Our gut is populated by robust and complex microflora, mostly bacteria, that form what is essentially an interdependent organ with a unique physiology that affects every aspect of our being. The foreign bacteria that create our microbiome are colonizers that live with us in a symbiotic relationship. A healthy gut is essential for the proper performance of many processes that promote overall health. 

Processes of Digestive Function

Poor digestive function can occur anywhere along the digestive tract. Medical evaluation of digestive function is important in identifying the specific processes impacted by, and contributing to, digestive health. To break it down: there are six key processes in the digestive system:


Eating is a much more complex process than just ingestion of energy and is deeply influenced by social and cultural factors. As humans, we gather and celebrate around food. Our various senses guide our eating behavior through a feedback mechanism to the brain, creating memory and comfort signals and resulting in hormone release. The environment around us impacts the digestive process before food has even been consumed. Humans also have a tremendous capacity as omnivores to chew foods, be it animal or plant-based. The complexity of eating is only the tip of the digestive iceberg, as the chain of processes is as diverse as the diversity of the food we ingest. 


An enormous amount of fluid is secreted into the digestive system. The stomach secretes between 1.2 and 1.5 liters (L) of fluid per day, mostly hydrochloric acid (HCl). The pancreas secretes another 1 to 1.5 L of fluid per day, mostly bicarbonate to neutralize the acid. The gallbladder and liver contribute another 1 L per day, mostly bile, and the small intestine adds close to 2.5 L per day (but also reabsorbs most of the fluid back into the body). Overall, the digestive system secretes and reabsorbs between 7 to 9 L of fluid per day, with an average stool output of about 200 milliliters (mL). Proper digestive function relies on the vast majority of all secreted fluid being reabsorbed. 

Mixing and Movement

Peristalsis, or motility, is the movement that propels food forward in the digestive tract. It prevents stasis and retrograde movement of food and waste. Poor digestive function can be triggered by poor peristalsis, or dysmotility, causing food or waste to travel in the wrong direction or stay put. Delayed gastric emptying, where food stays in the stomach for a long time, is quite common. Dysmotility in the small intestine can lead to bacterial overgrowth and dysbiosis. Proper motility in the gut is vital for sweeping away bacteria, creating an environment where bacteria cannot overpopulate or disrupt the microbial balance. 


The digestive process starts before food is even consumed. It is triggered through our senses—how we see and smell, the time of day, even our hormone levels. The physical breakdown of food starts in the mouth with the production of enzymes and continues in the stomach and intestines, where acid, more enzymes, and bile are produced and secreted. We cannot absorb any large molecule of food, so everything has to be broken down into tiny molecules that are brought into the body.    

Gut bacteria balance


Nothing is absorbed passively in the digestive tract. After food is digested, tiny molecules are recognized by the body as food and engaged at the border of the intestines, where they are actively absorbed and immediately met in the cell cytoplasm by chaperones, ready to escort them for processing. This is the essence of metabolism, and it costs us energy. Transporting nutrients that have been absorbed through the intestines and assimilating them into tissue and metabolic pathways is a high-energy process. Without all of these components working, nutrients cannot be adequately utilized by the body.


Toxins from food, byproducts of metabolism, and other chemicals are excreted mostly through bile. This then joins other waste matter in the intestines, insoluble fiber, and lots of bacteria, and is disposed of as stool. Further breakdown of nutrients in the colon by bacteria through fermentation (and putrefaction) is covered in another article.

Why Do I Need To Test Digestive Function?

With up to 74% of Americans living with common digestive symptoms such as gassiness, constipation, diarrhea, bloating, and abdominal discomfort, it is important to regularly test digestive function to help guide overall health. 

First, it is important to understand that our gut houses the majority of the immune system. Therefore, your ability to maintain proper digestive health is influenced by an unhealthy gut. This can lead to chronic ailments outside the gut.  

