If you believe the claims on various grocery items, you might think that better health is simply a matter of stocking your pantry with many of them: Pomegranate juice will take care of your heart, cereal will lower your cholesterol, and yogurt will fix your constipation.

So-called functional food, which manufacturers promise will reduce your risk of disease or boost your chances of optimal health, represents the fastest-growing category in the food industry. Food that is fortified with calcium, fiber, omega-3 fatty acids and vitamins accounts for $20 billion to $30 billion in annual sales, according to PriceWaterhouseCoopers. It predicts that sales will grow at an annual rate of 8.5 to 20 percent, far faster than the 1 to 4 percent forecast for the food industry overall.

What’s driving the demand? The Academy of Nutrition and Dietetics points to rising health-care costs and scientific research that links a good diet to a lower incidence of chronic disease. The problem? In most cases, the health claims are based on flimsy facts.

Food or drug?

The Food and Drug Administration doesn’t recognize functional food as an actual food category. As defined by the Federal Food, Drug, and Cosmetic Act, products with claims that they treat or alleviate disease are considered to be drugs and must meet the agency’s regulatory requirements, including proof that they are safe and effective for their intended use. So if you’re a manufacturer and you want to claim in ads and packaging that your product has health-promoting properties, there has to be credible science to back it up.

For example, the maker of POM Wonderful 100 Percent Pomegranate Juice and POMx liquid supplement maintains that it has scientific proof to support the claim that its products prevent or treat heart disease, prostate cancer and erectile dysfunction.

The Federal Trade Commission is disputing health claims about POM products. (Matt Rourke/AP)

But the Federal Trade Commission cracked down on the company in 2010 for making what it calls false and unsubstantiated claims.

“Any consumer who sees POM Wonderful products as a silver bullet against disease has been misled,” David Vladeck, director of the FTC’s Bureau of Consumer Protection, said in a press release announcing the agency’s administrative complaint. “When a company touts scientific research in its advertising, the research must squarely support the claims made. Contrary to POM Wonderful’s advertising, the available scientific information does not prove that POM Juice or POMx effectively treats or prevents these illnesses.” An administrative law judge issued a cease-and-desist order in May after finding insufficient evidence to support the manufacturer’s claims about reduced health risks.

The company filed a lawsuit in 2010 contending that the FTC was overstepping its authority by setting new standards for advertising food and dietary supplements. That litigation is still pending.

Honesty on labels

Health claims weren’t allowed on food products until about 20 years ago. As the FDA saw it, such a link would mean the products were being marketed as drugs. And if food was being promoted that way, manufacturers had to conduct clinical studies to provide evidence of safety and efficacy.

That changed in the early 1990s with the creation of a national system of nutrition labeling (the “Nutrition Facts” panels now found on food packages). Food manufacturers had opposed the effort, thinking it would reveal negative information about their products. They then lobbied for the right to promote the benefits of their products, and in response Congress passed another piece of legislation: the Nutrition Labeling and Education Act, forcing the FDA to permit substantiated health claims on food packages.

In 1994 Congress passed the Dietary Supplement Health and Education Act, which made it easier to put health claims on vitamins, minerals and herbal products. “We expected to see nutritional supplements or dietary supplements making health claims,” says Mary K. Engle, director of the FTC’s Advertising Practices division. “But then, about five years ago, we started to see those kinds of claims on foods — claims like ‘metabolism-enhancing’ and ‘immune-boosting,’ or something having to do with brain health or heart health.”

Food for function

Conventional wisdom suggests that consumers might be tempted to eat fortified food instead of taking medication, but a study in the journal Pharmacoepidemiology & Drug Safety found otherwise.

So what’s a health-conscious shopper to do? “Know thyself,” says Elizabeth Rahavi, director of health and wellness at the International Food Information Council Foundation, an industry group. “Consumers can ask themselves questions that can help guide their choices, such as ‘Is this a food that I commonly consume?’ Often the benefit of a functional food comes through repeated consumption.”

Copyright 2012. Consumers Union of United States Inc.