What Are the Benefits of Boiled Onions?

At less than 100 calories per cup -- less than 5 percent of the daily caloric intake based on a 2,000-calorie diet -- boiled onions make a welcome addition to a calorie-controlled diet. Boiling onions offers you a nutritional advantage over frying them, because boiling does not require the use of oil or butter, which would otherwise add calories to your meal. Consuming boiled onions also offers health benefits, because they help you reach your recommended daily intake of several vitamins and minerals.

Boiled onions offer health benefits thanks to their vitamin C content. A cup of boiled onions contains 11 milligrams of vitamin C, which is 12 percent of the daily intake for men and 15 percent for women, set by the Institute of Medicine. Vitamin C boosts collagen production, a process needed for bone and blood vessel health. It also plays a role in mental health by helping you produce norepinephrine, a chemical that regulates your mood.

Boiled onions serve as a source of dietary fiber, a type of carbohydrate that fights disease. Fiber helps lower your cholesterol and regulate your blood sugar levels, and it reduces your risk of Type 2 diabetes and cardiovascular disease. Fiber also helps move stool through your digestive tract, preventing constipation to keep you regular. A cup of boiled onions provides you with 2.9 grams of dietary fiber. This contributes 12 percent toward the daily recommended intake for women and 8 percent for men, set by the Institute of Medicine.

Incorporate boiled onions into your diet to reap the health benefits associated with their copper content. Copper nourishes your brain by helping make chemicals involved in brain communication, and it also supports the synthesis of myelin, a substance needed for brain function. Getting enough copper in your diet also supports your immune system so that it can protect you from infection. A 1-cup serving of boiled onions boosts your copper intake by 141 micrograms, or 16 percent of the recommended daily intake set by the Institute of Medicine.

Boiled onions provide other essential minerals, including phosphorus and manganese. Each cup of boiled onions provides 74 milligrams of phosphorus and 0.3 milligrams of manganese. That's 11 percent of your daily phosphorus requirements, as established by the Institute of Medicine, as well as 17 percent of the recommended daily manganese intake for women and 13 percent for men. Both phosphorus and manganese benefit your skeleton and keep your bones strong. Phosphorus also promotes healthy circulation and plays a role in cell communication, while manganese supports your metabolism and aids in wound healing.