Rich in Vitamin C, sulphuric compounds, flavonoids, and other phytochemicals, an onion a day may help keep the doctor away. Its sulphur-containing compounds are responsible for its pungent odour.
Onions are healthy whether they’re raw or cooked, though raw onions have higher levels of organic sulphur compounds that provide many benefits.
In fact, the World Health Organisation (WHO) supports
the use of onions for the treatment of poor appetite and to prevent atherosclerosis. It also recognises onion extract providing relief in the treatment of coughs and colds, asthma and bronchitis.
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.
Some health benefits of onions are as given below:
Onions encourage a healthy heart in many ways, including lowering blood pressure and lowering heart attack risk. A study in 2007 indicated that Quercetin, the compound most commonly associated with onions, may reduce blood pressure by an average of five millimetres of mercury.
The study, published in the Journal of Nutrition found a daily 730 milligram supplement of Quercetin led to significant reductions in the blood pressure of 22 people with high blood pressure (hypertension).
Moreover, researchers suggested in a 2002 study in the journal, Thrombosis Research, that it is a natural blood thinner that can prevent blood platelets from aggregating. When platelets cluster, the risk for heart attack or stroke increases.
High intake of garlic and onions was associated with significantly reduced risks of a wide-range of cancers. A large epidemiological study that involved almost 10,000 people with different types of cancers from Italy showed an inverse association between the frequency of use of allium vegetables like onion and the risk of several common cancers. This 2006 study was published in the American Journal of Clinical Nutrition.
Also, the European Prospective Investigation into Cancer and Nutrition (EPIC), which followed 521,457 subjects in 10 European countries, reported that an increase in the intake of onions by 10 grams per day was associated with a 30 per cent reduction in the risk of intestinal gastric cancer.
In another study, increased intakes of onions, researchers report in the British Journal of Nutrition, may reduce the risk of developing cancer of the colon by 50 per cent.
Consumption of garlic and onions may reduce the incidence of cholesterol gallstone formation by as much as 40 per cent. Consumption of a cholesterol-rich diet led to the formation of cholesterol gallstones (CGS), but supplementation of this diet with onion reduced the incidence of the gallstones, according to findings published online in the British Journal of Nutrition.
Protect against osteoarthritis
Human studies have shown that onion can help increase our bone density and may be of special benefit to women of menopausal age who are experiencing loss of bone density due to osteoarthritis.
A research from King’s College London, published in the BMC Musculoskeletal Disorders, suggested a potential for using specific beneficial compounds found in onion to develop treatments for the condition.
Osteoarthritis is the most common disabling joint condition affecting elderly adults, and has a significant impact on adults of working age. The cause, however, remains unclear.
The fibre in onions promotes good digestion and promotes good bacteria growth in the intestines. A 2005 study in Clinical Gastroenterology and Hepatology found that oligofructose a special type of soluble fibre, which promotes good bacteria growth in your intestines, may help prevent and treat types of diarrhoea.
Boost sexual performance
Fresh onion juice has aphrodisiac activity and may enhance male sexual libido and performance. Researchers at Jordan University of Science and Technology were searching for a natural way to help men with impotence problems to have sex. When they discovered that fresh onion juice increases testosterone concentrations in the blood, suggesting that onion may even help against impotence. Testosterone is the male sex hormone responsible for enhancing sexual libido and potency.
According to the researchers in the 2014 edition of the journal, Experimental Biology and Medicine, “The present study supports the hypothesis that Allium cepa has aphrodisiac activity and may enhance male sexual libido and performance”
Boost immunity against flu
Onions may boost the immune system and protect against flu. Researchers from the University of South Carolina and Clemson University report that stressful exercise increased the mice’s susceptibility to flu, but quercetin present in onion was found to negate these effects.
The findings published in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, indicated that onion could help reduce illnesses in people undergoing strenuous extensive exercise, soldiers and others undergoing difficult training regimens, as well as people under psychological stress.
Onion bulb extract could reduce high blood glucose and cholesterol levels. In a study presented at the Endocrine Society’s 97th annual meeting in San Diego, when the rats were given onion bulb extract – in combination with metformin, their blood glucose and cholesterol levels were significantly reduced.
Anthony Ojieh, lead investigator, said: “Onion is cheap and available and has been used as a nutritional supplement. It has the potential for use in treating patients with diabetes.
Also, Dr Jevas C. Ozougwu at the Physiology and Biomedical Research Unit, Department of Zoology, University of Nigeria, Nsukka, Enugu State, in his assessment of onion’s benefit for diabetes said dietary supplementation of onions compounds in diabetics may help to reduce over dependence on drug.