Probiotics — microorganisms that are supposed to help your digestion and boost your immune system — are one of the hottest food trends of the decade.

Just like these "good" bacteria, the number of yogurts, drinks, pills and so on has multiplied in the past few years.

But whether you're spending that money on help or hype is a confusing question, especially in light of a class-action lawsuit settled for $35 million last month against the Dannon Co.

The suit claimed that Dannon falsely represented the health benefits of the probiotics in Activia, Activia Lite and DanActive products, to encourage people to buy a more costly product.

A statement on Dannon's Web site said that as part of the settlement, Dannon will make the scientific names of the probiotic bacteria strains it uses more visible on product labels, and it will reimburse qualified consumers for the cost of buying the products. But the company admitted no wrongdoing. A Dannon spokesman said the company settled to "avoid the distraction and expense of litigation."

Yes, probiotics can be good for you, but it depends on the strain of bacteria and the amount consumed, according to Chris Cifelli, director of the nutrition research for the National Dairy Council, who was in Salt Lake City last month to give a presentation on probiotics to Utah dietitians.

The dairy industry is a major player in the probiotic trend. Between 2004-06, U.S. beverage manufacturers introduced more than 500 new yogurt and dairy-based probiotic drink products, according to Cifelli. Last year, 31 probiotic products came out from May-November 2008, and about 70 percent of them were dairy-based.

The generally accepted definition of probiotics is "live microorganisms, which when consumed in adequate amounts, confer a health benefit to the host."

We usually think that bacteria are bad. But yogurt and cheese are examples of what "good" bacteria can do when they ferment milk.

Actually, each person harbors two to three pounds of more than 400 different species of bacteria in their body. "We've living in their world; there's way more of them than us, and it's mostly a symbiotic relationship," Cifelli noted.