Introduction to gut health: What you need to know

Understanding the Gut: Anatomy and Function

The human body is composed of roughly 30 trillion human cells (Bianconi et al., 2012). Interestingly we are composed of roughly a similar number of bacterial cells (Sender et al., 2016). In addition to the trillions of bacterial cells, we are also made of many fungi and viruses collectively known at the microbiome. According to research, around 95% of the human microbiome resides within the gut (Cani 2018). This means the majority of the body's bacteria, viruses, and fungi are found in the gastrointestinal tract, primarily in the colon (Cani 2018). The gut, often referred to as the gastrointestinal tract, is a complex system that plays a crucial role in our overall health. It begins with the mouth, where the digestive process is initiated, and extends through the esophagus, stomach, small intestine, large intestine, and finally to the rectum and anus. Each part of this system has a distinct function, contributing to the breakdown of food, nutrient absorption, and waste elimination. Understanding the anatomy of the gut is essential for appreciating how it influences various aspects of health, including digestive health, immunity, and even mental well-being.

The gut is home to trillions of microorganisms, collectively known as the gut microbiota. This microbiome is essential for various functions, including digestion, nutrient absorption, metabolism, and the synthesis of certain vitamins. It also plays a critical role in immune function, as a significant portion of the body's immune cells resides in the gut.

Our gut bacteria also produce a wide variety of neurotransmitters and hormones, which are chemicals that send messages between the brain and gut through a network of 100 million nerve cells connected to the brain through the vagus nerve. These neurotransmitters can affect brain function, cognition (Miri et al., 2023), and mood (Appleton 2018). This complex network of neural connections that allows for communication between the gut and brain is also referred to as the gut-brain axis (Mayer 2011). The gut-brain connection further illustrates the significance of gut health in overall well-being. For example, research suggests that an unhealthy gut can contribute to anxiety, depression, and other mental health issues (Appleton 2018). This connection underscores the need for a comprehensive approach to health that considers the gut's role in mental well-being including mental clarity and emotional stability, especially in stress-prone populations like college students and parents.

Studies show that gut health significantly impacts various aspects of overall health, including immune function, metabolism, mental health, and even the development of chronic diseases like obesity, diabetes, heart disease, and certain cancers, primarily due to the complex interaction between the gut microbiome and the body's systems through the "gut-brain axis" and immune response pathways (De Vos et al 2022). Disruptions to the balance of this microbiome can lead to a range of mental and physical health issues. The intricate relationship between the gut and many chronic medical illnesses highlights the importance of maintaining gut health for overall health.

Most diseases such as obesity, heart disease, cancer, etc. develop in a complex fashion and stem from the interaction between our genes and environmental risk factors such as exercise, smoking, dietary patterns, stress, and other lifestyle factors. Since we are born with our genes, we generally cannot change them. Therefore, to modify our risk of chronic illnesses we have learned to modify our environmental risk factors. For example, to decrease the risk of lung cancer don't smoke or to decrease you chances of developing heart disease one must maintain regular exercise patterns. New research suggests that in addition to modifying our environmental factors we also have the ability to manipulate our microbiomes (David et al., 2014).

According to numerous studies research strongly indicates that altering your microbiome, particularly the gut microbiome, can significantly impact health outcomes, with studies showing that by manipulating the composition of gut bacteria through dietary changes, probiotics, or fecal microbiota transplantation, individuals can experience improvements in conditions like obesity, diabetes, inflammatory bowel disease, and even mental health issues (Wong et al., 2023 ) (Mousavinasab et al., 2023). Therefore, in addition to manipulating environmental factors such as healthy diet, exercise, etc. to achieve better health we can also change our microbiome to achieve optimal health outcomes.

Lifestyle changes can significantly improve gut health. Incorporating a diet rich in fiber, prebiotics, and probiotics can enhance microbiome diversity, which is crucial for a resilient gut. Regular physical activity, adequate sleep, and stress reduction techniques, such as mindfulness and yoga, also contribute to better gut health. These lifestyle modifications can lead to improved digestion, enhanced immunity, and greater overall health, making it vital for individuals to prioritize these changes in their daily routines.

Gut health is a cornerstone of overall well-being, influencing everything including both mental and physical health. As research continues to unveil the intricate connections between the gut and various health conditions, the importance of maintaining a balanced microbiome becomes increasingly clear. By adopting healthier lifestyles and making informed dietary choices, individuals can support their gut health, leading to improved quality of life and longevity. Embracing this knowledge empowers adults, parents, and young adults alike to take charge of their health and well-being through the lens of gut health.

Stay tuned for the next chapter: Habits that are wrecking your gut health

References:

Bianconi, E., Piovesan, A., Facchin, F., Beraudi, A., Casadei, R., Frabetti, F., … Canaider, S. (2013). An estimation of the number of cells in the human body. Annals of Human Biology, 40(6), 463–471.

Cani PD. Human gut microbiome: hopes, threats and promises. Gut. 2018;67(9):1716–25.

Sender, R., Fuchs, S., & Milo, R. (2016). Revised Estimates for the Number of Human and Bacteria Cells in the Body. PLOS Biology, 14(8).

David LA, Maurice CF, Carmody RN, Gootenberg DB, Button JE, Wolfe BE, Ling AV, Devlin AS, Varma Y, Fischbach MA, Biddinger SB, Dutton RJ, Turnbaugh PJ. Diet rapidly and reproducibly alters the human gut microbiome. Nature. 2014 Jan 23;505(7484):559-63.

Mayer EA. Gut feelings: the emerging biology of gut-brain communication. Nat Rev Neurosci. 2011 Jul 13;12(8):453-66.

Miri S, Yeo J, Abubaker S and Hammami R (2023) Neuromicrobiology, an emerging neurometabolic facet of the gut microbiome? Front. Microbiol. 14:1098412.

Appleton J. The Gut-Brain Axis: Influence of Microbiota on Mood and Mental Health. Integr Med (Encinitas). 2018 Aug;17(4):28-32.

Mousavinasab, F., karimi, R., Taheri, S. et al. Microbiome modulation in inflammatory diseases: Progress to microbiome genetic engineering. Cancer Cell Int 23, 271 (2023).

Wong MCS, Zhang L, Ching JYL, Mak JWY, Huang J, Wang S, Mok CKP, Wong A, Chiu OL, Fung YT, Cheong PK, Tun HM, Ng SC, Chan FKL. Effects of Gut Microbiome Modulation on Reducing Adverse Health Outcomes among Elderly and Diabetes Patients during the COVID-19 Pandemic: A Randomised, Double-Blind, Placebo-Controlled Trial (IMPACT Study). Nutrients. 2023 Apr 20;15(8):1982.