The GI Map Test and the Science of our Gut Microbiome
The GI Map Test and the Science of our Gut Microbiome
Our gut contains trillions of micro-organisms that are essential to our health. To this day, connections between gut health, immunity, metabolism, and the brain are still not well understood, but until recently, researchers studied these systems in silos. It wasn't until the late 20th century that research began to reveal their complex relationships, changing our understanding of human health as a whole. [1]
Imbalances in the gut microbiome have been shown to cause a wide range of chronic health conditions, spanning gastrointestinal disorders, metabolic diseases, autoimmune conditions, and even neurological and psychiatric illnesses. As a result, assessing the gut microbiome has become an increasingly important tool in medicine.
The gut's impact extends far beyond the gastrointestinal tract, with implications for the autonomic nervous system and other important regulatory systems in the body. The connections between gut microbes, the nervous system, immune system, and endocrine system have proven vital to maintaining overall health and well-being.
Several commercial labs have developed gut microbiome tests, which use various methods to assess the overall health of your gut. In this article, we'll attempt to provide an overview of the science behind it, what it means, and the broader health implications.
Systemic Health Impacts of the Gut
The gut is often thought of as just a digestive system, but its influence extends far beyond our stomachs. Research has revealed its impact on metabolic processes, immune function, neurological and mental health, the autonomic nervous system, and cardiovascular health.
Gastrointestinal Health
The gut microbiome is crucial for gastrointestinal health, aiding in digestion, nutrient absorption, and pathogen protection. Interestingly, the gut microbiome produces over 90% of the neurotransmitter serotonin in the human body, which not only influences our mood but also regulates intestinal movements. An imbalance in your gut's microbiota, referred to as dysbiosis, has been linked to inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). Recent studies have even shown that fecal microbiota transplantation has been an effective treatment for recurrent Clostridioides difficile infection, with success rates of up to 90%. [2]
Metabolic Health
The gut microbiome significantly influences metabolic health through several mechanisms. In terms of weight regulation, the ratio of Firmicutes to Bacteroidetes bacteria in the gut has been associated with obesity. Regarding glucose metabolism, certain gut bacteria produce short-chain fatty acids that improve insulin sensitivity. For example, Akkermansia muciniphila has been shown to improve glucose tolerance and reduce insulin resistance. In lipid metabolism, some gut bacteria can convert dietary choline into trimethylamine, which is further metabolized in the liver to trimethylamine N-oxide (TMAO). High levels of TMAO have been associated with increased risk of cardiovascular disease. [3]
Immune Function
The gut microbiome has shown to to control immune responses and communicates with immune cells to regulate the body's response to infections. Nearly 80% of the body's immune cells reside in the gut. The gut microbiome also influences the development of regulatory T cells, which prevent autoimmune reactions. Studies have shown that germ-free mice have impaired immune function, highlighting the importance of the microbiome in immune development. [4]
Neurological and Mental Health
The gut-brain axis represents a bidirectional communication system between the gut microbiome and the central nervous system. Some fascinating findings include the production of neurotransmitters by gut bacteria. For instance, certain strains of Lactobacillus and Bifidobacterium can produce gamma-aminobutyric acid (GABA), which affects mood and behavior. Alterations in gut microbiota have been associated with depression and anxiety. A study found that transferring fecal microbiota from depressed humans to germ-free rats induced depressive-like behaviors in the animals. The microbiome may also impact brain function and cognitive processes. For example, a study found that probiotics containing Bifidobacterium and Lactobacillus improved cognitive function in Alzheimer's patients.
Autonomic Nervous System
The gut microbiome interacts with the autonomic nervous system in surprising ways. Certain probiotics, known as "psychobiotics," can reduce cortisol levels and alleviate stress responses. For example, Lactobacillus rhamnosus has been shown to reduce anxiety-like behavior in mice by modulating GABA receptors. The gut microbiome influences the enteric nervous system, often called the "second brain," which controls gut motility. Short-chain fatty acids produced by gut bacteria can stimulate the release of serotonin from enterochromaffin cells, affecting gut motility. Some gut bacteria produce metabolites that can affect blood pressure. For example, certain gut bacteria can produce short-chain fatty acids that activate G-protein coupled receptors, leading to reduced blood pressure.
Cardiovascular Health
The gut microbiome has significant implications for cardiovascular health. Certain gut bacteria metabolites, particularly TMAO, have been associated with increased cardiovascular disease risk. A study found that individuals with high TMAO levels had a 2.5-fold higher risk of major adverse cardiovascular events. Some microbial metabolites can affect blood pressure. For instance, short-chain fatty acids produced by gut bacteria can promote the release of renin, influencing blood pressure regulation. The gut microbiome may also play a role in atherosclerosis development. Studies have shown that certain gut bacteria can influence cholesterol metabolism and inflammation, key factors in atherosclerosis progression.
Gut Microbiome Testing
Gut microbiome testing has become a valuable tool for understanding the complex ecosystem of micro-organisms residing in the human gastrointestinal tract. Various methods have been developed to analyze the composition, diversity, and function of the gut microbiome, each with its own strengths and weaknesses. This section explores the primary techniques used in gut microbiome testing, including their capabilities, insights, advantages, and drawbacks.
The GI Map Test, which was developed by Diagnostic Solutions Laboratory, employs quantitative PCR technology to provide a comprehensive analysis of the gut microbiome. This test offers valuable insights into various aspects of health, extending far beyond digestive issues to areas such as metabolism, immunity, and even mental well-being. The test analyzes over 24 commensal bacteria species, providing a detailed picture of the gut ecosystem. Interestingly, studies have shown that a healthy adult gut typically houses over 1,000 species of bacteria, with the total number of microbial cells outnumbering human cells by a factor of 10 to 1.
