CHICAGO — Diane Sotiros, of River Forest, Ill., wandered into a Starfruit Cafe in Chicago's Loop area recently and ordered a frozen kefir, even though she had absolutely no idea what it was.

Kefir (kee-fur) is a sour, yogurt-like drink popular in Europe, partly because it aids in digestion.

"I like it," said Sotiros, 48, happily eating a spoonful of soft-serve kefir mixed with chocolate chips. "I wanted some ice cream and I walked past the custard place because I thought this was more like frozen yogurt and it would be a better option."

Many trends in health food involve "superfoods" that are most popular outside of the United States and pack a potent punch against a score of health issues, from weak immune systems to aging. Introducing fickle American consumers to such products can be challenging, but places like Morton Grove, Ill.'s Lifeway Foods and Amafruits in Orland Park, Ill., forge ahead to change resistance to their products into acceptance.

"I think in every culture there's probably certain staples that are associated with health and longevity," said Julie Smolyansky, president and chief executive of Lifeway Foods, which makes the kefir served in Starfruit cafes. "I think that because of Americans' desire to be healthy, they're looking at all these different products that have superior health qualities associated with them."

One product Americans are looking at is acai, frequently sold as pills, supplements, juices, purees and powders. Yet, there is little agreement on what it is or what it does.

A Google search muddies the waters even more. The words "WARNING!" and "SCAM!" splatter the page alongside ads for the "real" or "100 percent pure" acai that claim to help you lose lots of weight. In August, the Federal Trade Commission obtained a temporary injunction against Central Coast Nutraceuticals Inc. in Phoenix to stop sales of acai supplements after the company allegedly bilked customers out of more than $30 million last year.

"It's almost like acai has been hijacked by a bunch of scam artists and quick-rich guys that are just trying to sell some snake oil," said Brandon Hovey, managing director of Amafruits, which sells acai products online.

Nevertheless, Hovey, 40, and his wife Rebeca, 35, launched Amafruits in mid-October, determined to set the record straight about the trendy fruit.

First, it is pronounced ah-sah-ee, Hovey said. It's not a berry, but a drupe — a fruit whose flesh surrounds a pit — slightly smaller than a grape and found in the Amazon. He said that when cultivated and maintained properly, acai is loaded with antioxidants, omega fatty acids, dietary fiber and essential amino acids. It naturally contains fat but no sugar and should be kept frozen until it's ready to eat.

Hovey said that many products overprocess the acai, store it improperly or add too many ingredients, diminishing the effectiveness of the fruit. Amafruits sells frozen acai purees, which can be thawed and consumed straight from the pack.

"The companies, I don't think they're mixing it with bad intent, but they're charging with bad intent," Hovey said. "They're just jumping on the acai bandwagon and marketing their juice as acai when it probably has maybe 20 or 30 percent acai."

But the Hoveys shouldn't expect the cavalry to arrive and vouch for their acai purees anytime soon. The FDA classifies acai as a dietary supplement instead of a drug, so manufacturers can market it without prior approval from the FDA. As long as the manufacturer stays within marketing guidelines, the product just has to include the disclaimer, "These statements have not been evaluated by the Food and Drug Administration."

"The letter of the law is, is it safe?" said spokeswoman Siobhan DeLancey. "In general, the FDA does not do a lot of testing."

Furthermore, nutritionists and scientists haven't agreed on whether acai and similar products work or are necessary to someone's health.

"I don't think there is one superfood," said Brooke Schantz, a registered dietitian at Loyola University Health System. "It is more of a trend and a gimmick than something you have to have to remain healthy. Yes, (acai) contains antioxidants, but you can get antioxidants from an orange."

That leaves the Hoveys with the arduous task of changing minds one at a time.

"It's a slow dialogue," Hovey said. "We're trying to battle these huge marketing messages, and sometimes people are going to buy what they've heard (about) more often. And a lot of times, what they've heard more often is not the truth."

While the Hoveys jockey for position in a very crowded market, Julie Smolyansky and her family took advantage of a much smaller one. Her father, Michael, started Lifeway Foods in 1986, making the kefir himself in the family home. Kefir is prominent in eastern European countries, such as the former Soviet Union, from where the Smolyanskys hail, so Michael's first customers were folks looking for a taste of home.

"The success of it happened as the result of lots of other Russians also being here and looking for this staple product that they missed a lot," Julie Smolyansky said. "He had a natural market in the beginning."

The company went public in 1988, listed on Nasdaq. Smolyansky said kefir gained wider appeal in the '90s as the health-food movement burgeoned and stores such as Whole Foods Market and Wild Oats created another audience for the product.

"Digestion issues are one of the biggest everyday health problems that Americans face," Smolyansky said. "I think people were definitely eager to try it when they heard about the benefits to the digestive system."

That didn't necessarily mean that people always liked it. When the family did a grass-roots event in the late '90s at Grant Park, people tried it "and they thought it was like Pepto Bismol," Smolyansky said. "The thought of them drinking it, they just couldn't fathom."

Then the Smolyanskys repositioned their product as a smoothie instead of drinkable yogurt, catering to the tastes of Americans.

"I think we became a different company about six years ago," she said. "It became kind of 'in' to drink your nutrition."

But getting people to enjoy kefir and getting stores to carry it were different processes. Smolyansky said Whole Foods Market, Dominick's and Jewel-Osco were receptive early on, but it took five years before Lifeway Kefir secured a permanent spot in Costco's Midwest stores.

"They probably were not ready for it," Smolyansky said. "But patience is a virtue. We kept up with it, and every year we would re-present them something new, and then ultimately it just stuck." A bottle of Lifeway Kefir even made a cameo in Miranda Hobbes' kitchen in this summer's "Sex and the City 2" film.

After her father died in 2002, Julie took over. Her brother, Edward, is chief financial officer, and their mother, Ludmila, is the chairman of the company, which has 220 employees.

The company opened the first Starfruit Cafe in Chicago's Wicker Park neighborhood in April 2008 and have since added three branches. Sales have more than doubled since 2007 to $58.1 million, with profit just under $21 million last year.

Meanwhile, the Hoveys are in startup mode. Brandon quit his job as a senior consultant with Towers Watson (formerly Watson Wyatt) in 2009 to start Amafruits. Brandon and Rebeca have invested about $100,000, much of which pays for keeping the fragile acai frozen in its journey from Brazil to a customer's house. They plan to expand, selling an acai sorbet and importing more fruits native to the Amazon.

"It's a bold step," Hovey said. "It's not something that I would do unless I was passionate about it."

He said they expect to see profits after next year.

"I have confidence that we're building a stable, long-term business here," he said. "It might be a little slower at first than we would like because of these misconceptions, but it's a challenge I'm willing to deal with and help people understand the truth."