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Gut Bacteria Changes Our Brain

A new study by researchers at McMaster University in Hamilton, Ontario now suggests that gut bacteria may also influence behaviour and cognitive processes such as memory by exerting an effect on gene activity during brain development.

Yet another example of how forces beyond our control shape our consciousness.  And another example of how powerful the most minute changes can have startling effects on our personalities and behaviors.

Bacteria colonize the gut in the days following birth, during a sensitive period of brain development, and apparently influence behaviour by inducing changes in the expression of certain genes.

The experiment was conducted on mice, which gives us a strong hint that the effect is similar in humans.  Mice lacking certain gut bacteria were found to have specific differences in the expression of three genes, each of which is associated with stress and emotional behaviors and feelings:

Brain-derived neurotrophic factor (BDNF) was significantly up-regulated, and the 5HT1A serotonin receptor sub-type down-regulated, in the dentate gyrus of the hippocampus. The gene encoding the NR2B subunit of the NMDA receptor was also down-regulated in the amygdala.

This fits squarely into the model of human cognition and “personality” that defies the Christian “Free Will” dogma.  Simply put, what we think of as our freedom of choice is highly limited, almost exclusively by factors beyond any human control.  By the time I perceive a choice, there have been hundreds, or thousands, or perhaps hundreds of thousands of environmental factors at work, each shaping my brain in ways that will alter my conscious perceptions.  My “choice” is better described as a “result” of accumulated data being fed through this “environmental algorithm” expressed as my brain.

While this has complicated implications for human interactions (how do we treat mental illness?  criminals?  the poor?  etc..) it’s quite clear how it impacts the notion of the Christian god.  He either lied or was mistaken about the “gift of free will.”  We humans are not free to choose any option in any situation.  Rather, we are bound by the constraints of our environment and our “brain algorithms,” and we literally are incapable of seeing things any way besides the way we see them.

In other words, we don’t have the kind of free will that would make the Jesus/heaven/hell doctrine sensible.

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Discussion

8 thoughts on “Gut Bacteria Changes Our Brain

  1. It’s a screwball way to go about designing free will, I agree with you there. But the position sophisticated theists take on issues like this is to say, “It’s logically possible that there’s some reason for this that we aren’t aware of,” and just accept that, all other things being equal, arguments from poor design are going to favor atheism (they presume, of course, that all other things are not equal).

    So even though our free will, if we have any, would be of a sort which unnecessarily exposes us to influence that might lead us away from faith, if we have some originative control over our actions, then that’s all the theists need to support the position they’ve staked out. Arminius’ doctrine that humans are totally depraved and unable to make any effort toward salvation doesn’t depend on our being free to choose any option in any situation. All his position depends on is our having a choice in the matter of believing or not believing in god.

    So it comes down to libertarianism, and whether that’s a rational position or not. If it is, then the theists can use it to support their theology.

    I would say that Dennet (despite being a determinist himself) has proposed a model of libertarianism which, although it wouldn’t be the preferred position for a materialist, is at least rational.

    In my view, neuroscience gets us part of the way toward understanding our minds, but not all the way home. After we’re done explaining neurons and information processing, we have one (or more) steps still to take, to get us to explaining how these physical processes result in phenomenal consciousness. Our understanding of this phenomena comes from our own conscious experience, and based on this experience, it’s reasonable to conclude that we have some originative control over our identities and actions.

    So with the caveat that the physical phenomena of the brain can prevent any kind of free will from being a possibility (an analogy would be a car with no steering wheel–even if there is a driver, he has little or no control over where he goes, and this would seem to describe patients with damage to their frontal lobes), I think we do have conditional free will.

    Posted by Ian | March 26, 2011, 6:38 pm
  2. Its so important to take pro-biotics every day to change the flora in your gut….I’m having a hard time convincing my friends but IT WORKS MIRACLES.

    Posted by Melody | March 26, 2011, 9:30 pm
  3. I remember reading about how even one bottle of formula disturbed the gut flora of an otherwise exclusively breastfed infant. I also know that seratonin is found in the gut as well. Couple that with modern diets almost devoid of pro-biotics that used to be common in fermented foods eaten by all cultures, and you might be on to something.

    Posted by Aldonza | March 30, 2011, 9:39 pm
  4. Thanks Aldonza. We westerners have such odd (and unnatural) diets, it’s no wonder we’re basically all insane. At one time, we’re bigger, stronger, faster, and generally better fed than ever before — just look at pro sports. But on the other hand, we’re eating so many processed foods, especially carbs and basically nutritionally empty “fillers.” And for the poor, it’s an awful situation. Just about everything you can afford when you’re poor is terrible for you.

    Posted by hambydammit | March 30, 2011, 10:01 pm
  5. If you are poor and can’t afford probiotics to change the flora in your system, and you care about it, you can make your own strong probiotics by using cabbage in a recipe for raw sauerkraut.

    Cabbage is super cheap!

    Posted by Melody | March 30, 2011, 10:15 pm
  6. *Agrees with Melody*
    Basic fermenting is pretty easy. Pickled veggies, sauerkraut/kimchee, yogurt/kefir, even fermented fishes (gags a little). I even have a recipe somewhere for fermented hot pepper sauce (like Tabasco). But eating these foods from the market isn’t the same. They’ve almost always been pasteurized, killing all the good bacteria that you’re trying to get! Yogurts have been re-adding the cultures after the fact to tout themselves as “probiotic”.

    Next up: raw milk.

    Posted by Aldonza | March 30, 2011, 10:36 pm
  7. Plus, the store bought sauerkraut has tons of salt in it! UGH!

    Probiotic yogurts can be expensive for many people. Concentrated capsules from brands like Phillips Colon Health, Align, Primal Defense ultra probiotics, cost only about $10-$25 a month and they guarantee you are getting your probiotics.

    Posted by Melody | March 30, 2011, 10:44 pm
  8. Thanks, Melody.

    My step father is just a good ‘ol country boy, not much book learnin’ n such. But I remember almost 20 years ago when he was feeling chronically ill, he buried cabbage in the yard til it got black and completely disgusting. Then he drank it.

    His country kimchi turned out to be the cure for damn near everything.

    These days, I make a lot of Asian cucumbers. Rice wine, rice wine vinegar, hot peppers, a little sugar, and a little salt. Only takes a day or so in a sealed plastic bag to pick up a ton of great flavor and pickle slightly.

    Re: Raw Milk: It’s true that raw milk can have bacteria harmful to pregnant women, fetuses, the very young and the very old. However, if you buy from a reputable source who knows his cow’s names, you’re going to be fine. Just be careful — I don’t know about everywhere else, but it’s illegal to sell raw milk where I live.

    Posted by hambydammit | March 31, 2011, 3:28 pm

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