Researchers discovered that fermented kombucha tea influenced gut bacteria and brain-related metabolic pathways while reducing depression-like behaviors in mice, suggesting a potential connection between fermented foods and mental health.
By yourNEWS Media Newsroom
Drinking kombucha may influence mood-related behavior through changes in intestinal bacteria and brain chemistry, according to new research from the University of Minnesota that found promising results in mice consuming the fermented beverage.
The study, published in Food Bioscience in September 2026 and highlighted by the university Oct. 15, found that mice receiving kombucha three times weekly exhibited fewer depression-like behaviors than those given water. Researchers also observed changes in gut microorganisms and compounds involved in communication between the digestive system and brain.
The findings add to growing scientific interest in the gut-brain axis, the complex relationship connecting intestinal microorganisms, immune activity, metabolism and neurological function.
Researchers cautioned, however, that the results are preliminary and do not establish that kombucha prevents or treats depression in humans.
The seven-week experiment involved 44 male mice divided between two dietary patterns. One group received a conventional laboratory diet, while the other consumed a Western-style diet containing higher levels of fat and sugar.
Within each dietary group, some mice received kombucha three times per week, while control animals received water.
Scientists evaluated behavior using established laboratory tests and examined bacterial populations and metabolic compounds in the animals’ intestines, feces and brains.
Mice consuming kombucha demonstrated reduced immobility during a forced-swim test, a response commonly used in animal studies to assess depression-like behavior.
That association appeared in animals eating either diet, suggesting that the behavioral findings were not limited to mice consuming healthier food.
However, reduced anxiety-related behavior, measured through a separate marble-burying test, appeared only in animals receiving the Western-style diet.
The different outcomes suggest that an individual’s underlying diet could influence how fermented foods interact with intestinal microorganisms and neurological processes.
The researchers also identified changes in the composition and activity of gut bacteria, including pathways involved in processing amino acids that participate in brain signaling.
Among the compounds examined were tryptophan and kynurenine, which are involved in metabolic processes associated with serotonin production, inflammation and neurological function.
Mice consuming the Western-style diet showed elevated levels of both compounds in brain tissue after receiving kombucha.
Although tryptophan is a precursor to serotonin, the findings do not demonstrate that kombucha directly increased serotonin production or explain how the observed metabolic changes affected behavior.
Additional differences appeared in animals consuming the standard laboratory diet.
Those mice showed increased fecal concentrations of acetate and butyrate, two short-chain fatty acids produced through microbial fermentation.
These compounds contribute to intestinal health and have been studied for their roles in maintaining the gut barrier, regulating inflammation and influencing metabolic signaling.
The Western-diet group also demonstrated lower spleen weight following kombucha consumption, a finding researchers said could indicate changes in immune-related processes.
However, spleen weight alone cannot establish a beneficial immune effect, and further investigation is necessary.
Lead researcher Noor e Huma, a graduate student in the university’s College of Food, Agricultural and Natural Resource Sciences, described the findings as an early indication that dietary microorganisms may influence mental well-being.
“This work shows preliminary and preclinical evidence that frequent consumption of kombucha could be associated with improvements in mental health,” Huma said.
“This research also shows the foods we consume should be valued in the context of mental health in addition to physical health.”
Kombucha is produced by fermenting sweetened black or green tea with a symbiotic culture of bacteria and yeast, commonly called a SCOBY.
The fermentation process produces organic acids and other compounds while introducing microorganisms that may influence the intestinal environment.
Unlike conventional soft drinks, traditionally fermented kombucha can contain live microbial cultures, although concentrations vary considerably among commercial products.
Researchers have increasingly investigated whether fermented foods can influence psychological health by modifying the gut microbiome.
Andres Gomez, an associate professor involved in the study, said the research supports further examination of microorganisms consumed through ordinary foods.
“Because fermented foods such as kombucha, sauerkraut and yogurt provide a healthy dose of beneficial bacteria when consumed, studies such as this and others show that ingesting good microbes from our food system may also contribute to keeping both our physical and mental health in balance,” Gomez said.
Nevertheless, the experiment has important limitations.
It involved a relatively small number of male mice, and laboratory assessments of depression-like behavior do not directly reproduce clinical depression in people.
The forced-swim test, for example, measures behavioral responses to an unavoidable stressor rather than diagnosing depression. Researchers continue to debate how reliably such tests predict human mental health outcomes.
The study also cannot establish whether changes in gut bacteria caused the behavioral effects or merely occurred alongside them.
Additional experiments will be necessary to identify the mechanisms involved and determine whether similar responses occur in female animals or humans.
Researchers plan to investigate more behavioral measures and examine how gut microorganisms communicate with the nervous system following consumption of fermented foods.
Human clinical trials would ultimately be required to determine whether kombucha offers measurable benefits for depression or anxiety.
Commercial kombucha products also differ in sugar content, alcohol concentration and the presence of live cultures, potentially affecting their nutritional properties.
For now, the findings suggest a promising direction for research into diet and the gut-brain connection, but they do not support replacing established mental health treatments with kombucha.
The study provides new evidence that fermented foods may influence biological pathways associated with mood, while leaving the question of whether those effects translate into meaningful human health benefits unanswered.
Source: Natural News
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