A peerless staple and a universal food, the onion has played a key role throughout culinary history. There is some evidence that onions were consumed in prehistoric times and were widely eaten in ancient Egypt, Greece, and Rome. Onions have historically been valued for their mystical significance and healing properties. In many cultures they were also a symbol of eternity. In the 1600s, Europeans consumed onions as a breakfast “health” food.
Onions and their relatives—which include shallots, garlic, scallions, and leeks—are known botanically as alliums. There are more than 500 alliums, and all of the edible species are bulbing plants that have a characteristic pungent smell or taste, which is produced once their layers of skin are cut.
China and India grow by far the most onions—28 percent and 18 percent, respectively—in world production. The US is a distant third at just under 4.5 percent.
Types of Onions
Onions come in an impressive array of sizes, colors, and shapes, each with subtle differences in taste or texture.
Onions, scallions, and shallots: Nutrition
Onions are low in calories and fat, and in most nutrients. However, they are a moderate source of fiber, vitamin C, vitamin B6, and potassium.
Like other onions, shallots are a good source of vitamin B6, though you would have to eat about 1/4 cup cooked (not impossible) to get more than 10 percent of the RDA for this vitamin. Shallots also provide some iron.
The green tops of young onions like scallions or spring onions provide beta carotene, while their bulbs provide a respectable amount of vitamin C.
For a full listing of nutrients, see the National Nutrient Database:
How to Choose the Best Onions
The best onions depend on how you plan to use them: Choose sweet onions to eat raw, but go for pungent storage onions for stews and soups.
How to store onions, scallions, and shallots
Whole onions should be kept in a cool, dry, open space, away from bright light, which can turn their flavor bitter. They do best in an area that allows plenty of air to circulate around them. Either spread them out in a single layer or hang them in a basket. Onions will absorb moisture, causing them to spoil more quickly, so don’t store them under a sink or place them near potatoes, which give off moisture and produce a gas that causes onions to spoil more quickly. Storage onions can last three to four weeks under these conditions, sweet onions about half as long. Humid weather will shorten storage time.
You can extend the life of onions, particularly sweet varieties, by storing them unwrapped in the refrigerator crisper.
Compared to storage onions, scallions and spring onions are quite perishable. Store them in the refrigerator in a tightly closed plastic bag and use them within three days; otherwise, the tops will begin to wilt.
Store shallots for up to a month in a cool, well-ventilated space. They will also keep in the refrigerator in a tightly closed jar.
10 Terrific Recipe Ideas for Onions
Onions, scallions, and shallots add subtle flavor to almost any dish, but first you face the challenge of chopping or slicing the onion without crying.
Published August 12, 2015