By Ernie Hood
The natural probiotics found in certain fermented foods such as sauerkraut and yogurt may be connected to improvements in social anxiety, according to a recent study by William and Mary psychology professors Matthew Hilimire and Catherine Forestell, along with Jordan DeVylder from the University of Maryland School of Social Work.
That’s the intriguing conclusion the group reached from a research project involving 710 William and Mary psychology students who responded to a detailed questionnaire that probed their neuroticism, social anxiety, exercise and dietary habits, specifically consumption of fermented foods.
There had been some prior research showing that probiotic consumption resulted in reduced anxiety. “We wanted to see if the results extended to social phobia, because social phobia is a prevalent anxiety disorder, and many people experience some symptoms of social anxiety even if they do not have diagnosable social phobia,” said Hilimire. They found that the young adults who ate more fermented foods had fewer social anxiety symptoms.
It’s all in your genome
The association between fermented foods consumption and social anxiety symptoms seen in the study was greatest among those at genetic risk for social anxiety disorder as measured by the personality trait known as neuroticism. Previous studies had shown that the genetic factors that contribute to variability in neuroticism can account almost entirely for genetic vulnerability to social anxiety. “This suggests that genetic variability likely plays an important role in the relationship between fermented food consumption and social anxiety,” noted Hilimire.
Study results showed that those at higher risk for social anxiety disorder, as indicated by high neuroticism, showed fewer social anxiety symptoms when they consumed more fermented foods.
The mind-gut connection
According to Hilimire, “It is likely that the probiotics found in the fermented foods are favorably changing the environment in the gut, and changes in the gut in turn influence social anxiety.”
The possible mechanisms behind those changes are unclear, and as a survey the William and Mary study shed no light on that question. But previous studies have suggested that decreased gut permeability, reduced gut inflammation, and increased levels of the neurotransmitter GABA, which is mimicked by anti-anxiety medications such as benzodiazepines, may be involved. Animal studies have shown that giving mice certain probiotics—the beneficial, health-enhancing microorganisms such as lactobacilli—has positive effects on their levels of depression or anxiety. “Giving these animals these probiotics increased GABA, so it’s almost like giving them these drugs but it’s their own bodies producing GABA,” Hilimire explained. “So your own body is increasing this neurotransmitter that reduces anxiety.”
With more bacterial cells than human cells in our bodies—the so-called gut microbiome—it would be strange if they did not have a strong influence on our health, Hilimire observed. So the mind-gut connection “definitely needs more exploration,” he said. “We have just begun to examine the tip of the iceberg, and I think many more exciting findings are to come in this field,” he noted.
The team plans a series of studies to continue exploring the mind-gut connection, including a randomized, controlled trial to more rigorously examine whether there is a causal relationship between fermented food consumption and social anxiety. It would involve administering fermented foods to subjects, as opposed to other research that has used probiotic supplements, which lack bioactive proteins found in the naturally fermented foods.
Hilimire would not speculate on the potential use of fermented foods to treat social anxiety, noting that the research is still very preliminary and that it would be irresponsible to make assumptions going forward. But as he pointed out, “fermented food is delicious…so why not eat it?”
So, the next time you’re feeling anxious, gobble down a yogurt or some dark chocolate or a bowl of miso soup. They can’t hurt, and just might make you feel a little bit better.