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Our Microbiome May Be Looking Out for Itself

Stashed in: Interconnectedness!, Science!, Influence!, Brain, Awesome, @dalailama, Science Too, health!, Microbiome, Health

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Our gut bacteria might be OUR PUPPET-MASTERS!!!

I can tell you with certainty that my gut bacteria is the boss of me!

Is this why I sometimes crave carbs??

Your body is home to about 100 trillion bacteria and other microbes, collectively known as your microbiome. Naturalists first became aware of our invisible lodgers in the 1600s, but it wasn’t until the past few years that we’ve become really familiar with them.

This recent research has given the microbiome a cuddly kind of fame. We’ve come to appreciate how beneficial our microbes are — breaking down our food, fighting off infections and nurturing our immune system. It’s a lovely, invisible garden we should be tending for our own well-being.

But in the journal Bioessays, a team of scientists has raised a creepier possibility. Perhaps our menagerie of germs is also influencing our behavior in order to advance its own evolutionary success — giving us cravings for certain foods, for example.

there are all sorts of reasons you crave carbs!!  and, yes, probably billions of bacteria craving them too!

It's hard to choose no carbs when billions of bacteria are outvoting me!

so true!!

Are animals our pets, or are we their servants?

both.  :)

If I was an alien who landed on this planet and I saw one creature picking up the poops of a second creature...

I'd say the second creature was in charge.


but if i saw a rope around the second creature's neck, i'd say the one picking up poop was in charge!

So... Cats are in charge of humans, and humans are in charge of dogs. :)

that sounds about right!

And the microbes are in charge of ALL of us!

boom!  there you go!  you brought it full circle, adam!

It's the circle of life!

Lion King circle of life

Lion King circle of life


Thank you. 

The more I learn about the microbiome, the more I realize what we know rounds to nothing. 

ugh.  ain't that the truth.

i think that green part on the graph just keeps shrinking!

pie chart what you don't know you don't know meme imgur

The inside of my head:

unknown unknowns

Time to open my mind:

unknown unknowns

those are both great!

Yeah, interestingly both came from a web search for "open mind".

you are a great web searcher!!

And to think, I've only begun...

Detective Troutgirl is on the case!

“One of the ways we started thinking about this was in a crime-novel perspective,” said Carlo C. Maley, an evolutionary biologist at the University of California, San Francisco, and a co-author of the new paper. “What are the means, motives and opportunity for the microbes to manipulate us? They have all three.”

The idea that a simple organism could control a complex animal may sound like science fiction. In fact, there are many well-documented examples of parasites controlling their hosts.

Some species of fungi, for example, infiltrate the brains of ants and coax them to climb plants and clamp onto the underside of leaves. The fungi then sprout out of the ants and send spores showering onto uninfected ants below.

How parasites control their hosts remains mysterious. But it looks as if they release molecules that directly or indirectly can influence their brains.

have you seen the "life in the undergrowth" nature movie by david attenborough? there is a part about these cordyceps fungi that is MINDBLOWING!  they are so beautiful and so creepy.  and the filming is breathtaking.

I haven't seen it but it looks wonderful:

Damn those chocolate craving bacteria!

Our microbiome has the biochemical potential to do the same thing. In our guts, bacteria make some of the same chemicals that our neurons use to communicate with one another, such as dopamine and serotonin. And the microbes can deliver these neurological molecules to the dense web of nerve endings that line the gastrointestinal tract.

A number of recent studies have shown that gut bacteria can use these signals to alter the biochemistry of the brain. Compared with ordinary mice, those raised free of germs behave differently in a number of ways. They are more anxious, for example, and have impaired memory.

Adding certain species of bacteria to a normal mouse’s microbiome can reveal other ways in which they can influence behavior. Some bacteria lower stress levels in the mouse. When scientists sever the nerve relaying signals from the gut to the brain, this stress-reducing effect disappears.

Some experiments suggest that bacteria also can influence the way their hosts eat. Germ-free mice develop more receptors for sweet flavors in their intestines, for example. They also prefer to drink sweeter drinks than normal mice do.

Scientists have also found that bacteria can alter levels of hormones that govern appetite in mice.

Dr. Maley and his colleagues argue that our eating habits create a strong motive for microbes to manipulate us. “From the microbe’s perspective, what we eat is a matter of life and death,” Dr. Maley said.

Different species of microbes thrive on different kinds of food. If they can prompt us to eat more of the food they depend on, they can multiply.

Microbial manipulations might fill in some of the puzzling holes in our understandings about food cravings, Dr. Maley said. Scientists have tried to explain food cravings as the body’s way to build up a supply of nutrients after deprivation, or as addictions, much like those for drugs like tobacco and cocaine.

But both explanations fall short. Take chocolate: Many people crave it fiercely, but it isn’t an essential nutrient. And chocolate doesn’t drive people to increase their dose to get the same high. “You don’t need more chocolate at every sitting to enjoy it,” Dr. Maley said.

Perhaps, he suggests, the certain kinds of bacteria that thrive on chocolate are coaxing us to feed them.

there is a great book on parasites called "parasite rex" that i thoroughly enjoyed.  the author, carl zimmer, also gave a talk on this american life once that is great:

Neat but why were you reading about parasites?

curiosity, i guess.

I love that you were curious about parasites. 

Bacteria might make us more or less social, too.

Research by Dr. Cryan and others suggests that a healthy microbiome helps mammals develop socially. Germ-free mice, for example, tend to avoid contact with other mice.

That social bonding is good for the mammals. But it may also be good for the bacteria.

“When mammals are in social groups, they’re more likely to pass on microbes from one to the other,” Dr. Cryan said.

We must run more tests!

If microbes do in fact manipulate us, Dr. Knight said, we might be able to manipulate them for our own benefit — for example, by eating yogurt laced with bacteria that would make us crave healthy foods.

“It would obviously be of tremendous practical importance,” Dr. Knight said. But he warned that research on the microbiome’s effects on behavior was “still in its early stages.”

The most important thing to do now, Dr. Knight and other scientists said, was to run experiments to see if microbes really are manipulating us.

Not to be a jerk, but there is no logical or practical scientific reason that we need to know whether they manipulate us before we can try to manipulate them. They use quite subtle hormonal mechanisms, we would merely be using brute-force attempts at artificial selection.

If they do manipulate us won't they thwart our efforts to try to control them?

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