In United States, the natural sugars of milk, fruits, vegetables, and grains account for about half of the sugar intake, the other half consists of concentrated sugars that have been refined and added to foods for a variety of purposes.
Sugars, important in nutrition, consist of monosaccharides, having the general formula C6H12O6, and disaccharides, having the general formula C12H22O11.
Although the monosaccharides consists of 3-carbon sugars (trioses), 4-carbon sugars (tetroses), 5-carbon sugars (pentoses), and 6-carbon sugars (hexoses), only the latter are important in human nutrition as sources of energy.
Three monosaccharides are important in nutrition: glucose, fructose and galactose. All three monosaccharides have the same number and kinds of atoms but in different arrangements.
Glucose, a 6-carbon sugar, is one of the simplest carbohydrates found in foods. While many foods contain traces of glucose, it is found in significant amounts only in fruits, such as grapes.
Most cells depend on glucose for their fuel to some extent and the cells of the brain and the rest of the nervous system depend almost exclusively on glucose for their energy.
Fructose, also a 6-carbon sugar, is found in ripened fruits and honey, both of these sugars can be utilizes by body as a source of energy. It is the sweetest of the natural sugars.
Other source of fructose include soft drinks, ready to eat cereals and other products sweetened with high fructose corn syrup.
Lactose, the 12-carbon sugar present in milk, is broken down in the intestine to glucose and lactose (6-carbon sugar), both of which can be used as sources of energy.
Maltose, another disaccharide, produced form starch in the malting of grains is much less effective sweetener than sucrose.
The used of added sugars had risen steadily over the past several decades, both in the United States and around the world, with soft drinks and sugared fruit drinks accounting for most of the increase.
Sugars
