Here Is How the Body Maintains Healthy Blood Sugar Levels
High blood glucose levels stimulate the release of insulin and inhibit glucagon secretion, leading to decreased blood sugar levels. On the other hand, low blood glucose levels inhibit insulin secretion and stimulate the release of glucagon, leading to a rise in blood glucose. These mechanisms help maintain your healthy blood sugar levels.
Effects of insulin
The islets of Langerhans are cells located in the pancreas and they are in charge of secreting hormones. Some islet cells secrete insulin and others secrete glucagon. The principal target organs of insulin are the muscles, liver, and fat cells. It helps them by:
1. Providing energy for these cells
2. Reducing blood glucose levels by stimulating entry of glucose into the cells
3. Breaking down glucose for energy in muscles and liver
4. Storing glucose as glycogen in the liver
5. Storing glucose as fat in fat cells
The muscle, liver, and fat cells can obtain and use glucose only if adequate amounts of insulin are available. Muscle cells use about 75 percent of all the glucose removed from the blood; the rest of cells in our body can use glucose without the help of insulin.
Other functions of insulin are:
1. To stimulate the entrance of amino acids (the building blocks of protein) into cells
2. To stimulate the production of new proteins from amino acids.
Effects of glucagon
Unlike insulin, glucagon causes blood glucose levels to rise by stimulating liver cells to produce and release glucose. The glucose is produced from glycogen in the liver, from the pool of amino acids in the blood and the liver, and from fats in the liver and fat cells.
The antagonistic effects of insulin and glucagon make up the body’s main mechanism for providing adequate and healthy blood glucose levels. Maintaining normal blood glucose levels is important for several reasons:
1. To prevent low glucose levels; this assures that all body cells receive enough glucose to obtain energy and building materials.
2. To prevent hypoglycemia, a condition that can be fatal.
3. To avoid high blood glucose levels; this prevents type 2 diabetes.
4. To secure the production of protein from amino acids. This protein is necessary for the formation and replacement of different parts of the body.
Healthy blood glucose levels
To determine the level of glucose in the blood, several tests can be done through the day. The level of sugar in the blood is often expressed as glucose per 100 ml (per deciliter) of blood plasma. Glucose levels may fluctuate irregularly within the normal range because of changes in body activity.
1. Fasting plasma glucose test
This is the most common way to diagnose diabetes. It is a blood test done early in the morning, after a night fast of at least 8 hours. These are the possible results:
- Less than 100 mg/dl (milligrams per deciliter) = normal fasting glucose
- More than 100 but less than 126 mg/dl = pre-diabetes
- More than 126 mg/dl = provisional diagnosis of diabetes. In this case, the diagnosis must be confirmed with a second test
2. Glucose tolerance test
The ability of the body to reverse a dramatic rise in blood glucose and restore glucose to normal levels is called glucose tolerance. For example, soon after a person has ingested a large quantity of sugar, the blood glucose level may rise above 200 mg/dl.
If that person has good glucose tolerance, blood glucose is brought down below 140 mg/dl within 2 hours of ingesting the sugars, and glucose levels stabilize at 80 to 115 mg/dl soon afterward.
This test is done 2 hours after taking 75 grams of glucose dissolved in water. Possible results are:
- Less than 140 mg/dl = normal glucose tolerance
- More than 140 but less than 199 mg/dl = pre-diabetes
- More than 200 mg/dl = provisional diagnosis of diabetes. The result has to be confirmed with a second test.
3. Casual plasma glucose test for diabetes
This blood test can be done any time of the day without regard to time since last meal. You are not required to abstain from eating prior to the test.
- More than 200 mg/dl plus symptoms of diabetes such as excessive thirst and urination, blurred vision, weight loss, fatigue, and frequent infections that do not heal.
Although aging has essentially no effect on the ability of the pancreas to regulate insulin levels, there is an average increase of insulin levels with age. This is not an age change but is associated with reductions in physical activity and increase body fat. Elevated insulin levels are associated with increased abdominal body fat near the waist.
This increase in insulin results because the muscle, liver and fat cells do not let enough glucose from the blood enter the cells, creating what is known as insulin resistance. Insulin resistance causes both high levels of glucose and insulin in the blood. Because blood glucose remains high, the pancreas releases more insulin into the blood, creating a further complicated situation.
You can reverse high levels of insulin and glucose in the blood by engaging in a program that combines adequate exercise and weight loss. Although insulin levels in the blood occur within a few days of starting such a program, regular exercise must be continued because the improvements begin to decline within three days of ending the program. If you do not continue exercising, the new improved levels of insulin will be lost within several days to two weeks.
To your health!
Emilia Klapp, R.D., B.S.