The Federal Trade Commission (FTC) has barred Tropicana from making unsubstantiated heart-health claims about its orange juice, as the agency says the company did in 2002 and 2004 ads. Among the ads' claims: Drinking two to three cups daily would lower systolic blood pressure by 10 points and raise HDL cholesterol (the good kind) by 21 percent. Neither the FTC nor Tropicana would make public the studies on which Tropicana relied. But FTC attorney Michelle Rusk said they were "not adequate to support such striking and specific claims."

The studies -- at least one of them funded by Tropicana and some of them involving as few as 24 participants or lasting as little as four weeks -- were conducted by researchers at the University of Western Ontario, the Medical College of Wisconsin and the Cleveland Clinic Heart Center.

While one study did show the cholesterol improvements cited in one of the contested ads, author J. David Spence noted in an interview that "the study was short-term, and it didn't show a reduction of stroke or heart attack risk." To make that connection, he said, "is an extrapolation."

The Rules Specific claims about a food's role in treating, preventing or curing a disease must have strong scientific backing. OJ cartons can note that foods rich in potassium and low in sodium may help reduce the risk of high blood pressure and stroke. The consumer can read the carton's nutrition facts panel to learn that OJ has lots of potassium and no sodium and make the connection himself. "Structure or function" claims -- vague statements linking ingredients to general health outcomes -- are subject to looser rules.

The Future Tropicana's Web page for its Pure Premium Healthy Heart juice -- the product that got the company in trouble -- lists nutrients found in OJ and their heart-healthy attributes without directly claiming that drinking the juice will improve cardiovascular health.

"We don't want to discourage companies who have healthy food products like orange juice from talking about health benefits," said Rusk. "But Tropicana really went beyond the science."

-- Jennifer Huget

OJ's benefits are real -- but overstated, says the FTC.