Second, nutrient absorption is particular. For example, fat-soluble vitamins (A, D, E, K) require bile for proper absorption; unfortunately, they are commonly malabsorbed in people with poor liver health. This can lead to weak bones and pathologic fractures, in the case of vitamin D deficiency, and bleeding problems due to lack of vitamins K. Another example is iron deficiency, so testing for specific nutrients can help uncover underlying concerns.

Additionally, direct communication between the gut and the brain substantiates a link between your digestive health and mental well-being. The brain-gut connection depends on the enteric nervous system, including the vagus nerve, which is the tenth cranial nerve, and gut hormones, like serotonin. In fact, about 90% of serotonin, also known as the “happy hormone,” is produced in the gut. So mental processes, such as learning, memory, and mood, depend heavily on gut health.

Testing your digestion allows gastroenterologists to examine the health and function of your digestive tract. They can identify if any symptoms you are experiencing are related to an underlying functional issue so that proper treatment can be advised. Early identification of poor gastrointestinal health is important for effective treatment and resolution of symptoms. 

Symptoms of Digestive Problems

Digestive function tests are important if you have any symptoms of poor digestive function. Symptoms vary across individuals, but there are general symptoms that may indicate early issues. You should reach out to your gastroenterologist for testing if you experience any of these symptoms regularly:

Gassiness and bloating
♦ Diarrhea
♦ Constipation
Abdominal pain
♦ Skin rashes or breakouts
♦ Unintentional weight loss or gain
♦ Fatigue or weakness
♦ Poor concentration/cloudy mentation

These symptoms can also indicate other health issues, which is why it is essential to get tested. Early identification may be necessary for effective treatment and maintenance of a healthy gut.  

Blood tests

Digestive Health Testing and Results

Several different tests can be done to evaluate digestive function. Tests are performed based on the symptoms you are experiencing and will allow your doctor to identify which part of the digestive system is affected. The doctor can then recommend the most effective treatment.

Blood tests: Blood is used to evaluate liver and pancreatic function, nutrient absorption, identify food allergies, rule out infection, measure protein level, lipids, and markers of an inappropriate immune response.

Stool tests: Stool is used to identify internal bleeding, rule out infections, and test for malabsorption. 

Imaging tests: X-rays, ultrasounds, and CT scans can help identify structural problems, like stool impaction, and more serious digestive issues. Nuclear scintigraphy, which uses nuclear tracers, can help detect problems with peristalsis or bile excretion. 

Endoscopy: An endoscopy involves inserting a long, thin tube directly into the body to detect mucosal disease. Abnormal tissue may be sampled by biopsy, and early cancer can often be resected.

Breath testing: Breath can be tested for gases, such as hydrogen and methane, which are produced in our intestines in response to a test meal (e.g., lactose). Breath can also be used to detect small intestinal bacterial overgrowth (SIBO) and lactose intolerance.  

Intestinal Permeability Testing: This is not readily available, but it’s designed to evaluate the permeability of the gut by ingesting a special sugar molecule and then measuring it in the blood.

Treatment for Poor Digestive Function

Treatment is going to depend on the identified cause of digestive symptoms. Bacteria, such as H. pylori, will need to be treated with antibiotics. An inappropriate immune response will need to be controlled with targeted medications, and bile-acid malabsorption will need to be sequestered by resin binders. But rather than pharmaceutical agents, for many conditions, the most immediate intervention is dietary and behavioral modification.

One important concept to learn is that you can maximize your gut's digestive capacity by adjusting the ingested load. By not overloading your digestive system by overeating foods that are difficult to digest, you can overcome common symptoms. Our capacity to digest certain food decreases with age, so it is important to adjust our eating habits as we get older so as not to overwhelm the system.   

Other commonly prescribed medications include antisecretory and prokinetic agents, although they are not recommended for chronic use. Surgical intervention is indicated for more serious complications along the digestive tract. Everyone should have regular colon screening starting at age 50 or maybe even sooner.


Natural Treatment for Your Digestive System

Unfortunately, our healthcare system is very reactionary, and medical treatments are primarily developed to react to specific problems rather than solve them. At 1MD Nutrition, we believe that natural and clinically effective ingredients can assist natural healing and prevent problems before they start. 

