Can a Japanese diet help with depression? Large study says yes

By Vijay Kumar MalesuReviewed by Susha Cheriyedath, M.Sc.Jun 18 2025

A major study finds that workers who stick to traditional or modernized Japanese diets report fewer symptoms of depression, highlighting the mental health power of culturally tailored nutrition.

Association between the Japanese-style diet and low prevalence of depressive symptoms: Japan Epidemiology Collaboration on Occupational Health Study. Image Credit: rocharibeiro / Shutterstock

In a recent study published in the journal Psychiatry and Clinical Neurosciences, a group of researchers evaluated the association between adherence to traditional and modified Japanese dietary patterns and the prevalence of depressive symptoms in a working Japanese population.

Background

Depression affects over 280 million people globally and is a major contributor to disability and economic loss. Among working adults, mental health challenges can hinder productivity and increase absenteeism. Nutrients such as vitamin D, folate, and omega-3 fatty acids play individual roles in maintaining mental health.

Researchers have been studying individual roles, but there is now growing interest in how overall dietary patterns affect our mental health. The Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) have shown consistent associations with reduced depressive symptoms in Western populations. However, research in Japan has yielded inconsistent results, partly due to the use of sample-specific diet scoring systems. Hence, further research is needed using culturally grounded dietary measures.

About the study

This cross-sectional study utilized data from the Japan Epidemiology Collaboration on Occupational Health (J-ECOH) study, which was collected between 2018 and 2021 across five companies and six study sites. A total of 12,499 participants completed a validated food frequency questionnaire and an 11-item Center for Epidemiological Studies Depression Scale (CES-D-11).

Dietary scores were calculated for both traditional and modified Japanese diets. The traditional score included white rice, miso soup, soy products, cooked vegetables, fish, salty foods, mushrooms, seaweed, and green tea. The modified score replaced white rice with whole or minimally processed grains, reversed scoring for salty foods, and added raw vegetables, fruits, and dairy products. Participants were classified into quartiles based on their respective adherence scores.

Multilevel Poisson regression with robust variance was used to calculate prevalence ratios (PRs) for depressive symptoms, demographic and lifestyle factors, and treating study site as a random effect. Sensitivity analyses excluded participants with known mental disorders and examined effects by COVID-19 periods and survey method.

Subgroup analyses were conducted based on age, sex, education, working hours, alcohol intake, smoking, and body mass index. Statistical significance was set at P < 0.05, and analyses were performed using Stata Multiprocessor (MP) version 18 statistical software.

Study results

Among 12,499 participants, 30.9% were identified as having depressive symptoms. The average participant age was 42.5 years, and women were 12% of the sample. It was observed that individuals with higher adherence to both traditional and modified Japanese diets were older, married, better educated, and more physically active. They also reported lower rates of smoking and long working hours.

There was a clear inverse relationship between diet adherence and depressive symptoms. For the traditional Japanese diet, the chances of having depressive symptoms decreased as diet scores increased, with adjusted PRs of 1.00 (reference), 0.94, 0.91, and 0.83. A similar trend was observed for the modified Japanese diet, with values of 1.00 (reference), 0.94, 0.83, and 0.80. In both cases, the trend was statistically significant (P for trend < 0.001).

These results remained consistent after excluding participants with a history of mental disorders. Both diets showed similar protective associations, despite the modified version including additional nutrient-dense foods.

Subgroup analyses revealed a stronger association among participants with higher educational attainment, possibly reflecting better health literacy. Interestingly, no significant associations were found among those working more than 46 hours per month, which the authors suggest may reflect stress and fatigue overriding any potential dietary benefits. The relationship held steady across the pre-coronavirus disease (COVID-19) and COVID-19 periods, indicating resilience to external stressors.

Mechanistically, the Japanese diet’s protective effect may stem from its nutrient-dense components. Folate in seaweed and vegetables may support the synthesis of neurotransmitters like serotonin and dopamine. Omega-3 fatty acids from fish are thought to have anti-inflammatory properties and support brain function.

Antioxidants found in green tea and vegetables may help reduce oxidative stress, while dietary fiber from soy, mushrooms, and seaweed may promote the health of the gut microbiota, which in turn influences mood through the gut-brain axis. Additionally, umami-rich foods like miso and fermented soy may help promote relaxation by reducing heart rate and stimulating the body’s parasympathetic nervous system.

Although the modified Japanese diet was designed to address deficiencies, such as low calcium and fiber, and high sodium, in the traditional version, both diets had similar impacts. This may be because between 62% and 84% of participants consumed the added components, such as dairy and whole grains, less frequently than the dietary score thresholds.

Overall, the findings emphasize the potential mental health benefits of holistic dietary patterns deeply rooted in cultural eating habits. The results may have significant implications for mental health strategies in workplace wellness programs and public health policies.

Conclusions

To summarize, this large-scale cross-sectional study demonstrated that higher adherence to both traditional and modified Japanese dietary patterns is associated with a lower prevalence of depressive symptoms among working adults.

While causality cannot be assumed due to the study’s design, and the findings may not be generalizable to all populations since participants were primarily from large, urban companies, the present findings align with previous research suggesting that culturally specific diets play a positive role in supporting mental health.

By incorporating nutrient-dense, whole foods commonly found in Japanese cuisine, individuals may experience psychological benefits. These insights may support the development of dietary interventions and public health strategies aimed at reducing depression through culturally relevant nutrition.