One of the hottest food marketing trends claims adding live bacteria to dairy products is a way to improve your digestive system, but can these products really boost your health?

According to the New York Times, yogurt maker Dannon, which claims their product Activia can help regulate your digestive system, is facing a class-action lawsuit saying the claims of a health benefit in the yogurt products are misleading and dupe consumers.

The company’s Activia and DanActive line of yogurt products contain live bacteria and claim to help regulate digestion and boost the immune system.

The suit, which was filed in United States District Court in California, seeks compensation for consumers who purchased the yogurt products based on what it says are “bogus claims,” the Times reported.

“Deceptive advertising has enabled Dannon to sell hundreds of millions of dollars worth of ordinary yogurt at inflated prices to responsible, health- conscious consumers,” said Los Angeles attorney Timothy G. Blood, of the firm Coughlin Stoia Geller Rudman & Robbins.

In response, Dannon issued a statement saying it “stands by the claims of its products and the clinical studies, which support them.  Dannon’s advertising has always been and will continue to be absolutely truthful, and Dannon will vigorously challenge this lawsuit.”

Probiotics are live microorganisms that, in sufficient amounts, confer a health benefit on the host. A growing body of research links probiotics to relief of digestive tract complaints such as irritable bowel syndrome, yeast infections, and diarrhea that results from certain illnesses. The idea is to increase the amount of beneficial bacteria in people’s intestinal tracts as a way to aid digestion, boost the body’s natural defenses and fight off harmful bacteria that can cause health problems.

Although scientific evidence shows probiotics can help, the Times reported that questions remain as to how well probiotics actually work in the real world, since some marketers may add untested amounts of the bacteria to various foods.  Only a handful of thousand probiotics have been tested in clinical trials and been shown to deliver specific health benefits when eaten regularly. Most probiotic products can be found in the dairy case or as dietary supplements, the Times said.