It might sound outlandish, but the idea that your diet can have a huge effect on your emotions has become the focus of an exciting new area of psychological research. The latest addition to this growing body of research comes from psychologists at the College of William & Mary, and finds a link between a diet high in fermented foods and reductions in neuroticism and social anxiety.
“It is likely that the probiotics in the fermented foods are favorably changing the environment in the gut, and changes in the gut in turn influence social anxiety,” Dr. Matthew Hilimire, an assistant professor of psychology and one of the study’s authors, said in a statement. “I think that it is absolutely fascinating that the microorganisms in your gut can influence your mind.”
The sauerkraut solution? With preliminary research — which has mostly been conducted on mice — suggesting that consuming probiotics might lessen symptoms of anxiety and depression, Hilimire and his colleagues decided to investigate whether eating probiotic-rich foods had a positive effect on personality and social anxiety.
For the study, which will be published in the August issue of Psychiatry Research, 700 undergraduates were asked about their consumption of foods such as sauerkraut, kimchi, kombucha, yogurt, fermented soy products, pickles and kefir. They were also assessed for Big Five personality traits and social anxiety, which is characterized by the tendency to feel uncomfortable in social situations and to fear being judged by others.
As hypothesized, eating fermented foods was correlated with decreased social anxiety. The link was strongest among individuals with high levels of neuroticism, a personality trait that’s characterized by negative emotions like anxiety, fear, moodiness, worry, envy, frustration and loneliness — meaning that the most neurotic people benefited the most from fermented foods.
Why? There are several possible mechanisms by which gut bacteria can influence mood. For starters, increasing the balance of good bacteria in the gut may decrease intestinal permeability, also known “leaky gut” — a condition that has been linked with depression. More good bacteria also generally means less inflammation, which may be connected to a decrease in anxiety, stress and depression. Probiotics may also reduce anxiety by increasing GABA, a neurotransmitter that tempers the brain’s fear response.
Those kombucha-drinking yogis may be onto something — the findings revealed that not only fermented foods but also exercise was associated with less anxiety and neuroticism.
Food for your mood. The idea that diet may be as important to mental health as it is to physical health has become buzzworthy not only in holistic health circles but also in the scientific community.
While the brain-gut connection is still a relatively new discovery, it’s becoming a subject of increasing interest to psychologists. In a study published this week in the journal The Lancet Psychiatry, researchers from the University of Valencia concluded, “A balanced diet is as important in psychiatry as it is in other medical specialties such as cardiology or endocrinology.”
Increasingly, it’s looking like a mood-healthy diet is one that’s high in probiotics. The William & Mary findings join an expanding collection of research on the gut microbiome that has suggested a positive effect of “good” bacteria on mental health. A 2013 UCLA study found that women who consumed yogurt twice a day for four weeks were less reactive to threatening stimuli, while a recent Oxford study showed consuming prebiotics — undigestible fibers that feed the “good” bacteria in the gut — has an anti-anxiety effect.
“Time and time again, we hear from patients that they never felt depressed or anxious until they started experiencing problems with their gut,” Dr. Kirsten Tillisch, the UCLA study’s lead author, said in a statement. “Our study shows that the gut-brain connection is a two-way street.”
Hilimire expressed enthusiasm about this burgeoning area of study and its wide-ranging implications for the field of psychology. With more research, it’s possible that traditional psychiatric interventions like psychotherapy and medication will be supplemented with lifestyle changes like exercise and a probiotic-rich diet.
“I think there is some skepticism that there can be such a profound influence, but the data is quite substantial now,” Hilimire said. “I think people would be accepting if they looked at the data, but the connection between the mind and gut is not something you typically think about as a psychologist.”
Until now, that is. While it’s too early to make specific dietary recommendations, incorporating more fermented foods into your diet certainly can’t hurt — and it could make a noticeable difference in your mood.