Research Emphasizes Association Between Inflammation, Diet, and Depression

Study finds adults with a pro-inflammatory diet have a greater incidence of depression


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A new study uses publicly available longitudinal data to explore the association between pro-inflammatory diets and depression in older adults. Researchers from across the U.S, Italy, and the UK used 8-year follow up data collected in North America and determined that participants with the highest pro-inflammatory diets had a 24% higher likelihood of developing depressive symptoms.

Photo Credit: Max Pixel

A growing body of research suggests that diet plays an important role in mental health/illness. For example, recent research has demonstrated that persons who have experienced a first episode of psychosis (FEP) are likely to have significant nutritional deficiencies. Nutrition has not only been found to play a role in the development of psychosis, but also in the risk of developing depression.

Research has found that elevated levels of inflammatory markers are often seen in persons with depression and that low inflammation diets, such as the Mediterranean diet, improve depression and quality of life scores. The authors of the present study sought to examine the relationship between diets with higher inflammatory potential and depression.

3,648 individuals were followed in an 8- year longitudinal study to explore the relationship between inflammation and depressive symptoms. Data were extracted from the Osteoarthritis Initiative (OAI) dataset from the University of California San Francisco. Dietary intake was measured using the Block Brief 2000 Food Frequency Questionnaire (FFQ). The Dietary Inflammation Index (DII) was utilized to assess the inflammatory potential of the participants’ diet.

Depressive symptoms were assessed with the Center for Epidemiologic Studies –Depression (CES-D) measure. Potential covariates were also extracted including; sex, body, body mass index, physical activity, race, smoking habit, educational attainment level, yearly income, statins use, NSAIDs or cortisone use, and general health.

At baseline, those with higher pro-inflammatory diets (DII scores) were:

  • More frequently smokers
  • Less educated
  • More frequently obese
  • Less frequently on statins
  • More likely to have higher depression scores (CES-D)

At 8-year follow up:

  • The incidence of depressive symptoms was significantly higher in people with higher DII scores at baseline
  • Those with higher DII scores had a significantly higher probability of depressive symptoms
  • Also associated with the onset of depressive symptoms:
    • Female sex
    • Higher BMI
    • Higher CES-D at baseline

This study suggests that a diet with a higher pro-inflammatory intake is associated with a higher incidence of depressive symptoms. In this longitudinal dataset, high DII scores resulted in a 24% higher risk of experiencing depressive symptoms than the lowest DIII scores. This study adds to the literature emphasizing the importance of diet in preventing depression and the relationship between inflammation and depression.



Shivappa, N., HĂ©bert, J. R., Veronese, N., Caruso, M. G., Notarnicola, M., Maggi, S., … & Solmi, M. (2018). The relationship between the dietary inflammatory index (DIIÂź) and incident depressive symptoms: A longitudinal cohort study. Journal of affective disorders, 235, 39-44. (Link)


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Bernalyn Ruiz
MIA Research News Team: Bernalyn Ruiz-Yu is a Postdoctoral Fellow in the Department of Psychiatry and Biobehavioral Sciences at the University of California, Los Angeles. She completed her Ph.D. in Counseling Psychology from the University of Massachusetts Boston. Dr. Ruiz-Yu has diverse clinical expertise working with individuals, families, children, and groups with a special focus on youth at risk for psychosis. Her research focuses on adolescent serious mental illness, psychosis, stigma, and the use of sport and physical activity in our mental health treatments.


  1. I agree with you, turtle, that we gloss over the role of diet. If I could maybe offer a reason why we rather stupidly underplay diet, I think it’s mainly because we are thinking of ways to get better, rather than prevention. The other thing is that what you see here is an association that isn’t, for me anyway, proof of cause. Nonetheless, diet should be much more emphasised in MH settings, if for no other reason than to offset for the metabolic effects of the drugs. It’s a no brainer on almost every level.

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  2. Not sure what role inflammation and poor diet played before my ramble in Psychiatric Wonderland. Since coming off my drugs I suddenly have a lot of symptoms that come with Chronic Fatigue Syndrome and I am sensitive or allergic to many things that never bothered me before.

    Autoimmune problems?

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  3. One step closer to that elusive biological explanation for depression. I guess these “scientists” want us to understand that feeling depressed as we get older has nothing to do with being lonely, losing loved ones and friends, retirement, financial insecurity, etc.

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  4. While healthy diets and exercise can protect against many health problems, this may be an example of correlation rather than causation.

    There is ample evidence that social class is a major determinant of health. Those who are better off socially and financially eat better, exercise more, experience less stress, and enjoy better health.

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  5. there are certain micronutrients that are essential…
    if you don’t eat them you die….and you get demented…
    example PELLAGRA…

    so does eating healthy help your brain..
    that is the question…correlation…causation…biology..
    what are we dealing with here…

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  6. Ironically psych drugs cause inflammation. And long term SSRI use blocks your ability to absorb micronutrients according to research not widely publicized. It’s in the UK Guardian and the article also says the drugs are ineffective at best.

    I keep eating yogurt/kimchi/saurkraut/kevita/other probiotic crap to no avail, Will need supplements forever. At least I’m off the drugs causing the damage.

    Blood tests have revealed I’m low in iron, magnesium, B12, D3 and about everything else. The doctor wouldn’t hazard a guess as to WHY.

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  7. -sigh- i do think social class is the big thing here, sadly. eating well boosts mood…unless you’re somehow eating well in oppression, low status, poverty, and social isolation. then…ya know…I would imagine the effects are minimal, at best.

    having said that, i do find Orthomolecular supplements help me, personally. I think the “trick,” if one can call it that, is to boost some vitamin+antioxidant levels well above what even the best diet could possibly provide. I think of it as a less expensive, more readily available, potentially healthful way of achieving some of what the psych drugs are billed as doing. and yet…

    even there, im thinking that once nutrition is good enough and one is cleared of major physical health problems, this “mental illness” business (and it is a business…a lucrative one, at that…) is pretty much as Szasz writes about…its pseudoscience on a good day, more like…a state-sponsored, godless religion that also functions as social control.

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