There is really more to onions than meets the nose. This common, lowly bulb is many times shunned by diners because of its pungent taste and lingering effects. However, past civilizations revered this ancient vegetable, and its health benefits may warrant stocking up on breath mints.
The onion has been eaten by humans since 5000 BC in its native Asia and Middle East, but researchers think it became a cultivated vegetable around 3000 BC. Six-hundred species of "onions" come from the genus Allium, and the name "onion" comes from the Latin unio, which means "single" or "one," referring to the single bulb and "union" of layers.
Now it's used as a tasty condiment on hot dogs and burgers, but ancient Egyptians held the onion in high esteem-worshipped it, in fact. Used as a form of currency, workers building the pyramids were paid with onions, and onions were entombed with their kings because they thought the concentric rings symbolized eternal life. Later, in the Middle Ages, people gave onions as gifts and even paid rent with them.
Onions come in all shapes, sizes and colors. In fact, there are about 600 kinds of onions and 120 documented uses for them.
These Vidalia onions are considered fresh and sweet, ideal for eating raw in salads or salsa. Because of their sugar and water content, they do not keep as well as storage onions.
Red onions not only add color but a healthy dose of anti-oxidants and flavonoids that reduce the risk of several cancers when eaten regularly.
Yellow onions and white onions have strong flavors. Most cooking onions are yellow onions, storage variety onions which can be kept for up to one month.
Greeks devoured them believing they were good for the blood. Roman gladiators rubbed them on their bodies thinking onions firmed up the muscles. In 6th century India, doctors utilized onions as medicine, a practice that became more widespread even into the 1600's.
Inexpensive and easy to grow, the onion has been accessible to the poor throughout the ages. Christopher Columbus arrived in the New World with an onion in hand to find that natives were already using wild onions. It was one of the first vegetables planted by the Pilgrims.
Fresh, storage, red, yellow or white, the different types of onions bring various flavors to the table. Examples of fresh onions with a softer texture, milder flavor and high water content include spring, green, scallions and sweet. Storage onions, which are drier and more intense in flavor, are generally red, yellow and white.
Scallions, green and spring onions are usually sold in bunches. The main difference is that spring and green onions have a small bulb base, and scallions' bases are straight. Because of the water, fresh onions don't keep as well. These can be stored in an airtight container or plastic bag in the refrigerator for up to one week.
Sweet onions are identified by place names of their origins: Walla Walla, Vidalia, Maui, Texas. They are good raw on sandwiches, salads and in dips or salsa with their milder, sweet flavors. The sugar and higher water content, though, causes them to deteriorate faster. Un-cut, they can be stored out of the refrigerator in a wire basket or mesh bag in a cool, dry, ventilated area for up to two weeks.
Storage onions are a bit heartier and, un-cut, should be kept unrefrigerated in a wire basket or mesh bag. Resting where it's cool, dark and dry, storage onions can be kept for as long as a month. Should they become soft or sprout shoots, throw them away.
In the United States, around 87 percent of the onions harvested are yellow onions. This all-purpose onion has a strong flavor and is usually used for cooking, for example in soups, sauces and onion rings.
Red, or Bermuda, onions are really purple in color. They are becoming more popular in the U.S. The flavor is slightly milder but crisper than the yellow onion and is used raw in salads, salsas or on sandwiches, especially for adding color to a dish. When cooking with red onions, add a little vinegar or lemon juice to keep the color from turning blue.
White onions are strong and flavorful like yellow onions, but slightly sweeter. They are virtually interchangeable, but the white onion has a cleaner finish with less after-taste. Cooking onions should always be done at low or medium heat. High heat will make them bitter.
Other members of the onion family include leeks (like large scallions with a mild flavor, great in soups), chives (considered an herb, best used fresh, flavor has a little bit of heat), and shallots (look like small onions with darker skins, cooking them mellows their hot flavor).
Throughout the centuries, doctors knew what studies are finding today: onions are healthy. The sulfur compounds in onions have been proven to lower the risks of certain cancers and slow tumor growth. Ovarian cancer, stomach cancer, colorectal cancer and laryngeal cancer have all been shown in research to respond to moderate (2-6 times per week) intake of onions in the diet. Other types of cancer, including esophageal and mouth cancers, have responded to daily intake of onions. One serving equals half a cup, or about one half of a medium sized onion.
The sulfur compounds also contribute to cardiovascular health and help protect the blood vessels and heart. In animal studies, these substances appear to be anti-coagulants, improve cell membrane functions in red cells and lower blood cholesterol and triglycerides.
Menopausal women with bone density concerns may want to try a daily serving of onions. Human studies show promising results.
Historically, onions have been used to treat respiratory ailments: sore throats, bronchitis and asthma. Today, the World Health Organization still recognizes onions for treating bronchitis, coughs, colds and asthma, as well as a measure of prevention in atherosclerosis.
In addition, onions have shown antibacterial properties in effective treatment of periodontal disease and bacteria in cavities. Used topically, onions can reduce inflammation from bee stings, cuts, blisters and boils. Today, studies are showing that onions are also able to address internal inflammation.
Some of the good stuff that onions have to offer seems to be concentrated in the outer layers. Utilizing as much of the onion as possible could increase the beneficial properties by as much as 20 percent. Cutting the onion just before use also increases the retention of some of these properties.
Why does cutting onions make people cry? When an onion is cut, cells are broken, and two enzymes combine to form an irritating gas. Ways to reduce the reaction include using a very sharp knife, chilling the onion before cutting, standing up so that your hands and eyes are far apart and standing near a window or fan to dissipate the gas. If your eyes are very sensitive to the gas, try wearing glasses or goggles while cutting. Cutting the onion under running water isn't recommended because beneficial enzymes and substances can be easily washed away.
And though onions aren't typically considered a "date" food, certain sects in India will not eat them because they are perceived as aphrodisiacs. So before saying, "Hold the onions," consider some of the benefits of adding a few slices to your sandwich.
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