The Importance of Gut Health for Pets: The Role of Bacteria

The Link Between Gut Health and Overall Wellness

Recently, there has been a surge of interest in gut health in the wellness community due to the ongoing research on the microbiome or gut flora. It has been scientifically proven that gut health and overall health are strongly connected, and this applies to animals as well as humans.

In 2018, I attended several seminars, conferences, and educational programs throughout the US and Europe. The microbiota and micro-biome were recurring topics in all of these sessions, with discussions focusing on their impact on the health of both humans and animals. Research has established that healthy gut flora is vital for the well-being of the host and should be considered an organ due to its critical role in almost every bodily function [1, 2].

Bacteria and Gut Health

Before we dive into all of these things, let’s talk about something most of us don’t want to: bacteria. Bacteria are everywhere, including on us and in us. In fact, according to the NIH Human Microbiome Project, they outnumber cells within the human body 10 to 1. The same ratio is believed to relate to dogs as well.  We are only just beginning to discover the importance of bacteria, viruses and fungi, and their role in our survival.

We’re starting to understand that an imbalance of microorganisms within the human body is linked to many health problems and diseases. Like humans, is it possible that lack of diversity, or imbalance, of microorganisms within the canine body could be the cause of many of their health problems? Research is not just suggesting, but proving it is.

Benefits of Exposure to Harmful Bacteria

In today’s world, we tend to associate all bacteria with harmful diseases, and we come across numerous ads for antibacterial products that reinforce this belief. However, not all bacteria are harmful, and avoiding healthy bacteria, viruses, and fungi can have detrimental effects on pet and human health. In fact, exposure to some types of bacteria that are considered harmful can strengthen the immune system and prevent allergies.

When you search for “human bacteria” and “dog bacteria” on Google, you’ll notice that the results differ greatly. The search for humans emphasizes the importance of diverse microorganisms, while the search for dogs warns against rare bacteria that can be deadly to humans. While there are risks associated with bacteria, viruses, and fungi, they don’t necessarily pose a significant human health risk.

We often try to prevent infections and diseases at all costs, but some of these illnesses may actually help our immune systems become stronger. Restricting exposure to healthy bacteria can be detrimental to the immune systems of both pets and humans.

Benefits of Exposure to Harmful Bacteria

A Finnish study discovered a link between exposure to higher levels of pathogens and an improved immune system. The research examined two human populations of different socioeconomic statuses living in similar geographic regions and climates to explore allergy prevalence [3].

Results showed that population A, with lower socioeconomic status, had a higher prevalence of harmful bacteria and other pathogens than population B with higher socioeconomic status. However, population B did not experience any negative impact from these bacteria and was actually healthier due to their exposure to them. Additionally, population B had a lower prevalence of allergies compared to population A.

The study concluded that exposure to certain types of pathogens can help develop a more responsive and effective immune system. This study suggests that exposure to some harmful bacteria may be beneficial for improving the immune system’s effectiveness.

Understanding Bacteria, Viruses, and Microbiota

Bacteria are tiny, single-celled organisms that are present in enormous quantities. They come in various types, and most are harmless.

Viruses, on the other hand, are even smaller than bacteria and can only reproduce within living cells. Although viruses can be harmful, they are also believed to serve a healthy function in the microbiota of both humans and animals.

Microbiota refers to the complete collection of microorganisms, including bacteria, fungi, viruses, and protozoans[4], that colonize a particular area. It’s important to note that microbiota includes neutral, beneficial, and pathogenic bacteria, and the community is continuously changing due to internal and external factors.

The micro-biome, which is often confused with microbiota, refers to the genes within the microorganisms that make up the microbiota. This concept was first introduced by Joshua Lederberg, who coined the term to refer to the ecological community of microorganisms sharing our body space[5]. The micro-biome plays an essential role in the digestive, immune, nervous, and endocrine systems[6].

Dysbiosis is an imbalance in the diversity of microorganisms within the microbiota and, therefore, the micro-biome.

The immune system is the body’s natural defense system against pathogens, and the microbiota contributes significantly to its function and effectiveness.

Probiotics are living microorganisms that offer health benefits to the host when consumed in sufficient amounts. People and dogs often take probiotics to support the gut microbiota or aid in digestion[7].

Prebiotics, on the other hand, are selectively fermented ingredients that cause specific changes in the composition and/or activity of the gastrointestinal microbiota[8].


Understanding the differences of these terms is crucial when it comes to maintaining a healthy micro-biota. From an immunological perspective, microorganisms are typically viewed as pathogens that the immune system recognizes and eliminates. In the case of gut microorganisms, the majority are non-pathogenic and actually contribute to proper digestion, behavior, and immune function [4]. Therefore, an imbalance in gut microorganisms, or dysbiosis, can turn the normally helpful micro-biota into a liability [9].

While it may seem like microbiology is unrelated to your career or the health of your furry friend, nothing could be further from the truth. In fact, safe and controlled supplementation with species-appropriate probiotics could be the solution to training difficulties, health issues, and behavioral concerns.

For questions, clarification, or suggestions on topics for future articles please do not hesitate to email me at

*This article is for informational purposes only. It is not meant to provide medical advice or replace the advice of a qualified veterinarian.


[1] Jandhyala SM, Talukdar R, Subramanyam C, Vuyyuru H, Sasikala M, Nageshwar Reddy D. Role of the normal gut microbiota. World J Gastroenterol. 2015;21(29):8787-803.

[2] Sekirov I, Russell SL, Antunes LC, Finlay BB. Gut microbiota in health and disease. Physiol Rev. 2010;90:859–904. [PubMed]

[3] Haahtela T, Laatikainen T, Alenius H, et al. Hunt for the origin of allergy – comparing the Finnish and Russian Karelia. Clinical & Experimental Allergy. 2015;(5):891. doi:10.1111/cea.12527.

[4] Sekirov I, Russell SL, Antunes LC, Finlay BB. Gut microbiota in health and disease. Physiol Rev. 2010;90:859–904. [PubMed]

[5] Lederberg J., McCray A. (2001) ‘Ome Sweet ‘Omics – A Genealogical Treasury of Words. Scientist Inc.: Philadel- phia, PA, 15, 8.

[6] Horsley A. The Physiological Response to Dysbiosis Impacting the Immune, Endocrine and Nervous Systems. Nutritional Perspectives: Journal of the Council on Nutrition. 2018;41(3):10-16.

[7] FAO/WHO (2002) Working group for drafting guidelines for the evaluation of probiotics in food. Available at : ftp://ftpfaoorg/es/esn/food/wgreport2pdf 2002.

[8] Gibson G.R., Scott K.P., Rastall R.A., Tuohy K.M., Hotchkiss A., Dubert-Ferrandon A. et al. (2010) Dietary prebiotics: current status and new definition. Food Science and Technology Bulletin 7, 1–19.

[9]. O’Hara AM, Shanahan F. The gut flora as a forgotten organ. EMBO Rep. 2006;7(7):688-93.