May 31, 2013

Glucose, Fructose, Sucrose

Glucose, fructose and sucrose are three types of sugar. Sugar production has been around for a few thousand years.  In 2011, worldwide production of table sugar was about 168 million tons.

Glucose, also known as dextrose, is the most common sugar. It is rarely found in food in its single molecular form, but is found as a building block for more complex carbohydrates. Foods containing glucose include: bread, pasta, cereals, rice, most fruits and vegetables, dairy products, maple syrup, pancake mixes, commercial salad dressings, and spices, and all foods containing sugar. Brain cells show a marked preference for glucose.

Fructose is the sugar that sweetens fruits, and it is also naturally present in some vegetables. One of the major differences between fructose and glucose is that cells require insulin to take up glucose from the bloodstream, but fructose is absorbed directly without insulin.  Fructose a healthier choice for individuals with diabetes than glucose or sucrose. Foods rich in fructose include, agave, apricots, blueberries, figs, dates, grapes, honey, and raisins.

Sucrose is made up of two smaller sugar units, glucose and fructose. Sucrose is the type of sugar you use in your kitchen and in cooking. It is usually derived from either sugar cane or sugar beets. An apple contains both fructose and glucose. Sucrose is digested into glucose and fructose before it enters the bloodstream.

Glucose, fructose, and sucrose contain identical amounts of energy. Each provides four calories per gram.  Glucose and fructose units are absorbed across the intestinal wall by active transit into the portal vein. They are then transported to the liver where they are converted to energy units. When reading food labels, sucrose can be listed as sugar, glucose can appear as dextrose, and fructose as corn syrup or high-fructose corn syrup.

Bottom line - Cells require a constant supply of energy to keep running. Glucose and fructose have identical chemical formulas. Glucose and fructose can be burned for immediate energy or stored as body fat. It is not important where sugar comes from. Too little and your body is deprived of much needed nutrients, too much and your body stores sugars as fat. There is a correlation between increased soda consumption and obesity, but no proven causation. Headlines about soda and obesity are mostly non-scientific mumbo jumbo designed to titillate, but not educate.