White onions have plenty of benefits to offer the human body. They're very low in calories and have almost no fat, cholesterol, or sodium. However, they are fairly nutrient-rich, full of antioxidants and amino acids necessary for bodily functions. Below are some of the basic nutrition facts for a whole medium white onion (about 94 grams). The percentages are based on a daily recommended value for a 2,000-calorie diet. Calories: 41 Total fat: 0.2 grams Cholesterol: 0 Sodium: 2.8 milligrams (0% DV) Potassium: 156 milligrams (4% DV) Total carbohydrates: 9.5 grams (3% DV) Dietary fiber: 1.3 grams (5% DV) Sugars: 1.3 grams Vitamin C: 8.1% DV Calcium: 1.6% DV Iron: 1.3% DV