New study shows that fermented foods like yogurt and tempeh can ease social anxiety.
Social anxiety is the third most prevalent anxiety disorder, affecting over 10% of the population. Social anxiety is characterized by an excessive, unreasonable fear of social situations, such as speaking in public, interacting with others in normal social situations, and may even make it difficult to use a public restroom, eat in front of other people, date, or speak on the phone. Thus, supposedly fun social engagements can feel overwhelming for many. Social anxiety has a genetic component, but is often treatable with cognitive behavioral therapy (CBT) and selective serotonin reuptake inhibitors (SSRIs). Emerging research has also found that improving gut bacteria via probiotics or fermented foods can further reduce anxiety, in addition to having other health benefits.
Gut Bacteria and Mental Health
Gut bacteria imbalances have been linked to symptoms of depression, anxiety, and worsened symptoms in schizophrenia. Probiotic (“good” gut bacteria) supplements and consuming foods high in probiotics, such as fermented foods, have been shown to alleviate psychiatric symptoms in a growing number of studies.
In one study, consumption of a fermented milk product decreased brain activity in response to viewing faces expressing negative emotions. The fermented milk product given to participants in this study contained several probiotics: Bifidobacterium animalis, Streptococcus thermophiles, Lactobacillus bulgaricus, and Lactococcus lactis. After four weeks of consuming this beverage, participants showed reduced activity in sensory, prefrontal, and limbic regions brain – areas that can be overactive in response to negative social stimuli. There was no such activity decrease in the brains of people in the control group, who consumed a non-fermented beverage. The important takeaway from this study is that consuming probiotics or foods that contain a sufficient amount of them, may be helpful for people who are particularly vulnerable to feeling anxious in the face of perceived negative feedback from others.
How Probiotics Help Reduce Anxiety
In another study, ingestion of the lactic acid bacteria Lactobacillus rhamnosus resulted in anxiolytic (anxiety-reducing) effects in laboratory mice. Other studies have found that probiotic treatment can minimize anxiety induced by gut inflammation. Anxiolytic effects have been linked to changes in a specific protein – brain derived neurotrophic factor (BDNF). BDNF plays an important role in the survival and maintenance of existing neurons (nerve cells), and the growth and development of new neurons. In addition, consuming probiotics is thought to improve GABA receptor expression. GABA is a neurotransmitter, or brain chemical, that has a calming effect on overexcited nerve cells.
In addition to the above, probiotics are thought to exert a positive effect on the vagus nerve. The vagus nerve is the longest of the cranial nerves, extending from the brainstem to the abdomen by way of multiple organs, including the heart, esophagus, and lungs. It is involved in unconscious body functions, such as keeping the heart rate constant and controlling food digestion, and also can be stimulated to slow one’s heart rate and exert a calming effect on the mind. Perhaps the easiest way to stimulate the vagus nerve is by doing deep breathing, such as diaphragmatic breathing, but consuming probiotics via food or supplements seems to have a beneficial effect, as well.
Can Eating Fermented Foods Reduce Social Anxiety?
A recent study was the first to examine whether probiotics could lessen symptoms of social anxiety. In this study of 710 college students, researchers assessed trait neuroticism, which is linked to social anxiety, as well as exercise habits in the previous two months and food consumption during the past month. They found that consumption of fermented foods – which are likely to contain probiotics – was negatively associated with symptoms of social anxiety. They also found that those participants at higher genetic risk for social anxiety disorder, as indicated by higher levels of trait neuroticism, showed fewer social anxiety symptoms if they had consumed a greater amount of fermented foods in the previous month. Additionally, exercise over the previous two months was linked to decreased anxiety.