Bugs may take a bite out of anxiety

A Japanese study found that a daily dose of probiotics may help soothe anxiety-induced gastrointestinal stress among med students during finals.

Will probiotics one day be part of students’ pre-SAT regimes along with spendy prep courses, lost sleep and parents’ prayers? The bugs might help soothe pre-test anxiety, according to a recent study of medical students at exam time.

Japanese researchers designed a double-blind placebo-controlled trial to see if a daily dose of probiotics could help stress-induced abdominal dysfunction and other symptoms of stress felt by med students during testing season. For eight weeks prior to exams, they gave half the group of subjects milk that had been fermented by L. casei strain Shirota every day while the other half drank a placebo.

Each week, the scientists measured certain physiological parameters, such as salivary cortisol (a stress hormone) levels. Weekly, the students answered questionnaires about levels of five common abdominal symptoms and anxiety levels.

According to the study’s results, daily consumption of the probiotic milk was associated with reduced gastrointestinal pain and dysfunction, as well as the feeling of being stressed out. It also dampened the rise in salivary cortisol, corresponding author Kouji Miyazaki, PhD, director of the Food Research Department of Yakult Central Institute in Tokyo, said in an American Society for Microbiology release. The study was published in Applied and Environmental Microbiology, a journal of the Society.

"These findings indicate that the stress responses are controlled by probiotics at a higher level of the stress system, through the brain-gut axis," said Miyazaki. "Thus, the probiotic strengthens the resilience of our stress response system."

There was no indication of whether the Japanese students who took the bugs got better test scores. An earlier study conducted by Oxford University researchers found that a daily dose of probiotics seemed to not only soothe anxiety levels but also enhance performance on a computer test that analyzed how they processed emotionally relevant information.

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