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Raw onion fights hypertension, prevents breast cancer

Onions contain beneficial sulphur compounds which can be destroyed by cooking. But many people do not know this fact. Even those who often cook with onion in the kitchen are not aware that allicin, an important bioactive nutrient in onion, is completely neutralised during food preparation process, reports Seye Adeniyi.

IF you belong to the category of people who do not like to cook with onions or who do not like to eat onions at all, you had better change your mind. Also, if you are one of those who do not like the odour of onion, garlic as well as other plants like leeks, chives, scallions - all of which are members of the allium family, it is advisable you have a rethink or change your perception about these plants.

In fact, the belief of many people is that onion has no other place or “home” than kitchen while some people cannot eat food or meal prepared with onion.

However, for those who like onion and can even eat it raw, scientists have advised them, to continue to be onion lovers because they are on the path to good health.

Though it is no longer news to many people that garlic prevents high blood pressure, however, the latest information emanating from scientists and nutritionists who have been working on different fruits and vegetables to know their disease-fighting chemicals/compounds and how such chemicals can be extracted and formulated into drugs reveals that onions should not only be regarded as a cooking ingredient but also a good drug because it can prevent and fight certain diseases especially cancers as well as mount road blocks against certain heart diseases like (arteriosclerosis (hardening of the arteries), bronchitis, dry or stubborn cough and most importantly, prevent irregular heart beat and abnormal blood pressure, that is, both hypotension and hypertension.

Scientists, in their latest study on onion and its effects on health, also showed that regular consumption of onion enhances proper function of the arteries and if used appropriately can even treat stubborn cough when combined with pure honey.

Onion (Allium cepa), they however advised, should not be relegated or confined to the kitchen alone, rather, this important cooking ingredient also deserves a space on our drug shelves and as such they advised people to be lovers of onion.

Moreover, the researchers sounded a note of warning to onion lovers and eaters, adding that it is only raw (uncooked) onion that is medicinal and not the cooked types as it is the belief of some people. It was further reported that onion is a natural drug which does not like heat, therefore, those who are in the habit of cooking onion with other foods believing that they will get the best in terms of nutrition and health are only deceiving themselves as they cannot benefit much from this cooking practices which have even become a tradition or habit in many homes, especially in Africa where people believe that to get the best out of any vegetable, it must be cooked until such vegetable “submits ”.

Researchers at the University of Utah who carried out the study, examined the health values in onion and discovered that quercetin, the compound most commonly associated with onions, may reduce blood pressure by an average of five millimeters of mercury (Hg) especially if eaten raw.

The study, which was said to be the first to report the blood pressure-lowering activities of this flavonol, found out that a daily 730 milligramme supplement of quercetin led to significant reductions in the blood pressure of 22 people with high blood pressure (hypertension).

Hypertension which is defined as having a systolic and diastolic blood pressure (BP) greater than 140 and 90 mmHg, affects about 600 million people worldwide and it is also associated with over seven million deaths.

The randomised, double-blind, placebo-controlled, crosssover study, considered to be the gold-standard for experimental interventions, added to an ever-growing body of reported health benefit of a compound called quercetin found in onion. Also, the flavonol (quercetin) have been previously documented to reduce the risk of developing certain cancers.

The researchers at the University of Utah did a comprehensive study on onion by recruiting 19 men and women with pre-hypertension (average blood pressure (BP) 137/86 mmHg) and 22 hypertensive people (average blood pressure (BP) 148/96 mmHg) for the study. The subjects were randomly assigned to receive a daily supplement of quercetin (730mg USANA Health Sciences) or placebo for 28 days.

Randi Edwards, the lead author and one of the researchers further reported that the hypertensive that received the quercetin supplement experienced remarkable reduction in systolic and diastolic BP of seven and five mmHg respectively, compared to placebo. However, no blood pressure (BP) changes were observed in the pre-hypertensive as a result of either intervention.

Although no mechanistic study was performed by the researchers, they suggested that flavonoid limit the production of angiotensin II, a molecule that constricts blood vessels (vasoconstrictor) leading to an increase in blood pressure.

Onion is one of the oldest herbs cultivated and apart from its nutritional value, its stalks also have power to prevent and treat stomach disease.

