Poor diet provides clue to metabolic abnormalities in schizophrenia

By Lucy Piper, Senior medwireNews Reporter

Patients with schizophrenia commonly have a poor diet, say UK researchers who believe this may partly account for the increased incidence of metabolic abnormalities in these patients.

The poor diet was mainly characterized by a high intake of saturated fat and calories and a low consumption of fiber and fruit, report Valeria Mondelli, from King's College London, and colleagues.

"Such [a] diet is likely to increase the risk of developing metabolic abnormalities, and may worsen metabolic abnormalities induced by other factors," they say.

"The diet and factors underlying poor dietary patterns may represent an important therapeutic target to control metabolic abnormalities in patients with schizophrenia."

The findings come from a literature search, in which 783 research studies focusing on the assessment of unhealthy lifestyle, metabolic abnormalities and cardiovascular risk in chronic patients with schizophrenia were identified. Of these, 31 on dietary patterns and their effects on metabolic parameters in schizophrenia were reviewed.

The patients' diets were assessed retrospectively in most cases and the instruments used for assessing dietary habits varied, ranging from structured questionnaires such as DINE and food frequency questionnaires to food diaries and computerized food tables.

Most of the studies agreed that schizophrenia patients had poorer diets than the general population, with just five studies failing to report a significant difference.

The poor dietary patterns are known to be linked to the development of metabolic syndrome in individuals without psychiatric disorders. Also, both high saturated fat intake and low fiber and fruit consumption are related to high levels of inflammatory markers, which in turn may promote the development or worsening of the metabolic syndrome, the researchers comment.

However, they were unable to clearly elucidate a link between poor diet and metabolic variables from the studies reviewed.

"We can only suggest that a poor diet represents one of the factors involved in the development of metabolic abnormalities," the team writes in the Journal of Psychiatric Research.

"With this view, it is important to clarify which factors may influence diet and consequently have a role in the development of metabolic syndrome."

Such factors may include antipsychotic treatment, stress, socioeconomic status, hypothalamic-pituitary-adrenal axis hyperactivity, low physical activity, and smoking, Mondelli et al suggest.

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