New kitchen trend promises relief from anxiety—would you try this yourself?
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“Dysbiosis is an altered state of the gut that favors pathogenic bacteria while also creating an environment where beneficial bacteria cannot thrive. This state of dysbiosis is seen in a wide variety of diseases and is an underlying component of a spectrum of mental health disorders.” – Megan Wroe, MS, RD
“While animal studies show a promising effect [of fermented foods on mental health], human research could add to that evidence and give us a more solid understanding of the relationship.” – Sotiria Everett, EdD, RD, CDN, CSSD
What you eat not only influences your physical health and energy levels, but growing research shows that it can also affect your mental health.
One area where this has been widely documented is with ultra-processed foods. “There are too many studies [showing that] the more ultra-processed food intake an individual has, the higher their risk of both metabolic diseases and mental health diagnoses,” says Megan Wroe, MS, RD, CNE, CLEC, a dietitian with Providence St. Jude Medical Center.
On the flip side, growing research suggests that foods that benefit gut health and promote the growth of gut-friendly bacteria, like fermented foods, could help alleviate mental health conditions like anxiety. Let’s dive in to the latest research—and see what the experts are saying.
It's all about the gut-brain axis
According to Wroe—eating nine or more servings per day of ultra-processed foods correlates with a “50% higher risk of developing depression than those who ate less than four servings per day,” she says, noting a 2023 study on the topic.[]
To date, many of the existing studies on the impact of fermented foods on mental health have mostly involved animals. More studies, particularly those involving human participants, are needed to substantiate the evidence.
A recently published study on mice drew upon the known, but poorly understood, connection between the amygdala, a brain region that regulates fear and anxiety, and the gut-brain axis.[] The study aimed to investigate how gut microbiota might affect anxiety. The researchers found that mice without gut microbes showed more anxiety-related behaviors, and introducing a microbe-derived metabolite to their system reduced their anxiety levels.
In discussing the study with MDLinx, Sotiria Everett, EdD, RD, CDN, CSSD, clinical assistant professor at Stony Brook University, noted that the metabolite the mice were given was indole, which the gut produces from digesting or processing the amino acid tryptophan. The study authors commented that the reduction in anxiety-related behaviors in the mice suggested a potential molecular mechanism by which microbe-derived indoles could regulate anxiety.
Happy gut = Stress-free mind?
One theory (flowing from the results of this study), says Dr. Everett, is that eating fermented foods, which are sources of dietary probiotics, may support a healthy colonization of gut bacteria. And the bacteria will make metabolites that are helpful for the host, including metabolites that help reduce anxiety by reducing the excitability of certain neurons that are associated with anxiety. The study authors speculated that indole-fortified foods might be considered as a therapeutic strategy for anxiety-related disorders.
Wroe explained how fermented foods could be an anti-anxiety hack by reversing dysbiosis or imbalanced microbiota.
“Dysbiosis is an altered state of the gut that favors pathogenic bacteria while also creating an environment where beneficial bacteria cannot thrive. This state of dysbiosis is seen in a wide variety of diseases and is an underlying component of a spectrum of mental health disorders,” she notes. “In replenishing the gut with both beneficial bacteria and the prebiotic fiber food they need to survive, we help to correct that dysbiosis. It’s never the only change that needs to happen in order to help diminish mental health symptoms, but it is a very important piece of the puzzle.”
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