Along with fats and proteins, glucose is an important fuel used by the body in daily functions. In fact, glucose could be considered the most important fuel because the brain cannot function without it. When glucose is in short supply, the healthy body has a number of unique ways of insuring that the brain gets what it needs by tapping into stored reserves or converting other fuel sources into glucose. When glucose levels get too high, like in diabetes, the body also has ways to insure that a healthy balance is maintained.
Glucose From the Diet
The most available source of blood glucose comes from the food you eat. Most well-nourished children and adults get all of the glucose they need principally from carbohydrates. Good sources of carbohydrates are baked goods, pasta and rice. Others include fresh fruit, fruit juices, candy and even certain types of vegetables. The specific amount of glucose you get from carbohydrates depends on what you eat and how much.
Diabetics must not only insure that they're getting enough glucose throughout the day, they must also take steps to insure that it's being well-regulated through the quality of food they eat, exercise and oftentimes medication. For them, carbohydrates that digest slowly, like baked goods, rice, fruits and vegetables make better choices than highly processed snack foods that cause their blood sugar to spike. On the other hand, if their blood glucose levels suddenly drop (like after long bouts of exercise or during illness), super sweet carbs like hard candy and other high-glucose supplements especially designed for diabetics are good to have around to bring glucose levels back up to within their normal range.
Normal Blood Glucose Levels
Under normal conditions, the body likes to keep blood glucose levels within a constant level. The normal blood glucose range for a healthy adult is 70 to 110 mg/dl. While blood glucose levels can rise and fall throughout the day, they generally remain close to this range. Certain things like eating high-carbohydrate foods can cause blood glucose levels to spike. On the other hand, extended exercise can cause blood glucose levels to drop. Both of these are generally transient responses and should return to normal within an hour or two after the event. Prediabetics typically have blood glucose levels between 110 to 139 mg/dl. Anyone with blood glucose levels over 140 mg/dl is probably a good candidate to be tested for diabetes.
The Role of the Pancreas
The pancreas is a small yet very important organ that sits below the liver. It produces two hormones that have distinctly different effects on your blood glucose levels. One hormone called insulin is secreted by the beta cells of the pancreas and is responsible for lowering the blood glucose level. An example would be during a game of basketball, when your muscles are very active. To insure that the muscles get the fuel they need, the pancreas secretes insulin, which helps the muscles use blood glucose. Type I diabetics typically have problems creating enough insulin. As a result, their blood glucose levels remain high unless properly managed through a coordinated program of diet, exercise and injectable insulin.
The opposite occurs with glucagon--a hormone secreted by the alpha cells of the pancreas and rarely a problem with diabetics. Instead of lowering blood glucose levels, glucagon causes the liver to release stored glucose into the blood. Glucagon can also stimulate active muscles into releasing glucose stored as glycogen into the bloodstream.
The Pancreas as the Conductor
Throughout a typical day, the healthy pancreas is always secreting a little of both hormones--balancing insulin and glucagon. If the blood glucose levels fall, the pancreas steps up the production of glucagon. If the blood glucose levels rise, such as with diabetics, the pancreas increases insulin levels. In rare situations where there is no available glycogen to convert into glucose, glucagon can also release glucose into the blood from other fuel stores like protein and fat.
Type II diabetics are faced with an even bigger challenge. Their pancreas creates enough insulin, which would normally reduce the level of glucose to a safe range, but the cells in their body have become resistant to it. As a result, even though the pancreas is doing its job, the diabetic still has higher-than-normal glucose levels unless she take steps to lower it through exercise, medications or both.
Too Much of a Good Thing
In some ways, diabetics are faced with the same challenges as their healthier counterparts. If they eat more calories than they expend, the glucose that's not used is stored as fat and glycogen. While this might just mean a few extra pounds for nondiabetics, added body weight for type II diabetics can make their bodies more resistant to insulin, exacerbating their disease.
One large part of diabetes management involves regular exercise. Daily participation in aerobic exercise not only lowers blood glucose, but it also makes the cells of the body (particularly the active muscles) more sensitive to insulin. As a result, the muscles use more circulating glucose, bringing the glucose level down.
