Before you throw out a banana because it has turned brown and seems past its eating prime, consider the potential nutritional benefits it provides. A brown banana has a higher level of antioxidants than yellow or green, unripe bananas. It's also easier to digest for people with digestive ailments, including irritable bowel and functional abdominal bloating.
A brown, yellow or green banana are all a good source of potassium, vitamin B-6 and fiber. As a banana reaches the brown stage, its concentration of antioxidants increases. Antioxidants are important in helping protect your body against disease-causing inflammation. As bananas turn brown, some of the micronutrients present do diminish. Store ripe bananas in the refrigerator to reduce this loss.
In brown bananas, the resistant starch has almost completely transformed into simple sugars. When you eat a brown banana, you're blood sugar spikes more quickly than it would when you eat a green one. Type-2 diabetics are thus recommended to avoid brown-spotted or fully brown bananas, which are mostly sugar. Less ripe bananas are healthier for people who are trying to cut back on sugar.
Because a brown banana is mostly simple sugar, it's easy to digest. People with irritable bowel and other digestive ailments may find brown bananas are more agreeable to their systems. Watch for brown bananas that are too far past their prime. If it smells, is squishy or shows signs of leaking or mold, it's not fit to eat.
A Japanese study published in a 2009 issue of "Food Science and Technology Research" determined that the brown spots on bananas produce a substance called Tumor Necrosis Factor, which breaks down abnormal cells -- including those that cause cancer. Brown bananas can't cure cancer, but consuming them might boost your immune function.