Goodness of onions
by Dr. Harold Gunatillake
Just as there is no pub with no beer, there is no kitchen without onions, with its pungent appetizing smell in the air, and the taste of onion filling out the flavours of any Asian cuisine. As a fact no Asian cooking is possible without a stock of onions at hand. Any house wife will go crazy with no onions for cooking.
The word onion is derived from the Latin word unio for "one", because the plant produces one bulb unlike its cousin garlic which produces many bulbs. The word union comes from the same Latin word, meaning unity like the compact layers of the cut onion.
Onions are mentioned in the Old Testament. Egyptians used it with garlic as a funerary gift to the Pharaohs, and were placed in their tombs. Onions were prescribed by ancient ayurvedic doctors for just about any ailment. The onions originated in Asia, the first written record appeared in Mesopotamia (now part of Iraq) dated 2400BC. It was then eaten raw by the poor people with a chunk of bread.
The raw onion is full of nutrients. Contains chromium up to 20%; Vitamin C 18%, dietary fibre 12%, manganese 10%, molybdenum 10%, Vitamin B6 8%, tryptophen 8%, folate 8%, potassium 7%, phosphorus 5%, copper 5% and 60 Calories in a cup of serving.
Health benefits are many in onions, and you got to eat at least one bulb freshly cut, daily with your meals to achieve the benefits. So what do you do for the smell? Brush your teeth immediately, which you normally should do, and a chewing gum will help.
Onions, like garlic belongs to the Allium family, and both are rich in powerful sulfur-containing compounds that are responsible for their pungent odors and for many other health promoting effects. Onions contain allyl propyl disulphide, while garlic contains allicin, diallyl disulphide, and others. Also, as mentioned above onions are rich in chromium, much more than in garlic, which is beneficial in enhancing insulin activity, secreted in the pancreas.
Blood sugar — Lowering effects
Diabetics should increase raw onion intake daily. It has been shown experimentally that allyl propyl disulfide in onions, is responsible for this effect on the blood sugar levels by increasing the amount of free insulin available. As insulin itself is a disulfide, the allyl propyl disulfide competes with insulin sites in the liver, where insulin is inactivated, thereby leaving more free insulin in the blood stream. This free insulin will then usher the glucose to receptors in the muscles and tissues where glucose is required, thus lowering the blood sugar level.
As mentioned above chromium in onions, improve glucose tolerance, and decrease the fasting blood glucose levels. This mineral also decreases total cholesterol and triglyceride levels, while elevating the good HDL - cholesterol levels.
Chromium levels in the blood are diminished by consuming refined sugars, white flour products, and lack of exercise.
It has been found that regular consumption of fresh onions brings down high blood pressure, and lowers cholesterol. Both these reduces atherosclerosis (hardening of blood vessels), diabetic heart disease, and reduces heart attacks and stroke. Onions thins the blood and reduces platelet activity, and slows blood clotting. For this reason, those who await major surgery should minimise onion intake for a few days.
There is additional information that those whose diets include onions, tea, apples and broccoli, daily being richest sources of flavonoids - gained a 20% reduction in their risk of heart disease
Colon Cancer Prevention
It has been shown that taking onions, as little as two or more times a week, is associated with a significant reduction in the incidence of colon cancer. Onions contain many flavonoids, and quercetin (one of them) reduces the growth of tumours in animals, and also prevents the colon being damaged by cancer producing chemicals. Other dietary sources of quercetin include tea and apples. Recent studies at Wageningen Agricultural University, the Netherlands, showed that the absorption of quercetin from onions is twice that from tea and more than three times that from apples. (ref: National Onions Association). Based on studies conducted at The University at Belfast, Ireland and Wageningen Agricultural University, the content of quercetin in onions is estimated to be between 22.40mg and 51.82 mg per medium sized onion ) 100 gram).
Prevention of Gastric Ulcers
Consumption of onions may be beneficial for reduced risk of gastric ulcers, by antioxidant activity against scavenging free radicals, and by preventing growth of the ulcer-forming microrganisms like Helicobacter pylori.
Onions help to boost bone health and prevent osteoporosis. A compound newly identified in onions with the long complex name of y-L-glutamyl-trans-S-1-propenyl-L-cysteine sulfoxide inhibits the activity of osteoclasts, which inhibits bone growth. Eating onions on a daily basis may prevent osteoporosis among women in their old age.
Anti-Inflammatory and Anti-Bacterial Activity
Onions reduce the pain and swelling in all forms of arthritis. It helps to prevent colds and flu and is beneficial to asthmatics. Both onions and garlic contain chemicals that inhibit lipoxygenase and cyclooxygenase, the enzymes that generate inflammatory prostaglandins and thromboxanes. These anti-inflammatory effects are not only due to vitamin C and quercetin, but to other active components called isothiocyanates. Onion soups are good during cold seasons and when you are threatened with flu.
Ointments made out of onions, available in our pharmacies, are said to prevent infections in wounds, and also lessen fibroblastic activity during healing, helping to diminish keloid formations in wounds.
Another use externally applied for age spots, freckles, warts, by mixing onion juice with vinegar, and rubbing into these areas.
Choosing fresh healthy onions at the supermarket the grocery stores, or wayside places, is not easy today. In other countries the large red and white onions are quite big, and easy to select, unlike the ones we see here. Obviously, less fertilizers and care is being given to our produce mainly grown in the dry zones, and imported from India.
One should choose onions that are clean, well shaped, very firm to pressure with no discolouration of the skin. One should not buy onions that smell acrid. There should be no openings at the top, and those that are sprouting are old, and should be discarded. Avoid those ones with soft spots on pressure, with dark patches. Fortunately our growers do not irradiate onions to kill the moulds and other parasites, and they are organically grown.
Onions should be stored at room temperature, possibly in a dark place, and a well ventilated area. It would be ideal to hang the onions in a wire basket, or in any perforated bowl so that air can enter from the bottom.
Onions should not be stored in the same basket with potatoes. They will absorb the moisture, and ethylene gas, causing them to spoil sooner.
Cut onions could be wrapped tightly in a plastic container and used within a day or two, as they lose nutrients rather quickly. Cooked onions should never be placed in metal storage containers, due to discolouration which occurs quickly. Freezing peeled or chopped onions will lose most of its flavour.
The colour of the onion gives some insight into its properties. The white onions are the strongest, followed by yellow, and red or the purple having the mildest flavour.
The writer is a cosmetic surgeon at the Oasis Hospital