Encyclopedia of Diets - A Guide to Health and Nutrition

OTHER

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Tish Davidson, A.M.

Diabetes mellitus

Definition

Diabetes mellitus is a condition in which the pan-

creas no longer produces enough insulin or cells stop

responding to the insulin that is produced, so that

glucose in the blood cannot be absorbed into the

cells of the body. Symptoms include frequent urina-

tion, lethargy, excessive thirst, and hunger. The treat-

ment includes changes in diet, oral medications, and in

some cases, daily injections of insulin.

Description

Diabetes mellitus is a chronic disease that causes

serious health complications including renal (kidney)

failure, heart disease, stroke, and blindness. Approx-

imately 17 million Americans have diabetes. Unfortu-

nately, as many as one-half are unaware they have it.

Background

Every cell in the human body needs energy in order to

function. The body’s primary energy source is glucose, a

simple sugar resulting from the digestion of foods contain-

ingcarbohydrates(sugars and starches). Glucose from the

digested food circulates inthe blood as a ready energy

source for any cells that need it. Insulin is a hormone or

chemical produced by cells in the pancreas, an organ

located behind the stomach. Insulin bonds to a receptor

site on the outside of cell and acts like a key to open a

doorway into the cell through which glucose can enter.

Some of the glucose can be converted to concentrated

energy sources like glycogen or fatty acids and saved for

later use. When there is not enough insulin produced or

when the doorway no longer recognizes the insulin key,

glucose stays in the blood rather entering the cells.

The body will attempt to dilute the high level of

glucose in the blood, a condition called hyperglyce-

mia, by drawingwaterout of the cells and into the

bloodstream in an effort to dilute the sugar and excrete

it in the urine. It is not unusual for people with undiag-

nosed diabetes to be constantly thirsty, drink large

quantities of water, and urinate frequently as their

bodies try to get rid of the extra glucose. This creates

high levels of glucose in the urine.

At the same time that the body is trying to get rid of

glucose from the blood, the cells are starving for glucose

and sending signals to the body to eat more food, thus

making patients extremelyhungry. To provide energy for

the starving cells, the body also tries to convertfatsand

proteins to glucose. The breakdown of fats and proteins

for energy causes acid compounds called ketones to form

in the blood. Ketones also will be excreted in the urine. As

ketones build up in the blood, a condition called ketoa-

cidosis can occur. This condition can be life threatening if

left untreated, leading to coma and death.

Types of diabetes mellitus

Type I diabetes, sometimes called juvenile diabe-

tes, begins most commonly in childhood or adoles-

cence. In this form of diabetes, the body produces

Target blood glucose levels for people with diabetes

Before meals 90 to 130

1 to 2 hours after the start of a meal less than 180

SOURCE: National Institute of Diabetes and Digestive and Kidney

Diseases, National Institutes of Health, U.S. Department of

Health and Human Services

(Illustration by GGS Information Services/Thomson Gale.)

Diabetes mellitus