Why are high blood sugar levels bad for you? Glucose is precious fuel for all the cells in your body -- when it's present at normal levels. But persistently high sugar levels behave like a slow-acting poison.

1. High sugar levels slowly erode the ability of cells in the pancreas to make insulin. The pancreas overcompensates, though, and insulin levels remain overly high. Gradually, the pancreas is permanently damaged.
2. All the excess sugar is modified in the blood. The elevated sugar in the blood causes changes that lead to atherosclerosis, a hardening of the blood vessels.

Because high sugar levels are everywhere, the body can be damaged anywhere. Damage to blood vessels, in particular, means no area is safe from too much sugar. High sugar levels and damaged blood vessels cause the multitude of complications that can come with diabetes:

• Kidney disease or kidney failure, requiring dialysis
• Strokes
  
• Heart attacks
  
• Visual loss or blindness
  
• Immune system suppression, with increased risk for infections
  
• Erectile dysfunction
  
• Nerve damage, called neuropathy, causing tingling, pain or decreased sensation in the feet, legs, and hands
  
• Poor circulation to the legs and feet, with poor wound healing

In extreme cases, because of the poor wound healing, amputation is required.

Keeping sugar levels closer to normal can prevent many of the complications of diabetes. The American Diabetes Association's goals for glucose control in people with diabetes are sugar levels of 70 to 130 mg/dL before meals, and less than 180 mg/dL after meals.

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