GUT SCIENCE

Persist Nutrition

Learning more about the biology of gut health and digestion can give you more motivation to take care of your digestive health, and why your body reacts poorly to digestive stressors. First, let’s start with some key terms:

  • Ingestion – process of taking in food and drink
  • Propulsion – process of moving food and drink through the digestive tract through a process called peristalsis
  • Secretion – the release of substances from cells or glands that will aid in digestion
  • Mechanical digestion – physically breaking down food into smaller pieces (mouth and stomach)
  • Chemical digestion – the chemical breakdown of foods into simpler nutrients to be used by cells 
  • Absorption – the process of watery absorption of nutrients into the bloodstream
  • Defecation – POOP… the discharge of food waste products from the body 
  • Gastrointestinal Tract – series of hollow organs joined in a long, twisting tube from the mouth to the anus. The hollow organs that make up the GI tract are the mouth, esophagus, stomach, small intestine, large intestine, and anus
  • Pancreas, Gallbladder, and Liver – supporting solid organs that secrete crucial chemicals for the digestive process
  • Mesentery – connective tissue that holds the long twisting gastrointestinal tract in place in the abdomen

What is Your Digestive System?

Here’s a further breakdown of the Gastrointestinal (GI) Tract:

 

Mouth – This is where mastication takes place to mechanically digest food. There is also a release of saliva to moisten the food and start chemical breakdown of starches. 

 

Bolus (broken down starches) – Chewed food mixed with saliva that is sent down the esophagus.

 

Esophagus – When food enters the esophagus, stretching of the walls will trigger nerves here that will initiate peristalsis in the gastrointestinal tract.

 

Stomach – the muscular stomach walls begin to pound your food into chunks.  Hormones will trigger release of hydrochloric acid and proteases that will begin to break down protein. Furthermore, hormonal release will also trigger the gallbladder to deliver bile into the next portion of the GI Tract.

 

Chyme – after a period of about 30mins of mixing and acidification, the resulting material is called chyme and will enter into the small intestine.

 

Small Intestine – this is the section of the gastroinstestinal tract where the vast majority of chemical digestion occurs. This is where smaller pulverized chyme from the stomach gets broken down into absorbable nutrients.

 

Duodenum – the liver, via the gallbladder, sends bile here to break down fats. This will help break them down into small sizes that are easier to digest.

 

Jejunum + Ileum – the second and third portion of the small intestine where food absorption into the bloodstream occurs. 

 

Large Intestine (aka Colon) – dead cells, fiber, and other non digestible food and food waste from the small intestine arrive here. Water is reabsorbed into the body in the colon. This is where our feces begins to form.

 

Rectum – feces is packed into the rectum from the large intestine, where stretch receptors will send signals to our brain when it is time to evacuate the bowels and defecate.

 

Anus – the hole that we defecate through and where the process of digestion comes to an end. This process can take anywhere from 30-40 hours in total and is a major investment of energy on the body.

See How It Works

What Is Your Microbiome?

Inside our digestive tract lives a complex colony of bacteria. This population of bacteria has implications on our health, digestion, and physical/mental well being. Collectively, this is known that the gut Microbiome. The Microbiome is impacted from the moment we come into the world as a baby. We have a sterile digestive tract when we are born, and it starts to colonize right away at birth. Our diet, stress, activity, sleep, and exposure to toxins and drugs throughout our life will impact the population of bacteria in our bodies. 

 

When the body doesn’t have the right balance of bacteria, other microorganisms can grow out of control. We can have fungal overgrowth as well as other pathogenic infections. A healthy vs. unhealthy microbiome can also begin to dictate how we interact with our food and our digestive health. 

 

Research is starting to suggest that gut health plays a role in mental health (depression and anxiety), inflammation, obesity, metabolic syndrome, diabetes, liver health, and many bowel disorders, including IBS.

 

How we eat and what we eat can heavily influence the Microbiome and the population density and balance of bacteria. The variety we include in our diet is a key contributor to population diversity which is a one way of measuring the health of the microbiome.

Recommended Reading

What Your Poop Can Tell You About Your Digestive Health

Our excrement is one of the best tools we have access to every single day to determine the operational health of our digestive system. We can learn so much about our overall health just from the look, feel, frequency, and smell of our poop. If no one has ever asked about your poop or you’ve never discussed it, how might you know that daily gas, bloating, constipation, or diarrhea are signs that your gut might need a little help?

So what is normal poop like? You should, at minimum, aim for one full evacuation of the bowels daily. This should feel like you got everything out without strain. The Squatty Potty is a great tool to get your body in a good position for defecation, or you can prop your feet on a similar sized object.

Normal frequency of bowel movements is from 1-3 times per day. Fewer or more bowel movements would be considered constipation or diarrhea, and warrants further investigation as to why this is happening. Your poop should be solid and smooth on the surface, gently sink to the bottom of the toilet, and have an earthy smell to it. If your poop is broken, loose, rock hard, lumpy, or small pellets, then you are experiencing a problem with your digestion. Refer to the Bristol Stool Chart for a guide on how to evaluate poop.

 

Generally speaking, it takes about 6-8 hours for food to be completely digested by the stomach and small intestine. From there, it moves into the large intestine, where it will spend up to 30 more hours getting worked on by the microbiome to break down undigested food particles (fiber) and have water reabsorbed into the body. In total, there can be a 36-50 hour investment that goes into food from the time it goes in your mouth and comes out of your bottom.

 

A big reason why the body holds onto food in the large intestine for those extra 30-40 hours is that it is very important to get back all the water that is injected into the digestive process by the mucosal tissue of the digestive tract. This is evidence that our body prioritizes hydration a great deal. It is, therefore, a good time to remind you that hydration and digestive health go hand in hand. We not only need adequate hydration to allow the cells of the digestive tract to do their job, but to also ensure efficient transit time of food through the large intestine. Be sure you are getting 60% of your body weight in pounds as fluid ounces of water each day.

 

With such a long time investment you must consider that food you eat can have an impact on your stool at just about any point from the time you eat it to the time to expel it. Even just 30-60mins into the digestive process, you may find yourself experiencing bowel distress that results in a suboptimal elimination. Our digestive systems are a complex nervous system and smooth muscle tissue, and triggers further up the chain can influence what is happening further down the chain.

 

Tracking your poop daily over time, along with adequate hydration and simplifying food choices, will help you see patterns over time and draw conclusions about what works best for your own body. This is also information that can be helpful to bring to your health care practitioner if continued symptoms warrant further care. You can track your worst bowel movement per day, or track each one (time and Bristol stool indicator) by adding extra detail to your day tracker. The more you track, the more you’ll learn and be able to help your body optimize your gut health.