The sweet spot: Researchers seek ways to reduce sugar

CHICAGO — Midway through the afternoon, when the belly yearns for snacks, three NutraSweet executives are going wild: cola, orange drink, citrus punch, chocolate milk, more cola, pound cake and crispy squares of coconut pie — all test-kitchen concoctions made with artificial sweeteners.

They consume two servings of everything. In quick succession.

As researchers have discovered, the quest to find a perfect, consequence-free artificial sweetener is deceptively difficult, littered with cloying, metallic and just plain odd-tasting chemicals.

Today, the research is receiving fresh attention — fueled by an expanding national waistline. Nutritionists believe that Americans' breathtaking intake of sugars in soft drinks and processed foods is partly to blame.

The U.S. Department of Agriculture estimates that the average American eats about 100 pounds of added sugars a year, up 30 percent since the 1980s.

Consumers are taking note, trying in small ways to clean up their act. Diet soft drinks' sales are growing at about 6 percent a year, while those of regular soft drinks are declining by as much as 2 percent.

After years of loading snacks with sugar, food manufacturers are developing more reduced-sugar brands so that consumers can have their cake and eat it.

Two strategies

To tackle the problem, some are cutting down just slightly on sugar in their products, or artfully combining high-intensity artificial sweeteners to find just the right combinations to mimic real sugar.

Other companies are turning to the latest research in genetics and chemistry. Now there are humming labs, seeking out "enhancer" chemicals that accentuate the effects of real sugars, thus allowing less to be used.

Shaving away sugar is no easy business.

Sugar does much more than merely sweeten. It provides crumbliness to a cake's interior, crispness to its outside and a richer taste to a soft drink.

Despite decades of research, artificial sweeteners — a $1 billion-a-year market in the United States — still taste noticeably unnatural.

"You could probably line up 30 different sweeteners and I could tell you what each one was, no problem," says Susan Schiffman, a sweetness researcher at Duke University Medical Center.

The human lust for sweetness runs deep. Even newborn babies have an innate love of sugar-flavored water.

An acquired taste

There is a sensible evolutionary reason for this: Sugar means fuel — 15 calories in each teaspoon. Homing in on rich sources in nature — fruits, berries, honey — is a key for creatures as varied as flies, birds and dogs.

Unlike the super-sharp sensors for pheromones and poisons, human sweet receptors are naturally blunt so that people notice only significant sources of calories. As for sugar, the more the better.

It's an instinct that proved useful back when calories were scarce. It is far less beneficial in a land flowing with candy, super-sized soft drinks and doughnuts.

A problem with cutting sugar is that its sweetness is tricky to imitate.

Artificial sweeteners stick to the same receptor but to different parts, and with different speeds and tightness. Those factors translate into subtle differences in onset of taste, intensity and length of sweetness.

Eureka!

The first artificial sweetener was found in 1879 by accident.

Two chemists at Johns Hopkins University, Constantine Fahlberg and Ira Remsen, were trying to make new chemical dyes from coal-tar derivatives when a vessel boiled over in the lab one day. Fahlberg failed to properly wash his hands before a meal and noted how sweet his fingers tasted.

He traced the sweetness back to a two-ringed chemical called benzoic acid sulfanilamide. Fully 300 times sweeter than sugar, it is indigestible by the body, and thus calorie-free. He later dubbed the chemical saccharin, from saccharum, the Latin word for sugar.

The pattern of serendipity has continued up until today.

Cyclamate, used in soft drinks until it was banned, was discovered in 1937 when University of Illinois graduate student Michael Sveda put his cigarette down near a compound he was testing as a possible anti-fever drug and later noticed he was smoking a sweet cigarette.

Aspartame was discovered in 1965 by chemist Jim Schlatter, who licked his finger while testing a new anti-ulcer drug for the pharmaceutical company G. D. Searle & Co.

Scientists now know of scores of sweet chemicals — monellin, stevioside, thaumatin, lugduname, glycyrrhizin, maltitol and the tasty but toxic dulcin, which was used as a sweetener during World War I (and poisoned several children.)

