A trip down the aisle of a typical supermarket can make a shopper dizzy with health claims for everything from candy bars to herbal teas. These so-called functional foods and beverages tout, among other things, their supposed energy-boosting, heart-helping and cholesterol-slashing benefits, and the boasts are legal as long as they are backed up by credible science, The New York Times reports.

The hype also has been a healthy additive to food industry revenues in recent years. Sales of functional foods and beverages hit $37.3 billion in the U.S. in 2009, up from $28.2 billion in 2005, according to the Nutrition Business Journal, a market research firm.

But faced with myriad health claims for thousands of packaged foods, consumers and regulators are left with the daunting task of sorting out food-label facts from fiction.

When Kellogg boasted that its Frosted Mini-Wheats made kids more attentive and that its Rice Krispies supported children’s immune systems, the Federal Trade Commission challenged the claims, and the cereal maker agreed to pull the ads.

“If people can’t rely on even the most trusted food brands to have good science backing up their claims, who can they rely on?” said Mary K. Engle, the director of the FTC’s advertising practices division.

Along with exaggerated health benefits, authorities also are troubled by another food trend: the lacing of baked goods with melatonin, an ingredient being promoted as a dietary supplement that helps people relax.

As the Times reported in a separate story, the Food and Drug administration says that if melatonin is used as an additive, it could be subject to regulatory action. But promoters of the baked goods so far have dodged regulators by characterizing melatonin as a dietary supplement, a category that does not require premarket approval by the FDA.

In the meantime, mayors in the Massachusetts communities of Fall River and New Bedford have urged bans on a product called Lazy Cakes, which is marketed as “the official relaxation brownie,” the Associated Press reports.

“We think the secret to a long life is being laid back and lazy,” says the company’s website, which promises that the chocolate treat will “ease you down” with “natural ingredients” like valerian root, rose hips and melatonin.

But officials complained that the playful packaging of the products can appeal to children, and that melatonin can be a dangerously potent substance.

“If you take it while you’re driving a car, you will find yourself in a ditch,” said Dr. David S. Seres, the director of medical nutrition at Columbia Medical Center.