Gastrointestinal health is, unsurprisingly, a primary focus of the GI Map Test. It can identify imbalances in gut bacteria that may lead to issues like "leaky gut" or dysbiosis. For instance, a lack of beneficial bacteria such as Lactobacillus or Bifidobacterium could suggest a compromised gut barrier.
The test can also detect harmful bacteria like H. pylori, which is estimated to infect about 50% of the world's population. H. pylori infection is associated with a 2-6 fold increased risk of developing gastric cancer, and its eradication reduces gastric cancer risk by up to 40%.
The test's findings have implications for metabolic health as well. Some bacteria, like Akkermansia muciniphila, are associated with better glucose control and lower obesity risk. Research has shown that individuals with higher levels of A. muciniphila have a 46% lower risk of developing type 2 diabetes.
The balance between Firmicutes and Bacteroidetes bacteria may also explain an individual's susceptibility to weight gain. Studies have found that obese individuals tend to have about 20% more Firmicutes and 90% fewer Bacteroidetes compared to lean individuals.
Moreover, the test measures β-glucuronidase, an enzyme that can affect estrogen metabolism and, by extension, body fat distribution. Elevated β-glucuronidase levels have been associated with a 2-3 fold increased risk of estrogen-related cancers in some studies.
Immune function is another area where the GI Map Test is extremely valuable. It measures secretory IgA, a key component of mucosal immunity. Low levels might indicate increased vulnerability to infections and food sensitivities. Interestingly, about 80% of all antibodies in the human body are secretory IgA, highlighting its importance in immune defense. The test can also detect parasites and opportunistic pathogens that might be challenging the immune system.
For example, it can identify Blastocystis hominis, a parasite found in up to 23% of individuals with irritable bowel syndrome (IBS). Some studies have suggested that certain strains of Blastocystis may increase gut inflammation by up to 5 times in susceptible individuals.
Interestingly, the GI Map Test provides valuable insights into neurological and mental health through its assessment of specific bacteria known to influence neurotransmitter production. For example, the test measures levels of Lactobacillus and Bifidobacterium species, which are crucial for the production of gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the brain. Adequate GABA levels are associated with reduced anxiety and improved mood regulation. The test also assesses Escherichia species, some of which are involved in the production of norepinephrine, a neurotransmitter that affects attention and responding actions.
Perhaps most significantly, the GI Map Test evaluates levels of Enterococcus and certain Streptococcus species, which together with some Escherichia strains, are responsible for producing up to 90% of the body's serotonin, a neurotransmitter crucial for mood regulation, sleep, and appetite control.
Research has shown strong correlations between gut bacterial compositions and various neurological conditions. For instance, studies have found that individuals with major depressive disorder have up to 35% less diversity in their gut microbiome compared to healthy controls, with notably lower levels of Bifidobacterium and Lactobacillus. The GI Map Test can detect these imbalances, potentially aiding in the diagnosis and treatment of depression.
The GI MAP Test provides insights into gut microbiome factors that may influence cardiovascular health. It can detect the presence of Trimethylamine N-oxide (TMAO)-producing bacteria, such as Prevotella and Desulfovibrio. Elevated TMAO levels have been associated with an increased risk of major adverse cardiovascular events, including heart attack and stroke.
The test also assesses the abundance of butyrate-producing bacteria, like Faecalibacterium prausnitzii and Roseburia spp. Butyrate, a short-chain fatty acid, has been shown to have protective effects on the cardiovascular system by reducing inflammation and improving endothelial function.
Additionally, it evaluates the levels of Akkermansia muciniphila, a beneficial bacterium that has been inversely associated with cardiovascular disease risk factors, such as obesity and insulin resistance. By providing a comprehensive assessment of the gut microbiome, the GI MAP Test can help identify potential imbalances that may contribute to cardiovascular health risks.
By analyzing these and other parameters, the GI Map Test provides a comprehensive view of the gut microbiome's impact on overall health. The insights gained from this test can inform personalized treatment strategies and preventive care approaches, potentially improving outcomes across a wide range of health conditions. As our understanding of the gut microbiome continues to evolve, tests like the GI Map are likely to play an increasingly important role in personalized medicine and holistic health care approaches.
Several commercial labs have developed gut microbiome tests, which use various methods to assess the overall health of your gut. In this article, we'll attempt to provide an overview of the science behind it, what it means, and the broader health implications.
References
- Yano JM, Yu K, Donaldson GP, et al. Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis. Cell. 2015;161(2):264-276. doi:10.1016/j.cell.2015.02.047 ↩
- Quraishi MN, Widlak M, Bhala N, et al. Systematic review with meta-analysis: the efficacy of faecal microbiota transplantation for the treatment of recurrent and refractory Clostridium difficile infection. Aliment Pharmacol Ther. 2017;46(5):479-493. doi:10.1111/apt.14201 ↩
- Ley RE, Turnbaugh PJ, Klein S, Gordon JI. Microbial ecology: human gut microbes associated with obesity. Nature. 2006;444(7122):1022-1023. doi:10.1038/4441022a ↩
- Depommier C, Everard A, Druart C, et al. Supplementation with Akkermansia muciniphila in overweight and obese human volunteers: a proof-of-concept exploratory study. Nat Med. 2019;25(7):1096-1103. doi:10.1038/s41591-019-0495-2 ↩
About the Author
Brock Sellers PhD
Brock is a research associate at Galen Scientific where he helps unravel systematic impacts of supplements. He studied organic chemistry and physics prior to becoming a researcher. He writes under a pseudonym to maximize journalistic freedom.