Why is gut health important? And what do microbes have to do with it?
First, what is the gut? The gut can be considered the gastrointestinal tract (GI tract), from mouth to rectum. According to the online Cambridge Dictionary, the gut is “the long tube in the body of a person or animal, through which food moves during the process of digesting food”1.
However, when talking about gut health, many more variables are involved, than just the health status of “the long tube”. The reason behind it is that our digestive tract is not just a long tube through which food is transported, digested, absorbed and excreted. In fact, this “tube” is populated with trillions of microorganisms. These microorganisms were commonly named “gut flora”; however, this term did not account for the many nonbacterial elements (e.g., archaea, viruses, and fungi), hence non-flora, that are normally found in the gut environment. The more appropriate term “gut microbiota” was later adopted to encompass this vast array of organisms and their interactions.
What is the microbiota and the microbiome?
Humans host a plethora of microorganisms, a complex ecosystem that strongly influences both the body and the genetic makeup of the individual. The most common microorganisms are bacteria, archaea, viruses, protozoa and fungi.
The collection of bacteria, archaea and eukarya colonizing the GI tract is termed the ‘gut microbiota’. Microbiome is the collective genetic material of the microbiota2. In other words, microbiota only refers to the microorganisms themselves whereas microbiome refers to the microorganisms and their genes.
The Human Microbiome Project revealed that the human microbiota consists of the 10-100 trillion symbiotic microbial cells harbored by each person, primarily bacteria in the gut; the human microbiome consists of the genes these cells harbor3,4. In this complex ecosystem the role of bacterial species, in what relates to health and disease, seems to be paramount when compared to other microorganisms of the microbiota. Scientists estimate that the number of microorganisms inhabiting the GI tract exceeds 1014, with approximately 300 to 500 bacterial species, comprising nearly 2 million genes. That is approximately 10 times more bacterial cells than all the cells in the human body and over 100 times the amount of genomic content as the human genome2,5. These numbers have been recently challenged by a 2016 study that estimated the actual ratio of human: bacterial cells to be close to 1:16.
The GI microbiome, after long years of oblivion, has finally received the attention of the medical and scientific community and numerous studies have been conducted, especially within the last two decades. What this research is showing us is that the GI tract is far more complex than previously appreciated and strong associations were found between gut microbiome and gut health and the immune system, endocrine regulation, mental health and emotional stress, skin health, autoimmune diseases and many chronic illnesses, such as type 2 diabetes and cancer.
The microbiome is implicated in a wide range of physiologic processes that are vital to host health including energy homeostasis, metabolism, gut epithelial health, immunologic activity, and neurobehavioral development7. Moreover, the microbiota offers many benefits to the host, through a range of physiological functions such as strengthening gut integrity or shaping the intestinal epithelium, harvesting energy, protecting against pathogens and regulating host immunity2.
What is gut health?
In light of the importance of the microbiome for our overall health, it is easy to understand that “gut health” is determined by much more than the physiological integrity and function of “the long tube”. In fact, it is the function and balance of the gut microbiome, throughout all the GI tract, that determines our gut health. A whole complex and intricate ecosystem of living organisms interacting with each other and with the environment, influencing genetic and phenotypic expression of the host – i.e., the human.
From this perspective, it becomes apparent that the health of our gut and a balanced microbiome are essential to our physical and mental health, immunity and much more. The beneficial interaction between microbiota and host is rooted in the communication between bacteria and other microbes and the host’s immune system. These microorganisms also participate and have key functions in diverse metabolic processes mutually beneficial, such as energy homeostasis and metabolism5,7.
The truth is that most of these microorganisms are beneficial for our overall health, many being essential for humans to survive and thrive. It has been a parallel evolution for millions of years. Having a wide variety of beneficial bacteria in the GI tract can enhance immune system function, improve symptoms of depression, help combat obesity, among numerous other benefits5. However, when these microorganisms become unbalanced, with too many of not so beneficial ones and too little good ones, issues start to develop, and the impact can be felt at many levels.
