Glucose and the Body.
What is Glucose?
Glucose is a monosaccharide (a sugar). Carbohydrates are broken down
during digestion into glucose. The body’s cells use glucose to make energy to fuel the
body. Sometimes the words blood glucose and blood sugar are used interchangeably.
The human body requires glucose for some of its most important functions. This simple sugar provides the energy needed to perform specialized processes such as digestion and cellular respiration.
What does it do?
Glucose is the primary energy source for the brain and a source of energy for cells throughout the body. This energy helps the cells carry out nerve cell conduction, muscle cell contraction, active transport and the production of chemical substances. When you eat foods that contain starches, enzymes from the saliva and pancreatic juices break them into maltose molecules. The small intestine makes glucose molecules by splitting the maltose. The bloodstream then carries the glucose to the liver for storage or for use as an energy source.
Hypoglycemia occurs when blood glucose levels fall below normal. Normal fasting blood glucose levels range from 70 to 99 mg/dL. Low blood sugar levels cause confusion, anxiety, weakness, hunger, dizziness, shakiness and difficulty speaking. Hyperglycemia occurs when blood glucose levels rise above normal. This condition causes frequent urination, excessive thirst and high levels of glucose in the blood and urine.
Diabetes is one of the most common disorders associated with glucose. In people without diabetes, a hormone called insulin carries glucose from food into the cells of the body. People with diabetes do not use insulin properly or do not make enough insulin in the pancreas. As a result, the glucose remains in the bloodstream instead of entering the cells, causing high blood glucose levels. Signs of diabetes include excessive thirst, unintended weight loss, dry skin, blurry eyesight, excessive hunger, fatigue, frequent urination and tingling in the feet.
A popular misconception is that glucose levels change only in response to eating sugary snacks and drinks. Because the body makes glucose from the maltose in food, any food that contains carbohydrates affects blood sugar levels. These foods include fruits, vegetables, breads and pasta. Physical activity and the use of diabetes medications also affect the amount of glucose in the bloodstream.