Open Food Labels. Search 816 ingredients⌘K

Study · Nutrients · 2021Conflicts declared

Miso and blood sugar control in type 2 diabetes

Takahashi F, Hashimoto Y, Kaji A, et al · Free full text

What it found

In a cross-sectional study of Japanese patients with type 2 diabetes, women who habitually ate miso soup had lower average HbA1c and less variation in HbA1c than women who did not.

No such link was seen in men.

What they found

Studies in people

HbA1c levels in women

In women, the average HbA1c was lower in those who habitually ate miso soup than in those who did not (7.0% vs. 7.3%). The standard deviation and coefficient of variation of HbA1c were also lower in the habitual miso group.

HbA1c variability in women

After adjusting for factors like age, BMI, diabetes duration, and diet, habitual miso consumption was linked to lower average, standard deviation, and coefficient of variation of HbA1c in women.

No link in men

In men, habitual miso consumption was not associated with any measure of blood sugar control, including average HbA1c, its standard deviation, or its coefficient of variation.

Other measures in women

Women who habitually ate miso soup also had lower fasting blood sugar and a lower percentage of hypertension than those who did not. Their intake of energy, protein, fat, and dietary fiber was higher.

Other findings

Miso types not studied

The study did not look at different types of miso, such as rice koji, barley koji, or soybean koji miso, so it is unclear if the type matters.

What the authors conclude

“This study demonstrated the relationship between habitual miso consumption and glycemic variability in female, but not in male, with T2DM.”
Takahashi F, Hashimoto Y, Kaji A, et al, 2021

Also in their conclusions

  • They conclude that habitual miso consumption is related to better blood sugar control, including less variability, in women with type 2 diabetes but not in men.
  • They say that miso soup consumption may help in the management of patients with type 2 diabetes.
  • They call for further research, including studies with more participants and randomized clinical trials, to confirm the findings.

How it was done

The authors wanted to know whether habitual miso consumption is related to blood sugar control, including blood sugar variability, in people with type 2 diabetes. Previous work had linked miso soup intake to lower insulin resistance, but the relationship with blood sugar control and variability was unknown.

They studied 290 patients with type 2 diabetes (160 men and 130 women) from two hospitals in Japan. Participants answered a diet questionnaire about the previous month, including how often they ate miso soup, and their HbA1c levels were collected from medical records over a year. Habitual miso consumption meant eating miso soup at least once a day.

What it can’t tell you

  • This was a cross-sectional study, so it can show a link between miso consumption and blood sugar control but cannot prove that miso causes better control.
  • The study only included Japanese people, so the results may not apply to other ethnic groups.
  • The frequency of miso soup intake was self-reported, which may not be accurate.

The paper

Title
Habitual Miso (Fermented Soybean Paste) Consumption Is Associated with Glycemic Variability in Patients with Type 2 Diabetes: A Cross-Sectional Study
Type
Study
Evidence
Studies in people
Summarised from
Full text
Licence
CC BY. Words in quotation marks are the authors’; the rest is our summary.
Cite
Takahashi F, Hashimoto Y, Kaji A, et al (2021). Habitual Miso (Fermented Soybean Paste) Consumption Is Associated with Glycemic Variability in Patients with Type 2 Diabetes: A Cross-Sectional Study. Nutrients. doi:10.3390/nu13051488Free full textPubMed 33924846DOI

Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error