More Bugs and Drugs


Emily Courtney describes the psychobiotics that have a beneficial psychoactive effect, and cites studies that show these microbes can foster decreased emotional reactivity, the temporary dampening of stress and anxiety, and improvements in both cognitive health and mood.

They produce “important neurotransmitters like GABA (the ‘calming’ chemical) and serotonin (the ‘happy’ chemical).” Peter Andrey Smith elaborates:

As an inhibitory neurotransmitter, GABA calms nervous activity, which explains why the most common anti-anxiety drugs, like Valium and Xanax, work by targeting GABA receptors.

He describes for his readers the microbe whose official Latin name is Lactobacillus rhamnosus. The creature is important because it produces GABA. When pregnant lab rodents are subjected to stress, damage is done. For some reason, those stressed mother mice do not pass on the necessary levels of L. rhamnosus to their litters.

A very big name in this field is that of gastroenterologist Emeran Mayer, who is both Director of the Oppenheimer Family Center for the Neurobiology of Stress, and co-director of the CURE: Digestive Diseases Research Center. In the Los Angeles Times, Deborah Netburn wrote that Dr. Mayer “explains how these microscopic organisms insert themselves into the running dialogue between the brain and the gut.”

Netburn quoted Dr. Mayer as saying:

There are receptors throughout our bodies that respond to signals from the microbes or the metabolites that they produce. For example, certain microbes can influence the production of the serotonin molecule, which plays a role in appetite regulation, food intake, well-being and sleep.

Dr. Mayer also said:

The hypothesis that microorganisms in our intestine have somehow managed to hack into our reward system, enabling them to make us crave for foods that are good for them is intriguing… If this concept turns out to be correct, one could speculate that as a by-product of this food-seeking strategy, alterations in mood may be a consequence, as dopamine plays a role in depression as well.

Psychobiotics can also promote the production of oxytocin, sometimes known as the cuddle hormone, and curb the production of the stress hormone, cortisol.

The body is an ecosystem where different life-forms compete for their piece of the action. Inside of us, empires of bugs are slugging it out. But even so, and this is the most mysterious thing about them, the different kinds of microbiota seem to possess a weird omniscience.

They know that total dominance is not the answer. In the gut, if “winner takes all,” the outcome is a Pyrrhic victory, because the host that houses them all will die. They seem to agree that an intricately negotiated balance is best.

Up to that point, however, they will aggress against each other, and whatever disease processes are triggered in our bodies, that’s just collateral damage. The best we can hope for is a quid-pro-quo situation, but we often wind up outnumbered and outgunned. They can weaponize our own feelings against us, and by manipulating our emotions, they persuade us to go on a consumption binge, or seek out foods that make us fat and sick.

For Psychology Today, Dr. Billi Gordon has written extensively of how, like all other living creatures, the bugs prioritize their own needs above any other considerations. Sure, they cooperate with our bodies to an extent, and do many beneficial processes for us, but no altruism is involved.

They’re in it for themselves, and their goal is to do whatever their particular species considers a win among their own kind. Gordon calls them micro-gangsters:

Therefore, in essence, gut organisms are really just microscopic thugs that hijack our bodies and behaviors for personal gain… Think of it like this: the Bloods, Wah-Chings, Grape Street Crips, Aryan Brotherhood, Enron executives, Junk Bond traders and Al Qaeda, serving life sentences in an overpopulated subterranean prison that has bribable guards who drink.

Your responses and feedback are welcome!

Source: “Psychobiotics: Probiotics for Your Mind,”, Undated
Source: “Why we feel emotions in our guts, and what microbes have to do with it,”, 07/08/16
Source: “A Hijacked Brain and a Tongue Held Hostage,”, 08/07/17
Photo credit: Ivaan Garcia via Visualhunt/CC BY-ND

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OVERWEIGHT: What Kids Say explores the obesity problem from the often-overlooked perspective of children struggling with being overweight.

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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