Why is good gut flora so important? Read about Dr. Natasha Campbell-McBride's knowledge on functions of the gut flora and why it's so important to human life.

Functions of the Gut Flora

December 10, 2018lectinfreemama

I had the privilege of attending Dr. Natasha Campbell-McBride’s all day seminar on Gut and Psychology Syndrome at this year’s Weston A. Price Foundation Wise Traditions Conference in Baltimore. This blog series will provide an in-depth explanation of her extensive research surrounding gut health, including: the many functions of the gut flora; what happens when the gut flora are damaged; the nutritional and lifestyle protocol she has used to help her patients recover from gut-borne learning disabilities. To read more about Gut and Psychology Syndrome,  Dr. Campbell-McBride’s book can be purchased HERE.

Learn about functions of the gut flora from Dr. Natasha Campbell-McBride at this year's Weston A Price Conference.
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Functions of the Gut Flora

While survival of the fittest has been a popular evolutionary theory since Darwin did some bird-watching in the Galapagos, our gut flora may disagree. Here’s why: on a microbial level, survival depends on cooperation instead of strength. The microbiomes with the smoothest and most efficient level of cooperation survive. What does a functioning, cooperating human microbiome do?


Why don’t most of us need to constantly supplement all the time with every vitamin and mineral our body needs? Not only do we get nutrition from food, but our gut flora recycle these things for us. They even reuse hormones and neurotransmitters! They know exactly what the body needs and when, and what form the nutrient must be in. Your healthy flora know more about what your body needs better than any blood test could determine. (1)


An estimated 85% of our immune system lives within the gut wall. And it changes and adapts rapidly. This mechanism for change depends on healthy gut flora to communicate what is needed. If the cells that comprise the immune system are the soldiers of the body, the gut flora are the intel. (2)


Using saunas, powders, patches, binders, and epsom salts? They’re like bailing water out of a sinking boat if your gut flora are damaged. Your microbes are the most powerful detox system your body will ever have. Here’s why: Healthy flora have the ability to tell the immune system to trap toxins and heavy metals like a clam shell and store them in fatty tissues where they can’t harm us. The body then flushes them out in delightful ways by any means possible. In other words, a person with healthy gut flora could have a dozen mercury-leeching dental fillings and eat tuna several times a week. That person would still be perfectly healthy. Why? Because the most powerful detox system in the world–the gut flora–are working in cooperation. (3)

Appetite & Mood

If you’re feeling helpless and not in control over your own life, this bit is not going to help: your gut flora are responsible for your personality, emotions, food cravings, and pretty much your entire sense of self. You are at the mercy of your microbes’ production of hormones such as serotonin, dopamine, and GABA. In fact, some gut microbes depend entirely on brain hormones to grow and survive. (4)

Origins of the Gut Flora

Scientists estimate that 100 trillion microbes colonize the intestinal tract of a human being–a beautiful synchrony of interdependence and survival through cooperation. See, the gut flora need things like fiber, starch, and…human brain hormones to survive. We can, through the art of eating and having a brain, provide for gut flora what they can’t do for themselves. They, in turn, provide for us what we can’t do for ourselves: digest plants. (5)

Plant Digestion

That’s right. The human body does not digest plants–it’s horribly set up for doing it. Our large intestine comes after the absorptive small intestine, which means all that wonderful plant nutrients passes through our intestinal tract unabsorbed and unusable. Until, that is, our colonizing gut flora get the job done! Healthy gut flora will digest those plant fibers for us and convert the nutrients into something our body can use. (6)


A recent discovery in the world of forest ecology may tell us a lot about how the fungi in our gut flora work. In forests, there is an underground bed of fungi that form a forest-wide communication network. The roots of all plants and trees have tiny hairs that “dial in” to this fungal inter-web. When plants are in distress, they send signals out to all other plants in the area to build resistance to specific adverse events, like a disease. (7)

Much like this forest ecosystem, fungi are the basis of our gut flora. The gut lining has tiny hairs that wave around the GI tract. Scientists theorize that these hairs communicate with the fungal network in our body. As in the subterranean forest network, our fungi may play a crucial role in building proper immunity throughout the body and defending against pathogens.  (8)

Individual Flora

Our gut microbes have evolved with us for millions of years. However, our environment plays a significant role in the makeup (or destruction) of our microbiome. Every morsel of food we eat, every molecule of air we breathe, and every object we touch contributes to the cloud of microbes in and around our GI tract. (9)

For newborns, the first dose of intestinal flora comes from the birth canal. Mom’s ovaries, fallopian tubes, uterus, placenta, and vaginal canal all have flora that mimic intestinal flora. When baby passes through the birth canal, the flora that passes onto the skin and into the mouth of the baby sets the foundation for that child’s digestion, immunity, and overall development.

–> Read more about maternal and fetal gut health HERE.

Damaged Gut Flora

Digestion, immunity, detoxification, nutrient absorption, cognitive ability–those are all pretty crucial jobs. When our flora are damaged, all the functions they perform are impaired. In severe cases, they stop working altogether. We are, for better or worse, at the utter mercy of our intestinal flora. The rise of chronic diseases and conditions shows just how much we depend on them for survival. In part 2 of this series, we’ll address what happens when our flora are damaged, and what will happen if we don’t take steps to fix it.


  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144392/
  2. https://www.hopkinsmedicine.org/research/advancements-in-research/fundamentals/in-depth/the-gut-where-bacteria-and-immune-system-meet
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3211517/
  4. https://www.newscientist.com/article/2095769-gut-bacteria-spotted-eating-brain-chemicals-for-the-first-time/
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5006193/
  6. https://www.sciencedaily.com/releases/2014/02/140212132851.htm
  7. http://www.bbc.com/earth/story/20141111-plants-have-a-hidden-internet
  8. http://coolinginflammation.blogspot.com/2009/11/biofilms-as-human-gut-mycorrhizals.html
  9. https://learn.genetics.utah.edu/content/microbiome/changing/
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