Onions are best known for two things: bad breath and tears. The popular vegetable found in most types of cuisine gives dishes their flavorful taste, transforming any meal to an aromatic experience. Raw onions not only provide an excellent taste for our palates, but provide therapeutic and antibacterial properties that cleanse and detox our bodies to eliminate disease.

Experts like Dr. Jonathan Stegall, an integrative medicine practitioner in Johns Creek, Ga., emphasize the beneficial properties of onions for our health. "Onions contain a high amount of sulfur compounds, which not only give onions their recognizable smell, but are also powerful detoxifying agents," he told Medical Daily in an email. With more than 100 sulfur-containing compounds, which are what cause the eyes to tear, onions can help prevent and treat ailments, from diabetes to heart disease, with daily consumption.

1. Asthma

Onions have antihistamine effects due to quercetin, an antioxidant that acts like an antihistamine and an anti-inflammatory agent. In test tubes, quercetin has proven to prevent immune cells from releasing histamine, which are chemicals that cause allergic reaction. Based on this observation, researchers believe the antioxidants may reduce histamine, and other allergic or inflammatory chemicals in the body, and can be a promising asthma treatment.

However, no human studies have examined whether it works or not. Stegall believes onions help alleviate asthma because they act as a powerful antioxidant. “Studies have shown that quercetin causes the bronchi of the respiratory tract to widen,” he said.

2. Cancer

Onions can help reduce cancer risk when combined with turmeric. Chemicals found in these two cooking ingredients. A 2006 study published in Clinical Gastroenterology and Hepatology found the combination of onions and turmeric creates a synergistic effect that reduces both the size and number of precancerous hosts in the intestine, therefore reducing colon cancer risk. Moreover, Stegall suggests regularly consuming onions can help detoxify potential carcinogens. Since they contain organosulfur compounds. “These compounds are found in the cell wall of the onion, and are released when the onion is chopped or chewed,” he said. 

3. Diabetes

A high intake of onions could mean the lower the level of glucose. The essential oil of an onion, allyl propyl disulphide, is found to mediate this effect, and lower blood sugar levels by increasing the amount of free insulin that is available. The allyl propyl disulphide competes with the insulin, which is also a disulphide, to occupy the sites in the liver where the insulin is inactivated. This is what leads to an increase in insulin available, which lowers blood sugar levels. A 1975 study published in the journal Clinica Chimica Acta; International Journal of Clinical Chemistry found onion’s essential oil led to a significant fall in blood glucose levels, and a significant rise in the serum of insulin levels after being administered to six normal volunteers after a 12-hour fast.

4. Heart Disease

When we think of heart healthy food, onions do not come to mind. However, quercetin is found to significantly reduce high blood pressure in hypertensive adults, according to a 2007 study published in The Journal of Nutrition. Moreover, this vegetable is considered to exceed the heart-protective properties of red wine. Stegall shared, “Onions are involved in maintaining good blood pressure, inhibit hardening of the arteries, and keep the arteries elastic.”

5. Tooth Decay

Raw onions may make our breath stink, but they can actually improve our oral health. Simply chewing a raw onion can strengthen teeth and eliminate bacteria that can lead to tooth decay. Two to three minutes of chewing on an onion can kill most germs in the mouth, according to Naturalsociety.com.

To stay healthy and prevent the onset of these diseases, eat an onion a day to keep the doctor away.