- Onion Basic Info.
- Onion Botanical Description.
- Onion Classification.
- Onion and History.
- Onions:Archeology and Registration.
- Onions and Phytochemicals.
- Onion Nutritional Analysis.
- Modern Research Update:Health Benefits.
- FAQ:Frequently Asked Questions of Onion.
- Onion Handlings:How to Select,Prepare,Store Onions?.
- Onion Trivia and Onion Cooking.
- Research Update:Allium cepa or common onion.
Modern Research Update:Health Benefits.:
Onions, like garlic, are members of the Allium family, and both are rich in powerful sulfur-containing compounds that are responsible for their pungent odors and for many of their health-promoting effects. Onions contain allyl propyl disulphide, while garlic is rich in allicin, diallyl disulphide, diallyl trisulfide and others. In addition, onions are very rich in chromium, a trace mineral that helps cells respond to insulin, plus vitamin C, and numerous flavonoids, most notably, quercitin.
Onion and anti-bacterial properties:
Onions have always held a place in folklore and folk medicine, but only recently have biochemists revealed their anti-bacterial properties, particularly against Helicobacter pylori, the ulcer-forming microorganism. Also, the more pungent onions exhibit strong anti-platelet and blood thinning activities in human blood, potentially adding protection against arteriosclerosis, cardiovascular disease, stroke, and heart attack. Other phytochemicals discovered in onions include disulfides, trisulfides, cepaene, and vinyl dithiins, each blessed with a variety of health-functional properties, including demonstrated anti-cancer and anti-microbial activities. The phytochemicals alliin (tasteless and odorless) and allicin (responsible for the garlic odor) are excellent antibiotics. Alliin is transformed into allicin when the onion (or garlic) plant tissue is crushed, releasing the enzyme allinase. Similar to oranges, onions are a good source of vitamin C, potassium, dietary fiber, vitamin B6, and folic acid. They also contain calcium, iron, have a high protein quality, are low in sodium, and contain no fat. Maybe you should reconsider the "hold" on those onions and think instead about an after-dinner mint or some raw parsley.
Onion and Aphrodisiacal tradition:
Early history of the onion is largely a mystery, but traces can be found in the archaeology of Central Asia, Iran, and Western Pakistan. Paleontologists believe that wild onions were a primary staple in man's prehistoric diet. Researchers agree that the onion has been in cultivation for more than 5,000 years and has long been valued because of easy storage, transportability, and convenience in cultivation. In ancient Egypt, onions were considered an object of worship, symbolizing eternity, and often accompanied the Pharaohs to their pyramid tombs. Onions are often found in early Egyptian paintings and hieroglyphics, and the aphrodisiacal properties of onions have been touted throughout the ancient cultures of the world.
Onion prevent gastric ulcers:
Studies have shown that consumption of onions may be beneficial for reduced risk of certain diseases. Consumption of onions may prevent gastric ulcers by scavenging free radicals and by preventing growth of the ulcer-forming microorganism, Heliobacter pylori.
Onion and strong anti-platelet activity:
University of Wisconsin-Madison researchers found that the more pungent onions exhibit strong anti-platelet activity.
Platelet aggregation is associated with atherosclerosis, cardiovascular disease, heart attack and stroke. A study in progress at the University of Wisconsin is determining the extent to which onion consumption and specific onion compounds affect the in vivo aggregation of blood platelets. "Using an in vivo model, we are beginning to investigate and, in some cases, confirm the potency of the onion as a blood thinner and platelet inhibitor. Onions may be among the vegetables that will be prized not only for their addition to our cuisine, but for their value-added health characteristics," said Irwin Goldman, Associate Professor of Horticulture, University of Wisconsin-Madison.
Onion increased bone mineral content:Boost Bone Health:
A recent study at the University of Bern in Switzerland showed that consumption of 1 g dry onion per day for 4 weeks increased bone mineral content in rats by more than 17% and mineral density by more than 13% compared to animals fed a control diet. This data suggests onion consumption has the potential to decrease the incidences of osteoporosis.
Milk isn't the only food that boosts bone health. Onions also help maintain healthy bones, suggests a study published in the March 2005 issue of the Journal of Agricultural and Food Chemistry.
A compound newly identified in onions with the long complex name of gamma-L-glutamyl-trans-S-1-propenyl-L-cysteine sulfoxide, GPCS, for short, inhibits the activity of osteoclasts (the cells that break down bone). The more GPCS given in this animal study, the more the bone resorptive action of osteoclasts was inhibited.
