Index of Dictionary Terms

F

Fasting Blood Glucose Test

A method for finding out how much glucose (sugar) is in the blood. The test can show if a person has diabetes. A blood sample is taken in a lab or doctor's office. The test is usually done in the morning before the person has eaten. The normal, nondiabetic range for blood glucose is from 70 to 110 mg/dl, depending on the type of blood being tested. If the level is over 140 mg/dl, it usually means the person has diabetes (except for newborns and some pregnant women).

Fats

One of the three main classes of foods and a source of energy in the body. Fats help the body use some vitamins and keep the skin healthy. They also serve as energy stores for the body. In food, there are two types of fats: saturated and unsaturated.
Saturated fats are solid at room temperature and come chiefly from animal food products. Some examples are butter, lard, meat fat, solid shortening, palm oil, and coconut oil. These fats tend to raise the level of cholesterol, a fat-like substance in the blood.

Unsaturated fats, which include monounsaturated fats and polyunsaturated fats, are liquserid at room temperature and come from plant oils such as olive, peanut, corn, cottonseed, sunflower, safflower, and soybean. These fats tend to lower the level of cholesterol in the blood. See also: Carbohydrate; protein.

Fatty Acids

A basic unit of fats. When insulin levels are too low or there is not enough glucose (sugar) to use for energy, the body burns fatty acids for energy. The body then makes ketone bodies, waste products that cause the acid level in the blood to become too high. This in turn may lead to ketoacidosis, a serious problem. See also: Diabetic ketoacidosis.

Fiber

A substance found in foods that come from plants. Fiber helps in the digestive process and is thought to lower cholesterol and help control blood glucose (sugar). The two types of fiber in food are soluble and insoluble. Soluble fiber found in beans, fruits, and oat products, dissolves in water and is thought to help lower blood fats and blood glucose (sugar). Insoluble fiber, found in whole-grain products and vegetables, passes directly through the digestive system, helping to rid the body of waste products.

Fluorescein Angiography

A method of taking a picture of the flow of blood in the vessels of the eye by tracing the progress of an injected dye.

Food Exchange

See: Exchange lists.

Foot Care

Taking special steps to avoid foot problems such as sores, cuts, bunions, and calluses. Good care includes daily examination of the feet, toes, and toenails and choosing shoes and socks or stockings that fit well. People with diabetes have to take special care of their feet because nerve damage and reduced blood flow sometimes mean they will have less feeling in their feet than normal. They may not notice cuts and other problems as soon as they should.

Fractional Urine

Urine that a person collects for a certain period of time during 24 hours; usually from breakfast to lunch, from lunch to supper, from supper to bedtime, and from bedtime to rising. Also called "block urine."

Fructose

A type of sugar found in many fruits and vegetables and in honey. Fructose is used to sweeten some diet foods. It is considered a nutritive sweetener because it has calories.

Fundus of the Eye

The back or deep part of the eye, including the retina.

Funduscopy

A test to look at the back area of the eye to see if there is any damage to the vessels that bring blood to the retina. The doctor uses a device called an ophthalmoscope to check the eye..