In a recent study published in the journal scientific reportResearchers explored how bathing in Japanese hot springs affects the gut microbiota of healthy individuals. Their results provide fascinating insights into the benefits of using therapeutic springs.
Study: Effects of bathing in different hot spring types on Japanese gut microbiota. Image source: PR Image Factory/Shutterstock
Drinking or bathing in hot spring or mineral water (called balneotherapy) is known to be beneficial for a variety of health conditions. People with skin and musculoskeletal conditions may benefit from improvements in quality of life and sleep, while thermal baths may also improve hypertension, stress, cardiovascular disease, osteoarthritis, fibromyalgia, and gynecological, rheumatological, and dermatological conditions. disease symptoms. Bath therapy is thought to improve outcomes for patients with psoriasis and atopic dermatitis by affecting the skin and gut microbiota.
Japan’s Onsen Law defines ten different categories or “types” of therapeutic hot springs based on the substances they contain and their respective concentrations. Differences in therapeutic benefit between these different types have not been studied. Additionally, it is unclear how they affect healthy individuals without pre-existing health conditions.
About the study
This study examined how bathing in different categories of hot springs affects the gut microbiome in a sample of healthy individuals. The participants were aged between 18 and 65 years old, lived in the Kyushu area, had not visited hot springs in the past two weeks, and did not suffer from any chronic diseases.
Participants were asked to choose a hot spring facility and soak in the same bathtub for at least 20 minutes each day for seven consecutive days. In addition to daily bathing, they continued to follow daily routines and regular meal times, and were asked to avoid excessive drinking and overeating. Those unable to follow these criteria were excluded from the analysis. Each participant had their fecal samples collected before and after the experiment. They were analyzed to identify the gut microbiota and find the most common genera.
A total of 127 participants (52 women) completed the study and their stool samples were analyzed. The types of hot springs they visit are simple, chloride, bicarbonate and sulfur. A spring is classified as simple if its temperature exceeds 25°C and less than 1g/kg of dissolved matter; as chloride if its chlorine content exceeds 1g/kg; and as chloride if its sulfur content is 2 mg/kg or more. Sulfur; bicarbonate if the dissolved HCO content exceeds 1 g/kg.3.
Comparison of relative abundance of intestinal microbiota before and after hot spring bathing. One of the stacked bars corresponds to a person. Each hot spring bathing group is shown as a whole, arranged starting with the individual with the highest bifidobacteria value on the left. The upper row represents before bathing and the lower row represents after bathing. The order of individuals in the upper and lower rows is not the same. ‘Double carb. ‘ means “bicarbonate”.
Seven types of bacteria increased significantly after the bathing experiment, including Oscillator and Parabacteroides In a simple spring bath, Ruminococcus, Oscillating bacteria, and Bifidobacterium bifidum among bicarbonate spring bathers, and Aristipes and another Ruminococcus Among bathers in sulfur springs. These, Oscillator are the only bacteria found in more than one group. Individuals using chloride hot springs showed no significant changes before and after the bathing intervention.
Among these bacteria, Bifidobacterium bifidum Showing the most significant changes, individuals showed a 2.8% increase after bathing in bicarbonate spring water.Using simple springs is associated with a 0.7% increase Parabacteroides. OscillatorThere was an increase in both groups, with the group using bicarbonate spring water increasing by 0.31% and the group using simple spring water increasing by 0.14%.Increase in sulfur springs Aristipes Concentration increased by 1.5% and Ruminococcus 2 0.87%.
The study is the first to examine the effects of hot spring bathing on gut microbiota, and the findings suggest that the unique mineral properties of different hot spring types can significantly alter the gut microbiome by increasing the concentration of certain bacteria. Further studies can use these baseline findings to determine how these unique chemical signatures can be used to target specific microbial responses.
Increased Bifidobacterium bifidum The concentration of bicarbonate spring water is of particular interest to users because it is known to increase glucose tolerance, relieve constipation, enhance intestinal immunity, and protect against enteropathogenic infections. Other bacteria have different effects— Parabacteroides May worsen symptoms of amyotrophic lateral sclerosis (ALS), but has also been linked to longevity.
The authors note that a significant limitation of this study is the lack of a control group and the use of before-and-after comparisons. Future research could use a “sauna control” or include a “no bathing” group to address this issue, while also drawing on input from other communities and populations to ensure generalizability. Further work in this area could lead to improved treatments for individuals with different health problems, ensuring an increase in healthy bacteria while limiting the increase in less beneficial genera.