Carbohydrates - Diet and Nutrition

Carbohydrates

Carbohydrates are the principal source of the body's energy and are also used in the synthesis of some cell components such as DNA. The two principal types of carbohydrates are simple sugars (found predominantly in fruit) and complex carbohydrates (found in grains, fruits, and vegetables). Of the simplest sugars, glucose is the most common. Glucose is a carbohydrate freely soluble in blood and cell fluids, and supplies energy to all the body's tissues. Although only small amounts of glucose are ingested, most foodstuffs (with the exception of fatty acids) must be converted to glucose before being utilized for energy in the body. Other simple sugars include fructose (one of the sweetest sugars) found in fruits and honey, sucrose (or common table sugar) harvested from sugar cane and sugar beets, and lactose, which is found almost exclusively in dairy products.

So long as it is consumed in the proper amounts, sugar is not harmful. Unfortunately, since many food manufacturers use sugars to flavor their products, Americans tend to consume an excess of sugar. It is estimated that the average American now consumes almost a third of a pound of refined sugar each day in synthetic foods. Some scientists, according to Peter Jarret, think that overconsumption of sugar may be related to several degenerative diseases and may cause a person's body to age more rapidly.

Complex carbohydrates are present in such foods as grains (wheat, rice, corn, oats, and barley), legumes (peas and beans), plant roots, leaves and stems (most vegetables), and some animal tissues. They consist of two major classes: starch, which is digestible and utilized to supply molecules for energy production and cellular structure; and fiber, which is not digestible but nevertheless important for removing wastes from the body. Starch is present in granules within seeds, pods, or roots of plants. The animal form of starch, glycogen, is found in muscle and liver. Most of the starch in an average person's diet comes from foods made from flour, such as bread, noodles, and pastries.