Could a bowl of yogurt and a soak in the hot springs be the recipe for better gut health? New research from Kyushu University suggests the two may work together to improve digestive well-being.
In a four-week study of 47 healthy adults, researchers found that eating yogurt containing beneficial bacteria increased gut microbiota diversity. Participants who ate yogurt also reported improvements in bowel habits, including stool frequency and consistency. But those who paired their yogurt with regular baths in Beppu’s chloride-rich hot springs saw even greater improvements in defecation status compared with yogurt alone.
“We have previously reported the beneficial effects of onsen bathing on the gut microbiota. However, little has been known about how the combination of diet and onsen bathing influences health,” said Professor Shunsuke Managi, who led the study, referring to the traditional Japanese practice of soaking in natural hot springs. “Although the sample size is small, our findings suggest that combining two accessible lifestyle interventions — yogurt intake and onsen bathing — may offer enhanced health benefits.”
Participants were randomly divided into three groups: a control group, a yogurt-only group and a yogurt-plus-onsen group. The yogurt group consumed 180 grams of low-sugar yogurt containing Lactobacillus bulgaricus and Streptococcus thermophilus after dinner daily. The yogurt-plus-onsen group followed the same regimen but also bathed in Beppu’s hot springs for at least 15 minutes every other day. Stool samples and questionnaires before and after the intervention showed clear changes: yogurt boosted microbial diversity, while the combination with hot springs produced the strongest improvements in digestive comfort.
The results, published in Frontiers in Nutrition, highlight growing interest in non-pharmaceutical strategies for gut health. Researchers also noted that the findings could lend scientific support to wellness tourism, particularly in regions of Japan known for their onsens.
While larger studies are needed to confirm the benefits, the research suggests that dietary and environmental habits together may offer a simple path toward better digestive health.
This study was supported by Meiji Co., Ltd., though the company had no role in study design, analysis or publication.