Think that bag of potato chips will make you happier than a healthy cup of yogurt? Think again. Eating yogurt has an emotional impact on your brain. Already known as a useful way to reduce stroke risk and improve digestion, yogurt may help people cope with mood, anxiety, stress and pain, according to researchers at the University of California, Los Angeles.
The essential ingredient, according to the researchers, is the living bacteria, known as probiotics, found in most forms of yogurt and also found within the body’s gut. Probiotic yogurt has already been shown to have beneficial effects for the human digestive system, such as helping treat diarrhea.
Evidence that bacteria eaten from food could directly impact brain function.
Now there is evidence that bacteria eaten from food could directly impact brain function.
All subjects were given a functional magnetic resonance imaging (fMRI) brain scan before and after their yogurt regimen. In addition, to get a picture of their emotional state, the women were given an emotional faces attention task, in which their brains were scanned while matching a series of emotional faces on a computer screen.
Women who ate the probiotic yogurt showed reduced brain activity in several critical regions, such as the somatosensory cortex and insular cortex, during the emotional task. The somatosensory cortex receives sensory information from all areas of the body and the insular cortex integrates sensory information from internal areas of the body such as the gut.
In contrast, women who ate non-probiotic yogurt or no dairy at all for a month showed either no change or an increase in brain activity in these regions.
In the non-emotional state, women who ate probiotic yogurt showed stronger neural connectivity between the periaqueductal grey – an area of the brain that responds to pain and emotion – to the prefrontal cortex, an area of the brain responsible for most decision making.
Dr. Emeran Mayer, the study’s senior author, explained that our diet can influence the way gut bacteria break down food. A Mediterranean diet rich in vegetables and fiber promotes the growth of healthy gut bacteria, while a diet loaded with fats and carbohydrates leads to a different set of gut bacteria that are less helpful to the human body.
“Now we know that [helpful gut bacteria] has an effect not only on metabolism but also affects brain function,” Mayer said.
The discovery that changes in the bacteria in the intestinal tract can affect the brain has significant implications and could point the way toward dietary or drug interventions to improve brain function.
Patients with irritable bowel syndrome (IBS) have imbalances in their gut bacteria and are often treated with probiotic substances, as well as peppermint oil and dietary fiber. In the future, the researchers hope to study a cohort of patients with IBS and other digestive disorders in an effort to identify the molecular signals that contribute to the shifts in brain responses induced by probiotic foods.