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September 26, 2014

Things That Terrify Us

Egad! Is your brain being told what to do by microscopic bugs in your GI tract???

In an article published in the September issue of BioEssays, scientists Joe Alcock, Carlo C. Maley, and C. Athena Aktipis reviewed the research on how microbiota affect the brain, and believe there's a strong case that bacteria influence overall eating behavior. It seems that the bacteria in our guts don't simply wait for whatever leftovers we have to offer. They actively seek out their preferred meals through tricksy deception.

“Microbes have the capacity to manipulate behavior and mood through altering the neural signals in the vagus nerve, changing taste receptors, producing toxins to make us feel bad, and releasing chemical rewards to make us feel good,” Aktipis says.

Around 100 million neurons are stationed in the gut, collectively forming the enteric nervous system, also called the "Second Brain." The enteric nervous system is connected to the human brain via the vagus nerve. Thanks to this setup, bacteria are granted streamlined pass to the brain, and they're equipped to take advantage. For example, microbes have genes that allow them to produce hormones like serotonin and dopamine.

Studies in humans have shown that probiotics can improve mood. In mice, the affects are even more pronounced. When a team transplanted the gut bacteria from fearless mice into more anxious mice, the anxious mice began displaying markedly bolder behavior. The behavioral change worked in reverse, too.

"Like microscopic puppetmasters, microbes may control the eating behavior of hosts through a number of potential mechanisms including microbial manipulation of reward pathways, production of toxins that alter mood, changes to receptors including taste receptors, and hijacking of neurotransmission," the researchers write.

Basically, bacteria will send positive signals to the brain when you eat foods that they like, and negative signals when you eat foods they don't like.

They haf vays of makink you pig out on purloined Heath bars.

Posted by Cassandra at September 26, 2014 08:15 AM

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So the bugs in my gut really like spicy food? Cool!

Posted by: MikeD at September 26, 2014 10:35 AM

Mine are telling me to consume vast quantities of expensive Cabernet... :p

Posted by: Cassandra at September 26, 2014 10:58 AM

That explains the gravitational pull I feel to donuts. I thought it was physics, but it's microbiology!

Posted by: Frank Karl at September 26, 2014 11:30 AM


Doctors who don't believe patients' reports of depression lifting after a round of antibiotics, naya-na-naya-na! Finally. Unfortunately, he's gone, but he can read the article there.

Posted by: htom at September 26, 2014 11:30 AM

"In mice, the affects are even more pronounced. When a team transplanted the gut bacteria from fearless mice into more anxious mice, the anxious mice began displaying markedly bolder behavior."

What, so the anxious mice suddenly started pooping anywhere they wanted instead of quietly off in a corner?
A healthy dose of bran will do the same thing, yanno.

Posted by: Evil Twin at September 26, 2014 12:15 PM

I always knew it my huband's fault when I put on weight, because he's such a good cook and inexplicably doesn't seem to want me to be thin. But now it turns out he's in league with my microbiota. It's enough to keep me up at night.

Posted by: Texan99 at September 26, 2014 07:46 PM

I wonder if, given my own apparent preference for very hot peppers and plenty of beer, I should worry that my gut bacteria are suicidal?

Posted by: Grim at September 26, 2014 09:39 PM

Or homicidal.

Posted by: DL Sly at September 27, 2014 05:13 PM

I suppose you know the song.

"Oh Moonshine, dear Moonshine,
Oh how I love thee.
You killed me own father--
But, ah, ye try me."

The chorus is good too:

"I'm a rambler, I'm a gambler;
I'm a long ways from home,
and if you don't like me, well, leave me alone.
I'll eat when I'm hungry, I'll drink when I'm dry,
And if moonshine don't kill me, I'll live till I die."

Actually, you're welcome to the moonshine. :) But a fine beer, after a good day's work...

Posted by: Grim at September 27, 2014 10:06 PM

I have moonshine in the freezer, and I do know the song well, my Pop having sung it to me many times over the course of my childhood.
And, up here we have many such fine local brews to be sampled and re-sampled. I've tried about 2 dozen now and still haven't covered the entirety of what is produced locally.

Posted by: DL Sly at September 29, 2014 12:42 PM