ByJERUSALEM POST STAFF

Participants following the washoku eating pattern were up to 20% less likely to experience depressive symptoms.

A large-scale study of 12,500 Japanese workers from 2018 to 2021 suggests that following the traditional Japanese diet, known as washoku, may reduce symptoms of depression among working adults.
Participants who closely adhered to the washoku diet were 17% to 20% less likely to experience depressive symptoms than those with low adherence. The study by the Japan Institute for Health Security provides specific evidence on how components of the Japanese diet could protect psychological well-being.
The washoku diet is characterized by high consumption of fish, vegetables, soy, and fermented foods. Key components include rice, miso soup, fish, seaweed, mushrooms, and green tea. Researchers created a scale from 0 to 9 indicating how closely participants followed this diet. A modified version of the diet expanded the scale to 0 to 11 by adding fruits, raw vegetables, dairy products, and minimally processed rice, emphasizing lower sodium intake.

Results showed that participants who scored higher on the diet scales reported fewer depressive symptoms. Seaweed, soy products, and the folic acid in vegetables assist in releasing neurotransmitters such as serotonin and dopamine, making them better alternatives to sugary comfort foods like ice cream and chocolate.

Oily fish rich in omega-3 fatty acids has anti-inflammatory effects. "Fatty fish contain omega-3 fatty acids, specifically EPA and DHA, which are very beneficial for brain health and are associated with improved mood and mental well-being," said Dr. Federica Amati, chief nutritionist at the app Zoe, according to Infobae. She added, "Plants also provide bioactive compounds that reduce inflammation and contribute to better metabolic health, another important factor for mental health."
The washoku diet includes a wide variety of vegetables of different colors that are cooked, fermented, or eaten raw. Notable vegetables in the Japanese diet include leafy greens like spinach and kale, roots like sweet potato, radish, and carrot, as well as seaweed. Dr. Amati explained that increasing the intake of plant foods and dietary fiber can improve mood. "Fermented foods may improve the gut microbiome and the gut-brain axis, which in turn protects mental health and helps reduce symptoms of anxiety and depression," she said.
Regular consumption of fermented foods is another essential component of the washoku pattern. Japanese vegetables are often fermented, enhancing their nutritional value and making them richer in probiotics—microorganisms that improve gut health and influence the central nervous system. The gut-brain axis plays a central role in emotional regulation, linking digestive health to mental well-being.
In addition to vegetables, the Japanese diet includes green tea and soy products such as miso soup made from soy. Soy contains isoflavones and phytoestrogens, which have been shown to reduce symptoms of depression. It also contains folate, a B vitamin that supports the nervous system and is relevant for neurological function. Dr. Amati emphasized that the Japanese way of eating is beneficial for satiety. "This in turn reduces the risk of overeating, obesity, and excess weight, which increase the risk of poor mental health," she said.

Several studies have shown that increasing omega-3 intake is associated with improved cognitive functions, such as greater concentration and memory, and may help reduce the risk of dementia and Alzheimer's disease. The washoku diet is high in fiber and low in saturated fat and added sugar. It limits red meat and sugary drinks, emphasizing whole foods that contribute to overall health.

Researchers noted that umami, a characteristic flavor of Japanese food, may stimulate the parasympathetic nervous system and contribute to mental stability, favoring relaxation. While regular exercise is often highlighted for its mood-boosting benefits, diet can sometimes be overlooked. A balanced, nutrient-rich diet like washoku could help lower symptoms of depression.
It's not about changing one's whole diet overnight but simply adding more whole foods like oily fish, leafy greens, fermented soy products such as miso or tofu, and seaweed. It's also important to cut back on processed snacks, sugary drinks, and red meat. Other lifestyle factors such as alcohol consumption, smoking, exercise, sleep, and obesity are also relevant to mental health.
The analysis supporting these findings was published in the journal Psychiatry and Clinical Neurosciences. The study's efforts to adjust statistical data minimized the impact of non-dietary factors, strengthening the evidence that the washoku diet may be an effective strategy for mental health care.