Autism and gut microbes: scientific theory about their link

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Hi

I found this interesting article today on the link between gut microbes and autism.

http://www.sciencedaily.com/releases/20 ... 095121.htm

What do you think?

Lower diversity of gut microbes was positively correlated with the presence of autistic symptoms in the study. The authors stress that bacterial richness and diversity are essential for maintaining a robust and adaptable bacterial community capable of fighting off environmental challenges. "We believe that a diverse gut is a healthy gut," Krajmalnik-Brown says.

The new study detected decreased microbial diversity in the 20 autistic subjects whose fecal samples were analyzed. Specifically, three bacterial genera -- Prevotella, Coprococcus and Veillonellaceae -- were diminished in subjects with autism, when compared with samples from normal children. (Surprisingly, these microbial changes did not seem directly correlated with the severity of GI symptoms.)

The discovery that changing the bacterial environment, or microbiota, 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 yogurt in our refrigerator that we may eat for enjoyment, for calcium or because we think it might help our health in other ways," said Dr. Kirsten Tillisch, an associate professor of medicine in the digestive diseases division at UCLA's David Geffen School of Medicine and lead author of the study. "Our findings indicate that some of the contents of yogurt 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."

The small study involved 36 women between the ages of 18 and 55. Researchers divided the women into three groups: one group ate a specific yogurt containing a mix of several probiotics — bacteria thought to have a positive effect on the intestines — twice a day for four weeks; another group consumed a dairy product that looked and tasted like the yogurt but contained no probiotics; and a third group ate no product at all.
Functional magnetic resonance imaging (fMRI) scans conducted both before and after the four-week study period looked at the women's brains in a state of rest and in response to an emotion-recognition task in which they viewed a series of pictures of people with angry or frightened faces and matched them to other faces showing the same emotions. This task, designed to measure the engagement of affective and cognitive brain regions in response to a visual stimulus, was chosen because previous research in animals had linked changes in gut flora to changes in affective behaviors.

The researchers found that, compared with the women who didn't consume the probiotic yogurt, 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 brainstem region known as the periaqueductal grey and cognition-associated areas of the prefrontal 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, Tillisch said.

I think that you should get together with the people who think that mitochondria are involved, the people who think that Autism is an inflammatory disease, the idiots who say that vaccinations cause Autism, and the nutters who swear that we're the next stage in human evolution. Then fight amongst yourselves.

The winner gets a pint of Jen & Berry's Indigo Rutabaga ice cream, imported from Planet X!

Too many theories ... not enough facts ...