How Do We Get Glucose?

Glucose is defined as a single sugar that is the main mechanism for energy production in your cells. Sugars are either simple or complex. A simple sugar, such as glucose, is a single saccharide or sugar unit. A complex sugar occurs when units of sugars are chemically bonded together to form a polysaccharide, according to the book "Nutrition: Concepts and Controversies" by Frances Sizer and Eleanor Whitney.


Dietary Glucose

Glucose is found in many forms of carbohydrates that you consume. It's the major building block of polysaccharides, or chains of sugars. Dietary glucose is found in mostly plant-based foods, including simple sugars, starches and fiber. Whatever kind of carbohydrate that you eat eventually gets broken down into its simplest form: glucose, according to Sizer and Whitney.

Digestion and Absorption of Glucose

Digestion of carbohydrates begins in your mouth. As soon as you start chewing food, your teeth and enzymes in your saliva begin to break down your food. Once it passes through your stomach and into your small intestine, the food you ate as a polysaccharide eventually gets broken down. Digestive enzymes convert polysaccharides into the simple sugar, glucose. Once carbohydrates are converted into glucose, sodium-glucose transport proteins remove the glucose from the small intestine and send them to the bloodstream, where they are transported to your liver. From there, your liver determines where they are needed most, according to the book "Anatomy and Physiology."


Gluconeogenesis is the process by which your body converts substances that are not glucose into glucose. This process usually only occurs under circumstances in which the body is starved of glucose or during intense exercise. During starvation, your body may begin breaking down proteins and turn them into glucose. This is because certain cells, such as brain cells, can only run on glucose. During intense exercise, byproducts of cellular metabolism are lactic and pyruvic acid. Your liver is able to absorb these acids and convert them to glucose. This is an ingenious way your body reduces blood pH and provides needed energy for your working cells, says the book "Exercise Physiology."


Certain conditions can affect the way your body handles glucose. For example, diabetes is a condition in which glucose clearance from your blood is impaired. Your body can still digest and absorb glucose, but the mechanism for glucose entering into your cells is affected. For a condition such as diabetes, intake of carbohydrates and blood glucose levels must be closely monitored, it says in "Exercise Physiology."

  • Nutrition: Concepts and Controversies; Frances Sizer and Eleanor Whitney
  • Anatomy and Physiology; Kenneth S. Saladin
  • Exercise Physiology; George A. Brooks, Thomas D. Fahey, Kenneth M. Baldwin

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