The Yogurt Made Me Do It
Wall Street Journal
by Jonah Lehrer
17 Sep 11
…As the neuroscientist Antonio Damasio writes, "The mind is embodied, not just embrained."
…new research explored the effect of probiotics on the brain.
The experiment, led by Javier Bravo at University College Cork in Ireland, was straightforward. First, he fed normal lab mice a diet full of probiotics. Then, Mr. Bravo's team tested for behavioral changes, which were significant: When probiotic-fed animals were put in stressful conditions, such as being dropped into a pool of water, they were less anxious and released less stress hormone.
How did the food induce these changes? The answer involves GABA, a neurotransmitter that reduces the activity of neurons. When Mr. Bravo looked at the brains of the mice, he found that those fed probiotics had more GABA receptors in areas associated with memory and the regulation of emotions. (This change mimics the effects of popular antianxiety medications in humans.)
Furthermore, when he severed the nerve connecting the gut and brain in a control group of mice, these neural changes disappeared. The probiotic diet no longer relieved the symptoms of stress.
Though it might seem odd that a cup of yogurt can influence behavior, the phenomenon has been repeatedly confirmed, at least in rodents. Earlier this year, Swedish scientists showed that the presence of gut bacteria shapes the development of the mouse brain, while French researchers found that treating human subjects with large doses of probiotics for 30 days reduced levels of "psychological distress." There's nothing metaphorical about "gut feelings," for what happens in the gut really does influence what we feel….
http://online.wsj.com/article/SB1000...066488938.html
