Onions are both flavorful and aromatic; and, they pack a nutritional punch. They are low in calories, a good source of chromium, vitamin C and fiber, and are low in sodium. Onions are also fat free and do not add cholesterol to your body. They even have the ability to lower bad cholesterol, low density lipoprotein, or LDL levels while raising good cholesterol, high density lipoprotein, or HDL, all because of the nutrient chromium.
History
Onions have been around for thousands of years. According to the World's Healthiest Foods website, they are native to Asia and the Middle East and were highly regarded by the Egyptians. The Egyptians often used onions as currency and even buried their kings with onions. Onions were used for medicinal purposes in India and were popular with ancient Greeks and Romans. Onions were inexpensive and their pungent odor made them desirable as a way to add flavor to many dishes.
Types
There are many varieties of onions, from sweet to spicy. They range in size and color and are grown in either warm or cold climates. Warmer climate onions are sweet onions, classified as storage onions. Colder climate onions are the more pungent onions, classified as white, yellow or red. According to the National Onion Association, onions contain quercetin, an antioxidant compound. These compounds help to fight free radicals, slowing damage to cells. Quercetin also helps to lower LDL cholesterol levels. Onions also contain organosulfur compounds, which have been shown to lower cholesterol levels as well.
High Density Lipoprotein
Cholesterol comes from the body or food, and is classified as either "good" or "bad." The "bad" cholesterol is low density lipoprotein, while the "good" cholesterol is high density lipoprotein. HDL cholesterol helps to rid excess cholesterol from the body. It traps the cholesterol and brings it to the liver where it is broken down and eventually eliminated from the body. It helps to keep LDL cholesterol from binding to artery walls.
Studies
According to the World's Healthiest Foods website, onions are high in sulfur-containing compounds and chromium, which have been linked to health-promoting effects. The Lowering Cholesterol website reports that a study at the King Abdulaziz University in 2000 showed that 44 adults given 200mg of chromium had increased levels of high density lipoprotein cholesterol after 8 weeks. Another study done at the University of North Carolina showed a 16 percent increase in high density lipoprotein cholesterol levels in 63 men suffering from hypertension, being treated with beta-blockers when chromium supplements were added.
Considerations
A general rule is the the more pungent the onion, the more health benefits it delivers. Onions can cause you to tear up when you cut them because the compound allyl sulfate is produced when sulfur compounds released by the onion are exposed to air, according to the World's Healthiest Foods website. Onions are not known to cause allergic reactions; their outer layer of skin helps to protect them from contaminants from pesticides.
