Drinking orange juice will ward off cataracts, cancers, and birth defects. It will also boost your immunity. Orange juice is an excellent source of vitamin C. It is also a potent anti-oxidant that will protect you against a variety of diseases. Vitamin C will prevent oxidative damage that could cause cells to become cancerous. It also improves immune-cell functioning which enables your body to fight off infections more efficiently. Orange juice is a great source of folate. This protects you against neural-tube defects in fetuses. If you want to get the extra benefit of bone protection, you can try some calcium-fortified orange juice. There are 115 calories in eight ounces of orange juice.