<i> Scott is a Times medical writer. </i>

The intrepid science of food engineering reached an improbable juncture at UC Berkeley recently when food scientist Benito de Lumen began designing a bean devoid of that disconcerting attribute for which the legume is best known.

De Lumen’s quest for a flatulence-free frijole is part of a booming field of food research that has already produced such seeming gustatory oxymorons as low-cholesterol eggs, dietetic chocolate ice cream and high-fiber hamburger buns.

The ability of scientists to design foods without their old drawbacks offers more than a promise of guilt-free gluttony: It holds out hope of controlling such threats as heart disease and cancer, linked to excesses in the American diet.

But whether engineered food will fulfill that potential remains to be seen. Some nutritionists have doubts. They warn that such foods, consumed immoderately, could lead to new nutritional problems on a par with those they are intended to avert.


“One could envision in the next 10 years that it would be possible to engineer any food that we eat that would be almost devoid of any nutritional content except for fiber, vitamins and minerals,” says Theodore Labuza, a food scientist at the University of Minnesota.

“Now it’s very possible that the incredulous consumer . . . would begin eating these products solely. So they would end up not with vitamin or mineral deficiencies but . . . protein deficiencies and energy deficiencies.”

What are the benefits and drawbacks of engineered foods? It is almost impossible to generalize. Some have no known shortcomings, but others may--especially if they shoulder out more healthful foods from the American diet, nutritionists say.

Low-fat and skim milk, for example, have no down-side. They offer all the benefits of whole milk without the fat and calories. Like modified mozzarella and ricotta cheese, they offer more protein, vitamins and calcium than the products they are designed to replace.


But fat substitutes don’t necessarily work that way. One, sucrose polyester, is not even digested by the body. That means that it has no calories or cholesterol, but that it also offers none of the essential fatty acids people need for growth and maintenance of their skin.

Such a shortcoming matters little if the product is used in moderation. What concerns some nutritionists is that it might be consumed in excess, drawing eaters towards foods that have suddenly been rendered innocuous and away from more fortifying alternatives.

“If we have both artificial sweeteners and fats, will people eat more cake?” wonders Audrey Cross, a nutritionist and lawyer at Columbia University School of Public Health. “And if they do, what will they be leaving out of their diet that they were eating before?”

Not only might people eat less fruit, but they actually may eat more sugar as well. It remains to be proven that substitutes for foods such as fats and sugar can accomplish what promoters say they can--that is, that they can reduce consumption of the real thing to recommended levels by substituting a less harmful alternative.

Per capita consumption of sugars has risen steadily since the introduction of artificial sweeteners, health experts point out. Artificial-sweetener use has also soared, leading some experts to wonder whether sweeteners stimulate some people’s appetite for sugar.

Obesity, too, has continued to increase.

“Thus far, there is no evidence that the proliferation of low-calorie foods, analogs and ingredients has affected the status of obesity in the United States,” the Institute of Food Technologists, a professional scientific society, reported recently. “National statistics . . . show an increase in the prevalence of obesity, certainly no decrease.”

The first federal health and nutrition survey, conducted between 1971 and 1974, found that 28.8 million American adults were obese, 8.4 million of them severely. The second survey, done between 1976 and 1980, found that the numbers had risen to 34 million and 13 million, respectively.


Part of the impetus for redesigning foods arises out of the growing evidence that diet plays a significant role in the development of chronic diseases--specifically, diseases such as hypertension, atherosclerosis, diabetes, liver disease and cancer of the breast.

Research indicates that one’s risk of contracting such diseases can be controlled by selecting carefully the foods one eats. Numerous scientific panels have urged Americans to eat less food heavy in fat, and more high-fiber foods such as vegetables and fruits.

“Engineering of foods, I think, is terrific,” says Wayne Bidlack, an associate professor of pharmacology and nutrition at the University of Southern California. “We can decide what nutrients need to be delivered where, and design products for whatever is lacking.”

Nearly 8,000 of the food products introduced in the United States in 1987 involved nutritional modification, industry statistics show. Of those, more than 400 boasted reduced calories, 159 lower fat, 120 reduced sugar and 55 added fiber.

The U.S. Food and Drug Administration is reviewing petitions to market two fat substitutes. Several sugar surrogates are in wide use and others are on the way. Fiber is being transferred, meats are being restructured. Even the walnut is up for grabs.

