Do you like beef jerky…salami…hot dogs? Do you like them enough to risk having a serious psychiatric episode? Before you answer that question, read this article.
Investigating how environmental factors, including diet, affect psychiatric illnesses, researchers at Johns Hopkins University conducted a 10-year study of more than 1,000 adults. Seven hundred of them had been diagnosed with psychiatric disorders and 300 had not. Part of the study included asking the participants questions about what foods they ate. During the course of the study, 217 participants were hospitalized with episodes of mania, a condition characterized by euphoria, hyperactivity, insomnia and delusional thinking.
Researchers were prepared for diet to be somehow associated with participants’ mental status, since it is already known that what we eat affects how we feel—a connection called the gut-brain axis. But one study result surprised them: There was a strong association between mania and eating cured meat. In fact, participants hospitalized for mania were three times more likely than other participants to have diets that included meats cured with nitrates. Further analysis revealed that beef jerky, turkey jerky and meat sticks—all of which are typically cured with nitrates—were the forms they most commonly consumed. No foods eaten by the participants other than meats cured with nitrates were associated with any psychiatric conditions. Nor were nitrate-containing meats associated with any other psychiatric illnesses (e.g., schizophrenia, schizoaffective disorder, bipolar disorder, bipolar depression or major depressive disorder).
Nitrates are already known to alter the balance of gut bacteria, and gut bacteria are known to affect neurotransmitters in the brain. To explore that connection, the researchers also tested rats. Each day, they fed some rats regular rat chow and others amounts of beef jerky equivalent to what humans would eat as a snack. After a few weeks, the rats fed beef jerky demonstrated behaviors associated with mania, such as insomnia and hyperactivity. And when the researchers compared the brains and gut bacteria of the two groups of rats, they found that the nitrate-consuming rats had changes to their brain chemicals and gut bacteria while the other rats did not.
While the human study shows only an association between nitrates and mania, not a cause and effect, researchers postulate that nitrates may be risky for people vulnerable to mania. The study did not pin down how much or how often nitrate-containing meat was eaten by participants, so it’s not possible to determine what might be a safe amount to consume. Nitrate-containing meats, which include salami and hot dogs, are unhealthy for other reasons, including being linked to certain cancers. For now, the researchers suggest that anyone at risk for mania should avoid foods with nitrates.
