Is eating yogurt really good for your health? Stroll around any health or grocery store these days and you’ll see lots of claims that the microorganisms in yogurt and other “probiotics” have all sorts of benefits. But, the truth is, virtually none of those claims has been proven.

New research, however, provides one of the first real clues that yogurt may indeed be helpful, perhaps by helping microbes found naturally in the digestive system process carbohydrates. Perhaps more importantly, the research indicates how scientists can vet such claims.

There’s been an explosion in recent years of interest and research into the “microbiome,” the trillions of bacteria, viruses, fungi and other microorganisms that form complex ecosystems populating the gut and every other nook and cranny of every human’s body.

Jeffrey Gordon of the Washington University School of Medicine in St. Louis has pioneered the field. In his latest research, Gordon and colleagues studied gut bugs of seven pairs of female twins in their 20s and 30s. For four months they consumed yogurt containing five strains of bacteria--Bifidobacterium animalis, Lactobacillus delbrueckii, Lactococcus lactis and Streptococcus thermophilus. The researchers purposefully did not name the yogurt because they did not want to be seen as endorsing any particular product, Gordon said during a telephone interview.

In a paper published in the journal Science Translational Medicine, the researchers found that the yogurt did not seem to alter the fundamental composition of the twins’ gut bacteria. Similarly, the same five species of bacterium found in the yogurt had no affect on sterile laboratory mice that had had 15 members of a typical human gut microbial community transplanted into their digestive systems.

But additional analysis did find the addition of the microbes in the yogurt affected the activity of the genes of the microbes in the gut and “metabolites” they produce, indicating that they were facilitating the digestion of complex carbohydrates.

The study was not designed to specifically determine whether that translates into health benefits. But enhanced processing of carbohydrate can help alleviate constipation, bloating and perhaps even conditions such as irritable bowel syndrome.

Beyond the potential health implications, the researchers say the research indicates that the kind of mouse model used in the study could provide valuable tools to understanding how the microbiota and various probiotics affects human health.

“Some of the questions are: ‘Are the health claims made for these organisms generalizable to people? How effective are they in a disease context? And does that vary in different humans?’ Given the complexity of the microbiome, it’s gong to be very important to try to create model we can study,” Gordon said. “In this time of exploding information about the microbiome, we have to understand how the microbiome functions. We can’t just describe its part. This model allows us to interrogate the effect of different probiotics.”

In an article accompanying the study, Jordan Bisanz and Gregor Reid of the University of Western Ontario in Canada said the research offered a “valuable roadmap... to guide future research” about how microbes affect the microbiome.

“The incredible precision and thoroughness of the ... study will not be easy to duplicate, but they have certain laid a valuable pathway for others to follow,” they wrote.