Onions may be especially beneficial for women, who are at increased risk for osteoporosis as they go through menopause. Fosamax (Alendronate), the drug typically prescribed to prevent excessive bone loss, works in a similar manner, by destroying osteoclasts, so they do not break down bone. Potential negative side effects of Fosamax include irritation of the upper gastrointestinal mucosa, acid regurgitation, esophageal ulcers and erosions. Potential negative side effects of eating onions: onion breath.
A -Glutamyl Peptide Isolated from Onion (Allium cepa L.) by Bioassay-Guided Fractionation Inhibits Resorption Activity of Osteoclasts:
One gram of onion added to the food of rats inhibits significantly (p less than 0.05) bone resorption as assessed by the urinary excretion of tritium released from bone of 9-week-old rats prelabeled with tritiated tetracycline from weeks 1 to 6. To isolate and identify the bone resorption inhibiting compound from onion, onion powder was extracted and the extract fractionated by column chromatography and medium-pressure liquid chromatography. A single active peak was finally obtained by semipreparative high-performance liquid chromatography. The biological activity of the various fractions was tested in vitro on the activity of osteoclasts to form resorption pits on a mineralized substrate. Medium, containing the various fractions or the pure compound, was added to osteoclasts of new-born rats settled on ivory slices. After 24 h of incubation, the tartrate-resistant acid phosphatase positive multinucleated cells, that is, osteoclasts, were counted. Subsequently, the number of resorption pits was determined. Activity was calculated as the ratio of resorption pits/osteoclasts and was compared to a negative control, that is, medium containing 10% fetal bovine serum only and to calcitonin (10-12 M) as a positive control. Finally, a single peak inhibited osteoclast activity significantly (p less than 0.05). The structure of this compound was elucidated with high-performance liquid chromatography-electrospray ionization-mass spectrometry, time-of-flight electrospray ionization mass spectrometry, and nuclear magnetic resonance spectroscopy. The single peak was identified as -L-glutamyl-trans-S-1-propenyl-L-cysteine sulfoxide (GPCS). It has a molecular mass of 306 Da and inhibits dose-dependently the resorption activity of osteoclasts, the minimal effective dose being ~2 mM. As no other peak displayed inhibitory activity, it likely is responsible for the effect of onion on bone resorption.
Anti-Cancer and Antimicrobial:Colon Cancer Prevention:
In addition to quercetin, onions contain the phytochemicals known as disulfides, trisulfides, cepaene, and vinyl dithiins. These compounds have a variety of health-functional properties, including anticancer and antimicrobial activities.
The regular use of onions, as little as two or more times per week, is associated with a significantly reduced risk of developing colon cancer. Onions contain a number of flavonoids, the most studied of which, quercitin, has been shown to halt the growth of tumors in animals and to protect colon cells from the damaging effects of certain cancer-causing substances. Cooking meats with onions may help reduce the amount of carcinogens produced when meat is cooked in certain ways.
Anti-Inflammatory and Anti-Bacterial Activity:
Several anti-inflammatory agents in onions render them helpful in reducing the severity of symptoms associated with inflammatory conditions such as the pain and swelling of osteo- and rheumatoid arthritis, the allergic inflammatory response of asthma, and the respiratory congestion associated with the common cold. Both onions and garlic contain compounds that inhibit lipoxygenase and cyclooxygenase (the enzymes that generate inflammatory prostaglandins and thromboxanes), thus markedly reducing inflammation. Onions' anti-inflammatory effects are due not only to their vitamin C and quercitin, but to other active components called isothiocyanates. These compounds work synergistically to spell relief from inflammation. In addition, quercitin and other flavonoids found in onions work with vitamin C to help kill harmful bacteria, making onions an especially good addition to soups and stews during cold and flu season.
Onions are also a source of vitamin C, potassium, dietary fiber and folic acid. They also contain calcium, iron and have a high protein quality (ratio of mg amino acid/gram protein). Onions are low in sodium and contain no fat.
The higher the intake of onion, the lower the level of glucose found during oral or intravenous glucose tolerance tests. Experimental and clinical evidence suggests that allyl propyl disulfide is responsible for this effect and lowers blood sugar levels by increasing the amount of free insulin available. Allyl propyl disulfide does this by competing with insulin, which is also a disulphide, to occupy the sites in the liver where insulin is inactivated. This results is an increase in the amount of insulin available to usher glucose into cells causing a lowering of blood sugar.
