A Simple Guide To Complex Carbohydrates

Today the potato is back, welcomed again as a favorite by restaurant patrons, owners of microwave ovens, and even the U.S. Surgeon General. For the potato, along with fruits, grains, and other vegatables, is a good source of today's nutritional darling, complex carbohydrates.

Since ancient times, foods containing complex carbohydrates have been considered the traditional nourishers. The Bible tells of how the complex carbohydrate manna miraculously sustained the children of Israel during their progress through the wilderness. Bread, of course, became known as the staff of life, and potatoes, a New World food, were grown on the private lands of Frederick the Great in 1774 to set an example to the German people as an inexpensive and easy way to avoid starvation. Potatoes, breads, cereals, and other foods high in complex carbohydrates have always been regarded as cheap and essential - a staple for the poor. Now, however, as diets high in fats are being linked to heart disease and some cancers, as protein-rich meals are no longer the breakfast of champions, as high dietary fiber (found mostly in complex carbohydrates) is reported to possibly reduce the risk of colon cancer and heart disease, and as Americans learn that a 5-ounce steak has more calories than an equal amount of bread, pasta or potatoes (hold the butter), complex carbohydrates are becoming the chosen food of health-conscious diners in the 1990's. What Are Complex Carbohydrates?

U.S. Surgeon General C. Everett Koop in his 1988 Report on Nutrition and Health recommended reduction in four areas (fats and cholesterol, weight, sodium and alcohol). Only one area received a positive recommendation from the Surgeon General - "complex carbohydrates and fiber." The report says: "Increase consumption of whole grain foods and cereal products, vegetables (including dried beans and peas), and fruits."

According to John Vanderveen, director of the division of nutrition at FDA's Center for Food Safety and Applied Nutrition, complex carbohydrates should make up about 55 percent of the calories in our daily diet, with fat making up 30 percent or less and protein the remainder. In an 1,800-calorie daily diet, that 55 percent represents about 250 grams of complex carbohydrates - nearly 1,000 calories.

Complex carbohydrates, or polysaccharides, are made mostly of long strands of simple sugars. They are found in grains, fruits, legumes (peas and beans), and other vegetables. Complex carbohydrates include three types of dietary fiber - cellulose, hemicellulose and gums - and starches.

A single starch molecule may contain from 300 to 1,000 or more sugar units. The giant molecules are packed side by side in a plant root or seed, providing energy for the plant.

All starches are plant materials. Cereal grains, such as wheat, rice and corn, are rich sources of starch, constituting a large part of the world's food supply, generally in the form of breads and pastas. Starches are also found in potatoes and legumes.

Starchy foods, once avoided by dieters as fattening, are actually a good source of energy for those who want to lose weight. Many people think that starchy foods such as bread, potatoes and pasta are high in calories. They aren't - until the bread is thickly buttered, the potatoes generously topped with sour cream, and the macaroni mixed with cream and cheese sauce. Starches (and proteins) provide only four calories per gram, while fat provides nine calories per gram. Without the toppings, or with only moderate amounts, complex carbohydrate foods can be less fattening than animal-protein foods that naturally contain fat.

What's more, a diet high in carbohydrates just may be more slimming than a diet of comparable calories that is high in fat. Studies still are preliminary, but a research report published in the January 1989 American Journal of Clinical Nutrition suggested that "altering the composition of the diet in favor of a higher carbohydrate-to-fat ratio may decrease the incidence of obesity." The researchers also found that when the participants switched to a diet high in complex carbohydrates, they became full more quickly and unconsciously decreased their caloric intake.

Dietary Fiber

Along with starches, fiber - the other important category of complex carbohydrates - is also gaining popularity for health reasons. (Glycogen is another type of complex carbohydrate, but one that is not of major importance as a nutrient. It's found in small amounts in animal tissue.) And like starches, dietary fiber is found abundantly in plants, especially in the outer layers of cereal grains and the fibrous parts of fruits, legumes, and other vegetables. (See, "Fiber: Something Healthy to Chew On" in the June 1985 FDA Consumer.)

"The discovery of a new dish is more beneficial to humanity than the discovery of a new star," wrote the 18th century French jurist and writer Anthelme Brillat-Savarin. All over 20th century America, people are discovering bran muffins, whole-grain bread, lentil soup, and a host of other foods in addition to the traditionally recognized roughage in cabbage and prunes.