As a gastroenterologist who is also a nutrition specialist, my mission with 1MD Nutrition’s digestive supplement suite is to create the most effective supplements available on the market. Each of our key ingredients was hand-picked by me for its proven scientific significance in a data-driven analysis for optimizing digestive function. The combination of these potent ingredients is an effective way to provide natural and safe everyday care for your digestive system. 

Digestive enzymes: Digestive enzymes are the simplest and most direct way to increase digestive capacity. They help breakdown food more efficiently on contact and therefore reduce the amount of work needed to be done by the gut. EnzymeMD® contains eight potent, plant-based digestive enzymes and an essential probiotic that works together with the enzymes to stimulate proper digestion and support overall digestive health

Probiotics: Complete Probiotics Platinum® is a proprietary blend of robust and potent probiotic strains, including L. rhamnosus GG, specifically developed to upregulate digestive capacity. This blend works through an indirect approach, triggering host responses that help improve digestion and create an environment more conducive to a healthy microbial balance. In turn, this also promotes immune health.

Prebiotics: Prebiotics are a kind of digestive fiber that feeds good bacteria in your gut. Fostering a healthy microbial balance by supplying your microbiota with plenty of prebiotic fuel allows you, the host, to enjoy the benefits of better digestion. PrebioMD® is the most advanced restorative prebiotics supplement available today, and it’s doctor-formulated to help balance your microbiome and encourage proper digestive function. PrebioMD® is also unique in that it incorporates targeted bacteriophages that can help foster eubiosis. As a result of the increased resistance to antibiotics we have, research has taken a closer look at bacteriophages as a way to treat bacterial infections. It is possible to treat dysbiosis more accurately with a bacteriophage, which is a highlighted benefit of this patented 1MD Nutrition formula. 

L-glutamine: L-glutamine is an amino acid that serves as the main energy source for enterocytes, which are the cells that line the intestines. GutMD® is a revolutionary formula combining four powerful, clinically studied ingredients, including L-glutamine, to support gut lining integrity, strengthen overall digestive health, and promote critical immune system support.

HMO: HMO (human milk oligosaccharides) are found in both GutMD® and BiomeMD®. These amazing, natural molecules, which are found exclusively in human milk, have multiple functions similar to both probiotics and prebiotics, plus they act as direct immune modulators. The HMO in our supplements is identical to the ones produced naturally and can upregulate digestive function and improve the immune response

1MD Nutrition's digestive suite is a natural and effective solution for all individuals who experience everyday digestive stress and want to restore a healthy balance to their gut. At 1MD Nutrition, we strongly believe in making healthy lifestyle choices, including eating a balanced diet and exercising regularly. Supplements such as EnzymeMD®, BiomeMD®, PrebioMD®, GutMD®, and Complete Probiotics™ Platinum can add a natural way to help promote digestive health without making too many dietary changes. This can hopefully offer a viable alternative to chronic intake of pharmaceutical medications. 

Healthy digestive system

Final Thoughts

Your digestive health can benefit in a number of ways by supplementing your diet with 1MD Nutrition’s digestive suite products. Whether you choose to start with EnzymeMD® for a more direct approach to increasing digestive capacity or choose one of our probiotics supplements for a more long-term effect, the products will improve your digestive function, which translates into better overall health.  

PrebioMD®  can be used in conjunction with both digestive enzymes and probiotics to maximize the effect by helping nourish the good bacteria that live inside of you, while GutMD® with L-glutamine, helps fuel your enterocytes for optimal functionality and enhanced gut lining integrity.

Digestive health is of great importance for your overall well-being, and millions of people experience digestive symptoms daily. Testing digestive function is an important step in identifying potential problems or damage early on. But in addition to this, supporting digestive function with natural supplements may provide a great solution to many digestive problems.

Dr. David Kahana


Dr. David Kahana is board certified in Pediatrics and Gastroenterology through the American Board of Pediatrics (ABP), as well as Medical Nutrition through the National Board of Physician Nutrition Specialists.