What Does an Onion Do for Your Body?

by Suzanne Allen

One of the most significant sources of antioxidants in the human diet is onions, reports Cornell University Associate Professor Rui Hai Lui. These antioxidants provide this vegetable with its sweet flavors and distinct aroma. Consuming onions supplies your body with soluble fiber and flavonoids, antioxidant compounds that fight free radicals. These flavonoids assist in thinning your blood, decreasing inflammation and fighting cancer.

Blood Thinner

Onions may assist in thinning your blood, as they contain thiosulfinates -- the agents that provide an onion with its pungent odor and cause teary eyes when you come in contact with this vegetable. Additionally, this sulfur compound prevents platelets in your blood from aggregating and operates as a natural blood thinner. When platelets cluster in your blood, your risk for experiencing a stroke or heart attack significantly increases. Thiosulfinate concentrations are more prevalent in onions with a dry consistency and high-carbohydrate content. Eat your onions raw for maximum thiosulfinate content, as cooking onions significantly decreases the quantity of this compound. If you take a prescription blood thinner, consult with your physician about consuming onions in conjunction with your medication, as you do not want your blood to become too thin.

Fiber

Fiber is present in all plant-based foods, including onions. Consuming fiber in your diet assists in regulating your blood sugar, decreasing your bad cholesterol, promoting healthy intestinal functioning and maintaining an optimal body weight. Onions also contain a special form of soluble fiber known as fructan. When you consume fructan, this soluble fiber turns into a gel-like substance in your colon and converts to fatty acids. These fatty acids act as a natural laxative, stimulating bowel movements. The fructan in onions, inulin fructan, promotes the growth of good bacteria in your intestines, which may combat any infections in your colon.

Anti-Inflammatory

Onions may help reduce inflammation, as they contain organosulfurs -- antioxidant compounds that assist in combating inflammation. Inflammation in your body can cause and exacerbate symptoms of asthma, arthritis and heart disease. According to a 2010 study published in “Molecular Aspects of Medicine,” regular consumption of organosulfur compounds from onions and garlic can prevent the development of cardiovascular disease. Organosulfurs decrease inflammation in the blood vessels, a sign of heart disease, by separating blood platelets and inhibiting the production of toxic substances.

Anti-Cancer Benefits

Onions are packed full of anticancer compounds, such as flavonoids and phenolics. Shallots, Western Yellow, Northern Red and pungent yellow onions assist in inhibiting the growth of cancer cells, which may protect against the development of colon and liver cancer. Onions with higher antioxidant quantities offer greater protection against certain types of cancer than onions with fewer antioxidants. For example, the Western Yellow contains 11 times more antioxidants than the Western White and provides the strongest protection against the production of liver cancer cells. The Western Whites contain the least amount of antioxidants among onion varieties and offer the least protection against cancer cells.