Here is a quiz — what organ or organ system in the body is both an internal and an external organ that is the primary avenue of exposure of the internal body to the environment?

If you answered your gut, intestines, etc. you are correct. The stuff inside the gastrointestinal tract (stomach and intestines) is considered to be outside the body until the cells that line the tract absorb it. The surface area of the gut is the largest in the body (bet you thought it was the skin!), about the size of a doubles tennis court.

Approximately 90 percent of the immune system’s activity occurs in the gut — the gut is connected to the outside environment, see where I am headed?

The gastrointestinal, digestive or enteric system, or just the gut, starts at the mouth and ends at the anus. Accessory digestive organs that play major roles are the liver, gallbladder and pancreas.

With that anatomy lesson out of the way, you may not realize that there is a huge pathway of communication from the gut to the brain via the enteric nervous system. This system is so large that the major neurotransmitters or messengers live here. So important to the functions of our body this system is often referred to as the second brain.

Included in this system is the vagus nerve one of the cranial nerves which originates in the brain and influences the heart. Hence the terms “gut reaction” or “I feel it in my gut.”

The vagus nerve, the main nerve in the enteric nervous system thus has a direct pathway of communication to the brain. Most of the nerve’s fibers transmit information from the gut to the brain, not vice versa.

While there are many, many functions involved in this system, my goal was to mention microbiomes. Microbiomes are bacteria, viruses, yeasts and fungi that reside deep in our body, on our skin and inside cells. Our unique microbiome is influenced by age, birth route, breast fed or not, travel, medications, environmental influences, diet, illness and many other factors making it similar to your fingerprint.

Recent research shows the microbiome has a profound influence on health and well-being. The importance of the gut microbiome is so critical that many experts consider the gut microbiome another organ system. This important system, however, is made up of 3.5-to-5 pounds of non-human life forms!

The numbers are mind-boggling, the gut hosts more than 100 trillion microorganisms representing tens of thousands, or possibly more, species. There are microbes that can cause diseases, beneficial microbes that don’t cause harm and ones that actually benefit the host and the microbe.

Our diet appears to play a crucial role in the balance and composition of the gut microbiome. Scientists are studying how the microbiome can be manipulated to develop alternative preventative and treatments for some conditions. Research is also being done to understand the microbiome’s role in glucose response in diabetics, weight loss, personalized medications and treatments, production of neurotransmitters, probiotics, some areas of treatment for depression and mood control, and boosting the immune response to name a very few.

I don’t have enough room to write about microbiomes or the ability to understand their influence enough to translate. The research being done into this world that frankly seems like another solar system, is mind numbing. Other than keep your eyes and ears open for advances occurring at unbelievable speed, the best medicine continues to be eat less sugar and refined flour, more whole foods and as many vegetables as possible.

— Robin Gaudette is the aquatics wellness coordinator at the Redmond Area Park and Recreation District. Contact her at robin.gaudette@raprd.org.