There are more chain-sugar carbohydrates, the oligosaccharides, which are of lesser importance. But here are a few facts about what they are, where they’re found, and how your body uses them
You don’t have to concern yourself with getting enough of these carbohydrate sugars. Common foods like oatmeal, Cream of Wheat, and brewer’s yeast, as well as less common foods such as sea vegetables and fungus-type foods, are all good sources. But your body synthesizes pentoses to meet its needs, so the amount in these foods may be eliminated by the body anyway.
Pentose carbohydrates are the “genetic librarians” in every body cell. They help to store and reproduce information relating to your genetic heritage. One pentose, ribose, is necessary for the formation of ribonucleic acid, RNA, the chemical in your cells that holds the codes for protein synthesis. Another pentose is L-xylose. “ Essential pentosuria” is a disorder that is genetically passed on. When it is present, L-xylose is lost in the urine. This has been the cause of clinical confusion since this sugar depletion disorder can produce diabetes-like sugary urine even though diabetes is not present.
If you like beans but they don’t like you, blame it on the two carbohydrates raffinose and stachyose, commonly found in legumes. It is suspected that the reason for this incompatibility is that gas is formed when the bacteria in the large intestine acts upon them. This occurs because the enzymes in your small intestine are not equipped to break down these two carbohydrates into usable components. While raffinose is made up of galactose, glucose, and fructose, and is thus a three-sugar carbohydrate, stachyose has one more saccharide and thus is known as a tetrasaccharide. Raffinose occurs minimally in legumes, grains, and molasses and in a beet-sugar end product; stachyose occurs only in legumes. Soybeans are the best source. Many people are not aware that cellulose roughage is also a carbohydrate. We will discuss fiber in the next section.
Not all sugars are alike. They are broken down into three classes simple, double, and complex. The complex carbohydrates include starches, fibers, dextrins, and a few others. Of the simple sugars, fructose contributes the greatest sweetness. Glucose also called grape sugar, dextrose, corn sugar (made into corn syrup), or blood sugar is very similar but not as sweet. These two sugars combine to produce the double sugar sucrose, table sugar, the most refined and overconsumed of all food ingredients. The other double sugars, maltose, and lactose are also frequent food additives.
The complex carbohydrates are not sweet but starchy. They are found in grains, root vegetables, nuts, and seeds, and are combined with other nutrients. These are refined to produce white flour, white rice, white bread, pastries, and other products with little food value and lacking most of the B vitamins needed to digest them.
Sugars and starches appear everywhere in nature. They are manufactured by plants, and even by animals, which produce lactose (milk sugar) and glycogen (a starch). It is best to eat carbohydrates in their natural form, in fresh fruits and vegetables and whole grains, rather than in the huge quantities found in refined sugar, flour, and cereal products that your body was not really designed to assimilate.
Other, lesser-known complex carbohydrates include pentoses (found in oats and brewer’s yeast) such as ribose, one of the bases of RNA; and raffinose and stachyose, found in legumes. They are another reason why your diet should always be varied enough to assure your body of every food element needed for day-to-day optimum health. No one food group and no one group of carbohydrates provide it all.