This collection of blog posts will address the basics of the digestive process as well as go into the pathophysiology of the digestive process. It will also address dietary, lifestyle, and supplement recommendations to support the body in different pathophysiology. Part 1 goes through the basics of the digestive process and a few external factors that may hinder peak digestion.

Do you often have gas and bloating, indigestion, GERD, or burping after eating? In our current culture, these symptoms are often overlooked or even taken as “normal” because they are so common. If your body is digesting food properly, these symptoms would not occur. Digestion is one of the most important processes in the body. Without good digestion, it doesn’t matter how good the food you are eating is because your body will not be able to digest it and you won’t reap the benefits of the food you are eating.

Thus, maximizing digestion is one of the keys to having good health. There are many factors that play into having good digestion. Talking about all of these factors in depth could fill up many books, so in the upcoming posts we are just going to dive into the basics of the digestion process, some of the most common reasons why you don’t have peak digestion, and how those can be addressed through diet, lifestyle, and supplementation. In this post, we will focus on the physiology of the digestive process and external factors that can hinder this process, then in the upcoming posts we will focus on pathophysiology in the digestive system.

First, let’s look into the the basics of the digestive process beginning in the mouth and ending in the intestines. Digestion is made up of both mechanical and chemical processes. The mechanical process of digestion consists of grinding and crushing the food as well as the mixing of food with digestive enzymes as it is pushed down the digestive tract. The chemical process of digestion consists of the breakdown of food using enzymes and stomach acid. The digestive process begins in the mouth with the chewing of food. Saliva contains the enzyme salivary amylase, which starts the digestion of starch in the mouth. 

This is often an overlooked part of the digestive process, especially by people who tend to eat fast, eat while doing other things, or who talk a lot while eating. Not only does chewing help physically break down the food, it also signals the rest of the digestive system to get ready to do its job, and the saliva contains salivary amylase, an enzyme that helps to break down starch molecules into smaller sugars. 

After being chewed, the food is now transported through the esophagus and into the stomach. The mechanical digestion of food in the stomach consists of the stomach churning and gyrating to mix the food with digestive secretions, including hydrochloric acid and pepsin. The main chemical digestion occurs by means of the protein digestion team of pepsin and hydrochloric acid. Pepsinogen, the inactive form of pepsin, needs the lower pH environment created by hydrochloric acid to transform into pepsin, the active form of the enzyme that is responsible for the first part of protein digestion. Without proper levels of hydrochloric acid, pepsin would not be activated and the digestion of proteins and mineral absorption would be hindered, leading to digestive issues with proteins and potential mineral deficiencies. Pepsin needs a pH of 1.6-2.5 for optimal activity.

Protein digestion starts in the stomach and consists of the highly acidic environment created by hydrochloric acid disrupts the structure of proteins by exposing their peptide bonds. Then, Pepsin cleaves the peptide bonds and breaks the polypeptide protein chains into smaller peptides and amino acids. The process is then continued by the other enzymes in the small intestine. Food remains in the stomach for anywhere between 45 minutes and 4 hours. Once the food leaves the stomach, it is now referred to as chyme. 

Next we head to the small intestine where it takes chyme around 2-4 hours to make its way down the 21 foot long small intestine. The small intestine helps with digestion, absorption and the transport of ingested nutrients. It is divided into three segments: the duodenum, jejunem, and ileum. Absorption of minerals mainly happens in the duodenum, absorption of water-soluble vitamins, proteins, and carbohydrates mainly happens in the jejunem, and absorption of fat-soluble vitamins, fat, and cholesterol mainly happens in the ileum. Other organs that secrete digestive juices into the small intestine include the pancreas, liver, and gallbladder. The pancreas secretes pancreatin, which includes enzymes needed for different aspects of digestion into the small intestine.

Amylase is an enzyme that breaks down carbohydrates into sugars, lipase breaks down fats into fatty acids and glycerol, and proteases, including trypsin, chymotrypsin, and carboxypeptidase, break down proteins into smaller peptides and amino acids. Proteases also are responsible for keeping the small intestine free from unwanted bacteria, yeast, and parasites. 

The liver produces bile and either directly secretes it into the small intestine or sends it to the gallbladder for storage. Bile helps with the absorption of fatty acids and fat-soluble vitamins. It also helps keep the small intestine safe from unwanted microorganisms. 

Lastly, we head into the large intestine otherwise known as the colon, which is 5 feet in length and absorbs water, electrolytes, and, in limited amounts, some of the final products of digestion. The health of our colon is largely determined our food intake and lifestyle, this is one of the reasons why dietary fiber is so important because it feeds the colon cells.

