruits and vegetables helps to support the structure of capillaries.

High homocysteine

A controlled trial showed that eating a diet high in fruits and vegetables containing folic acid, beta-carotene, and vitamin C effectively lowered homocysteine levels. Healthy people were assigned to either a diet containing a pound of fruits and vegetables per day, or to a diet containing 3 1/2 ounces (99g) of fruits and vegetables per day. After four weeks, those eating the higher amount of fruits and vegetables had an 11 percent lower homocysteine level compared to those eating the lower amount of fruits and vegetables.

Multiple sclerosis (MS)

In one survey, researchers gathered information from nearly 400 people (half with MS) over three years. They found that consumption of vegetable protein, fruit juice, and foods rich in vitamin C, thiamine, riboflavin, calcium, and potassium correlated with a decreased MS risk.

Health benefits and concerns for vegetables
Many health benefits and concerns associated with this food are applicable to other vegetables. Read about health benefits and concerns for vegetables for a full description.

The information presented in this website is for informational purposes only and was created by a team of U.S. registered dietitians and food experts. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements, making dietary changes, or before making any changes in prescribed medications.