“I think the food supply is very, very difficult to make your way through intelligently--for a consumer or for a nutritionist,” says Joan Gussow, a professor of nutrition and education at Teachers College, Columbia University.

Yet, deciphering the nutritional benefits and drawbacks of engineered foods is left largely to the consumer: The FDA regulates food additives and foods for special dietary uses, but its scrutiny is limited largely to the product’s safety.

The agency examines an additive’s chemical structure and the levels at which it is toxic in animals. But it does not address whether the product is nutritionally beneficial or desirable, says Gerad L. McCowin, who heads the FDA’s division of food and color additives.


“That there’s a synthetic fat substitute or an artificial sweetener available, in and of itself, is neither good nor bad societally or nutritionally,” he says. “What’s good or bad is how the individual combines those various foods.”

A prime target of food engineering is fat. Fats currently make up 37% to 40% of the average American adult’s caloric intake, but experts in heart disease and cancer have recommended that Americans lower that level to 30% or less.

Most attempts to reduce fat in animal products have involved simple physical steps such as close trimming of beef cuts. Through selective breeding, farmers have also been reducing the back fat in hogs and abdominal fat in poultry.

So-called restructuring--dismantling a piece of meat and putting the parts back together as a new product--is being used to produce leaner meat. Although researchers say that salt is added to the meat in the process, they say it is in quantities too small to taste.

Some new “lite” deli meats may have a greater problem with salt, according to the Institute of Food Technologists. For that reason, the group concluded that modified convenience foods may offer little nutritional advantage over carefully selected fresh meats.

But the most radical assault on fats is coming from substitutes.

Sucrose polyester is made by chemically linking several fatty acid molecules to a molecule of sucrose, or table sugar. Because of its structure, it is not metabolized by the body and therefore contributes no fat, calories or cholesterol.

Procter & Gamble, which calls the product Olestra, has applied to the FDA to use it in shortenings and oils. If used widely, Olestra theoretically could replace up to 35% of the fat in retail shortening and up to 75% of the fat used for frying snack foods and in deep frying.

At those levels, the company figures that Olestra consumers could cut their daily fat consumption by five grams out of an average intake of 80 to 90 grams. The percentage of fat calories in their diets would drop from 37% to 35%, according to the company.

The other fat substitute before the FDA is Simplesse, produced by the NutraSweet Co. It consists of milk and egg protein cooked and blended in such a way as to simulate what food scientists like to call the “mouth feel” of fat.

Unlike Olestra, Simplesse is digestible. But it has less than half the calories of ordinary fat. It would be used in products such as salad dressing, mayonnaise and ice cream, but not for cooking. NutraSweet predicts it could reduce a person’s fat calories to 32%.

“The fat substitutes . . . offer exciting opportunities for us to have the satisfaction we get out of products that contain fats without the extra weight gain,” says Fred Caporaso, chairman of food science and nutrition at Chapman College in Orange. “That’s kind of neat, I think. As long as they’re safe.”

The FDA is studying the safety of the fat substitutes. Both companies say their products are harmless in the context of a balanced diet--although NutraSweet notes that Simplesse should not be eaten by people sensitive or allergic to milk or eggs.

As for Olestra, Procter & Gamble says it would not affect absorption of dietary proteins and carbohydrates or of most fat-soluble vitamins. Because it could reduce absorption of Vitamin E, the company intends to supplement Olestra with that vitamin.

One consumer group, the Center for Science in the Public Interest, has challenged Procter & Gamble’s safety claim and the animal studies on which it is based. It has asked the FDA to require more studies exploring the long-term effects of Olestra use.

One professor of food science at the University of Arkansas raised a more philosophical objection to the advent of foods that are not what they seem.

“It puts an intellectual dimension in eating that I’m personally concerned about,” says Harry E. Snyder. “I just don’t want to ask every time I sit down, ‘Is this real or fake and should I adjust accordingly?’ I want to know it’s all real food.”

A second target of food engineering is sugar. Three low-calorie and non-nutritive sweeteners are being used widely, despite questions about their effects on health and despite the fact that consumption of sugars has continued to rise.

The oldest is saccharin, a non-nutritive sweetener that is not metabolized and therefore non-caloric. It remains in use under special Congressional dispensation in spite of research data suggesting it may contribute to bladder cancer.

