The sugars and starches described in the previous section are known as the available carbohydrates.
But there is another, very important form of complex carbohydrates besides these. They provide no known nutrients; they pass right through the digestive tract and are eliminated, virtually impervious to the barrage of powerful enzymes, acids, and microorganisms that pulverize and digest the rest of your food.
Yet without them, you are subject to such problems as constipation, diverticulitis, appendicitis, and cancer of the colon.
These unavailable carbohydrates, the indigestible polysaccharides, are, of course, the fibers found in fruits, vegetables, and grains. Fiber is so prevalent in plants that it is absurd that Americans rarely get enough of it. Cellulose is more abundant than any other organic compound in the world. The name “unavailable carbohydrates” refers to the fact that these carbohydrates are not metabolized in the body not to lack abundance!
The members of the fiber family include cellulose, hemicellulose, lignin, pectin, agar, alginates, and vegetable gums such as carrageen (Irish moss).
When you eat an apple you are getting a little fructose, a bit more glucose, and a lot of cellulose. These carbohydrates don’t compete with one another. The sugars provide sweetness, and cellulose lends strength. If you looked at cellulose under the microscope, you would see a strong fibrous substance that does not dissolve in water. These properties make it desirable for many commercial purposes; for example, natural clothing fibers such as cotton are made of cellulose. Considering its physical qualities, it should come as no surprise that cellulose occurs largely in the cell walls of plants, shaping and supporting each cell and the plant as a whole.
Despite the fact that cellulose is indigestible and yields no vitamins, minerals, or nourishment for your system, it is indispensable. Fiber keeps your intestines swept out. The microflora in your large bowel degrades cellulose only slightly, but this unavailable carbohydrate is available to prevent clogged bowels and colon. Along with absorbing water to make your stool soft, and adding bulk and weight so it can pass easily, cellulose absorbs toxins and helps eliminate them from your system.
Fiber is crucial to digestion. One of its most important roles is to stimulate the intestinal movements, peristalsis, which pushes the food to pass through the digestive tract. Thus, fiber is a natural laxative far healthier than the artificial, chemical laxatives to which so many Americans are addicted, and which actually end up preventing peristalsis from proceeding normally. Unlike chemical laxatives, fiber gives the muscles along the walls of your intestines the exercise they need to keep functioning properly for you.
Many staple foods are rich in valuable roughage. Cellulose is found in the outer or bran layer of grains, such as whole rye, brown rice, and wheat kernels. There is no need to sprinkle bran on your food if you eat the whole grains in the first place. Bran is just one of the layers discarded when the grain is refined. Why pay extra to the manufacturers to buy again what they shouldn’t have separated from your grain in the first place?
Cellulose is also found in the “stringy” section of common fruits and vegetables, especially the ones that call for lots of chewing apples, celery, and carrots, for example.
Should you eat your vegetables cooked or raw? A good cellulose source may in some cases be a poor nutrient source if you don’t break down at least some of the cellulose of the cell walls by chewing, cooking, or steaming. A high-fiber root vegetable such as a carrot is one example of food whose nutrients are available If you chew it well or cook it. Grinding or sprouting are other ways to treat whole grains so that the nutrients they contain will be available to your body cells.
Though fiber is easily available in nature, there are foods that contain virtually no fiber. Any food that has been highly processed by the manufacturer, fruit juices without any pulp or sediment, honey so clear you can see through it, Minute Rice, and most white bread have negligible amounts. Some relatively natural foods like meat and fowl are nearly fiber-free, too.
Cellulose is often found with pectin, another “roughage” carbohydrate derived mostly from fruits such as grapes, apples, peaches, plums, and berries. This complex sugar may help keep your cholesterol levels low and healthy. Pectin absorbs and holds water. If you are a home jam and jelly maker, you have probably used pectin to turn fruit juice into fruit spread. But pectin is more than a gelling agent. It is a polysaccharide that is beneficial, especially when used as it occurs naturally with large amounts of cholesterol-lowering fiber. Although vegetables supply this complex sugar, too, the richest fruit pectin sources are plums, real apple juice (79 percent), and blackberries (53 percent).
Agar, like pectin, is used as a gelling agent. Agar comes not from fruits but from seaweed.
VEGETABLE GUM AND ALGINATES
The vegetable gum carrageen (Irish moss) and the alginates (from seaweed) are often added to packaged foods like ice cream. They smooth out the texture of mixed ingredients. They are harmless food additives, although they may be added to foods whose texture wouldn’t seem of such high quality without them.
A Riddle About Carbohydrates
If both vegetables like carrots and snacks like caramels contain carbohydrates from which glucose is derived for energy, why does one supply quick energy while the other doesn’t?
Part of the answer concerns the slow pace of digestion of complex carbohydrates. The candy is composed largely of refined sugar, so your body converts it rapidly into its two main carbohydrate components fructose and glucose and within minutes you feel a lift as it is picked up by your bloodstream.
By comparison, nature had something else in mind with a vegetable, with its more nourishing but complicated combination of carbohydrates. The various polysaccharides are broken down at a slower pace than table sugar. The energy from sunlight that photosynthesis has locked into the carrot’s starches and sugars take longer to become available but also lasts longer.
Another part of the answer concerns the role of fiber indigestion. The carrot has fiber, but the empty-calorie snack has none. The indigestible fiber helps lubricate the gastrointestinal tract and assures normal digestion and elimination; however, it also locks some of the starches and sugars inside the carrot’s cells.
There is a way to get a “quick energy” lift from a carrot, though. Put it through a juicer! (If you don’t own one, many health food stores, snack bars, and restaurants now do, and sell fresh carrot juice.) This will pulverize the cell walls and make the sugars (and starches) inside more quickly available for digestion and absorption.
This is a much healthier dose of sugar than that from caramel. Since it is less concentrated and smaller in quantity, it does not contribute to stress by causing blood sugar levels to fluctuate, as does the candy. Drinking small quantities of carrot juice won’t give you hypoglycemia. Too much candy may.
The unavailable carbohydrates are among the most important. They provide no energy yet without them we are liable to suffer the loss of energy that comes from poor digestion.
Cellulose, from the cell walls of plants, is also known as dietary fiber or roughage. It stimulates peristalsis and keeps the intestines clear of residue and toxic wastes. It absorbs water from the intestines, adding bulk and weight to the stool and making it smooth and easy to eliminate. It is found in whole grains, fruits, and vegetables. It beats chemical laxatives hands down since it prevents the intestines and colon from getting lazy and out-of-practice.
Other unavailable carbohydrates are used in home and industrial food processing. They include pectin, agar, alginates, and vegetable gums.