In addition, onions are a very good source of chromium, the mineral component in glucose tolerance factor, a molecule that helps cells respond appropriately to insulin. Clinical studies of diabetics have shown that chromium can decrease fasting blood glucose levels, improve glucose tolerance, lower insulin levels, and decrease total cholesterol and triglyceride levels, while increasing good HDL-cholesterol levels. Marginal chromium deficiency is common in the United States, not surprising since chromium levels are depleted by consuming refined sugars, white flour products, and lack of exercise. One cup of raw onion contains almost 20% of the Daily Value for this important trace mineral.
The regular consumption of onions has, like garlic, been shown to lower high cholesterol levels and high blood pressure, both of which help prevent atherosclerosis and diabetic heart disease, and reduce the risk of heart attack or stroke. These beneficial effects are likely due to onions' sulfur compounds, its chromium and its vitamin B6, which helps prevent heart disease by lowering high homocysteine levels, another significant risk factor for heart attack and stroke.
Onions have been singled out as one of the small number of vegetables and fruits that contributed to the significant reduction in heart disease risk seen in a recent meta-analysis of seven prospective studies. Of the more than 100,000 individuals who participated in these studies, those who diets most frequently included onions, tea, apples and broccoli,the richest sources of flavonoids,gained a 20% reduction in their risk of heart disease.
Onion compound may help fight osteoporosis:
Besides adding flavor to food, onions also may be good for your bones. Researchers at the University of Bern in Switzerland have identified a compound in the popular vegetable that appears to decrease bone loss in laboratory studies using rat bone cells. Although further studies are needed, the current study suggests that eating onions might help prevent bone loss and osteoporosis, a disease which predominately affects older women. The disease results in an estimated $17 billion in medical costs in the United States.
In the current study, the researchers analyzed the active chemical components of white onions and found that the most likely compound responsible for the decreased bone loss was a peptide called GPCS. The researchers then obtained a group of isolated bone cells from newborn rats and exposed the cells to parathyroid hormone to stimulate bone loss, then exposed some of the treated cells to GPCS. Treatment with GPCS significantly inhibited the loss of bone minerals, including calcium, when compared to cells that were not exposed to GPCS, according to the researchers. Additional studies are needed to determine whether GPCS will have a similar effect in people, how much onion or GPCS is needed for a positive effect on bone health, and to determine the mechanism of action of GPCS on bone cells, the researchers say.
If you want to avoid stooped shoulders, fragile hips or cracked ribs as you age, embrace the lowly onion in your diet. White varieties, in particular, could be a boon to those facing osteoporosis because of GPCS, part of the group of molecules called peptides that help link various amino acids in a defined order.
Don't wait until you're a grandma to peel yourself an onion. WHO, the World Health Organization, lists osteoporosis second only to heart disease as the major healthcare problem in the world, affecting more than 30 million people, most of them women.
To determine the effectiveness of GPCS, Researchers at the University of Bern isolated bone cells from newborn rats and treated those cells to parathyroid hormone in order to stimulate bone loss. Some of these cells were exposed to GPCS and others were left unexposed. The conclusion was that the GPCS "significantly inhibited the loss of bone minerals, including calcium."
This research will continue with experiments on humans to determine whether GPCS will have a similar reaction and how much is needed for bone health.
This is not the first time that onions have been studied for their health benefits. Cornell University researchers reported that stronger flavored onions are better cancer fighters than mild ones, particularly New York bold, western yellow, and shallots, which inhibited the growth of cancer cells in the colon and liver.
In addition to peptides like GPCS, onions contain flavonoids/polyphenols called quercetin which is known to prevent various diseases particularly certain cancers and cardiovascular disease, making onions an ingredient in the recipe against heart disease which kills about 17 million people per year throughout the world.
Fortunately, onion producers are already up to the task of helping people add more of the veggie to our diet. An easy to grow vegetable, onion production has increased at least 25% over the past 10 years with world production currently at 14 million tons, second only to tomatoes.
The pungent odor and awesome strength of the onion was a mystery to ancient man. An old Turkish legend explains it rather profoundly. It tells that when Satan was thrown out of heaven, garlic sprouted where he first placed his left foot, and onions grew where he placed his right foot.
When plague raged throughout Eastern Europe, people thought it was caused by evil spirits, and they used onions and garlic as good luck charms to chase off those spirits.
People hung strands of onions and garlic from their doorways, their windows, and even around their necks to keep the vampires away.
Some cultures thought of the onion family as having sexual powers. Even today, a Middle Eastern bridegroom wears a clove of garlic in his lapel to assure himself of a successful wedding night.
