Onions are warm and sweet. It has expectorant, diuretic, stomach invigorating, intestine moistening, detoxification and insecticidal functions, and onion extract also has bactericidal effect, which can improve gastrointestinal tension and increase digestive tract secretion. Nutritional value of onion 1. Onion has the function of dispersing wind and cold because onion bulbs and leaves contain an oily volatile called propylene sulfide. 2. Onions are nutritious and spicy. It can stimulate the secretion of stomach, intestine and digestive gland, stimulate appetite and promote digestion. Onion contains no fat, and its essential oil contains a mixture of sulfur-containing compounds that can lower cholesterol. 3. Onion is the only one that contains prostaglandin A at present. Prostaglandin A can dilate blood vessels and reduce blood viscosity, so it can lower blood pressure, reduce peripheral blood vessels, increase coronary blood flow and prevent thrombosis. It can resist the action of pressor substances such as catecholamine in human body, and promote the excretion of sodium salt, thus lowering blood pressure. 4. Onion has a certain refreshing effect, which can help cells make better use of glucose, reduce blood sugar and supply heat energy to brain cells, and is a good diet vegetable for patients with diabetes and listlessness. 5. Onion contains a substance called phlogiston 9, which is one of the most effective natural anticancer substances known at present. It can prevent the variation of biochemical mechanism in the body and control the growth of cancer cells, thus having anti-cancer and anti-cancer effects. 6. Selenium, a trace element contained in onion, is a strong antioxidant, which can eliminate free radicals in the body, enhance the vitality and metabolic ability of cells, and has the effects of preventing cancer and resisting aging.

7. Onions also contain a certain amount of calcium. In recent years, Swiss scientists have found that eating onions often can improve bone density and help prevent osteoporosis.