In Part 1, the microbiome was introduced, and if you missed it, read here.  The far reaches of its influence were mere suggestions.  Part 2 we will look in some depth to how the microbiome affects the whole body.  Part 3 will look at what helps and harms our microbiome so we can make educated choices on what we consume.

Researchers are finding disturbances of the microbiome creates disease, including obesity, diabetes, mental health, autism spectrum disorder, and immunity.  

Obesity

Obesity has multiple factors, including genetics, lack of exercise, or too much intake of food.  But the microbiome controls our metabolism too.  It influences the way we store fat, balance blood sugar, express genes, and controls hunger/satiated hormones.  It can come down to the balance between two specific strains: Bacteroides and firmicutes.   The ratio of these two bacteria can determine whether you are obese or skinny.  If you have too much firmicutes bacteria, it removes more calories from your food, the body absorbs more, leading to weight gain.  What we eat will either support the growth of firmicutes or bacteroides.  There is an interesting research paper here to read more about it.

Research in mice and obesity suggests the power of influence of the gut microbiome. They gave two thin mice differing fecal samples.  One from an obese mouse and one from a lean mouse, feeding them the same diet.  Yup you read that correctly - they transferred poop right into their gut!  Why? Because it contains the microbiome. The results? The thin mouse with the obese microbiome became obese. So the bacterial diversity of the microbiome can also set the stage for obesity.  

FMT and Autism

Let’s talk about poop now. The same fecal transfer of humans with Autism Spectrum Disorder (ASD) induced similar neurobehavior of ASD in mice.  Before you poo poo the results in mice, they are trying this with humans.  Researchers are in clinical trials using Fecal Microbial Transplants (FMT) from healthy humans to diseased humans in order to reconstitute the microbiome.  They are showing progress in the direction of Autism.  FMT and microbiome issues are not a singular cure for Autism symptoms.  There are genetic and environmental factors to be considered.  In his book Brian Matters, Dr Permutter’s young ASD patient had a history of overuse of antibiotics and stomach aches growing up. GI conditions are among the symptoms around Autism, but may be more of a sign the gut microbiome is unbalanced, which sends incorrect signals to the whole system.  In a stool test, he was lacking a certain strain of bacteria in his gut microbiome.  A strict probiotics course showed improvements in his symptoms, but an FMT helped his symptoms improve even further.

 Immunity

Gut microbiome can affect the metabolic output not only in the gut, but the entire system, including immunity. When infecting mice with respiratory virus, researchers introduced Lactobacillus johnsonii, a microorganism in the small intestine, to see if truly the gut microbiome helps with the greater system.  The microbiome elicited an immune response resulting in these mice versus the control, showing the idea that a healthy biome can increase the immunity against viruses.  Inflammation is also controlled by the microbiome. Not only does reducing inflammation help with our immunity, but can impact our mental health. 

Mental Health

This is a new field of research, and findings are showing the same chemicals produced in the brain are also produced in the gut.  It’s also called the gut mind axis.  The availability of these chemicals to the brain is largely dependent on the activity of gut bacteria.  This points to the microbiome’s job of regulating our mental health.  Antidepressants increase the availability of the neurotransmitter serotonin, yet tryptophan, the precursor to serotonin, is regulated and created by the gut bacteria, making it available for the brain.  But that’s not all.  Depression is also an inflammatory disease.  Inflammation controlled by the microbiome is more reason to look at the inflammatory nature of diets containing refined carbs, high blood sugar, wrong types of fats, as well as a sedentary/over exercised lifestyle.  The inflammation may reduce the production of tryptophan.  Researchers are now looking to see if antidepressants work to reduce inflammation as well as supply serotonin.  Looking at women with high blood sugar, there is a connection between depression and diabetes.  In fact, women with diabetes are 30-53% more likely to develop depression.  Thanks for all these facts, Paula, now what do we do??  Although all bodies are different, it’s all about what to eat, and what to avoid.  

In Part 3 we will look at solutions to diversifying your gut microbiome. I really recommend Dr David Perlmutters’ “Brain Maker” if you would like to learn much more!  This is just an introduction on a very fascinating field!