
About our Digestive System
Your digestive system is made up of the digestive tract – a long unbroken “tube” that extends from your mouth to your anus (gum to bum as we call it!) – and other abdominal organs that play a role in digestion such as the liver and pancreas.

The digestive system is complex and full of surprises.
Fun Facts about the Digestive System
- Food travels about 30 feet through your body.
- Because food is propelled through your digestive tract by muscles, rather than gravity, you can digest food upside down.
- The stomach’s volume can increase from about 1/5 cup (when empty) to more than 8 cups after a large meal.
- The small intestine has the approximate surface area of a tennis court.
- Your digestive tract is comprised of 100 million mesh-like body neurons, which is the network of nerve cells referred to as the enteric nervous system. It is so extensive that some scientists are calling the enteric nervous system our “second brain.”
- The gut microbiota communicates by producing and storing over 30 neurotransmitters (chemical messengers in the body). In fact, your gut microbiota produces over 95% of serotonin (known as “the happy chemical”), directly affecting your mood, and wellbeing. (1),(2)
The 5 Stages of Digestion
The 5 stages of the digestive system are:
- Ingestion (Taking food into body)
- Digestion (Breaking food down)
- Absorption (Moving food into cells)
- Assimilation (Making food part of cell)
- Elimination (Removing unused food)
When working well, the digestive system breaks down the food we eat into nutrients the body can absorb. In humans, proteins are broken down into amino acids, starches into simple sugars, and fats into fatty acids and other small molecules. The bloodstream distributes these nutrients to the rest of the body, and waste products are passed out as feces. Depending on what you’ve eaten, it can take anywhere from several hours to several days to fully digest food.
How Things Go Wrong
Every section of the digestive tract is prone to specific disorders – some of them a mere nuisance, others highly disruptive, and still others potentially fatal. In some cases, getting tested and diagnosed early can reduce or eliminate the need for treatment. Even if long-term treatment is required, today’s treatment options and management strategies make it possible to control the symptoms of most digestive disorders – and in some cases, to prevent their progression.
The diagram below illustrates some of the factors that may contribute to digestive problems or aggravate digestive conditions that already exist.

Smoking can harm all parts of the digestive system, contributing to such common disorders as heartburn and ulcers. Smoking also increases the risk of Crohn’s disease and (especially in women) appears to raise the risk of gallstones.(4) Consuming alcohol, meanwhile, worsens heartburn and diarrhea. (5)
It was once thought that stress could actually cause certain digestive disorders, such as peptic ulcers. We now know that stress doesn’t cause ulcers to develop, though it can certainly worsen an existing ulcer. Increased stress can also trigger a flare in Crohn’s disease, ulcerative colitis, and irritable bowel syndrome (IBS). (5)
Certain medications may cause either transient or persistent digestive symptoms. In some cases, the symptoms can be counteracted with other drugs. Missing doses can also increase symptoms or complications of digestive disorders, so it’s important to take your drugs as prescribed. (5)
Most people in good digestive health have a healthy weight and don’t regularly experience symptoms like heartburn, gas, constipation, diarrhea, nausea or stomach pain. If you’re experiencing such problems on a regular basis, learn more about what may lie behind your symptoms. If you have blood in your stool, unexplained loss of weight or appetite, or a sudden change in your bowel habits, see your doctor as soon as possible.
Why Gut Health Matters
- Canada has one of the highest rates of IBS in the world, at about 18% compared to 11% globally
- 40% of those suffering from IBS also experience high rates of anxiety and depression
- 80% of your immune system is within the gut lining, imbalances in gut microbiome can lead to autoimmune diseases, including Crohn’s disease
- Too much “bad bacteria” can lead to inflammation and ultimately disease such as gastritis and colorectal cancer
How Healthy is your Digestion?
- Do you have proper hunger and satiety cues, including morning hunger?
- Can you eat most foods without discomfort or pain or digestive upset?
- Don’t often burp, unless after large meals or carbonated beverages?
- Eat a variety of plant-based foods and fermented foods?
- Have 1-2 bowel movements per day without straining and poop looks like a long snake?
- Can eating tolerate most foods (excluding allergies)?
On the other hand, some indicators of not-so-healthy digestion:
- Do you wake up feeling bloated or can’t eat in the morning?
- Often feel bloated or discomfort after eating?
- Have a bowel movement less than once per day and/or have to strain to have a bowel movement?
- Have urgent poops more than 3 times per day?
- Have gas after meals or randomly throughout the day?
- Having many food intolerances?
Watch the video from NutriProCan Dietitian Lisa Spriet below to learn all about gut healthy foods, supplements (probiotics, prebiotics, etc), and other lifestyle factors that improve gut health.
If you have a digestive condition, you are not alone
Digestive disorders touch the lives of millions of Canadians every year. Because few people speak openly about their digestive symptoms, the magnitude of the problem is not fully appreciated. The devastating impact of diseases such as cancer and heart disease is well known to many Canadians.
What fewer people may realize is that digestive diseases have at least as great an impact on our society and its individuals. Some digestive disorders, such as colon cancer and inflammatory bowel disease (IBD), can shorten life. On the whole, however, digestive disorders tend to have a greater impact on the quality of life than on its duration. Most digestive diseases strike people during their most productive and energetic years, severely disrupting employment, leisure activities, finances, personal relationships, and family life.
Digestive Condition Alarm Symptoms
Digestive symptoms may stem from a temporary illness such as a flu, a reaction to certain medications, or a more chronic underlying condition.
The following symptoms signal a problem that requires prompt medical attention:
- Diarrhea that lasts more than five days
- Unintended weight loss
- Persistent vomiting
- Black, tarry stools
- Bright red blood in your stool or bloody diarrhea
- Unexplained fatigue
- Pain in the stomach area that improves or worsens when you eat
- Persistent fever
- Pain when having a bowel movement
- Localized abdominal pain
- Abdominal pain that is persistent and severe or that wakes you from sleep
- Difficulty swallowing, chest pain, feeling there is an obstruction in your throat
- Persistent heartburn that is not relieved with over-the-counter antacids
If you have these alarm symptoms, your family doctor may refer you to a gastroenterologist – a doctor who specializes in the diagnosis and treatment of diseases affecting the digestive system.
References:
- MediLexicon International. (n.d.). Gut microbes important for serotonin production. Medical News Today. Retrieved January 13, 2022, from https://www.medicalnewstoday.com/articles/292693
- Carpenter, D. S. (2012, September). That gut feeling. Monitor on Psychology. Retrieved January 13, 2022, from https://www.apa.org/monitor/2012/09/gut-feeling
- Health Canada; Fibre (2019, January 22). Government of Canada. Retrieved from https://www.canada.ca/en/health-canada/services/nutrients/fibre.html
- Smoking and your digestive system. National Digestive Diseases Information Clearinghouse.
- Cross R. Avoiding digestive health problems. University of Maryland Medical Center. www.umm.edu/ibd/digestive_health_problems.htm
- Fermented Foods. (n.d.). Retrieved from https://isappscience.org/for-scientists/resources/fermented-foods/