Diabetes occurs when the body has trouble using the sugar it gets from food for energy. Sugar builds up in the bloodstream. High blood sugar can have immediate effects, like blurry vision. It can also cause problems over time, like heart disease and blindness.

There are two main types of diabetes: type 1 diabetes (once called juvenile-onset diabetes) and type 2 diabetes (once called adult-onset diabetes). Both are caused by problems making or using insulin, a hormone that makes it possible for cells to use glucose, also known as blood sugar, for energy.

When you eat, your body breaks down carbohydrates into a simple sugar called glucose. It also produces a hormone called insulin that signals the body's cells to absorb glucose from the bloodstream. Type 1 diabetes occurs when the body doesn't make enough insulin, or stops making it altogether. Type 2 diabetes occurs when the body's cells don't respond to insulin. Either way, since sugar can't get into cells, it builds up in the bloodstream. 

Too much sugar in the blood can cause a range of uncomfortable symptoms. These include:

  • blurry vision
  • intense thirst
  • need to urinate often
  • fatigue
  • numbness or tingling in the hands or feet

Type 1 diabetes often comes on suddenly. It usually strikes children and teenagers, but can appear later in life. It is an autoimmune disease, meaning it happens because the body's immune system mistakenly attacks and destroys the body's insulin-making cells. Type 1 diabetes can't be cured, but it can be managed by taking insulin before eating.

Type 2 diabetes takes longer to develop. It can begin any time from childhood onward. Type 2 diabetes is usually triggered by being overweight or obese and not getting much physical activity. Treatment for type 2 diabetes includes weight loss if needed, daily exercise, a healthy diet, and medications.

Diabetes Articles

No heart risk-or benefit-from diabetes drug Onglyza

In the largest and most comprehensive study of the heart effects of a diabetes drug, the blood sugar-lowering drug saxagliptin (Onglyza) showed no benefit in protecting against heart disease or stroke. Importantly, the drug also did not increase cardiovas (Locked) More »

How to get more potassium

Certain fruits and vegetables deliver a significant amount of potassium with comparatively low carbohydrates, making them better food sources for people with diabetes. They include asparagus, tomatoes, green leafy vegetables, strawberries, and nectarines. More »

RX for heart failure: coffee

Drinking two cups of coffee a day may protect against heart failure, likely by lowering the risk of high blood pressure and diabetes. (Locked) More »

Bypass best for people with diabetes

People with diabetes often need a procedure to improve blood flow and avoid a heart attack. Those who undergo bypass surgery tend to live longer and are less likely to have a heart attack than those who undergo angioplasty. A noninvasive test such as CT can be used to determine whether someone with diabetes is at increased risk for heart attack. More »

New pill better targets rheumatoid arthritis

In November 2012 the FDA approved tofacitinib (Xeljanz), a potent new treatment for people with rheumatoid arthritis. Methotrexate, taken orally, is the first line of defense. Doctors also prescribe injectable biologic therapies (Enbrel, Humira) that quiet certain inflammatory cytokines. The new drug, which comes as a pill, targets another type of inflammatory molecule than do the two biologics. The new drug has a short-term safety profile similar to the biologic therapies, with a slightly higher rate of shingles. (Locked) More »