Using just a pinprick of blood, Ixcela measures gut-specific metabolites to provide a personalized wellness plan that helps you feel and look great. Below is a list of metabolites we test. These metabolites are either produced by, or used by your gut microbiome. Since reporting indivdual values is not that helpful for most people, Ixcela results show how these metabolite levels impact five areas of health: Gastrointestinal Fitness, Immuno Fitness, Cognitive Acuity, Emotional Balance, and Energetic Efficiency.
Our test is backed by scientific studies. Learn more about the metabolites we test as well as relevant references.
Indole-3-propionic acid (IPA), a strong neuroprotective antioxidant, is a key indicator of a healthy gut microbiome.[1,2] IPA plays a crucial role in regulating intestinal permeability. Healthy intestines allow nutrients to pass into the bloodstream, but prevent potentially harmful substances from migrating to areas of the body where they could cause inflammation and gastrointestinal (GI) distress. Low levels of IPA may indicate a weak population of the bacterial colony Clostridium sporogenes, a beneficial bacterial strain in the gut.
Indole-3-lactic acid (ILA) is found in fermented foods and produced by some gut bacteria from the amino acid tryptophan. Proper levels of ILA are important for the production of other essential metabolites, like indole-3-propionic acid (IPA). Low or high levels of ILA may indicate gut bacteria dysbiosis (bacterial imbalance), which can lead to a variety of adverse symptoms, including gastrointestinal (GI) distress, inflammation, poor immune system, sleep disturbances, skin inflammation, and negative health outcomes.
Indole-3-acetic acid (IAA) is a naturally occurring plant hormone that is also produced by some gut bacteria. Proper levels of IAA maintain beneficial Lactobacillus species of gut bacteria. IAA is a precursor to other important metabolites, like indole-3-propionic acid (IPA).[5,6] Both high and low levels of IAA can indicate a potential dysbiosis (bacterial imbalance), which can lead to a variety of adverse symptoms, including gastrointestinal (GI) distress, inflammation, poor immune system, sleep disturbances, skin inflammation, and negative health outcomes.
Tryptophan (TRP) is an essential amino acid, which means that it must be included in the diet because the body cannot produce it. Tryptophan is used by the body and gut bacteria to manufacture several important metabolites, including serotonin, kynurenine, and the indole metabolites.[7,8,9] Tryptophan crosses the blood-brain barrier and is essential for regulating normal brain processes that affect mood, behavior, sleep, memory, and learning.[10,11] As a result, tryptophan is important for intestinal function and a healthy brain. Low levels of tryptophan can disrupt the function of several important systems.[8,10]
Serotonin is a tryptophan metabolite. Approximately 90% of serotonin is produced by cells of the gut lining, where gut bacteria help to regulate and support the production of serotonin. Serotonin is a neurotransmitter linked to mood regulation, muscle health, gut health, brain health, and the ability to fall asleep. Serotonin is one of the most important signaling molecules within the gut, where it helps to initiate digestion.
Kynurenine (KYN) is a tryptophan metabolite made in the liver. Gut bacteria influence the conversion of tryptophan into kynurenine. Due to kynurenine’s critical role in the body’s inflammatory response, high levels of kynurenine can indicate chronic infection and/or deficiency of vitamin B6, a vitamin important for the creation of red blood cells.[19,21] Because B vitamins influence kynurenine production and metabolism, high or low levels of kynurenine may be due to vitamin B deficiencies.
Indoxyl sulfate (IDS) is produced in the liver from the breakdown products of tryptophan created by colon microbes.[22,24] Specifically, when tryptophan enters the large intestine, it is converted to indole and then indoxyl sulfate in the liver. Proper levels of IDS can have antioxidant properties and have been associated with kidney and heart health. IDS is also considered a uremic toxin (a compound filtered by kidneys). Elevated IDS may be related to, strength training, a high protein and low fiber diet, tryptophan supplementation, or a dysbiosis in the small intestine.
Tyrosine (TYR) is a nonessential amino acid found in the diet. It is a building block for several neurotransmitters. When tyrosine is present, gut bacteria produce enzymes that support the production of these important neurotransmitters that regulate mood, behavior, and general feelings of well-being. Specifically, tyrosine is involved in the production of dopamine and initiative-oriented behavior. Sufficient tyrosine is also essential for the thyroid gland to produce hormones T3 and T4, which regulate growth, metabolism, body temperature, and heart rate.