Only a handful have been approved by the Food and Drug Administration for use as sweeteners: saccharin (most commonly known by the ubiquitous pink Sweet'N Low packets); acesulfame K (a less-known saccharin-like chemical); aspartame (in Diet Coke and Pepsi and the little blue packets of Equal); sucralose (in yellow Splenda packets); and neotame, the most recently-discovered sweetener, more than 7,000 times sweeter than sugar.

The problems in removing sugar from products have sparked a revolution in taste science.

Could there be a way to make a little bit of sugar pack a big dollop of sweetness?

Fooling the buds

It's an approach that has been embraced by Senomyx Inc., of San Diego, whose research has been supported by food heavyweights Campbell Soup, Coca-Cola and Nestle.

Three years ago, Senomyx identified the receptor in the taste buds responsible for sweet taste — the one to which sugar and artificial sweeteners bind to create the sweetness in cake, soda and candy.

In the company's reception area, a picture of two mice nuzzling a berry-topped chocolate cake hangs on a wall. Nearby is an image of the sweet receptor, zig-zag in shape.

The receptor is made up of two long proteins, T1R2 and T1R3, that are stuck on the surface of cells and work together to impart sweet taste. Millions of receptors reside in the taste buds in the moist crevices of the tongue, cheek and soft palate.

Part of each receptor hangs into the mouth's slimy void and the other end into the cell. When a sweetener binds, a message is sent into the cell's interior and ultimately to the brain.

Senomyx is seeking needles in haystacks — chemicals that enhance the efficiency of the sweetness receptor (or, in other projects, saltiness or savoriness).

Inside a laboratory lined with cell incubators, technicians tend to mammalian cells bathed in salmon-pink serum. The cells have been engineered to manufacture the human sweet receptor — in effect, they are tiny fake taste buds that glow green when exposed to sugars.

Gauging the glow

In another room, machines scan 384 chemicals at a time, measuring the glow produced by each sample. Researchers Cyril Redcrow and Poonit Kamdar watch as results come up on a screen: numbers, letters and wavy graphs that indicate how strongly the cells respond.

"Oh, see — there's a hit right there," says chief scientific officer Mark Zoller, pointing to a spot where one of the wavy graphs has an extra-high peak.

Senomyx has trawled through 200,000 chemicals and found several hundred sweetness-enhancer candidates.

The company is now tinkering with two, dubbed S299 and S679.

In Chicago, among a rainbow-like product display at NutraSweet are a New Zealand beverage called Budget Pineapple and a gallon-sized bottle of Peach Flavored Drink: Both use artificial sweeteners because they are often cheaper than sugar and high-fructose corn syrup.

In the case of some honey-wheat pretzels on display, an artificial sweetener was added to cut down on honey that was clogging the manufacturer's pretzel-extruding machine and also stopping the pretzels from rising.

Matchmaking

NutraSweet's Sweet Spot test kitchen is trying to combine artificial sweeteners so that one makes up for the deficiencies of the other in mimicking the precise nature of sugar.

"Number 267 finished cleaner, with a good cola flavor at the end," says Ihab E. Bishay, NutraSweet's vice president for research and developing who was sipping a small plastic beaker of the cola sample in the test kitchen, as he does several times a week.

Bishay and two other executives turn next to two chocolate milks — one partly sweetened with neotame. They bite into two pound cakes, one reduced one-third in sugar, with sweetener taking up the slack.

The cakes are identical in taste and moisture. But the crust gives the artificially sweetened one away: It's less crispy and crumbly.

The rich and buttery cake, loaded with fat and flour, seems to challenge some of the logic of the enterprise. Reducing sugar in foods might be a health boon — or might possibly backfire, like low-fat foods before them.

"It doesn't turn the pound cake into a healthy food — especially if you eat 30 percent more thinking it's a low-calorie pound cake," says Michael F. Jacobson, executive director of the Center for Science in the Public Interest, a Washington-based consumer group.

Nonetheless, the quest continues.