Recent studies on the gut microbiome of humans revealed that healthy individuals tend to have a diverse microbiota, while people experiencing health issues, present less diversity of microorganisms, mainly bacteria, and an increased number of those often associated with disease. As the authors of a 2017 article wrote, “given the close symbiotic relationship existing between the gut microbiota and the host, it is not surprising to observe a divergence from the normal microbiota composition (generally referred to as dysbiosis) in a plethora of disease states ranging from chronic GI diseases to neurodevelopmental disorders2.” The difficult question then becomes: is the microbiota influencing the risk of certain diseases or is the disease determining the gut microbial populations?
Probably both are true, says Dr. Gail Hecht in an article for the Time Magazine8. Going back to the 2017 article, “whether dysbiosis of the microbiota is a cause or a consequence of the disease is therefore likely to exacerbate the progression of the disease and affect the type of strategies needed to restore symbiosis2.”
What impacts your gut health?
The modern busy life of many people impacts their gut health. Too much stress, little sleep, emotional struggles, poor food choices (such as processed and high sugar foods), eating too much food and too often and not hydrating well are some of them. But also taking over the counter medications (such as painkillers and acid reflux, diabetes and psychiatric drugs), have been linked to changes in microbiome, and especially frequent cycles of antibiotics that kill both harmful and beneficial bacteria.
A very interesting link that has received special attention is that between the gut and the brain, the “gut-brain axis”. This is a pathway through which signals from the gut can affect neurotransmitters in the brain, and vice versa, with complex repercussions in mood associated disorders like depression and anxiety.
A very important factor that highly influences individual’s microbiota is birth environment and breastfeeding. People born from natural birth and breastfed tend to have more diverse and resilient microbiota.
How to Help our Gut?
All the factors mentioned above, and others related with personal variables, will have an impact in the microbiome with repercussions in gut health. Both the microbiome and the integrity and function of the gut will affect your overall health, especially the immune system, but also the brain and heart, endocrine function, nutrient absorption, weight, skin and even chronic illnesses, such as cancer. Studies show that changes in the GI microbiome are associated with diseases in humans and animals including inflammatory bowel disease, asthma, obesity, metabolic syndrome, cardiovascular disease, immune-mediated conditions, and neurodevelopmental conditions such as autism spectrum disorde7.
Due to this multitude of contributing factors and possible symptomatology, it may be hard to identify exactly which symptoms are a result of gut microbiome imbalances. It is probably not possible to dissociate any symptom from some form of gut imbalance. However, the most common symptoms associated with the gut are those related to the GI tract, such as stomach and digestive issues, gas, bloating, heartburn, constipation and diarrhea, and diseases like inflammatory bowel disease. But there are other not so obvious signs that something might be going awry: fatigue, poor sleep, skin issues, cravings and food intolerances, weight fluctuations and even autoimmune conditions and mood disorders.
A healthy gut will help prevent and reduce inflammation and enhance immunity. With lower level of inflammation and balanced immune systems the human body is much less vulnerable to both internal and external aggressions. In general, with a healthy gut and balanced microbiome, you will feel great, energized and resilient. But is that possible?
Yes. There are several approaches you can take to improve your gut health. As always, we like to incentivize natural ways to achieve health. Simple, affordable and attainable steps. Here are 10 tips to help you get started!
- Better sleep
Sleep is essential for health and healing and improving your sleep will greatly improve your gut and overall health. Design a sleep routine that works for you. A simple way to start is by avoiding strong stimulus and screens after dark.
- Reduce stress
Try meditation, yoga, qigong, relaxation techniques, or just some music you love.
Time-restricted eating and periodic fasting have been shown to be beneficial for the microbiota. Do them daily or regularly for better results.
- Listen to your body
Notice how you react to foods and avoid those who give you discomfort. Listening to our body, both physically, mentally and emotionally is very important to create a good connection with your microbiome.
- Intolerances and allergies
Consider testing for food intolerances and potential food allergies. Adapt your diet accordingly. Consult with a specialist in the microbiome and gut health.
- Avoid processed and high-sugar foods
Diets rich in high-processed foods and foods high in added sugars contribute to bacterial imbalances, mainly a decrease in good bacteria and increase in harmful species. These foods also lead to increased cravings.
- Hydrate and eat healthy, organic foods
The staple for any healthy gut, is appropriate hydration levels and healthy foods. Drink plenty of water throughout the day and eat a diet rich in vegetables, fruits and fiber. Add fermented foods to your eating habits. Buy organic as much as possible and do not clean too much or disinfect the vegetables! Microbes are naturally present in healthy soils and vegetables grown organically are a great source of those helpful microorganisms.
