Rejection Expert—The Microbiome


Soon after show business personality Jamie Kilstein accepted that he was an alcoholic, he understood that his relationship to food was also one of addiction and said:

Once you admit you have a problem, you have a new agenda: to get healthy. To be better. You will find other loves. You will find healthy food that makes you stronger. You will stop when you’re full. You will see your old self in the shadow of the drunk guy puking his guts out.

Isn’t it amazing how those tiny little critters inside us can call the shots? They decide to eject the contents of Kilstein’s stomach, and there is nothing he can do about it. Consider this quotation from Gut: The Inside Story of Our Body’s Most Underrated Organ, by Giulia Enders:

Vomiting is a “tour de force performance,” particularly when sparked by powerful emotions: “It’s really your inner digestive tract sacrificing itself because it would like to have this energy from this food. But instead, it will shoot it out to save energy it would otherwise use for digestion.”

First-time opiate users usually throw up, regardless of the administration route—drink cough syrup, take pills, snort mashed pills or shoot up, it doesn’t matter. Some addicts of morphine, heroin, and other drugs continue to vomit throughout their junkie careers, and some even consider the experience a plus.

Speaking of morphine, a University of Chicago study defined the “bad influence of morphine upon normally harmless bacteria living in the human gut.” A bug called Pseudomonas aeruginosa is often a member of a person’s microbiome, and usually it doesn’t bother us. Previous research had found that when these particular bacteria are disturbed, for instance by surgery, they can turn nasty and attack their host, who already has enough trauma to deal with.

As if that were not aggressive enough, Professor of Surgery John Alverdy learned that P. aeruginosa does not care for the common post-surgical analgesic. The body normally produces some morphine-like chemicals, and apparently those are tolerable in normal amounts. But when a big hit of post-op painkiller comes on board, the critters have a hissy fit. The hospital’s website says:

Activated by morphine, P. aeruginosa suppressed the natural production of mucus in the intestine, disrupted the epithelial cells that line the gut, and provoked the immune system to release various immune factors. offers a charmingly detailed description of how the enteric nervous system (ENS) reacts to toxic intrusion:

When a pathogen crosses the gut lining, histamines and other inflammatory substances are secreted from the immune cells in the gut wall. These substances are then detected by the ENS, which notifies the body and the brain to dispose of the pathogens through diarrhea or vomiting.

Up in the brain, the chemoreceptor trigger zone collects information about any foul substances that have found their way into the bloodstream, and tells the vomiting center to get busy:

In an important step approaching the climax of the vomiting process, the vomiting center issues a command to have the small intestine send a fair portion of its contents back into the stomach. This starts about one minute before vomiting and lasts about 45 seconds…

Known as the retrograde great contraction, this reflex serves to dilute the stomach acid and neutralize it somewhat, to curtail damage to the teeth, esophagus, and everything in between. There is disagreement about why the retrograde great contraction takes place. Is it just that the stomach contents need something pushing from below, and more volume, to make expulsion happen? Some researchers say it’s logical that the small intestine would also want to empty part of itself, because the objectionable substance reached that far, where it had the bad fortune to meet up with some cranky microbes that reported it to headquarters.

Bonus Reader Testimonial

Once, through sheer automatic, robotic eating, I managed to put away a whole tubular can of potato chips. Suddenly I knew I’d better get into the bathroom fast, but I couldn’t make it to the toilet. My digestive system was like one of those water cannons police use to subdue crowds of protesters. It decorated the shower curtain, the sink, the floor, and it was quite a cleanup job. There are some feelings in life that you never want to recapture, and projectile vomiting is right at the top of the list.

Your responses and feedback are welcome!

Source: “I’m an Alcoholic Dude With an Eating Disorder. Hi.,”, 09/03/13
Source: “Say hello to your little friends: Making sense of gut bacteria,”, 06/07/15
Source: “Morphine’s Bad Influence on the Microbiome,”, 03/14/12
Source: “Get to Know Your Microbiome for Health & Wellness,”, 06/05/15
Image by Jade Jackson

Image by stu spivack

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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.

Food & Health Resources