Study finds that individuals diagnosed with schizophrenia, bipolar disorder, and depression have diets that are more inflammatory and higher in calories.

In a letter to the editor recently published in World Psychiatry, researchers describe a study comparing the difference in nutrition and diet-associated inflammation between people diagnosed with a serious mental illness (SMI) and the general population. The authors found that, when compared to controls, those diagnosed with schizophrenia, bipolar, and depression had diets with a higher inflammatory index and higher total energy, carbohydrate, sugar, total fat, and saturated fat intake.

Previous research has demonstrated the existence of a relationship between having a diet higher in pro-inflammatory foods and depression. The authors of the present study, point out that research has shown that persons diagnosed with SMI have higher levels of peripheral inflammatory markers. Having diets with a higher caloric intake and excessive consumption of high-fat and high-sugar foods increase levels of systemic inflammation as well as the risk of diabetes and cardiovascular mortality.

Using Data from the UK Biobank study, individuals who had received a diagnosis of a recurrent depressive disorder, bipolar disorder (type I or II), or schizophrenia and healthy controls were selected from the UK Biobank participants. Almost 70,000 participants were included in the data analysis, of which 54,000 were used as controls.

The schizophrenia, bipolar, and depression groups all showed significantly higher total calorie, carbohydrates, sugar, total fat, saturated fat, and protein intake. No significant changes were noted when adjusting for ethnicity, body mass index, education, and social deprivation. The authors also analyzed the inflammatory index of the participants. Data revealed that participants with a schizophrenia and depression diagnosis had diets with a significantly higher inflammatory index when compared to controls.

The authors explain that this data revealed, “people with SMIs have higher intakes of obesogenic nutrients and more inflammatory diets than the general population.” They suggest, “further consideration should be given to increasing consumption of nutrient‐dense foods that are known to reduce systemic inflammation.”

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Firth, J., Stubbs, B., Teasdale, S. B., Ward, P. B., Veronese, N., Shivappa, N., … & Sarris, J. (2018). Diet as a hot topic in psychiatry: a population‐scale study of nutritional intake and inflammatory potential in severe mental illness. World Psychiatry, 17(3), 365. (Link)