Consumption of processed meat may lead to mania

A number of genetic and other risk factors are linked to the manic episodes that characterize bipolar disorder. These factors are unable to explain the cause of these mental illnesses and researchers are increasing their emphasis on environmental factors, such as diet. Findings of this study add to evidence that certain diets and the types and amounts of bacteria in the gut might contribute to mania and other disorders affecting the brain.

"Future work on this association could lead to dietary interventions to help reduce the risk of manic episodes in those who have bipolar disorder or who are otherwise vulnerable to mania," says Dr. Yolken.

For the study, Those with psychiatric disorders were recruited from patients receiving care at the Sheppard Pratt Health System in Baltimore. Individuals with no history of psychiatric disorders were recruited from posted announcements at local health care facilities and universities in the region. Their records were studied between 2007 and 2017.

Key Findings:

• Among people who had been hospitalized for mania, a history of eating cured meat before hospitalization was approximately 3.5 times higher than the group of people without a psychiatric disorder.


• Cured meats were not associated with a diagnosis of schizoaffective disorder, bipolar disorder in people not hospitalized for mania or in major depressive disorder.


• No other foods about which participants were queried had a significant association with any of the disorders, or with mania.

"We looked at a number of different dietary exposures and cured meat really stood out," says Yolken. "It wasn't just that people with mania have an abnormal diet."

"It's clear that mania is a complex neuropsychiatric state, and that both genetic vulnerabilities and environmental factors are likely involved in the emergence and severity of bipolar disorder and associated manic episodes," says Seva G. Khambadkone, Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, U.S. "Our results suggest that nitrated cured meat could be one environmental player in mediating mania."

"Lower odds of association were found between eating nitrated dry-cured meat and other psychiatric disorders. We further found that the feeding of meat preparations with added nitrate to rats resulted in hyperactivity reminiscent of human mania, alterations in brain pathways that have been implicated in the human bipolar disorder, and changes in intestinal microbiota. These findings may lead to new methods for preventing mania and for developing novel therapeutic interventions," concluded the authors.

For more information log on to https://doi.org/10.1038/s41380-018-0105-6