Probiotics are not always good for you

Researchers at the University of Texas at Austin investigated the mechanism of how a disease develops using human organ-on-a-chip technology, showing in the process, that probiotics may not be good for everyone.

They used a ‘gut inflammation-on-a-chip’ microphysiological system to confirm that the intestinal barrier disruption is the onset initiator of gut inflammation. The results of the study also casts doubt on the conventional wisdom of taking probiotics – live bacteria that are considered good for gut health and found in supplements and foods such as yogurt – on a regular basis. 

According to the findings, the benefits of probiotics depend on the vitality of one’s intestinal epithelium, or the gut barrier, a delicate single-cell layer that protects the rest of the body from other potentially harmful bacteria found in the human gut.

“By making it possible to customize specific conditions in the gut, we could establish the original catalyst, or onset initiator, for the disease,” said Assistant Professor Hyun Jung Kim, in the department of biomedical engineering who led the study. “If we can determine the root cause, we can more accurately determine the most appropriate treatment.”

“Once the gut barrier has been damaged, probiotics can be harmful just like any other bacteria that escapes into the human body through a damaged intestinal barrier,” said Woojung Shin, a biomedical engineering PhD candidate who worked with Prof Kim on the study. “When the gut barrier is healthy, probiotics are beneficial. When it is compromised, however, they can cause more harm than good. Essentially, ‘good fences make good neighbors.'”

Shin plans to develop more customized human intestinal disease models such as for inflammatory bowel disease or colorectal cancer in order to identify how the gut microbiome controls inflammation, cancer metastasis and the efficacy of cancer immunotherapy. 

The results of the study were published in the journal Proceedings of the National Academy of Sciences.