- Eat prebiotic foods
These foods will help feed the good bacteria in your gut, contributing to bacterial diversity and population balance.
- Consider taking a good probiotic
Not all probiotics are good for everyone and not everyone needs them. It is not one size fits all. Consult with a specialist to evaluate your needs and supplement accordingly.
- Be grateful and present when eating. Eat slowly and chew your food well
This will activate your parasympathetic nervous system for better digestive function. This will also enhance digestion and absorption of nutrients.
Most of these tips are lifestyle changes that you can start implementing today!
However, for some people there might be the need for further investigation into what is really happening, especially if the symptoms are permanent, acute or recurring. There are several screening methods and tests that can be done, according to the individual characteristics and symptoms, to evaluate the health of the gut. This is even more important when symptoms are linked to chronic or autoimmune disease. Consulting with a specialist is advisable in these cases, not just to have a correct diagnosis, but a personalized action plan for a healthier gut and microbiome.
To finish beautifully on such a fascinating topic, as Dr Zach Bush stated: “The microbiome has now come to be seen as the foundation of human life, health, and most interesting… human consciousness itself. Grandiose and ridiculous to the medical mindset, it is thoroughly obvious to the naturalist. We cannot exist apart from the biology of the microbiome. So, how could we possibly rise to a high level of awareness without the connection to this rudimentary source of intelligence? 9”
We believe the answer is we cannot. The time has arrived for you to connect with your microbiome and enhance your gut and overall health.
- Meaning of: gut . https://dictionary.cambridge.org/us/dictionary/english/gut, accessed June 2, 2021
- Thursby E, Juge N. Introduction to the human gut microbiota. Biochem J. 2017 May 16;474(11):1823-1836. doi: 10.1042/BCJ20160510. PMID: 28512250; PMCID: PMC5433529.
- Ursell LK, Metcalf JL, Parfrey LW, Knight R. Defining the human microbiome. Nutr Rev. 2012 Aug;70 Suppl 1(Suppl 1):S38-44. doi: 10.1111/j.1753-4887.2012.00493.x. PMID: 22861806; PMCID: PMC3426293.
- Turnbaugh PJ, Ley RE, Hamady M, Fraser-Liggett CM, Knight R, Gordon JI. The human microbiome project. Nature. 2007 Oct 18;449(7164):804-10. doi: 10.1038/nature06244. PMID: 17943116; PMCID: PMC3709439.
- Quigley EM. Gut bacteria in health and disease. Gastroenterol Hepatol (N Y). 2013 Sep;9(9):560-9. PMID: 24729765; PMCID: PMC3983973.
- Sender R, Fuchs S, Milo R. Revised Estimates for the Number of Human and Bacteria Cells in the Body. PLoS Biol. 2016 Aug 19;14(8):e1002533. doi: 10.1371/journal.pbio.1002533. PMID: 27541692; PMCID: PMC4991899.
- Barko PC, McMichael MA, Swanson KS, Williams DA. The Gastrointestinal Microbiome: A Review. J Vet Intern Med. 2018 Jan;32(1):9-25. doi: 10.1111/jvim.14875. Epub 2017 Nov 24. PMID: 29171095; PMCID: PMC5787212.
- Macmillan, A. “Here’s Everything You Need to Know About Gut Health.” TIME. Updated April 1, 2019| Originally Published March 25, 2019. https://time.com/5556071/gut-health-diet/.
- Bush Z. Knowledge – Gut Health https://zachbushmd.com/knowledge-gut-health/, accessed June 4, 2021.
Vanessa Pinto graduated with a degree in Biology and Masters in Ecology from Lisbon University. After graduating, she underwent a series of professional and personal growth experiences, including being an officer in the Portuguese Army, working in countries as diverse as Iceland and Costa Rica. Vanessa became certified as a Yoga and Meditation teacher in rural India.
Being a compassionate person by nature, Vanessa is able to bring her connectedness when working with others while enhancing the importance and practicality of a pragmatic evidence-based approach to facilitating lasting and permanent change. Vanessa is a certified health coach whose specialties are nutrition, exercise, and mind/ body connection. She works both in Portugal, Thailand and USA, where she develops her work closely with people diagnosed with cancer, mainly in the areas of nutrition, movement and health education.