PT on the Net Research

The Importance of Bacteria in Gut Health

Gut health is a hot topic in the health and fitness industry, as the health of the gut affects the health of other systems of the body and the mind. Ensuring that the gut is inhabited with a diverse colony of beneficial bacteria may be a key factor in helping the gut stay healthy.

Learning Objectives: 

  1. Understand the importance of your intestinal flora.
  2. Review factors that help and hinder the balance of bacteria in your gut.
  3. Learn good sources of probiotics to replenish your gut.

Bacteria Is No Longer the Enemy 

While antibacterial cleaning products and antibiotics were very popular in the past, this is quickly going out of favor as research demonstrates that chronic use may be detrimental to many systems of the body. Bacteria is no longer the enemy to be feared or eradicated. In fact, many kinds of microorganisms are essential for optimal health and wellbeing. And strangely enough, the human body is made up of far more bacteria than human cells. The bacteria in the body outnumber human cells by 10-fold and about 70%, or about 1-1.5 kg in an average adult, are located in the gut. With the acknowledgement that many kinds of bacteria are necessary and live in a symbiotic relationship with the human body, more researchers are studying how to optimize these populations to prevent and treat disease.Gut Diagram

Studies have shown that infants need exposure to both beneficial and pathogenic bacteria in order to develop a well-functioning immune system. The conveniences of modern society - such as refrigeration, treating water, and food processing - may rob the body of this opportunity and affect the functioning of many systems. Research has demonstrated that the microorganisms that live in the gut may be involved in:

Individuals with an imbalance in their intestinal flora, known as dysbiosis, can experience a wide range of health challenges. These may include:

Obviously, there may be other causal factors for the disorders above, but gut flora is definitely implicated in their causes and treatments. While treating clients who have these conditions may be outside the scope of practice as a trainer, prevention is not. By helping clients maintain a healthy population of gut bacteria and repopulate the gut with beneficial bacteria, trainers may be able to enhance the preventative measures used with clients.

Origin of and Influences on the Intestinal Flora

In utero, the human gut is sterile. The first exposure to bacteria is through the vaginal canal at birth. This population continues to expand and diversify through diet, environmental exposures, and antimicrobial therapies. While some factors (like which populations of bacteria are present in the birth canal) cannot be controlled, clients can control the foods, antimicrobials, and probiotic supplements that they consume. 


Food affects the bacteria that live in the gut for better or for worse. Carlo Maley, PhD, director of the UCSF Center for Evolution and Cancer, said "The gut is like a living ecosystem and it is continuously evolving. It is evolving so much so that measurable changes in the intestinal flora (bacteria) of the gut can be observed within as little as 24 hours after making a dietary change."  

As gut health is relatively still a new field of study, foods to include have not necessarily been identified. However, it is clear that chemicals and preservatives in foods can detrimentally alter our intestinal flora. Processed foods contain preservatives, refined sugars, and other chemical ingredients. Conventionally grown (non-organic) foods contain chemicals and neurotoxins. The Environmental Workers Group (EWG) produces two lists: “Clean Fifteen” and “Dirty Dozen Plus” to inform consumers of the non-organic foods that have the least and the most chemical residue, respectively.

Foods on the “Clean Fifteen” include:

Foods on the “Dirty Dozen Plus” include:


  1. Eat foods that are organically grown.
  2. If non-organically grown foods are consumed, avoid foods on the “Dirty Dozen Plus.”
  3. Limit consumption of processed foods and refined sugars.

Antibacterial Drugs, Supplements, and Cleaning Products

Antibacterial Drugs

The word antibiotics literally means “against life.” While antibiotics may be necessary to eliminate bacterial infections in various systems of the body, antibiotics don’t just kill the bad bacteria at the site of the infection. Many good bacteria are eliminated as well. Without the protection of these microorganisms, health conditions, such as those listed earlier, antibiotic-associated diarrhea, and a compromised immune system are more likely to occur. 

While some studies have shown that intestinal bacteria returned to pre-treatment levels within a month, other studies have shown that the levels are disrupted even two years after taking a single round of antibiotics. The difference in how long it takes for the intestinal bacteria to return to pre-treatment levels may be influenced by several factors. These may include: the general health of the gut pre-treatment, the diversity of bacteria in the gut, the potency of the antibiotic taken, the length of the antibiotic treatment, and previous antibiotic treatments.    

Antibacterial Supplements

Those who choose a more holistic approach to health may think that taking herbs is a safe route. While herbs with antibacterial properties, like oregano, may not have all of the side effects of pharmaceutical antibiotics, they are not without concerns. When taken for extended periods of time, some of these herbs may cause a build-up of toxins in the liver and kidneys and adversely affect gut flora.


  1. Avoid over-using antibiotics and natural antibacterial herbs. 
  2. Consume probiotic foods and supplements when antibiotics and antibacterial herbs are taken (see more in the section below).


Probiotics seem to be the new buzzword in the health and fitness industries. The literal translation of the word "probiotic" is "for life." They are preparations, found in supplements and cultured foods, containing beneficial microorganisms. While more research needs to be done on the effect of probiotics for both treatment of diseases and preventative measures, some studies have shown that probiotics have many benefits and relatively no side effects.

Some findings indicate that saccharomyces boulardii (a yeast) and lactobacilli (a bacteria) may prevent antibiotic-associated diarrhea if taken during the course of the antibiotic treatment. Other probiotics have been shown to decrease anxiety and depression. Still others have been shown to help treat inflammation in the intestines.

For clients who have health conditions, it is best for a doctor to recommend which strains will be most beneficial for their condition. However, for preventative measures, clients who are generally in good health should consume a variety of cultured foods and a probiotic supplement with many strains of bacteria. 

Cultured foods include yogurt, keifir, kombucha, and fermented vegetables. Of these, fermented vegetables is the better choice. Many people are sensitive to dairy products (yogurt and keifir) and others are sensitive to added sugars, such as those found in kombucha. Fermented vegetables, such as sauerkraut and kim chi, can be purchased from health food stores or made at home.


  1. Avoid taking probiotics at the same time as antibiotics to get the full effect of both. Each should be separated by at least 3 to 4 hours.
  2. Consume a variety of probiotic strains, both through supplements and cultured foods. 


The health of the gut is of great importance to the overall health of the mind and body, and it all starts with having a healthy population of bacteria in the gut.  While clients can’t go back in time and ensure that they were exposed to a wide array of bacteria as a child, trainers can educate them on the relationship between their gut health and the overall functioning of their body. Help clients make better choices when it comes to consuming organic foods and probiotic foods and supplements. Teach clients about the side effects of taking antibacterial drugs and supplements. Through education and preventative steps, clients may be able to improve their gut health and prevent the onset of many health conditions.


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Environmental Workers Group. (2015). Retrieved 2015, from: and

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