In a new study of the mind-gut connection, eating fermented foods, which contain probiotics, were associated with reduced symptoms of social anxiety for student participants.
Giving new meaning to the old cliché of "you are what you eat," the research team says this is the first in a series of studies they are planning, hypothesizing that the right food could complement the efforts of psychologists when it comes to mental health.
"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," said Dr. Matthew Hilimire of Willian & Mary University in the US. "I think that it is absolutely fascinating that the microorganisms in your gut can influence your mind."
The researchers constructed a questionnaire that asked students about their consumption of fermented foods over the past month, and around 700 students responded.
It also questioned students about their exercise frequency and consumption of fruits and vegetables in the interest of controlling for other healthy habits that are reputed as mood boosters.
"The main finding was that individuals who had consumed more fermented foods had reduced social anxiety but that was qualified by an interaction by neuroticism," says Hilimire. "What that means is that that relationship was strongest amongst people that were high in neuroticism."
The questionnaire was incorporated in a mass test administered in the university's Introduction to Psychology class in the fall semester of 2014.
A secondary finding of the study, published in Psychiatry Research, revealed exercise could potentially reduce social anxiety.
The researchers say an experimental version of their study is in the works to investigate a causative mind-gut connection.
Looking at pre-existing animal models and human experiments of the past, Hilimire says he believes a causative mechanism exists.
"Assuming similar findings in the experimental follow-up, what it would suggest is that you could augment more traditional therapies -- like medications, psychotherapy or a combination of the two -- with fermented foods, dietary changes and exercise," he says.
In January, an international collaboration on the topic was published in The Lancet Psychiatry, stating that mounting evidence indicates vital relationships between diet quality and mental health.
Evidence is so compelling, they say, that psychiatry and public health should recognize and embrace nutrition as a key component of mental health.
Studies have demonstrated that omega-3s, B vitamins -- especially folate and B12 -- choline, iron, zinc, magnesium, S-adenosyl methionine (SAMe), vitamin D and amino acids are linked to brain health, the researchers remarked.
"While we advocate for these to be consumed in the diet where possible, additional select prescription of these as nutraceuticals -- nutrient supplements -- may also be justified," said lead author Dr. Jerome Sarris.