As snowy white granules rain down on a cup of coffee, words appear across the TV screen: "Sprinkle your coffee with something other than guilt."
Then, the narrator intones: "Try the first great-tasting, zero-calorie, natural sweetener borne from the leaves of the stevia plant. Truvia. Honestly sweet. Find it at your grocery store."
It's not exactly pure spring water, but the newest sugar substitute on the market is getting buzz for its origins in flora rather than the lab.
The Food and Drug Administration said in December that an extract of stevia was safe to eat, and about the same time, the food-supply giant Cargill Inc. launched the commercial for tabletop packets of Truvia. In coming months, more products with the extract will join a crowded market of diet products that caters to some 194 million American consumers, according to the industry group Calorie Control Council.
The Coca-Cola Co. plans to use Truvia to make Sprite Green, and Odwalla will use it in some of its juice. PepsiCo has products with PureVia, its version of stevia, in the pipeline. Cargill has been selling sweetener packets since October under FDA rules that allow a company to market such additives it has studied and considers safe.
The stevia extract used by food makers comes from the leaves of a South American plant in the chrysanthemum family, and it has been consumed for decades in other countries, including Japan. This may push some consumers who are weary of other artificial sweeteners, such as saccharin and aspartame, that have in the past drawn questions about their safety.
Still, critics argue that "natural" doesn't necessarily mean healthier. U.S. government officials had maintained a ban on stevia since the 1970s because they were not convinced that it wasn't toxic. The government agreed the extract used by the food companies was safe after newer tests; Cargill says it has done three years of study. But some fear the sweetener hasn't gotten a proper vetting in the United States, where consumption of sugar substitutes is higher than in other countries.
"We argued for better testing before it was approved," said Michael F. Jacobson, executive director of the Center for Science in the Public Interest. Jacobson said testing has linked stevia to reproductive problems in lab animals, among other issues.
"Natural" doesn't have an official FDA definition, and some plants are toxic, said Ihab Bishay, a Chicago-based chemist and spokesman for the Institute of Food Technologists, a membership organization for people who work in food science and related professions. He has consulted for NutraSweet, but currently doesn't work with sweetener makers.
"The public feels reassured by a 'natural' label, but that doesn't make it better," Bishay said.
But he says sweeteners are safe because toxicity often has to do with quantity. Because sugar substitutes are many times sweeter than sugar, less is needed for the same effect, making them safe in the amounts people normally consume them. Consumers will eventually decide which stay on the market, based on taste, Bishay said. He prefers aspartame, or NutraSweet, for the taste.
Peter Butko, an associate professor of pharmaceutical sciences at the University of Maryland School of Pharmacy, agrees substitutes are safe and added that those who look to sugar as the more natural choice need to realize that unless they are eating sugar beets, they are getting a processed product. Sugar is linked to obesity and the maladies associated with it. He said most sweeteners work because they aren't metabolized in the system and turned into fat.
But that is not an endorsement of unrestrained use of sugar substitutes. Splenda, for example, is packaged with agents to make it seem more like sugar, and that makes is almost as calorie-dense as sugar, he said.
Artificial sweeteners are "safe in the amounts we consume them, and I do have Splenda packets at home," Butko said. "But I'm trying to limit it. Everything in moderation, whether it's sugar or Splenda."
The FDA and the World Health Organization have set standards for consumption of sweeteners, though dietitians say they are safety limits rather than nutritional recommendations.
Angela Ginn-Meadow, a registered dietitian and spokeswoman for the American Dietetic Association, said Americans drink too much diet soda and drop too many packets of sweeteners into their coffee. She suggested "retraining your taste buds" to enjoy beverages without added sweeteners. Or even better, drink water, milk or fruit or vegetable juices.
"Diet Coke is a great alternative to drinking a caloric beverage, but it's got a lot of extra additives and little in the way of nutrition," she said. "It needs to be consumed in moderation."
Here are some commonly used sweeteners; their brand names; the safe amount to consume, according to the Food and Drug Administration and World Health Organization; and concerns that have been raised.
* Brand name: Sweet 'N Low
* Approved: Regulation began in 1958, though it was used before then.
* Safe to consume: 5 milligrams per kilogram of body weight, or up to 3 packets a day for a 150-pound person
* Notes: Studies on animals showed a link to bladder cancer, but in 2000 saccharin was removed from a government list of cancer-causing chemicals after more studies on humans. A warning label was also removed.
* Brand names: NutraSweet, Equal
* Approved: 1981
* Safe to consume: About 40 milligrams per kilogram of body weight, or up to 15 cans of diet cola a day for a 150-pound person
* Notes: Studies in 2005 and 2007 on rats found a link to brain tumors when consumed over a lifetime, though subsequent research concluded that the results didn't apply to humans. Later studies that claimed higher instances of lymphoma and leukemia were found to be flawed.
* Brand name: Splenda
* Approved: 1998
* Safe to consume: 15 milligrams per kilogram of body weight, or up to 15 cans of diet cola a day for a 150-pound person
* Notes: The latest studies show no problems with consumption, though the maker hit a marketing bump after claiming it was "made from sugar" when it is produced through a process using chlorine.
* Brand names: Truvia, PureVia
* Approved: 2008
* Safe to consume: 4 milligrams per kilograms per body weight, or up to 3.5 packets a day for a 150-pound person
* Notes: Stevia, until recently, was available only as a dietary supplement. Some studies showed a link to reproductive problems and other issues, although critics of the studies say the quantities were higher than humans would consume.
Source: Center for Science in the Public Interest, the Institute of Food Technologists, National Cancer Institute, FDA and WHO