An FDA move to ban saccharin has been suspended until at least 1992 pending further research. Products containing saccharin bear a health warning, but reviews by the American Medical Assn. and food technologists have failed to establish a health risk.

A second sugar substitute is aspartame, or NutraSweet, a protein that carries with it four calories per gram. Because it is up to 220 times as sweet as table sugar, aspartame can be used in such small amounts that it is virtually non-caloric.

It appears to be safe in moderation, numerous groups have determined. Yet, there have been anecdotal reports of vision problems, seizures, headaches and dizziness. Aspartame accounts for four of every five complaints to the FDA concerning adverse reactions to food additives.

The third available sweetener is acesulfame K, also known as Sunette. Approved in July, 1988, for use in dry mixes for beverages, instant coffee, puddings, non-dairy creamer and chewing gum, it is not metabolized and therefore contributes no calories to the diet.

Professional opinion about the benefits of artificial sweeteners remains mixed. Bidlack calls aspartame “probably the most outstanding thing that happened to the sweetness market” because of its safety and sweetening power. But others are more skeptical.

“I think health professionals are still wondering whether there’s any real value in making a sweet product that doesn’t have any health benefits of any kind,” Snyder says. After all, he says, there is no evidence that sweeteners have cut overall sugar consumption.

The next frontier for food engineers is cholesterol, believed by many researchers to be a prime culprit in cardiovascular disease. Because more than a third of dietary cholesterol comes from eggs, many researchers have focused on eggs first.

Some farmers claim to have already produced reduced-cholesterol eggs through selective breeding and control of chickens’ diets. Some chickens have been fed fish oil, believed by some to lower cholesterol levels. But the eggs have occasionally ended up smelling of fish.

Other researchers are testing more esoteric techniques.

Donald Beitz, a professor of animal science and biochemistry at Iowa State University, is working with an enzyme produced by bacteria in the human gut. According to Beitz, the enzyme breaks down cholesterol into an innocuous product that is then excreted.

Beitz has tested extracts containing the the enzyme on milk, ground pork and egg yolk and has produced the expected breakdown product. He is now attempting to develop more of the enzyme, which he hopes some day might be available to be sprinkled on high-cholesterol foods.

One other area that has attracted food engineers’ attention is fiber--specifically, adding fiber to foods. Epidemiological studies have linked reduced rates of some cancers and gastrointestinal diseases to diets heavy in high-fiber foods.

For that reason, food manufacturers have begun supplementing baked goods with sugar beet fiber and apple and oat fiber. So-called light breads often contain added fiber, as do many cereals and high-fiber hamburger buns.

The U.S. Department of Agriculture has developed something called fluffy cellulose to serve as a non-caloric fiber replacement for flour. Derived from sugar beet pulp or other agricultural byproducts, it can replace up to half the flour in cake or bread.

There appear to be no risks involved with such products, according to experts in the nutritional benefits of fiber, although some note that excess fiber could limit absorption of important dietary minerals in a person with a marginal diet.

Yet, many nutritionists are skeptical about fiber supplements. They advise consumers to rely instead on naturally high-fiber foods. Some say it is not clear that the health benefits of high-fiber foods such as fruits and vegetables come solely from the fiber.

“When you consume fiber in food, you consume a whole range of nutrients,” says Barbara Schneeman, a professor of nutrition at UC Davis. “If you select some of these fiber supplements, you may not be getting the whole package of nutrients.”

“All kinds of fiber are being sold out there,” Labuza says. “We don’t really know whether (some) perform the function people think they perform, and if taking them out of one food and putting them in another they would still have the same function.”

One check on the proliferation of some engineered foods so far has been the ability of manufacturers to market their products. Outdated regulations on food composition have made some companies reluctant to manufacture nutritionally improved foods.

But food producers insist consumers are often slow to change, too.

They say many Americans raised on the taste of high-fat foods are often unwilling to accept nutritionally improved versions--particularly since fat accounts for much of the tenderness, juiciness and flavor of meat and dairy products.

“First and foremost in the minds of these dairy companies is taking out the fat but making sure it tastes good,” says Robert Boynton, executive director of the Dairy Institute of California.

“It doesn’t do any good if you give them a product that’s low in fat but doesn’t deliver. That’s really the challenge: How you make products that are good for them but still appealing?”