In sixth century India onions were used as a diuretic. They were also considered beneficial for the heart, the eyes, and the joints.
During Colonial times in the U.S., a slice or two of wild onions was thought to be a cure for the measles.
In Chinese medicine, globe onions (allium cepa) are said to calm the liver, moisten the intestines, and benefit the lungs. Raw onions are prescribed for constipation, for lowering high blood pressure, and for healing wounds or ulcers of the skin. Spring onions, or scallions (allium fistulosum), are used to induce sweating. One application for the common cold is to take 20 spring onions and simmer them with rice to make porridge. Add a little vinegar and eat while it is warm. Then wrap yourself up in blankets to induce sweating.
Some health studies have shown raw onions to be effective in lowering overall cholesterol while raising HDLs, the good cholesterol. Additionally, onions kill infectious bacteria, help to control blood sugar, aid in dissolving blood clots, and help to prevent cancer.
At the University of California at Berkeley, researchers found that yellow and red onions, along with shallots, contain quercetin, a powerful antioxidant that acts as an anti-cancer agent to block the formation of cancer cells. One and one-half to three and one-half ounces of raw onions eaten regularly contain enough quercetin to offer cancer protection. White onions lack this antioxidant.
Researcher Terrance Leighton, Ph.D. of the University of California at Berkeley also learned that quercetin deactivates the growth of estrogen-sensitive cells often found to cause breast cancer.
Asthma sufferers may also benefit from a hearty dose of onions. Researchers discovered a sulfur compound contained in onions that can prevent the biochemical chain reaction that leads to asthma attacks.
Selenium, a trace mineral found in onions and garlic, has also demonstrated anti-cancer abilities.
Uses in Foods:
Though the onion has not yet distinguished itself in American cuisine, it certainly has in other countries. The British love their stuffed onions. The French created onion soup, a universal favorite. The gourmet onion tart developed in Alsace, a northeastern region of France. Bhaji, a flavorful onion fritter, comes from India. A soubise an onion sauce or puree, also came from the cuisine of France and frequently accompanied lamb or mutton dishes.
Onion-skins are usually considered the discards of the vegetable, but not always. Some people have discovered their powerful ability to lend a rich golden color to soups and to dye yarn and fabric. The Greeks traditionally use red onion-skins to dye their Easter eggs a bright pinkish red.
If you're counting calories, you might want to take advantage of the low-calorie content of sweet raw onions. With 1/2-cup of chopped raw onions, you'll tally up a mere 30 calories. If you cook those same onions, you're up to a only 46 calories.
On the protein scene, 1/2-cup of cooked onions touts 1.4 gms, while the raw have .9 gms. The fat content of this quantity barely registers at .2 gm for cooked onions, and .1 gm for raw.
The folic acid content offers a surprising 15.8 mcg for the cooked, and 15.2 mcg for raw.
Both raw and cooked onions have trace amounts of B vitamins, iron, and zinc but stand out with potassium, magnesium, and calcium. While potassium registers 174.3 mg for 1/2-cup cooked onions, raw onions come in at 125.6 mg. Vitamin C, though not record-breaking, delivers 5.5 mg and 5.1 mg respectively.
Scallions pack a powerful punch of vitamin A with 193 IU for 1/2 C. raw with their tops. Folic acid registers 32.0 mcg, and vitamin C offers 9.4 mg.
Be sure to include scallions in your salads frequently for their high calcium, potassium, and magnesium scores.
And don't forget the powerful antioxidants delivered by onions. Quercetin has anti-cancer agents.
Culinary and medicinal uses:
Onions are available in fresh, frozen, canned, and dehydrated forms. Onions can be used, usually chopped or sliced, in almost every type of non-dessert food, including cooked foods and fresh salads, and as a spicy garnish; they are rarely eaten on their own, but usually act as accompaniment to the main course.
Depending on the variety, an onion can be sharp and pungent or mild and even sweet.
Chopped, it is one of the three vegetables considered the holy trinity of Louisiana Creole and Cajun cuisine.
Cocktail onions, or pickled pearl onions, are used to garnish drinks such as martinis.
They appear to be at least somewhat effective against colds, heart disease, diabetes, and other diseases and contain antiinflammatory, anticholesterol, and anticancer components.
In many parts of the underdeveloped world, onions are used to heal blisters and boils. In the United States, products that contain onion extract (such as "Mederma") are used in the treatment of topical scars.
In 2005, a poll of 2,000 people revealed that the onion was Britain's favourite culinary vegetable.
- 1.Onion,Classifications,Tradition,History,Magical,Modern Updated.
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