Diabetes

Diabetes mellitus (DM or, simply, diabetes) refers to a group of diseases that affect how your body uses sugar (glucose). Glucose comes from the foods you eat. Glucose is essential to health because it is an important source of energy for the cells that make up your muscles and tissues and it is the brain's main source of fuel. If you have diabetes, no matter what type, it means you have too much glucose in your blood, although the causes may differ. Too much glucose can lead to serious health problems.

Insulin is a hormone that helps the glucose get into your cells to give them energy. With type 1 diabetes, your body does not make insulin. With type 2 diabetes, the more common type, your body does not make or use insulin well. Without enough insulin, the glucose stays in your blood. Although type 1 diabetes can develop at any age, it typically appears during childhood or adolescence. Type 2 diabetes, the more common type, can develop at any age, though it is more common in people older than 40.

Potentially reversible diabetes conditions include prediabetes — when blood sugar levels are higher than normal, but not high enough to be classified as diabetes — and gestational diabetes, which occurs during pregnancy but may resolve after the baby is delivered.

Over time, having too much glucose in your blood can cause serious problems. Diabetes can lead to damage of your eyes, kidneys, and nerves, and it can cause heart disease and stroke.

A blood test can show if you have diabetes. Exercise, weight control, and sticking to your meal plan can help control your diabetes. Treatments will vary depending on the type of diabetes you have.

To understand diabetes, first you must understand how glucose is normally processed in the body.

Insulin is a hormone that comes from a gland situated behind and below the stomach (pancreas). The pancreas secretes insulin into the bloodstream and the insulin circulates, allowing glucose (sugar) to enter your cells. Insulin lowers the amount of sugar in your bloodstream. As your blood sugar level drops, so does the secretion of insulin from your pancreas.

Glucose is a source of energy for the cells that make up muscles and other tissues. Glucose comes from 2 major sources: food and your liver. Sugar is absorbed into the bloodstream, where it enters cells with the help of insulin. Your liver stores and makes glucose. When your glucose levels are low, such as when you have not eaten in a while, the liver breaks down stored glycogen into glucose to keep your glucose level within a normal range.

Type 1 and type 2 diabetes are conditions characterized by high blood glucose levels caused by either a lack of insulin (type 1) or the body's inability to use insulin efficiently (type 2). Two factors are important in the development of both type 1 and type 2 diabetes: a predisposition to the disease is inherited and then something in your environment triggers the onset of the disease.

The exact cause of type 1 diabetes is unknown. What is known is that your immune system attacks and destroys your insulin-producing cells in the pancreas. This leaves you with little or no insulin. Instead of being transported into your cells, sugar builds up in your bloodstream. Type 1 diabetes is thought to be caused by a combination of genetic susceptibility and environmental factors, though exactly what many of those factors are is still unclear. One trigger might be related to cold weather. Type 1 diabetes develops more often in winter than summer and is more common in places with cold climates. Another trigger might be viruses. Perhaps a virus that has only mild effects on most people triggers type 1 diabetes in others. Early diet may also play a role. Type 1 diabetes is less common in people who were breastfed and in those who first ate solid foods at later ages.

Type 2 diabetes has a stronger link to family history and lineage than type 1, although it too depends on environmental factors.

In prediabetes — which can lead to type 2 diabetes — and in type 2 diabetes, your cells become resistant to the action of insulin, and your pancreas is unable to make enough insulin to overcome this resistance. Instead of moving into your cells where it is needed for energy, sugar builds up in your bloodstream.

Exactly why this happens is uncertain, although it is believed that genetic and environmental factors play a role in the development of type 2 diabetes. Being overweight is strongly linked to the development of type 2 diabetes, but not everyone with type 2 is overweight.

During pregnancy, the placenta produces hormones to sustain your pregnancy. These hormones make your cells more resistant to insulin. Normally, your pancreas responds by producing enough extra insulin to overcome this resistance. But sometimes your pancreas cannot keep up. When this happens, too little glucose gets into your cells and too much stays in your blood, resulting in gestational diabetes. This condition is often reversible after the baby is delivered.

Talk with your pharmacist or doctor if you have increased thirst, frequent urination, fatigue, or blurred vision, or a family history of diabetes. Seek emergency care for very high blood sugar with confusion, vomiting, or fruity-smelling breath.