Chemicals in processed meat snacks, such as salamis and hot dogs, can contribute to mania, an abnormal mood state characterised by hyperactivity, euphoria and insomnia. The study, done by researchers from Johns Hopkins University and published in the journal Molecular Psychiatry, found that people hospitalised for an episode of mania had more than three times the odds of having ever eaten nitrate-cured meats than people without a history of a serious psychiatric disorder.
Mania, a state of elevated mood, arousal and energy that lasts weeks to months, is generally seen in people with bipolar disorder, but can also occur in those with schizoaffective disorder. Manic states can lead to dangerous risk-taking behaviour and can include delusional thinking, and most of those affected experience multiple hospitalisations in the course of their psychiatric illness.
Nitrates have long been used as preservatives in cured meat products and have been previously linked to some cancers and neurodegenerative diseases, so Yolken suspected they may also explain the link to mood states such as mania. In experiments with rats, researchers analysed the gut bacteria of the animals. They found that rats with nitrate in their diet had different patterns of bacteria living in their intestines than the other rats.
Moreover, the animals had differences in several molecular pathways in the brain that have been previously implicated in bipolar disorder. While the team also cautions that it’s too early to take any clinical messages from the results, and occasional cured meat consumption is unlikely to spur a manic episode in most of the population, Yolken said the findings add to evidence of the multiple factors that contribute to mania and bipolar disorder.