Diabetes (Diabetis) 101: Defining the Disease and How to Test for It

(Part 1) Originally published September 3, 2008
Written by Ella Andersen

Amid the many health problems facing America today, two prominent problems are thrust into the forefront: obesity and diabetes. With soaring rates of obesity and diabetes reaching number six on the Centers for Disease Control's Causes of Death in the United States list, the time has come to really take a closer look at these illnesses. Most know about diabetes and obesity, but what is known to a lesser extent about these particular disorders is an underlying cause: insulin resistance. The purpose of this paper is to analyze the underlying contributing factors that fuel these problematic disorders; the main points are diabetes and insulin, insulin resistance, causes of insulin resistance, obesity and insulin resistance, and finally, potential solutions.

Diabetes and Insulin

Though many Americans suffer from diabetes (according to the Centers for Disease Control, approximately 15.8 million in 2005), comparatively few know about the underlying cause and the relationship between diabetes and insulin. Firstly, to accurately address the diabetes issue, a description of diabetes and insulin is needed. Insulin is a hormone secreted by the pancreas and its primary function is to lower blood glucose (sugar) levels as needed along with maintaining the balance of lipids and amino acids in blood. When simple carbohydrates are consumed, they are easily broken down, and blood glucose rises. When glucose levels rise, insulin is released by the pancreas to lower said glucose levels (Powers, R.). After the glucose levels have returned to normal, insulin levels in the blood are lowered as well (Biology 1073).

Diabetes mellitus (its technical name) is a disorder of inappropriate blood-insulin levels and is divided into to two sub-groups: type I and type II (Biology, 1073 and Contemporary Nutrition, 126). Type I diabetes, according to Biology, is characterized by the pancreas being attacked by immune cells (1073). Subsequently, there is not enough insulin circulating in the blood, and blood glucose is not utilized by cells but remains circulating in the blood at very high levels (Biology 1073). This is problematic because cells are not able to garner enough of the energy needed to perform necessary actions. If left untreated, type 1 diabetes mellitus can be fatal.

In type II diabetes, the pancreas is not being attacked by immune cells; rather, the cells lose their ability to respond to insulin. This form of diabetes mellitus is more prevalent in America than type I diabetes, being estimated to afflict approximately 10-15 million Americans (Biology 1073). Again, if this disorder is left untreated, the results can be fatal because of dangerously high levels of insulin and glucose in the blood.

Insulin Resistance

Insulin resistance comes into the picture with type II diabetes and only this form. Gilesa Wilcox et al, in her article Insulin and Insulin Resistance defines insulin resistance in this manner, "Insulin resistance is defined where a normal or elevated insulin level produces an attenuated biological response (2); classically this refers to impaired sensitivity to insulin mediated glucose disposal (3)." In more plain terms, insulin resistance is the loss of responsiveness that occurs on the insulin-receptor of a cell (particularly liver, muscle and fat cells, with the liver losing sensitivity first, then the muscle and then the fat cells); this leads to type II diabetes. Insulin resistance can be detected in three ways: fasting glucose test, glucose tolerance test, and the euglycemic clamp test. First, to determine whether or not someone is afflicted with insulin resistance, according to the National Diabetes Information Clearinghouse (NDIC), a physician will examine a patient's fasting blood glucose levels. A fasting blood glucose level higher than 100-125 mg/dL is not indicative of diabetes, but it can be indicative of insulin resistance and is above normal levels.

The second test is the glucose tolerance test. This test measures blood glucose levels after an overnight fast and then again two hours later measuring blood glucose levels after something sugary (typically some kind of juice) has been consumed. A blood glucose reading between 140-199mg/dL is quite high, still not indicative of diabetes, but high enough to engender concern that left untreated, the patient will develop diabetes (Powers, R.).

The third testing measure is the most accurate way to determine insulin resistance: the euglycemic clamp test. Though it is the most accurate measure, it is also the most inconvenient measure. According to NDIC, the euglycemic clamp test is employed by investigators to more accurately measure glucose metabolism. In the euglycemic clamp test, "...insulin is infused to maintain a constant plasma insulin level. Glucose is then infused and, as the plasma level falls because of the action of insulin, more glucose is added to maintain a steady level. The amount of glucose infused over time provides a measure of insulin resistance," (Goutham Rao, M.D.) It is not commonly used in doctors' offices due to its expense, but is worth mentioning because, as stated before, it is the most accurate way to determine insulin resistance status (NDIC).

These tests, though highly accurate in detecting insulin resistance, still are not totally effective in concretely diagnosing the condition. Furthermore, pre-diabetes (as it is also known) is typically asymptomatic making it even more difficult to detect; however, severe cases of insulin resistance can manifest themselves as a condition known as acanthosis nigricans. Acanthosis Nigricans is characterized by dark skin patches that form on elbows, knees, knuckles, armpits, and the neck (sometimes a dark ring around the neck or a patch on the back of the neck)(NDIC). Other than the aforementioned condition which is only seen in the most severe cases of insulin resistance, there are no apparent symptoms.

In Part 2 of this series, the causes of insulin resistance will be examined.

About the author

Ella Andersen is a college student who intensely researchs topics on health and nutrition. In college, she is furthering her love of nutrition by pursuing a degree in clinical dietetics.
This passion for natural health, nutrition and wellness has driven her to run her own blog:
http://www.snhbw.blogspot.com