Excess sugar can damage the walls of the tiny blood vessels (capillaries) that nourish your nerves, especially in the legs. This can cause tingling, numbness, burning or pain that usually begins at the tips of the toes or fingers and gradually spreads upward. Poorly controlled blood sugar can make you end up losing all sense of feeling in the affected limbs. Damage to the nerves that affect the gastrointestinal tract can cause problems with nausea, vomiting, diarrhea or constipation. For men, erectile dysfunction can be a problem. The kidneys contain millions of tiny clusters of blood vessels that filter waste from your blood. Diabetes can damage this delicate filtering system. Severe damage can lead to kidney failure or irreversible end-stage renal disease, requiring dialysis or a kidney transplant. Diabetes can damage the blood vessels of the retina (diabetic retinopathy), potentially leading to blindness.
Diabetes also increases the risk of other serious vision problems such as cataracts and glaucoma. Nerve damage in the feet or poor circulation in the feet, increases the risk of various foot complications. If it is not treated, cuts and blisters can become serious infections. Serious damage may require toe amputation of the foot or even leg. Diabetes may leave you more susceptible to skin problems, including bacterial and fungal infections. Gum infections can also be a concern, especially if you have a history of poor dental hygiene. Diabetes can cause a decrease in the normal bone mineral density, increasing your risk of osteoporosis. It may result in serious complications during pregnancy. High levels of blood sugar can be dangerous for the mother and baby. The risk of miscarriage, stillbirth defects and birth are increased when diabetes is not well controlled. For the mother, diabetes increases the risk of diabetic eye problems, pregnancy-induced hypertension. Hearing impairments may occur more often in people with diabetes.