Yogurt and Hot Springs: A Promising Combination for Gut Health

Researchers from Kyushu University have found that consuming yogurt not only boosts the variety of gut microbiota but also changes its makeup. Interestingly, when paired with bathing in chloride hot springs after yogurt consumption, individuals reported better bowel movements than with yogurt alone.

This suggests that these two lifestyle approaches—eating yogurt and soaking in hot springs—could work together for improved health, potentially offering new avenues for preventive medicine.

The findings were shared in the journal Frontiers in Nutrition.

A healthy gut is essential for overall wellness, influencing digestion, immune response, and even brain function. Yogurt is rich in prebiotic bacteria like lactic acid bacteria and bifidobacteria, which help in modifying the gut microbiota and delivering various health perks.

In their study, the researchers honed in on Japanese hot springs, known as onsens. “We’ve highlighted the benefits of onsen bathing on gut health before, but not much is known about how combining diet with onsen bathing impacts wellness,” remarked Professor Shunsuke Managi of Kyushu University’s Urban Institute, who led the study.

To explore this, the team worked with Beppu City, famous for its onsens, to look at the effects of hot spring baths after having yogurt.

A total of 47 healthy adults participated in the study, all of whom hadn’t visited onsens for 14 days prior. They were randomly divided into three groups: a control group, a yogurt group, and a yogurt plus onsen group.

The control group received no treatment, while the yogurt group consumed 180 grams of low-sugar yogurt with specific probiotic strains each evening. The yogurt plus onsen group also visited Beppu’s chloride springs for at least 15 minutes every two days.

Before and after the four-week study, participants provided stool samples and completed a questionnaire assessing their bowel habits, including stool frequency and consistency.

Results showed a notable increase in gut microbiota diversity in the yogurt group, along with shifts in various bacterial populations. However, the changes did not extend to the control or yogurt plus onsen groups. That said, both the yogurt and yogurt plus onsen groups reported considerable improvements in their bowel movement ratings, with the latter group seeing even better outcomes.

This indicates that while yogurt may enhance gut diversity, combining it with onsen bathing could amplify these benefits for bowel health.

“Our sample size is modest, but our results point to the potential advantages of merging two accessible lifestyle options—yogurt consumption and onsen bathing—for enhancing gut microbial diversity and bowel health in healthy adults,” Managi explains.

“These findings are particularly significant as more individuals seek non-medical, lifestyle-based health strategies. This research could also lend support to evidence-based wellness tourism, especially in areas known for their onsens, by scientifically backing health-focused travel and related services.”

For further information, refer to the study by Jungmi Choi et al, titled “Dietary and environmental modulation for the gut environment: yogurt promotes microbial diversity while chloride hot springs improve defecation status in healthy adults,” published in Frontiers in Nutrition (2025).