Xanthine (XAN) is a metabolite of the purine pathway. In the digestive tract, xanthine induces hydrochloric acid production and promotes secretion of pepsin from cells lining the stomach, which aids in digestion. However, elevated xanthine can lead to oxidative stress and increase risk of inflammation. Elevated xanthine may be the result of caffeine intake, cardiovascular overtraining, and/or physical and emotional stress. Xanthine accumulation during strenuous cardiovascular exercise can limit energy output, in turn affecting performance.
3-Methylxanthine (3MXAN) is a purine metabolism-breakdown product of caffeine and the drug theophylline (commonly used to treat lung diseases).[29,30] Metabolites of the purine pathway are significant because they affect both the gut and the brain. In the gut, 3MXAN increases hydrochloric acid and pepsin secretion, which both aid digestion. Elevated 3MXAN may be related to the consumption of caffeinated beverages and foods like coffee, tea, and chocolate.
Uric acid (UA) is the final product of purine metabolism. Gut bacteria play a role in converting other purine metabolites into uric acid. Metabolites of the purine pathway are important because they affect both the gut and the brain.[33,34] Purines are key components of cellular energy systems, cellular signaling, and DNA and RNA production. When uric acid is within optimal levels, it has been shown to act as a strong antioxidant and play a role in our immune response. High uric acid levels can lead to inflammation.
The gastrointestinal (GI) tract is an organ system comprising the esophagus, stomach, and the large and small intestines. The GI tract is responsible for the swallowing and digestion of food, absorption of nutrients, and generation of waste. The GI tract is also home to trillions of microbes, known as the gut microbiome, which has been found to be vital to GI and systemic health, modulation of the immune system, and regulation of brain function.1–3 GI health and fitness revolves around maintaining the structural integrity of the intestinal wall and maintaining optimal levels of biochemicals and gut microbes. A number of metabolites associated with gut health are measured using the Ixcela Internal Fitness™ test kit, resulting in your Gastrointestinal Fitness score.
The immune system’s response to various physiological perturbations plays a significant role in maintaining optimal internal health. Additionally, research has shown that the relationship between the body’s immune system and the gut microbiome is inter-dependent, with both systems producing compounds that affect each other.1,6–9 A healthy gut improves the body’s ability to fight infection. Growth and development of the gut microbiome over the human lifespan, especially postnatally and through infancy, also influences development of the immune system and vice versa.1,10 Normal levels of antibodies and immune cells, stable gut wall integrity, and lack of food allergies are some characteristics of a healthy immune system. The Immuno Fitness score is a measure of immune health and is modulated by certain key metabolites.
Emotional well-being is one of the most important factors in the overall health of an individual. The body’s response to stress—physical, physiological, or psychological—is a key determinant in regulation of emotional state,3,14 and studies increasingly support that the gut microbiome is a major contributor to stress response3,14,15 and thus emotional well-being. Through various biochemicals, the gut microbiome has been linked to affecting mood, anxiety, and other conditions modified by stress.3,14-16 Your Emotional Balance score is a measure of emotional health and is modified by the composition of microbes and levels of metabolites in the gut.
In the last decade, there has been tremendous research about the complex bidirectional communication between the brain and gut microbiome. Through numerous studies, it has become evident that the gut microbiome regulates, and is itself regulated by, the brain via various hormones and signaling molecules.3,5,14,15 Effects of the gut microbiome on the brain have been linked to certain types of microbial species residing in the gut.3,20 Through mechanisms such as stimulation of the nervous system, production of toxic metabolites, and change in intestinal wall permeability, the gut microbiome influences neurological chemistry and function, enhancing cognitive function.3,5,14–16 Cognitive Acuity is a measure of gut-mediated neurological health.
Major functions of the gut are digestion of food and absorption of nutrients, and the gut microbiome plays a critical part in these processes.1,4,11,21 Microbes in the gut synthesize molecules known as short-chain fatty acids from nondigestible dietary components.1,22,23 These molecules act as a source of energy for the body and promote cellular mechanisms that maintain tissue integrity. Additionally, studies have found that harvesting energy from food is a microbial species-dependent process.24,25 Thus, having the right microbes in your gut will improve your daily energy levels. Your Energetic Efficiency score is reflective of the gut microbiome’s ability to effectively harness energy for the body.
*These statements have not been evaluated by the FDA. These products are not intended to diagnose, treat, cure or prevent any disease.