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

New concerns about diet sodas

There are growing doubts about whether diet sodas help people lose weight and avoid diabetes. Research has shown that sugar-free sodas may be linked to the development of metabolic syndrome—a condition that often precedes or accompanies diabetes. Many artificial sweeteners may actually increase the brain’s desire for sugar. Even the soda container may pose problems. Many cans are lined with a substance called bisphenol A (BPA). Research has shown that people with higher levels of BPA in their body are more likely to have high blood pressure and heart trouble. (Locked) More »

Blood sugar on the brain

Years of poorly controlled diabetes have a devastating effect on the cardiovascular system, kidneys, and brain. High blood sugar may also harm thinking and memory power even in people who do not have diabetes. In a group of men with cardiovascular disease or risk factors, higher-than-normal blood sugar was linked to all forms of dementia, including Alzheimer’s disease. (Locked) More »

Glycemic index and glycemic load for 100+ foods

The glycemic index is a value assigned to foods based on how slowly or how quickly those foods cause increases in blood glucose levels. Also known as "blood sugar," blood glucose levels above normal are toxic and can cause blindness, kidney failure, or increase cardiovascular risk. Foods low on the glycemic index (GI) scale tend to release glucose slowly and steadily. Foods high on the glycemic index release glucose rapidly. Low GI foods tend to foster weight loss, while foods high on the GI scale help with energy recovery after exercise, or to offset hypo- (or insufficient) glycemia. Long-distance runners would tend to favor foods high on the glycemic index, while people with pre- or full-blown diabetes would need to concentrate on low GI foods. Why? People with type 1 diabetes and even some with type 2 can't produce sufficient quantities of insulin—which helps process blood sugar—which means they are likely to have an excess of blood glucose. The slow and steady release of glucose in low-glycemic foods is helpful in keeping blood glucose under control. But the glycemic index of foods tells only part of the story. What it doesn't tell you is how high your blood sugar could go when you actually eat the food, which is partly determined by how much carbohydrate is in an individual serving. To understand a food's complete effect on blood sugar, you need to know both how quickly the food makes glucose enter the bloodstream, and how much glucose it will deliver. A separate value called glycemic load does that. It gives a more accurate picture of a food's real-life impact on blood sugar. The glycemic load is determined by multiplying the grams of a carbohydrate in a serving by the glycemic index, then dividing by 100. A glycemic load of 10 or below is considered low; 20 or above is considered high. Watermelon, for example, has a high glycemic index (80). But a serving of watermelon has so little carbohydrate (6 grams) that its glycemic load is only 5. More »

How often should you get your blood sugar checked?

People who have diabetes risk factors should get their blood sugar checked. If it’s normal, they should get it checked again in three years. If it’s not normal, they should get it checked yearly. Risk factors include being older than 45, being overweight (with a body mass index of 25 or higher), a sedentary lifestyle, a family history of type 2 diabetes, a history of high blood pressure or high cholesterol, or a heritage that is African American, Hispanic, American Indian, or Asian American. (Locked) More »

Weight-loss surgery for uncontrolled diabetes

People with obesity and uncontrolled diabetes who underwent weight loss surgery lost much more weight, had better blood sugar control, and used fewer diabetes medications than people treated with medications alone.  (Locked) More »