As if diarrhea and vomiting weren’t punishment enough, researchers now believe that a bout of food poisoning could make you less intelligent later in life.
If you’ve had food poisoning before, you’re more likely to have poor learning skills, poor memory, and develop schizophrenia, according to parasitologists and evolutionary biologists at Charles University in the Czech Republic.
Previous research has identified this link in the weeks and months after food poisoning develops.
But scientists involved in these studies have attributed this to the fact that people simply do not feel themselves immediately after feeling sick.
Some of the early symptoms of food poisoning include vomiting and diarrhea, but in the long term, some studies have shown that this parasite can cause changes in memory.
But new research suggests that personality changes caused by food poisoning last long after recovery.
The experts, from Charles University in Prague, focused on two specific microbes that affect a wide swath of the population and can survive in the body for long periods of time.
One, called Toxoplasma gondii, is responsible for 800,000 cases of food poisoning each year in the U.S. Toxoplasma can be found in all types of meat, but is particularly common in pork, lamb and venison, according to the FDA.
The other, Borrelia spp, is a bacteria responsible for Lyme disease, which affects approximately 476,000 people every year in the US
Toxoplasma gondii is a parasite that can attack many different types of hosts, from humans to cats, according to to the CDC. In addition to spoiled meat, it is found in contaminated water and in the excrement of sick cats.
Nearly a quarter of people who passed through adolescence said they contracted the parasite, according to Dr. Jeffery Jones, an epidemiologist and pediatrician at the Centers for Disease Control. It causes about 24 percent of foodborne illness deaths in the US.
If you are healthy, accidentally ingesting some of this parasite will probably only give you a mild infection.
The prevalence of toxoplasmosis in the U.S. generally increases with age, according to Dr. Michael Greger of Nutrition Facts.
But if you’re immunocompromised or pregnant, you could have a sudden, intense episode of vomiting, chills, diarrhea, sweating and weakness in response to the parasite, according to doctors at Baylor College of Medicine. This could be why we see more toxoplasma infections in the U.S. as people age, according to Nutrition Facts.
According to the CDC, the parasite does not leave your body after you stop feeling sick; it often stays within you for life. Most people will have very few noticeable symptoms, but if you are immunocompromised you may develop flu-like symptoms.
The study, which was published in the magazine Parasitological folia, surveyed 7,762 people with an average age of 42 years.
Approximately 962 of those people reported testing positive for Toxoplasma and 1,778 of those people reported being infected with Borrelia.
Each of the respondents completed a series of tests designed to measure personality traits, memory and cognitive abilities.
People who had toxoplasma food poisoning before had slower reaction times and less accurate responses to a common neurological test called the Stroop Test.
A photo of the toxoplasmosis parasite under the microscope. You can contract this through undercooked meat or infected cat feces.
A common version of the Stroop test involves participants looking at colored words written in different colored fonts. For example, the word blue could be written in a green font and the word orange could be written in a pink font.
Participants must identify the color of the word, not the word itself.
The Stroop test is used in laboratories to measure attention span, memory, mental acuity and intelligence, according to lesley university.
Generally, if participants’ responses were slower or less accurate, researchers indicated this as a sign that their memory or intelligence was poorer.
The study authors say their results indicated lasting effects of the infections, as behavioral changes did not only occur in people who were in poor health due to the virus.
The participants still had worse memory even after their physical symptoms had disappeared, the authors reported, meaning the parasite caused chronic problems.
Toxoplasma may affect memory by changing the amount of neurotransmitters the brain releases, study suggests
A 2021 study A study of 800 adults in Taiwan found that people who suffered from toxoplasmosis food poisoning were 2.8 times more likely to develop dementia than those who did not. Additionally, people who were treated for the disease were less likely to develop dementia than those who were not.
Additionally, it has been shown that rodents that have been infected with this parasite have worse memory and more difficulty navigating their enclosures, according to to a 2023 study from the Pasteur Institute of Iran.
The disease has also been linked to other neurological changes, such as schizophrenia. A 2022 study from the Federal University of Rio de Janeiro found that people who had been infected with toxoplasma were more likely to develop schizophrenia than people who had not contracted the parasite.
Besides cat poop, the most common way people contract the toxoplasmosis parasite is by eating undercooked and infected meat.
Scientists aren’t exactly sure how this parasite changes the brain. But a theory, explained in a 2023 article from the Ahvaz Jundishapur University of Medical Sciences in Iran, said the parasite could alter the levels of chemicals in the brain that control mood, memory and emotions.
The study found that exposure to toxoplasma caused an increase in a chemical called dopamine and a decrease in a chemical called serotonin in the rodents’ brains. This caused changes in memory and behavior.
Another theory is that the parasite living in your body long-term can cause a small but constant immune response in your body, which over time can wear down your brain. according to Dr. Michael Gregerpublic health specialist and nutritionist.
The researchers in the Czech study concluded that although these diseases seemed to be related, they could not yet prove how they were related.