ANSWER: D-mannose is a type of sugar that is found naturally in some fruits, vegetables, and other plants. Some sources of naturally-occurring D-mannose include cranberries, pineapples, and apples. It can also be extracted from the bark of certain trees, such as the birch tree.
If you are looking to incorporate D-mannose into your diet, you can eat these foods or look for products that contain D-mannose, such as cranberry juice or D-mannose supplements. It is always important to talk to a healthcare provider before using any dietary supplement, including D-mannose, to make sure it is safe for you to take.