At first glance, onions do not appear to be nutritional powerhouses, especially when they've been sauteed in oil and are gracing the top of a hamburger. Don't be deceived, however. Onions, regardless of how they are prepared, contain nutrients and compounds that can promote a healthy body.
Basic Nutritional Data
The manner in which you prepare a vegetable can significantly impact its nutritional profile. Such is the case with onions, a low-calorie, nonfat food that gains a significant amount of calories when sauteed. A 1-cup serving of sauteed onions provides 115 calories. Most of these calories come from the oil in which the onions are sauteed. In addition to 9 grams of fat, a one-cup serving of sauteed onions provides 7 g of carbohydrates and 1 g of protein.
Vitamins and Minerals
Onions do not have an exceptional amount of any one nutrient. They do, however, provide small amounts of a wide range of vitamins and minerals, which when combined with a healthy diet, will help you get the nutrients you need. A 1-cup serving of sauteed onions provides calcium, potassium, zinc, iron, vitamin K and several of the B vitamins. Sauteed onions also provide small amounts of each amino acid.
Onions provide quercetin, a flavonol associated with disease prevention. A study in the March 2009 "European Journal of Nutrition" found that people who consumed the most onions had a lower rate of heart attacks. Onions appear to reduce the risk of cancer as well. Research published in the November 2006 "American Journal of Clinical Nutrition" discovered that people who eat onions and other allium-containing vegetables on a frequent basis have less likelihood of getting cancer.
Making Sauteed Onions Healthier
Give sauteed onions a healthier nutritional profile by sauteing them in a monounsaturated oil such as olive oil. If you're watching your weight, you can eliminate all of the fat from sauteed onions entirely, which will save 85 calories per cup of onions. Serve sauteed onions with other healthy foods, including grains. Researchers at the Central Food Technological Research Institute in India discovered that eating onions increases the bioaccessibility of iron and zinc in grains, according to the July 2010 "Journal of Agricultural and Food Chemistry."