Understanding The Mystery Of Your Body And Glucose

Understanding a diagnosis of diabetes starts with understanding how the body absorbs glucose, which is blood sugar, as well as how it is regulated in the body. Diabetes, either type 1 or type 2, results from an inability of the body, specifically the pancreas, to correctly regulate blood sugar through the release of two opposing action hormones. To understand just how glucose works in the body it is essential to start at the point of food consumption.

The Basic Breakdown of Food Into Glucose

The act of consuming almost any type of edible material allows sugar, in the form of glucose, to enter into the digestive system and then into the blood. Some sugar breakdown begins to occur as soon as the food is in the mouth due to enzymes found in the saliva. As the food containing the glucose enters into the intestines the more complex sugars, known as polysaccharides, are broken down into simple sugars or monosaccharides, which include glucose.

This initial breakdown of complex sugars into glucose is due to glycosidases that are produced by the pancreas as well as the intestine itself. Glycosidases are enzymes that cause the breakdown in the linkage in the polysaccharides leading to the building blocks of glucose and other type of monosaccharides. Other components of the intestines, the intestinal flora, aid in the breakdown of some of the most complex types of sugars including sucrose and lactose.

Once the foods consumed are broken down into glucose, the glucose still needs to cross from the digestive system into the blood system. This is done by specific glucose transporters located in the intestinal walls. These are actually membrane proteins that allow the glucose to pass through the interior and exterior layer of membrane of the intestines into the blood system. Once in the blood the glucose circulates through the body and can be used immediately by the cells as fuel.

Individuals that are obese, have high levels of fatty acids in the blood and also make poor food choices that rapidly produce glucose and additional fatty acids may have greater problems with proper functioning of the pancreas. There may be symptoms of hyperglycemia, impaired glucose tolerance, and diminished insulin action in the muscles and fat tissues of the body.1 This in turn affects how the body handles the glucose that is present in its effort to maintain a constant supply to the cells.

Dealing With Glucose Supply

Glucose is the energy source for the body, similar to the gas in a car which keeps the engine running and the wheels turning. The body needs to have a way to store glucose and provide a steady and level amount to the cells in the body. Immediately after eating and while food is digesting there is a naturally high level of glucose in the blood since it is being transported from the digestive system to the bloodstream. However, once digestion is complete the supply will end, which naturally causes a drop in the glucose available to the body cells.

The body has a mechanism by which glucose levels can be maintained through the storage of surplus glucose after eating and the release of glucose into the blood as levels drop during fasting. This is done by a chemical reaction in the body that chains glucose molecules together to create a new material known as glycogen. Glycogen is stored in the liver and the muscles and is then released when the concentration of glucose in the blood drops below a specific level.

This storage and release mechanism is controlled by two hormones in the pancreas that work as on and off switches. Insulin is one and glucagon is the other. Insulin is made in the beta cells in the pancreas, specifically the islets, which are endocrine cells. When insulin is produced by the pancreas due to high levels of blood glucose, the liver and muscle cells store glycogen. In addition, the fat cells become active and use glycerol and fatty acids to further store the glucose in a form that can be used at a later time. The higher levels of insulin in the blood also stop the process of gluconeogenesis or the production of glucose from materials already stored in the body. Protein production is also triggered in response to the higher levels of amino acids in the body.

Insulin resistance occurs in the body for several reasons that are not clearly understood. When this happens the cells of the body do not absorb the available glucose for immediate use and the surplus is not stored. New research indicates that besides the known cellular pathways there may also be a genetic component.

When insulin resistance is not present, the body continues to store glucose until the blood concentration drops. At this point the pancreas produces glucagon, which has the opposite effect of insulin. It is made in the alpha cells of the islets of the pancreas and triggers the body to stimulate gluconeogenesis and glycogenolysis, the breakdown of stored glycogen in the liver and muscles. In a healthy individual that blood glucose concentration will remain at approximately 90 mg per 100 ml of blood throughout the day.

A healthy diet can help in controlling the blood glucose levels, even in an individual already diagnosed with type 2 diabetes and also designated as obese. In a small study group a low carbohydrate diet maintained for two weeks resulted in an increase in insulin sensitivity by approximately 75%. 3

Glucose and Diabetes

Individuals with type 1 diabetes have very low levels of insulin in their blood due to destruction or lack of functioning in the beta cells in the islet cells of the pancreas. Individuals with type 2 diabetes have normal or low functioning pancreatic cells but the other cells of the body are not responding to the insulin present or are unable to utilize the insulin present. Most people with type 2 diabetes have elevated levels of insulin in their blood.

High levels of insulin in the blood, combined with the other symptoms of diabetes, can result in serious health complications. Initially after eating, blood glucose levels spike since the body is not responding to the insulin that should cause the excess glucose to be stored. The body cells signal that they need glucose, despite an abundance in the blood, which triggers gluconeogenesis and glycogenolysis. This further adds to the levels of blood glucose in the body while also breaking down the natural stores in the muscles, liver and kidneys. This excessive amount of glucose is eliminated in the urine, putting additional burden on the filtration systems of the kidneys.

People with type 2 diabetes that is not managed will lose weight, urinate frequently, be very fatigued, be chronically dehydrated and thirsty and will also feel hungry most of the time. The lack of energy to the cells will result in poor circulation, chronic fatigue and difficulties with muscle cramping and exhaustion.

In addition, a process known as ketoacidosis, which occurs because of the high levels of metabolism of fatty acids, occurs within the body. This can result in a range of health problems from respiratory to circulatory and central nervous system failures and irregularities.

References

1 Ohtsubo, K., Chen, M. Z., Olefsky, J. M., & Marth, J. D. (2011). Pathway to diabetes through attenuation of pancreatic beta cell glycosylation and glucose transport. Nature Medicine , 1067-1075.

2 Houstis, N., Rosen, E. D., & Lander, E. S. (2006). Reactive oxygen species have a causal role in multiple forms of insulin resistance. Nature , 944-948.

3 Broden, G., Sargrad, K., Homko, C., et al. (2005). Effect of a Low-Carbohydrate Diet on Appetite, Blood Glucose Levels, and Insulin Resistance in Obese Patients with Type 2 Diabetes. Annals of Internal Medicine , 403-411.

This article was originally published July 12, 2012 and last revision and update of it was 9/10/2015.