"Eating foods high in fiber has been found to reduce symptoms of chronic constipation, diverticular disease and some types of 'irritable bowel,'" states the brochure Dietary Guidelines for Americans, from the U.S. Departments of Agriculture and Health and Human Services. "It has been suggested that diets low in fiber may increase the risk of developing colon cancer," the guidelines add.

The Surgeon General also finds in the Nutrition and Health report that "there is some indication that plant fiber may reduce blood pressure levels." These effects emphasize the importance of whole grains, dried beans and peas, carrots, and other once overlooked sources of complex carbohydrates.

Carbohydrates For Health

The Surgeon General recommends in his 1988 report increasing consumption of complex carbohydrates as the best alternative to eating fats and cholesterol. The report implies that Americans already eat enough protein and should not increase their intake of this nutrient.

Steak and egg breakfasts for athletes in training have fallen out of favor because, contrary to previous beliefs, excess protein is not essential to build muscles. "If the minimum dietary protein requirements are met, the size of the muscle depends on the physical demands made upon it, rather than the extra amount of protein in the diet," says Sharon Vitousek, M.D., a physician and athlete, in an article on nutrition needs of athletes published in Nutrition Today. Vitousek also suggests that, to meet higher calorie requirements, athletes should increase all foods found in a good diet. (For more about the special dietary needs of athletes, see "Nutrition and the Athlete" in the May 1987 FDA Consumer.)

Some athletes today are loading up on complex carbohydrates in order to increase glycogen (animal carbohydrate) stores in muscles. Building glycogen reserves may improve endurance in some activities, such as running marathons. However, Vitousek adds that glycogen-loading diets for sports may be less effective than originally thought.

Diebetics also may benefit from a diet high in complex carbohydrates and low in fat and sugar, according to the American Dietetic Association. Some researchers believe that dietary fiber improves the ability of diabetics to process blood sugar.

Please Pass The Complex Carbohydrates

Complex carbohydrates have become as American as, well, the baked potato. Fast food chains are now selling this staple alongside the usual french fries. According to one worldwide fast food chain, in 1988 alone the company sold over 70 million 10-ounce baked potatoes. Customers can top their potatoes with everything from sour cream and chives to cheese and broccoli, but they also can opt for the low-calorie, low-fat, plain no-topping version (or with just a little margarine).

Baked potatoes are also making their way into the homes of nine-to-fivers who want a quick but warm and nutritious dinner. Microwave ovens can turn out a baked potato in a matter of minutes instead of an hour, a discovery that delighted early microwave users. (By 1990, according to industry estimates, 70 percent of homes will have microwave ovens.)

Yet, potato consumption has actually remained relatively stable over the past two decades compared to the recent increase in popularity of other complex carbohydrates. The U.S. Department of Agriculture's Economic Research Service (ERS) date show that per capita consumption of potatoes, including sweet potatoes, was 128 pounds in 1987. (USDA figures include food wastage and other non-food use, so they reflect more than food actually consumed. However, the data are useful in spotting trends in consumption.) While potato consumption was virtually unchanged, other complex carbohydrates have been on the rise. Per capita consumption of wheat flour in 1987 was 128 pounds, up 15 percent from 1970. Judith Jones Putnam of the ERS suggests that one reason for the increased use of flour is the rise in consumption of pasta products, up from nearly 8 pounds per person in 1970 to 17 pounds in 1987.

High-fiber breakfast cereals also are showing substantial sales gains. At the same time, awareness that fiber may help prevent colon and other cancers has tripled, according to FDA studies. All together those dieters, athletes, and other health-conscious people have made complex carbohydrates - once a simple staple for the poor - into a new-found "in" food.

RECOMMENDED BOOKS

The Healthy Carb Diabetes Cookbook

Complex Carbohydrates in Foods

The Complex Carbohydrate Handbook

The Mcdougall Program: 12 Days to Dynamic Health

SOME GOOD SOURCES OF STARCH AND FIBER

Good Sources of Starch

Breads, both whole-grain and white

Breakfast cereals, cooked and ready-to-eat

Flours, whole-grain and white

Pastas, such as macaroni and spaghetti

Barley and rice

Legumes - dried peas, beans and lentils

Starchy vegetables, such as potatoes, butter beans, corn, potatoes, sweet peas, lima beans, and navy beans

Good Sources of Fiber

Whole-grain breads, other grain bakery products

Whole-grain cereals, cooked and ready-to-eat

Legumes - kidney beans, lima beans, navy beans, and split peas

Fruits, especially the skins and edible seeds

Nuts and seeds

Dale Blumenthal is a member of FDA's public affairs staff.