Sugars Found In White Bread

White bread is often used as a reference food for glycemic index, or GI, tests because of how rapidly it affects blood glucose levels. White bread has such an impact on blood glucose because of its high carbohydrate and sugar content, which is quickly digested and absorbed into the bloodstream, converted to glucose and used for immediate cellular energy. White bread is made from wheat flour, although it goes through an elaborate milling process in which the bran and germ of the seeds are stripped, resulting in a loss of nutritional value. Aside from water, carbohydrates make up the majority of the weight and caloric value in white bread.

Total Sugars

According to the USDA National Nutrient Database for Standard Reference, 1 slice of commercially prepared white bread, weighing 25 g, contains 12.65 g of total carbohydrates. Of those carbs, 1.08 g is in the form of sugars. Sugars are simple carbohydrates that can contain either one or two saccharide molecules. Carbohydrates are ultimately broken down into their basic sugar molecules when digested, and they are used for energy, stored as glycogen or as fat, or used to build protein.

Monosaccharides

Monosaccharides are simple sugars containing just one saccharide. A slice of white bread contains 0.34 g of the monosaccharide glucose and 0.46 g of the monosaccharide fructose. Glucose is a natural sugar found in both food and the human bloodstream, and it is the main source of energy for the human cell. Fructose is a natural sugar found in fruit and honey. The human bloodstream can absorb small amounts of fructose, but this sugar is generally converted to glucose after digestion.

Disaccharides

Disaccharides are simple sugars consisting of two attached saccharide molecules. All disaccharides contain glucose as one of their building blocks. According to the USDA, a slice of commercially prepared white bread contains 0.28 g of the disaccharide maltose. Maltose, or malt sugar, is formed from two units of glucose attached together. Maltose is commonly found in beer and germinating grains, and it is the least common disaccharide in nature.

Starch

The majority of the carbohydrates in a slice of white bread, according to the USDA, exist in the form of starch. Of the 12.65 g of carbohydrates per slice, 10.15 g come from this plant-derived polysaccharide. While not a sugar, starch is a complex carbohydrate composed of hundreds of units of glucose. Starch is exclusive to plant foods, and when digested in the human body it is broken down into its individual glucose units, releasing sugar into the bloodstream.