The natural sugar in oranges may be the same type as granulated sugar, but you don't have to worry as much about its effect on your health. Oranges contain three different forms of natural sugar, but the sugar gives you an energy boost without spiking blood sugar because it's part of a whole food.
Three Types of Natural Sugar
Fructose is commonly known as "fruit sugar," but it's not the only type of natural sugar in fruits. In fact, it's usually found with other sugars, according to International Food Information Council. That holds true for oranges because they contain fructose, glucose and sucrose. Fructose and glucose consist of a single unit of sugar, so they're called monosaccharides.
When glucose and fructose bind together, they create the disaccharide sucrose. Each sugar imparts a different level of sweetness. According to the Calorie Control Council, fructose is twice as sweet as sucrose and glucose is the least sweet of all.
Amount in One Orange
One medium-sized navel orange contains 17.6 grams of total carbohydrates, which includes 11.9 grams of natural sugar, according to the USDA FoodData Central. Sucrose accounts for half of the total sugar. Another 23 percent of the total comes from glucose, while fructose represents 27 percent of the sugar in an orange.
One navel orange has 69 calories. Almost 48 of the total calories come from sugar because each gram of sugar provides 4 calories, according to the USDA.
Effect on Blood Sugar
The glycemic index rates carbohydrate-containing foods according to how much they raise your blood sugar. According to Harvard Health, oranges have a glycemic index score of 40.
On the glycemic scale, scores under 55 fall into the low category, so oranges have a small effect on blood sugar. This is due to fiber. One navel orange contains 3.1 grams of dietary fiber, or about 8 percent of women's and 12 percent of men's recommended daily intake. More important, oranges are a good source of soluble fiber, which slows the digestion of sugar and prevents a large spike in blood sugar.
According to the Academy of Nutrition and Dietetics, including more low-glycemic index foods in your diet, like oranges, may help keep you feeling full longer so you eat less, which may make it easier for you to get to and maintain a healthy weight. For people with diabetes, eating more low-glycemic foods may improve insulin resistance and blood sugar, as well as lower cholesterol and triglyceride levels.
Sugar With Nutritional Benefits
Oranges illustrate another reason why natural sugar is healthy, while sugar added to foods contributes to weight gain: They're filled with nutrients; added sugar is just empty calories.
One navel orange supplies 82.7 milligrams of vitamin C. This value exceeds women's recommended dietary allowance of 75 milligrams and nearly fulfills the 90 milligrams of vitamin C men should get daily. You'll also get folate, vitamin B6, potassium and calcium. Oranges contain beneficial phytonutrients called flavonoids. One in particular, hesperetin, may help lower cholesterol and provide antioxidant protection.
- USDA FoodData Center: "Oranges, Raw, Navels"
- Harvard Health Publishing: "Glycemic Index and Glycemic Load For 100+ Foods"
- Harvard Health Publishing: "Use Glycemic Index to Help Control Blood Sugar"
- Drug Bank: "Hesperetin"
- National Institutes of Health: "Nutrient Recommendations: Dietary Reference Intakes"
- USDA: "How Many Calories In One Gram of Fat, Carbohydrate or Protein?"
- International Food Information Council: "Fruits in All Forms"
- Calorie Control Council: "Fructose"
- Academy of Nutrition and Dietetics: "What Is Glycemic Index?"