Fiber also helps keep up frequency of bowel movements, which is essential to good health because otherwise waste products remain in our system for a longer time, the quantity of bowel movements, decreases stool transit time, and may be a preventative factor in protecting the colon from diseases such as constipation, colon cancer, diverticulitis, hemorrhoids, and irritable bowel syndrome. 

So, now that we know a little more about the basics of the digestion process, let’s talk about what can go wrong in digestion and how to address this with diet, lifestyle, and supplementation. One of the top things that can hinder digestion is stress. There are two parts of the nervous system: parasympathetic and sympathetic. The parasympathetic nervous system governs digestion, repair, restoration, and rejuvenation while the sympathetic controls the fight or flight response of the body. The sympathetic nervous system activates the fight or flight response, which shunts blood flow and energy to the skeletal muscles and brain so that the body’s energy is not focused on digestion. 

Additionally, chronic stress has a direct impact on the parts of the digestive process. It can weaken the intestinal barrier leading to increased gut permeability, which allows bacteria and toxins to enter the bloodstream, otherwise known as “leaky gut”. It can alter gut motility, which can speed up or slow down digestive processes. Stress triggers the release of pro-inflammatory cytokines, which can further exacerbate inflammatory conditions of the gut including IBS and Crohn’s Disease. It also decreases hydrochloric acid and enzyme production, which can lead to gas, bloating, and malabsorption. 

Addressing stress with diet, lifestyle, and supplementation is a large topic that will be addressed in future blog posts, however there are a few things we can discuss here that can help with stress management. Dietary management for stress focuses on following an overall healthy and whole foods diet with limited to no processed foods and added sugars. Some things to focus on are eating a diet of assorted colors of fruits and vegetables, eating mindfully of blood sugar control by focusing on high fiber foods and foods low on the glycemic index, eating more omega-3 fatty acids, monosaturated fats, and healthy sources of saturated fats rather than trans fats and too many omega-6 fatty acids.

If you do not get enough omega-3 fatty acids in the diet or simply want an easy way to know you are getting enough in, you can also supplement with omega-3 fatty acids. Some of our top picks are Omega 900 TG Active Factors, Pro Omega Nordic Naturals, and Vegan Omega DHA-EPA as a vegan option. Eating foods to nourish the gut will also help with stress because the gut and the brain are connected, so a healthy gut microbiome supports the brain and can help decrease stress levels. Again, the gut-brain axis is another large topic that will be focused on in a later blog post.

Lifestyle management of stress includes getting enough exercise, practicing breathing with the diaphragm, practicing good time management, and using aromatherapy. Some of the top essential oils to diffuse or apply topically for stress management are Lavender, Bergamot, and Clary Sage. There is also a blend available that has all these oils and a few more that are great for stress management called Stress Recovery.

Some supplements that can be helpful for stress include, L-Theanine, Vitamin C, B Vitamins, Magnesium, and GABA. L-Theanine is an amino acid derived from green tea that helps stimulate alpha brain waves which are the brain waves during a relaxed state. Some of our recommended brands with an L-Theanine supplement include Pure Encapsulations, Thorne, and Integrative Therapeutics.

Vitamin C is needed to support the adrenals which is the main organ that needs to be supported in stress because it is in charge of secreting cortisol, the body’s “stress hormone” during times of stress. It is also excreted more during times of stress, so it is important to replenish the body with Vitamin C during stress. Some of our recommended Vitamin C supplements include our Bio C Complete, featuring bioflavonoids, Vitamin C with Flavonoids Thorne, Buffered Vitamin C Powder Thorne, and Amla-C if you are looking for a food based Vitamin C.

B Vitamins are needed to produce neurotransmitters that help with stress management and Pantothenic acid is needed to support the adrenals as well. Some options for B Vitamin supplements include Basic B Complex Thorne, B Activ Xymogen, and Liposomal Methyl B complex Quicksilver.

Magnesium helps increase GABA, the neurotransmitter that helps manage stress and anxiety, so it is important to supplement with Magnesium during stress and possibly additional GABA if needed. A good form of magnesium for stress is Magnesium Glycinate because the magnesium is attached to the amino acid glycine, which has a relaxing effect on the brain because it acts as an inhibitory neurotransmitter; this form is also one of the better absorbed forms of magnesium. The brands we recommend are our Magnesium Glycinate, Magnesium Glycinate by Pure, and if you want to try a powder, Thorne has a Magnesium Bisglycinate powder.

