I have always been interested in the relationship between diet and depression. Of all the food items yogurt is one that has consistently yielded the most improvement in my symptoms. Yogurt was unique in that it reduced my stress while at the same time increasing my motivation/energy. Additionally, I have also been interested the relationship between the vagus nerve and mood disorders. Recently there has been research that confirms my experience with diet and my intuition that the vagus nerve is somehow involved. This most recent study was performed on humans whereas previous studies were only on animals.
The vagus nerve connects the brain with the gut. A considerable percentage of the nervous system is devoted to the gut and to me that implies that something very important is going on there.
Scientists had already found that the brain sends signals to the gut, which is why stress and other emotions can contribute to gastrointestinal symptoms. The new study of 36 women show that the signals also travel the opposite way.
One method of research included brain imaging which is somewhat controversial. The fact that there was reduced activity in the part of the brain that deals with cognition agrees with previous studies on antidepressants which have shown decreased activity in the prefrontal cortex in responders. Perhaps the reduced activity in the areas associated with cognition were due to less anxious thoughts?
The women all had a functional magnetic resonance imaging (fMRI) brain scans before and after the one-month study period, which included asking the participants to match a series of faces showing angry or fearful expressions on a computer screen to other faces that appeared, the Daily Mail reported.
The women who ate the probiotic yoghurt had reduced activity in the part of the brain that handles aspects of cognition and emotion, while the women who ate non-probiotic yoghurt or no dairy showed either no change or an increase in activity, the results showed.
The study was relatively small and further studies are needed to confirm the connection.