Onion is a stimulant and mild counter irritant. Another good thing about onion is that crushed raw onion can be applied on the forehead to get quick relief from headaches. Red small onions can also be used as an expectorant. If onion is sliced and soaked in pure honey say for 2 to 3 days, it can be used to treat dry, stubborn cough that has defied all orthodox cough syrups.

It should be emphasised that it is only raw, uncooked onion that can do all these as cooked type cannot treat illnesses and diseases. Crushed small onion can also be mixed with sugar candy to help in softening phlegm and prevent cough recurrence.

Regular eating of raw onion also helps to reduce cholesterol level in the obese or overweight people because it increases the level of high density lipo-proteins. Apart from helping to prevent coronary heart disease, artheriosclerosis, thrombosis and high blood pressure, onions are also beneficial in the treatment of urinary tract disorders. For example, onion tackles burning sensations that is often experienced while passing urine if there is a staphylococus induced infection. Also one can get quick relief from unnecessary urine retention in the bladder by taking onion-sugar mixture.

Sulphur compound present in raw onion will also help to prevent the growth of cancer cells. Likewise, onion is also good and effective in the treatment of anaemia, bleeding piles, stomach aches, while the juice can be applied externally as an antiseptic. It also prevents and can treat teeth disorders. The Indians, Chinese and the Egyptians know and appreciate the medicinal value of onion as well as garlic.

Onion stalks is also a useful herbal materials especially in the treatment of severe anaemia. Onion produces strong odour and pungent taste and contains essential oils and organic sulfides. The principal chemical constituents in onion is the sulphur-containing volatile oil called allyl propyl disulfide. This is a chemical that is responsible for the irritation and tears that do come out of one’s eyes when cooking with onion. It should be noted that cooked onion does not possess all the above values. For instance, if uncooked or raw onion is eaten, the volatile oil is excreted through the lungs and saliva, thus giving a characteristic odour to the breathing. Cooked onions however does not possess the characteristic odour because this volatile oil in onion evaporates when exposed to heat.

According to the information supplied by the National Centre for Complementary Medicine, raw or uncooked onion as well as garlic show the progression of atherosclerosis and fight stomach cancer. Raw onion consumption also helps in preventing blood clots. Organic sulphide compounds like methylallyl sulfide as well as the sulphur-containing amino-acids (i.e. s-allycysteine) help in preventing or lowering cholesterol.

Onion also helps in maintaining the elasticity (flexibility) of the major arteries that pump blood from the heart to the rest of the body (i.e. the aorta). It also helps in reducing the blood’s viscousity (stickiness), thus preventing blood clotting.

Other medicinal values of eating raw onion are as follows:
Compounds in onion can decrease cholesterol production by up to 60 per cent. There is a specific constituent of onion that decreases cholesterol production in the liver by as much as 60 per cent. A researcher, Dr. Yu-Yen Yen, once said that the cholesterols - lowering effects of garlic and onion are likely to be from inhibition of the cholesterol synthesis in the liver by a combination of water-soluble sulphur containing compounds that onion contains.

• Onions according to the Journal of the American Diatetic Association (ADA) contains phenolic phytochemicals. These biologically-active compounds possesses an important disease-preventing property. The high levels of phenolic flavonol of onion also make it a strong disease fighter. Unfortunately, cooking fresh onions could destroy as much as 82 per cent of these important nutrients.

• Onions significantly reduces the risk of breast cancer. This was also confirmed in the European Journal of Epidemiology of December, 1998, which showed that the greater the consumption of both raw onions and garlic, the lower the risk of developing breast cancer.

Asked to comment about the healing power of onions, naturopaths like Drs. Nurudeen Animasaun, Kayode Oniyelu, and Olufemi Adekunle, all agreed on the health values and benefits of onion. The naturopaths were of the consensus opinion that even our nose and eyes do recognise and appreciate the healing power of onions. According to Dr. Nurudeen Animasaun, “the minute that pungent odour of onion or garlic tickles your nostrils, the whole body system immediately reacts and the brain react by telling you that a powerful drug had been perceived. The body also reacts by telling you that you are dealing with something strong and powerful. It is the sulphur-rich smell that can boost your long-term well-being,” he stated.


Publication date: 3/21/2008


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