More Vagus Nerve Knowledge

The previous post listed some activities of the vagus nerve as having to do with…

[…] stomach expansion, stomach contraction, gastric acid release, stomach content release into the small intestine, digestive pancreatic enzyme secretion and the sensations of both hunger and fullness.

Who is in charge of those departments? Who tells the vagus nerve what messages to convey? It now appears that the directives carried from this area of the body originate with the gut microbiome (as differentiated from, for instance, the skin microbiome).

The notion does seem rather radical, and it feels appropriate to resist the idea that just about everything we are, and do, is fundamentally determined by our colonies of gut bugs. Although we may diligently seek help from various treatment modalities, it is very likely that, where mood and behavior are concerned, the little critters are running the show.

Not surprisingly, the same cluster of functions performed by and related to the stomach, is heavily influenced by bariatric surgery, which causes a faction of professionals to wonder: Rather than subject children to the ordeal of surgery, if the same benefits can be achieved by somehow controlling the vagus nerve, why not concentrate on that? How can it be done?

The vagus nerve has been compared to an “information superhighway” that conveys messages from the gut to the brain. It seems that if we could influence the microbiota in regard to the messages they dispatch through the vagus nerve, that might help. It has even been suggested that “probiotic bacteria could be tailored to treat specific psychological diseases.”

This sounds like a great idea when the potential benefit for autistic children, for one example, is considered. They tend to become obese, because that is a side effect of the only drugs that are approved to treat their condition. This is also true of the drugs used against anxiety, epilepsy, and depression. If the body could be induced to manufacture its own meds to deal with those conditions, the results would be pretty spectacular… and apparently, thanks to the efforts of its microscopic tenants, it can.

The gut-brain axis is a thing

For, Carla Delgado described how ultra-processed foods can cause inflammation in the gut, as well as in other parts of the body, and how the inflammation connects with mental symptoms of anxiety and depression. This information comes from Dr. Uma Naidoo of Massachusetts General Hospital, who is credentialed as not only a psychiatrist and nutrition specialist but also a professional chef.

Nutritional Psychiatry does not insist that correlation equals causation — however, the evidence against ultra-processed foods is quite damning. By all indications, the brain is tightly bound to the gut microbiome because of the vagus nerve connection, which is compared again to a “fast two-way highway sending signals and chemicals back and forth.” Dr. Naidoo is quoted:

We produce over 90 percent of our body’s serotonin — as well as other neurotransmitters which govern mood — outside the brain, in the gut where our food is digested and broken down into vitamins, minerals and other nutrients. This enables a natural symbiosis between food and the body’s brain chemistry.

Do emotional and mental disorders cause overeating? Obviously. Does overeating cause mental and emotional disorders? Undoubtedly. And right there in the middle of everything, facilitating the two-way communication, is the vagus nerve.

Your responses and feedback are welcome!

Source: “How Ultra-Processed Foods Can Affect Your Mental Health,”, 10/24/22
Image by NIH Image Gallery/ATTRIBUTION 2.0 GENERIC

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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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