An onion a day may very well keep the doctor away. The onion, like garlic, is a member of the Allium family, and both are rich in sulfur-containing compounds that are responsible for their pungent odors and for many of their health-promoting effects. Although Sathya Sai Baba urges us to take Sathwic food, He says that the onion, generally considered Rajasic, has its advantages. In His discourses, He has praised this humble onion by endorsing the popular Telugu saying, "the good done by the onion (ulli) is not done by your own mother (thalli)!'' He recommends that we take one white onion a day to reduce the buildup of cholesterol in the blood vessels. He has also praised onions for improving our digestive power.

The onion (Allium Cepa) is packed with health promoting chemicals. In particular, it has three families of compounds that provide benefits to health— fructans, flavonoids and organosulfur compounds. Fructans are carbohydrate molecules that help maintain digestive health by supporting beneficial bacteria. Onions are especially rich in the flavonoid called quercetin, a powerful antioxidant. The organ sulfur compounds in onions are formed when the onion is cut and the cell walls are disrupted. Combined, these compounds provide powerful protection against many illnesses such as cancer, heart disease, respiratory illnesses, diabetes, and infections.

Onion and the Heart

Heart attacks
In a study published in the European Journal of Nutrition, Italian researchers, found that those who had a diet rich in onions (consuming one or more onions a week) were 22 percent less likely to have a heart attack than people who hardly ever ate onions.

Onions raise the level of “good” HDL cholesterol and lower the “bad” LDL cholesterol
When it comes to onions the more pungent the onion the better. Research has shown that eating onions raises levels of ―good‖ HDL cholesterol. Just eating half a medium size of the hotter or more pungent variety of the raw yellow or white onion, or its equivalent juice a day is usually enough to dramatically raise ―good‖ HDL cholesterol by an average of 30% in about three out of four heart patients, according to Dr. Victor Gurewich, a cardiologist and professor of medicine at Harvard Medical School, USA, who advises all his patients with coronary heart disease to eat onions daily. But he says that this effect is lessened the more the onions are cooked. Of the more than 150 chemicals found in onions, researchers are not quite sure which ones boost the ―good‖ HDL, but they are quite sure that raw onions work better; cooking reduces or destroys the onion's powers to raise HDLs. The active agent appears to be the one that gives the onions their strong, pungent taste. The major effect comes from the hotter white and yellow varieties rather than the milder onions although milder onions affect your health in different ways.

Research has shown that eating onions can lower your ―bad‖ LDL blood cholesterol. In one study, forty- five healthy people in New Delhi were given a 3000-calories-a-day high-fat diet for fifteen days. Their blood cholesterol rose from an average 219 to 263. But, just eating one tablespoon or 10 grams of onion a day with their fatty meals dramatically reduced their blood cholesterol to an average 237.

Onions Discourage Blood Clot Formation
Onion, like aspirin, serves as an anti-coagulant, which helps prevent dangerous blood clots that obstruct the flow of blood through the circulatory system. These obstructive clots choke off the oxygen supply to different parts of the body such as the heart or the brain causing heart attacks or stroke. While some onion chemicals keep the platelets (that form the clots) from sticking together, others dissolve clots as they form. After a decade of research, British and Indian scientists have offered powerful evidence that onions are the best choice for your heart. In a study, they first fed men a very high fat meal, with butter and cream, and noted that their clot-dissolving activity dropped markedly. Then they gave them the same fatty meal, but this time added two oz. (about 60 g.) of onions, raw, boiled or fried. Blood drawn two and four hours after the fatty meal revealed that the onions had completely blocked the fat's damaging blood-clotting abilities. In fact, less than half a cup of onions completely reversed the ability of fat to block the clot-dissolving activity.

These studies, which show the beneficial effect of consuming onions on the heart, may very well explain the French Paradox—the fact that there is a low incidence of heart disease in French people despite the fact that French people generally consume a diet high in saturated fats. This would make sense as almost no French recipe excludes the onion. In fact a large survey showed that onion and garlic lovers had better blood profiles (cholesterol, triglycerides and HDLs) than those who avoided these two members of the Allium family. Even those who ate some onions such as a cup of onions a week showed lower blood cholesterol and better cardiovascular health.

Onions and Blood Pressure
When one group with hypertension was given 730 mg. of quercetin a day for 28 days, their blood pressure dropped between 2 and 7 points Systolic and 2 to 5 point Diastolic compared with no change in the group given the placebo.

In another study, 2-3 tablespoons of onion essential oil lowered blood pressure in 67% of people with moderate hypertension. Their Systolic level fell an average of 25 points and their Diastolic readings fell 15 points.

After seven years of research on the health effects of onions, one set of researchers concluded that one should take 100 grams of onion (about 2/3 cup) per day to do away with heart disease or high blood pressure.

Onions Can Help Prevent Osteoporosis
One study found that onion intake rivaled the effects of prescription drug Alendronate (Fosamax) given to prevent and treat osteoporosis (thinning of the bone) in women after menopause. In this study, researchers studied ovariectomy induced bone loss in rats that were treated with Alendronate or onion powder. The ability of onions to counteract bone loss came close to that of Alendronate (Fosamax). Onions seem to strengthen bones without the unpleasant side effects of Fosamax such as bone and joint pain, nausea, ulcers, acid backup and rashes to mention a few.

Researchers at the University of Bern, Switzerland have found that a chemical compound—a peptide called GPCS—found in onions inhibits the activity of osteoclasts (the cells that break down bone) and thereby slows down bone loss. When bone cells of newborn rats that were exposed to parathyroid hormone to simulate bone loss were treated with the GPCS compound extracted from the white onion, loss of bone minerals, including calcium was significantly inhibited.

Other studies have shown that consuming onions increases bone mass, bone thickness and bone mineral density. Such encouraging animal and human studies highlight the benefit onions can provide to menopausal women who are experiencing bone density loss. One research study that analyzed the nutritional data of 35 million women showed that daily consumption of onions in pre-menopausal or post- menopausal women was associated with robust benefits in bone density while infrequent consumption of onion (once a month or less) was not associated with much benefit to bone health. This indicates that post-menopausal women may decrease their risk of hip fracture through daily intake of onions.