Onions are truly a globally popular vegetable. The French love onion soup, pasta has onions as a side dish, the Greeks are the best at seasoning with onions, and Indians are especially fond of raw onions. In China, onions are also the most common vegetable eaten in many households, sautéed, chilled and stewed. In terms of nutrition, onions are indeed a very good health vegetable, not only rich in dietary fiber and minerals and vitamins. Moreover, onions contain the same spicy elements as onions and garlic, and have a strong odor that stimulates gastric acid secretion, improves appetite as well as sterilizes and prevents colds. What’s more, onions are rich in quercetin (the highest content in fruits and vegetables), which belongs to the flavonoid phytochemicals and has the effect of dilating blood vessels and promoting blood circulation, which is beneficial for reducing capillary fragility and preventing atherosclerosis. Therefore, for middle-aged people, onion is a healthy vegetable to be eaten properly and more often, which is helpful for controlling blood lipids and anti-aging. There are three kinds of onions in the market: purple-skinned, yellow-skinned and white-skinned onions. 1. Purple-skinned onions have the highest content of dietary fiber, various minerals and health components, but they have the strongest flavor and spiciest taste, and are best eaten fried. 2. White skin onions have the most tender and juicy flesh and the least spicy flavor, and can be eaten raw or as a salad. 3. Yellow-skinned onions are suitable for cooking seafood. Scrambled eggs with onions are good for middle-aged and elderly people, and fried cucumbers with onions are also good, light and refreshing. You can also learn from the French to make onion soup to drink, onion slices, oil hot onions will be fried on low heat until golden brown, the pan with the right amount of water, slow simmer for about an hour.