Miso soup intake and stomach symptoms in a Japanese population survey
What it found
People who drank miso soup every day reported fewer acid reflux and indigestion symptoms than those who rarely had it.
This was seen in 9,364 adults in Japan.
What they found
Studies in people
Fewer overall stomach symptoms
People who drank miso soup every day had lower total symptom scores than those who had it less than once a week. The difference was 1.1 points on the scoring scale used.
Less acid reflux reported
Daily miso soup drinkers reported fewer acid reflux symptoms. This link held up even after accounting for age, sex, weight, smoking, alcohol, and other eating habits.
Less indigestion reported
Those having miso soup daily also reported fewer indigestion symptoms compared to those who rarely drank it. This was true regardless of other lifestyle factors measured in the survey.
Other findings
What is in miso soup
A typical bowl is made by dissolving fermented soybean paste into Japanese broth along with items like vegetables or tofu. One tablespoon of the paste provides roughly 32 calories, plus small amounts of protein, fat, and carbohydrates.
Possible reason for findings
The authors suggest that amino acids and salt in the broth might help the stomach empty faster. Because the soup also contains soybean protein, it may be especially good at speeding up digestion.
What the authors conclude
- They conclude that drinking miso soup every day was linked to lower scores for acid reflux and indigestion in this Japanese community group.
- They note that faster stomach emptying caused by ingredients in the broth could explain why daily drinkers reported fewer symptoms.
- They advise that more research following people over time is needed to see if miso soup actually protects against worsening stomach problems.
How it was done
The authors previously found that certain building blocks in Japanese broth helped the stomach empty faster. They wanted to see if drinking miso soup, which contains this broth, was linked to fewer stomach complaints in everyday life.
They surveyed 9,364 adults living in a Japanese city about how often they ate various foods, including miso soup. The participants also filled out a questionnaire about their stomach and acid reflux symptoms. The researchers then looked for links between how often people drank miso soup and their symptom scores.
What it can’t tell you
- Because everyone was surveyed at just one point in time, this cannot prove that miso soup causes fewer stomach symptoms. People who drink miso soup daily might simply have other habits that keep their stomachs comfortable.
- The study only looked at adults in one Japanese city, so the results might not apply to people in other countries who eat different diets.
The paper
- Title
- Reduction in Gastroesophageal Reflux Disease Symptoms Is Associated with Miso Soup Intake in a Population-Based Cross-Sectional Study: The Nagahama Study
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Mano F, Ikeda K, Sato T, et al (2018). Reduction in Gastroesophageal Reflux Disease Symptoms Is Associated with Miso Soup Intake in a Population-Based Cross-Sectional Study: The Nagahama Study. Journal of nutritional science and vitaminology. doi:10.3177/jnsv.64.367Free full textPubMed 30381627DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error