Probiotic yogurt shown to affect mood in new study

Much has been written in recent years about the role of gut bacteria in our health. For the most part, the scientific research points to a number of beneficial outcomes of having an optimal amount good bacteria, also known as probiotics, in our stomachs.

Previous research has made links between good bacteria and heart health, blood pressure, obesity, autism and diabetes.

And now, a study from the University of California, Los Angeles (UCLA) is suggesting a connection between probiotics consumed through yogurt and our mood.

"Time and time again, we hear from patients that they never felt depressed or anxious until they started experiencing problems with their gut," says lead author Dr. Kirsten Tillisch, an associate professor at UCLA. "Our study shows that the gut-brain connection is a two-way street."

Also see: The big problem with Greek yogurt

The conclusions of the study are a little dicey in that the researchers have not come to any specific conclusions about whether probiotics affect our mood for better or worse -- though the implication is that it affects it for the better.

As well, it's worth noting that previous Canadian research in rats shows that those feed a bacteria-rich diet exhibited less anxious and depressive symptoms than ones with a bacteria-deprived diet.

Here is how Tillisch and her team tested the affects of yogurt on the brain.

They recruited 36 women betweeny the ages of 18 and 53 who had a healthy average bod mass index, averaging 23 kg/m². The women were randomly assigned to one of three groups: one that ate a yogurt with live bacterial cultures twice a day for one month, another that ate a dairy product that tasted like yogurt but didn't contain living bacteria, and another that was given no dairy products.

All 36 women got fMRI scans while at rest and during an "emotion-recognition task." The task involved being shown frightened or angry faces and the women were told to match the emotions to other frightened or angry faces.

Also see: Can probiotic yogurt help your seasonal allergies?

The women who ate the real yogurt had decreased activity in the part of the brain that regulates body sensations while performing the task. However, in their resting state, they showed increased connectivity in the periaqueductal gray region and the pre-frontal cortex, which are related to cognition and emotion.

"Our findings indicate that some of the contents of yogurt may actually change the way our brain responds to the environment," says Tillisch.

Again, the researchers conclusions are not very specific. Yet perhaps their most significant finding is that while scientists have known for some time that the brain sends signals to the gut, the authors claims this is the first study to prove the signals travel the opposite way as well.

What are your thoughts on how yogurt affects your mood? Have you noticed a relationship?