The constituents of onions that are thought to be mainly responsible for the benefit are sulfur compounds like S-methylcysteine and flavonoids such as quercetin. In the study to be published in the journal Nutrition, scientists found onions can reduce levels of glucose and lipids, as well as decrease oxidative stress, boost insulin secretion and stimulate antioxidant enzyme activity.
Onion Juice Cuts Blood Sugar of Diabetic Rats by 70
PercentEarlier research also indicates onion extract lowers blood sugar, and preliminary clinical trials show the magnitude of the reduction is sufficient to be of use in treating diabetes. In fact, an Egyptian study discovered onion juice decreased the blood sugar levels of diabetic rats by 70 percent.
Another promising study published in 2010 in the Macedonian Journal of Medical Sciences examined the effect of essential oil of onion on diabetes-induced rats. The treatment resulted in a significant lowering of blood glucose and lipids along with an increase in insulin. Moreover, all the microscopic differences in cells and tissues in the diabetic rats disappeared.
Other Health Benefits of Onions
Aside from their antidiabetic properties, research shows onions help prevent blood clots, reduce high blood pressure and raise HDL, known as good cholesterol. One study found that people who consumed the most onions and other flavonoid-rich foods had a 20 percent lower likelihood of heart disease.
The healthful compounds in onions can help fight several kinds of cancer. In a Chinese study, men who consumed at least one tablespoon of chopped onions or related vegetables, such as garlic or leeks, per day had approximately half the prostate cancer risk of men who consumed less than one-fourth tablespoon of the vegetables per day.
Onions may also be beneficial for bone and joint disorders. Some evidence suggests they can preserve bone, which would help prevent osteoporosis, while the anti-inflammatory properties of the sulfur compounds can help alleviate the swelling and pain of arthritis.
How to Add Onions to Your Diet
The more pungent onion varieties contain the most healthful compounds, and the vegetable has the most health benefits when eaten raw.
Raw:Add raw onions to green salads and sandwich salads made of tuna, chicken or egg. They can also be incorporated into fruit chutney recipes.
Cooked:Add onions to stews, soups and stir-fries in addition to any meat or vegetable dish. Another option is to bake an onion for an hour in the oven and eat it with salt, pepper, olive oil, flavored vinegar and herbs.