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According to the American Diabetes Association, more than 18 million people in the United States have diabetes. Dr. Oz says that although diabetes can be managed, it's important to pay the right kind of attention to the disease. "One of the problems with diabetes is that you feel normal, so you don't take things seriously," he says.

What diabetics can't see is how blood vessels can shrink, causing harm to the kidneys. On the left is a normal kidney; on the right, a damaged kidney. The good news is that Type 2 diabetes can be prevented through exercise and diet.