Onion lowers cholesterol, inhibits hardening of the arteries, enhances elasticity of blood vessels, and helps to maintain healthy blood pressure. ... In addition to limiting your intake of fats and sugars, eating onions can get your blood sugar-and your weight-on the right Furthermore, onions contain fiber and folic acid, a B vitamin that helps the body make healthy new cells. Onions are healthy whether they're raw or cooked, though raw onions have higher levels of organic sulfur compounds that provide many benefits