Does Inflammation Lead to Depression?

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For decades, we’ve heard that depression is related to imbalances of neurotransmitters in the brain, including serotonin, norepinephrine, and dopamine. But a growing body of research suggests depression may also be connected to a more prevalent biological process: inflammation.

Inflammation is the body’s natural immune response to stress, infection, and injury, helping the body heal. But, when it becomes chronic, inflammation increases the risk for a wide variety of health problems including heart disease, diabetes, Alzheimer’s disease, stroke, autoimmune disease, and more.

Neuroinflammation and Mental Health Problems

Researchers have found that chronic inflammation can spread to the brain, a condition called neuroinflammation, which is associated with mental health problems. A 2024 analysis of more than 585,000 people published in JAMA Psychiatry found that elevated inflammatory markers are associated with a higher risk of developing a diagnosed psychiatric disorder.

To further investigate this, health researchers have been testing anti-inflammatory interventions to treat depression. A systematic review published this month in the journal Nature Translational Psychology pulled together data from 31 randomized controlled trials to assess whether anti-inflammatory treatments helped reduce depressive scores among older adults. The researchers focused on older adults because chronic inflammation is a hallmark of the aging process.

They found that anti-inflammatory interventions—including omega-3 fatty acids, herbal medicines, and dietary interventions—were more effective than placebo in reducing depressive scores for older adults with depression. Participants using anti-inflammatory interventions showed similar improvements to those taking anti-depressants.

Anti-inflammatory Diet

An earlier study collected information about diet and depression symptoms from 12,000 older adults living in China. It found that people with more diverse diets and those who followed an anti-inflammatory diet were less likely to experience symptoms of depression.

The take-home message: Research suggests that reducing inflammation—including eating foods that reduce inflammation—may help reduce symptoms of depression.

Nutritional research has identified a variety of foods known to reduce inflammation in the body. They include tomatoes; olive oil; green leafy vegetables; nuts; fatty fish, including salmon, mackerel, tuna, and sardines; and fruits, including strawberries, blueberries, cherries, and oranges.

Researchers have also identified foods that lead to inflammation, including refined carbohydrates, such as white bread and pastries, fried foods, sugar-sweetened beverages, beef, processed meats, margarine, shortening, and lard.

In short, eating a well-balanced diet that includes leafy greens, fruit, tomatoes, and healthy fats may help to reduce symptoms for people with depression.

Visit Cornell University’s Bronfenbrenner Center for Translational Research’s website for more information on our work solving human problems.