Onion (scientific name: Allium cepa), also known as the ball onion, onion, jade onion, onion, Dutch onion, skin teeth, etc., . Liliaceae, onion genus biennial herb. Onion contains prostaglandin A, which can reduce peripheral vascular resistance and blood viscosity, and can be used to lower blood pressure, refresh the mind, relieve stress and prevent colds. In addition, onions can also remove oxygen free radicals in the body, enhance metabolism, anti-aging, prevention of osteoporosis, is suitable for middle-aged and elderly health food.
Onions are widely distributed in China, cultivated throughout the north and south, and are one of the main vegetables in China. China's onion origin mainly in Fujian, Shandong, Gansu, Inner Mongolia, Xinjiang and other places.
Onions are biennial or perennial herbs. Root string-like, thick green cylindrical hollow leaves, the surface has a waxy; leaf sheaths fat scale-like, dense in the shortened stem around the formation of bulbs (commonly known as onion head); umbels, white small flowers; capsule. The outer edge of the rhizome is covered with a thin layer of skin (white, yellow or red), and inside is a layer of flesh, usually white or yellowish.
The onion is a very common and inexpensive home remedy. Its flesh is tender, juicy and spicy with a mild flavor, good quality and suitable for raw food. Native to western Asia, in China are cultivated throughout the four seasons are available. Onions for food for the underground parts of the fat bulb (i.e., onion head). In foreign countries, it is known as the "Queen of vegetables", high nutritional value.
Onions are rich in nutrients, not only rich in potassium, vitamin C, folic acid, zinc, selenium, and fiber and other nutrients, but also two special nutrients - quercetin and prostaglandin A. These two special nutrients, so that the onion has a lot of other foods irreplaceable health effects:
1, prevent cancer
The onion is the most important food in the world.
1, to prevent cancer
Onion cancer prevention effect from its rich selenium and quercetin. Selenium is an antioxidant that stimulates the body's immune response, thereby inhibiting the division and growth of cancer cells, while also reducing the toxicity of carcinogens. Quercetin, on the other hand, inhibits cancer-causing cell activity and stops cancer cell growth. A survey showed that often eat onions than do not eat the chance of people suffering from stomach cancer 25% less, due to stomach cancer deaths 30% less.
2, the maintenance of cardiovascular health
Onions are known to be the only vegetables containing prostaglandin A. Prostaglandin A can dilate blood vessels. Prostaglandin A can dilate blood vessels, reduce blood viscosity, which will produce lower blood pressure, increase coronary blood flow, prevent thrombosis effect. Onions are rich in quercetin, which is highly bioavailable, and scientists have reported that quercetin may help prevent the oxidation of low-density lipoproteins (LDL), for atherosclerosis, can provide important protection.
3, stimulate appetite, help digestion
Onions contain onion garlic chorine, has a strong aroma, processing due to the pungent odor and often make people cry. It is this special flavor can stimulate gastric acid secretion, enhance appetite. Animal experiments have also proved that onions can improve gastrointestinal tension, promote gastrointestinal peristalsis, thus playing the role of appetizing, atrophic gastritis, gastric dynamics, dyspepsia and other causes of loss of appetite has a significant effect.
4, bactericidal, anti-cold
Onions contain phytobactericides such as allicin, have a strong bactericidal ability, can effectively resist the influenza virus, prevent colds. This phytochemicals through the respiratory tract, urinary tract, sweat glands, can stimulate the cell walls of these locations to secrete, so there are expectorant, diuretic, sweating and antibacterial antiseptic effect.
Suggestions: Purple onions are more nutritious
According to the skin color, onions can be divided into white, yellow and purple skin three. From the point of view of nutritional value assessment, the purple skin onion nutrition is a little better. This is because purple-skinned onions have a more pungent flavor compared to the other two varieties of onions, which means they contain more allicin. In addition, the purple-skinned part of the purple-skinned onion contains more quercetin.
5, onions on the "rich disease" has a very good prevention
For external wind-cold headache, nasal congestion, heavy body, cold, fever, no sweat. Coca-Cola 500 ml, add onion 100g shredded, ginger 50g shredded, a small amount of brown sugar, slow fire boil about 5min, drink while hot.
In recent years, it was found that, in addition, onions can effectively prevent "rich people's disease", onions contain yellow urobutyric acid, which can make the cells better use of sugar, thereby reducing blood sugar. Onions also contain prostaglandins, which can expand blood vessels, reduce peripheral vascular resistance, promote sodium excretion, so that the increase in blood pressure down.
Onions contain a small amount of cotton seed sugar is a functional oligosaccharide, is the onion against harsh environments (cold, drought) of the important sugar. Cotton seed sugar can proliferate human bifidobacteria, play a laxative, lipid and blood pressure.
The onion also contains diallyl sulfide, which has the function of preventing vascular sclerosis and lowering blood lipids. Onions can also be measured in the quercetin-containing cortical substances, in flavanol ketone-induced formation of ligands have diuretic and decongestive effect, these are beneficial to the prevention of obesity, hyperlipidemia, atherosclerosis and other diseases, and the onion's drying and detoxification function is consistent.
6, other medicinal effects
(1) contained prostaglandin A is a strong vasodilator, can fight against catecholamines and other pressurizing substances, to promote the excretion of sodium salts, there is a role in lowering blood pressure;
(2) contains sulfide can promote fat metabolism, with lowering of blood lipids, antiatherosclerosis effect;
(3) onion flavonoids can reduce the platelet Viscosity, eating onions can prevent blood clots, reduce the probability of heart attack and cerebral thrombosis;
(4) onions contain organic substances similar to the hypoglycemic drug methylsulfonylurea, which can significantly reduce blood glucose levels;
(5) sulfide, selenium, and other trace elements contained in the inhibition of gastric cancer, esophageal cancer, colon cancer, breast cancer, etc.;
(6) volatile oils contained in the onion can be helpful to the old man to improve his sex life, the old man can eat onions. (7) onions can improve the bone density of experimental rats, eating onions can prevent osteoporosis;
(8) onions are rich in vitamin C, niacin, they can promote the formation of intercellular matrix and damage to the repair of the cell, so that the skin is smooth, red and elastic, with a cosmetic effect. Containing sulfur, vitamin E, etc., can prevent unsaturated fatty acids to generate lipofuscin pigment, can prevent age spots.
It should be noted that the following categories of people are not suitable for the use of onions
1, patients with skin diseases should not eat onions.
2, people with eye diseases can not eat onions, the condition will be aggravated.
3, patients suffering from gastrointestinal diseases can not eat onions, which can easily lead to aggravation.