In the human study, people were asked if they had eaten meat sticks in the form of turkey and beef jerky, "meat sticks", prosciutto and salami. Rats that had nitrates added to their diets started to display signs of hyperactivity within a few weeks of consuming the nitrates.
Patients taken to hospital with manic episodes were more than three times more likely to have recently eaten meats such as ham, salami or beef jerky.
For the first study, the researchers didn't even intend to look at cured meats, said study co-author Faith Dickerson, director of the Stanley Research Program at Sheppard Pratt Health System.
"Our findings only tell us that patients hospitalized with mania had an increased history of cured meat consumption compared to healthy controls, and that in animal studies the consumption of nitrated cured meat led to mania-like behavior and brain changes in rats", the researchers said in an email to Laboratory Equipment. Mania is characterized by hyperactivity, euphoria and insomnia. Nitrate-cured meats, which are the things like bacon or beef jerky that have been connected to broad times of hyperactivity, a sleeping disorder, and consideration misfortune in individuals encountering hyper scenes.
"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 maniac episodes", explained Seva Khambadkone, doctoral student at the varsity.More news: United States tariff war to adversely affect worldwide trade: China
To find whether these nitrate-filled meats potentially contribute to mania, experiments with rats were conducted.
There is a wide range of underlying genetic risk factors that are linked to manic episodes, however researchers have been also been looking to environmental factors to see how diet or lifestyle habits affect certain psychiatric conditions. One group ate the store bought nitrate beef jerky and the other ate the nitrate free version.
Eating the occasional cured meat will not cause a manic episode in most people, the study authors pointed out.
Professor Robert Yolken said: "We looked at a number of different dietary exposures and cured meat really stood out".More news: British Police Identify Russian Suspects Behind Skripals' Poisoning, Media Says
Rather the study calls for further research to explore how diet can impact psychiatric disorders.
They found that rats with nitrate in their diet had different patterns of bacteria living in their intestines than the other rats. The animals also had differences in several molecular pathways in the brain that have been previously implicated in bipolar disorder.
That evidence includes a 2016 study which found that people with migraine headaches have higher levels of a bacterium that breaks down nitrates, suggesting that the bacteria may be playing a part in causing the migraines.
Nitrates are chemicals that are sometimes added to processed and cured meats as preservatives.More news: Thunder, Hawks and 76ers agree to deal centered around Carmelo Anthony