GABA supplements we recommend include GABA Douglas, Pure GABA Montiff, or Zen 200mg Allergy Research Group, which is a blend of L-Theanine and GABA. 

Another thing that can hinder digestion is poor eating habits including not chewing properly, random meal times, drinking too much water while eating, and poor food combining. As discussed above, chewing is essential for proper digestion because the process begins in the mouth with the mechanical chewing, chemical mixing of food with salivary amylase in saliva, and preparing the digestive tract to work. If you don’t chew properly, you force your body to use more stomach acid during digestion, which increases digestive time and could lead to sluggish digestion and a feeling of heaviness after eating. Each bite should be chewed at least 20 times to ensure that the food is fully liquified to make it easier on your digestive tract.

Having meals at set times helps your body be more prepared to digest foods because it learns when to anticipate food coming in and thus when digestive enzymes need to be present to digest that food. Drinking too much water when eating dilutes hydrochloric acid and thus impedes digestion. You should not drink more than a half a cup of water during mealtimes and should limit water intake 30 minutes before and after meals to promote peak stomach acid productivity. Proper hydration during the day is necessary for proper digestion because the body needs water to produce digestive juices and to break down food, so proper hydration not during mealtimes is best for good digestion.

Another thing that can hinder digestion is improper food combining. Food combining is important to make sure your digestive system can handle the load you are asking it to digest all at once and to make sure that there is no fermenting food due to differences in digestion time between different types of foods. Fruit digests fast due to their simple composition of water, sugar, and fiber, so combining it with other foods can cause the fruit to remain fermenting in the stomach while it is waiting for the other food to be digested, which can result in gas and bloating. Thus one rule of food combining is that fruit should be eaten on an empty stomach 20-30 minutes before meals and can be combined with other fruits apart from melon which needs to be eaten alone. Another rule is not to mix concentrated starches, such as grains and potatoes, with proteins. Protein needs an acidic environment for digestion while starches require an alkaline environment in the small intestine to be digested. The starches inhibit the secretion of hydrochloric acid in the stomach which interferes with the breakdown of proteins in the stomach, leading to partially digested protein which can become a toxic byproduct of digestion. This combination makes the GI tract take much longer and work much harder to digest food which could lead to tiredness and the desire to nap after a meal because all of your energy is taken up by digestion.

A third rule is to make sure to limit the amount of fats with proteins because fats inhibit the secretion of gastric juices needed for protein digestion. However, fats go very well with vegetables because it helps with the absorption of fat-soluble vitamins in the vegetables.

A fourth rule is not to mix two types of animal protein because it makes it harder for the stomach to digest all the protein; plant sources of protein are easier to digest so it is better to combine an animal and plant source of protein if the combination of proteins is needed. Finally, non-starchy vegetables are easy for the body to digest and can be eaten with anything. See the image below for a summary of the food combining rules. 

In the next post, we will dive into pathophysiology of the stomach concerning digestion. Until then, try and examine your eating habits regarding water around meals, chewing, food combining, and stress to see if you can make simple changes to maximize digestion. If you want a sneak peak of what we will talk about in future digestion blog posts, check out the category: Digestion & Gut to see what supplements are commonly used to support digestion. 

References

Haas, E.M. (2006). Staying Healthy with Nutrition: The Complete Guide to Diet and Nutritional Medicine: 21st Edition. Ten Speed Press. 

Holland, M. (2025, April 4). The Dynamic Duo of Protein Digestion: Pepsin and Acid Partners. MedShun. https://medshun.com/article/where-pepsin-and-acid-work-to-digest-protein 

Immel, J. (2025). Incomplete Chewing. JoyfulBelly College of Ayurvedic Diet & Digestion. https://www.joyfulbelly.com/Ayurveda/symptom/Incomplete-Chewing/1712

Immel, J. (2025). Irregular Schedule/Eating Times. JoyfulBelly College of Ayurvedic Diet & Digestion. https://www.joyfulbelly.com/Ayurveda/symptom/Irregular-schedule-eating-times/583 

Murray, M.T. & Pizzorno, J. (2012). The Encyclopedia of Natural Medicine: Third Edition. Atria. 

Nutraphoria School of Holistic Nutrition. Lesson 7: Food & Health. Rules for Food Combining. https://onlinelearning.nutraphoria.com/mod/lesson/view.php?id=651&pageid=353 

Santiago, E. (2025). The Gut-Stress Connection: How your Gut Health and Stress are Interdependent. Perque. https://www.perque.com/the-gut-stress-connection-how-your-gut-health-and-stress-are-interdependent/