The onion has been used as an ingredient in various dishes for thousands of years by many cultures around the world. World onion production is steadily increasing so that onion is now the second most important horticultural crop after tomatoes. Onions (Allium cepa) belong to the lily family, the same family as garlic, leeks, chives, scallions and shallots. There are over 600 species of Allium. The plants can be used as ornamentals, vegetables, spices, or as medicine. Onion is characterized by its rich content of thiosulfinates, sulfides, sulfoxides, and other odoriferous sulfur compounds. The cysteine sulfoxides are primarily responsible for the onion flavor and produce the eye-irritating compounds that induce lacrimation. The thiosulfinates exhibit antimicrobial properties. Onion is effective against many bacteria including Bacillus subtilis, Salmonella, and E. coli.
- Onion has both culinary and non culinary uses.
- Onions have particularly large cells that are readily observed at low magnification; consequently, onion tissue is frequently used in science education for demonstrating microscope usage.
- Onion skins have been used for dye.
- Onions have a variety of medicinal effects. Early American settlers used wild onions to treat colds, coughs, and asthma, and to repel insects. In Chinese medicine, onions have been used to treat angina, coughs, bacterial infections, and breathing problems.
Onion is a powerful anti-septic that is rich in Vitamin A ,Vitamin B,Vitamin C. It is a potent source of Calcium, Phosphorus, Potassium, Carbohydrates, Protein, Calories, iron and dietary fiber.
The World Health Organization (WHO) supports the use of onions for the treatment of poor appetite and to prevent atherosclerosis. In addition, onion extracts are recognized by WHO for providing relief in the treatment of coughs and colds, asthma and bronchitis. Onions are known to decrease bronchial spasms. An onion extract was found to decrease allergy-induced bronchial constriction in asthma patients.
Onions are a rich source of flavonoids, substances known to provide protection against cardiovascular disease. Onions are also natural anticlotting agents since they possess substances with fibrinolytic activity and can suppress platelet-clumping. The anticlotting effect of onions closely correlates with their sulfur content. Just by eating half a medium raw onion daily can significantly lower cholesterol and help prevent heart attacks.
Whether you eat it raw or cooked, onions help to lower blood pressure naturally. It also thins the blood, dissolve blood clots and clear the blood of unhealthy fats.
Onion extracts, rich in a variety of sulfides, provide some protection against tumor growth. Fructo-oligosaccharides in onions stimulate the growth of good bacteria in the colon and help reduce the risk of tumors developing in the colon.
Add plenty onion in your cooking to help relieve chronic constipation and flatulence.
The high content of iron in onion makes it beneficial for the treatment of anemia.