The Role of the Microbiome in Addiction

"Ultrasound Image of My Large Intestine"
“Ultrasound Image of My Large Intestine”

What is the role of the microbiome in addiction? Nobody knows for sure, but mounting evidence indicates that the gut plays a large part in the body’s reaction to addictive substances. The question is worth asking. Tens of thousands of bacterial species inhabit our intestinal tracts.

They are being intensely investigated, and many discoveries suggest that these bugs can do a vast number of things. Sure, they help us digest food. Some of them regulate fat storage in the body. All of them have their preferences regarding nourishment and environment, and if they are displeased, they can make it known in ways that we find unpleasant.

Metabolism, obesity, gene activity, food preferences, neural pathways, the brain—all of these phenomena are interrelated in a complicated pattern of reciprocal influence and commutual cause and effect.

Nature continues to drop tantalizing hints that an overarching Unified Field Theory might embrace all these things. It is even possible that our gut flora dictate whether or not we are prone to addiction. We’ve already seen a round-about link. For instance, Candida (which lives in our gut, among other bodily sites) can cause Leaky Gut Syndrome, which in turn has been linked to a great many autoimmune conditions. People suffering from these painful disorders often self-medicate with opiates or other analgesics, leading to addiction.

A new book by neurologist David Perlmutter, Brain Maker: The Power of Gut Microbes to Heal and Protect Your Brain–for Life, which journalist Wendy Leung describes as containing “alluring tips on how to achieve neurological wellness through dietary changes and probiotic enemas.” Could this healing and protection of the brain include repairing whatever goes wrong up there to cause addiction?

Michael Pollen reminds us that the microbiome manufactures amino acids, short-chain fatty acids, neurotransmitters, enzymes, and even some vitamins. It constantly sends out signaling molecules that “talk to, and influence, the immune and the metabolic systems.” He goes on to say:

Some of these compounds may play a role in regulating our stress levels and even temperament: when gut microbes from easygoing, adventurous mice are transplanted into the guts of anxious and timid mice, they become more adventurous.

A Microbiome Thought Experiment

Here is a thought experiment: say that a certain type of microorganism prefers for its host to be fat, and has the ability to actively promote the growth of fat. Of course its ambition would be to colonize the nearest human digestive system. What if the proprietor of that digestive system has a gene that can either welcome the microorganism or reject it? That gene is the landlord who either allows the prospective tenant to sign a lease or sends the poor beggar on its way.

But how does the landlord decide whether to be generous or hard-hearted to a microbe? What switches on that gene? What if it turned out that the enabler of that gene is some characteristic of high fructose corn syrup, or monosodium glutamate, or one of any number of possible molecular presences? What if all addiction lives in the gut, ruled over by members of some of the thousands of species of bacteria that make their homes there?

What if addiction itself could be cured by the administration of prebiotics? Scenarios seem possible in which several different approaches to childhood obesity could all be used to ensure that no child faces the misery of addiction to overeating. What if there is a universal field theory that reconciles various schools of thought related to obesity?

Your responses and feedback are welcome!

Source: “Say hello to your little friends: Making sense of gut bacteria,”, 06/07/15
Source: “Some of My Best Friends Are Germs,”, 05/15/13
Image by miguel

One Response

  1. I’m neither a child nor obese, but have been researching the connection between the microbiome and mental health. I’ve struggled with depression for as long as I can remember, and alcoholism and drug addiction in more recent years. When I read how our microbiome can affect how alcohol is digested, a light bulb went off – could it also influence how some are more likely to develop an alcohol or drug addiction? There’s an obvious connection between mental health and addiction, so it almost makes too much sense. I’ve recently began consuming as many fermented foods as my taste buds will allow, on a near daily basis and this is the happiest I’ve ever been since puberty, when my mental health problems began. My skin is clearing up after CONSTANT breakouts in the past few years. I even drink casually now – I no longer have the desire to be constantly drunk, or binge drink to the point of sickness. I feel as though I’ve found the holy grail. I write this comment in the hopes of helping others that are like me.
    Fermented foods have saved my life.

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About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
You can contact Dr. Pretlow at:


Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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