Probiotic yogurt may change brain function

Eating pro-biotic yoghurt can not only alter your gut bacteria for the better, it may also change your brain function, scientists say.

Researchers now have the first evidence that bacteria ingested in food can affect brain function in humans.

In a small study of healthy women, between the ages of 18 and 55, researchers found that women who regularly consumed beneficial bacteria known as probiotics through yoghurt showed altered brain function, both while in a resting state and in response to an emotion-recognition task.

The discovery that changing the bacterial environment, or micro-biota, in the gut can affect the brain carries significant implications for future research that could point the way toward dietary or drug interventions to improve brain function, the researchers said.

"Many of us have a container of yoghurt in our refrigerator that we may eat for enjoyment, for calcium or because we think it might help our health in other ways," said a Dr .

The research findings indicate that some of the contents of yoghurt may actually change the way our brain responds to the environment. When we consider the implications of this work, the old sayings 'you are what you eat' and 'gut feelings' take on new meaning, said a researcher.

Researchers divided the women into three groups: one group ate a specific yoghurt containing a mix of several probiotics twice a day for four weeks; another group consumed a dairy product that looked and tasted like yoghurt but had no probiotics; and third group ate no product at all.

They found that, compared with women who didn't consume the pro-biotic yoghurt, those who did showed a decrease in activity in both the insula - which processes and integrates internal body sensations, like those from the gut - and the somatosensory cortex during the emotional reactivity task.

Further, in response to the task, these women had a decrease in the engagement of a widespread network in the brain that includes emotion-, cognition- and sensory-related areas. The women in the other two groups showed a stable or increased activity in this network.

During the resting brain scan, the women consuming probiotics showed greater connectivity between a key brain-stem region known as the periaqueductal grey and cognition-associated areas of the pre-frontal cortex.

The women who ate no product at all, on the other hand, showed greater connectivity of the periaqueductal grey to emotion- and sensation-related regions, while the group consuming the non-probiotic dairy product showed results in between.

The researchers were surprised to find that the brain effects could be seen in many areas, including those involved in sensory processing and not merely those associated with emotion.

What causes dyslexia

A research carried out at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, has discovered an important neural mechanism underlying dyslexia and shown that many difficulties associated with dyslexia can potentially be traced back to a malfunction of the medial geniculate body in the thalamus. 

The results provide an important basis for developing potential treatments. 

People who suffer from dyslexia have difficulties with identifying speech sounds in spoken language. 

For example, while most children are able to recognise whether two words rhyme even before they go to school, dyslexic children often cannot do this until late primary school age. Those affected suffer from dyslexia their whole lives. However, there are also always cases where people can compensate for their dyslexia. 

"This suggests that dyslexia can be treated. We are therefore trying to find the neural causes of this learning disability in order to create a basis for improved treatment options," said the researcher. 

Between five and ten percent of the world's children suffer from dyslexia, yet very little is know about its causes. Even though those affected do not lack intelligence or schooling, they have difficulties in reading, understanding and explaining individual words or entire texts. 

The researchers showed that dyslexic adults have a malfunction in a structure that transfers auditory information from the ear to the cortex is a major cause of the impairment: the medial geniculate body in the auditory thalamus does not process speech sounds correctly. 

This malfunction at a low level of language processing could percolate through the entiresystem. This explains why the symptoms of dyslexia are so varied.

The researchers conducted two experiments in which several volunteers had to perform various speech comprehension tasks. When affected individuals performed tasks that required the recognition of speech sounds, as compared to recognize the voices that pronounced the same speech, magnetic resonance tomography (MRT) recordings showed abnormal responses in the area around the medial geniculate body. 

In contrast, no differences were apparent between controls and dyslexic participants if the tasks involved only listening to the speech sounds without having to perform a specific task. 

The problem, therefore, has nothing to do with sensory processing itself, but with the processing involved in speech recognition. 

No differences could be ascertained between the two test groups in other areas of the auditory signalling path. 

The findings of the Leipzig scientists combine various theoretical approaches, which deal with the cause of dyslexia and, for the first time, bring together several of these theories to form an overall picture.

The researchers' next project is now to study whether current treatment programmes can influence the medial geniculate body in order to make learning to read easier for everyone in the long term.