How healthy are oranges for you and do they have antioxidants? Here's the big shocker most people aren't aware of... the orange juice you buy from the grocery store has had most of its antioxidants destroyed. This is from the pasteurization (heating) of the juice during production, which is used to destroy bacterial pathogens. Afterward, the manufacturer will add back in a chemical form, ascorbic acid, which they then call vitamin C. Technically it is, however naturally occurring vitamin C contains other by products aside from just ascorbic acid.
Thankfully when you eat the raw fruit you don't have to worry about that, as you're getting the orange's natural vitamin C content. This is responsible for much of a fresh orange's ORAC value. In addition, this fruit is a good source of phenolic compounds hesperidin and anthocyanins, as well as the caretenoids beta-cryptoxanthin and lycopene, all of these contribute to its antioxidant content.
The health benefits of oranges include prevention of anemia, which is caused by iron deficiency. Even though they're a poor source of iron, their vitamin C helps with the body's absorption of it from other foods (1). It has been suggested that because oranges are a rich source of citric acid and citrates, they may help with the prevention of kidney stones (2). Because they are so sweet many assume they must have a high glycemic index (GI) but the good news is that fresh oranges are relatively low with a GI of around 40 (it could be slightly more or less depending on the variety and ripeness). The reason for this is because of its high fiber content, which slows down the rate at which your body breaks down and absorbs the carbs (sugars).
USDA Database for the Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, Release 2 - Prepared by Nutrient Data Laboratory, Beltsville Human Nutrition Research Center (BHNRC), Agricultural Research Service (ARS), U.S. Department of Agriculture (USDA) - May 2010