Chronic constipation is a condition where people have infrequent, difficult elimination of the bowels. Many times it’s due to problems with motility in the colon, but the small intestine can also be a problem.
Often, people rely on motility aids to goose things along. Of course, this improves symptoms and allows the person to “go”. But this doesn’t solve the problem, it manages the symptom.
Generally, a high fiber diet effectively treats constipation. In the colon, fiber adds bulk, and bacteria within our microbiome convert fiber in to metabolites that promote motility there.
But in the small intestine, fiber may slow down motility. If that happens with you, your problem may involve how well you digest your food. This is due to something called the ileal brake.
Anatomy of the small intestine
Our digestive tract ensures we properly digest and absorb our food. Bile and other enzymes break down the large protein, fats and carbohydrates in our food in to absorbable nutrients that enter the bloodstream and lymph.
Without these systems in place, it would be deadly. We depend on nutrients from our food for survival. Luckily there are back up systems in place to make sure that we thoroughly digest and absorb our food. The ileal brake is one of these systems.
There are 3 sections of our small intestine with different functions. The duodenum is the section of our small intestine immediately adjacent to our stomach. Semi-broken down enters the duodenum from the stomach for further processing by enzymes, bile, and mechanical mixing.
Next is the jejunum, where time allows enzymes and bile to continue to work on what we’ve eaten. Most absorption occurs in the duodenum and jejunum.
The ileum is the final part of the small intestine, adjacent to the colon. This is the final area of the small intestine, and since the small intestine is where digestion and absorption occur, the last place we access most of the nutrients we consume.
The ileal brake and chronic constipation
The ileocecal valve separates the ileum from the cecum, the first part of the colon. Since the colon is poorly designed for nutrient absorption, undigested and unabsorbed food in the ileum requires more time.
When fats, proteins, and carbohydrates enter the ileum, they trigger something called the ileal brake. The ileal brake slows down motility in the stomach, duodenum, and jejunum to allow food more time for digestion.
Fat is the greatest trigger of the ileal brake, but proteins and carbs also have an effect. Furthermore, there is also a jejunal brake that does the same thing: it slows down motility in the stomach and duodenum when too much undigested food enters the jejunum.
When we consume fiber, this dilutes the food in our small intestine and moves it forward. This makes fiber a problem for people with poor digestion because it essentially stretches food further along the small intestine.
As a result, undigested fats, proteins, and carbs trigger the ileal brake and decrease motility in the small intestine.
Chronic constipation isn’t the only problem
Constipation is only one that pops up due to too much baking. If food sits in the small intestine for too long without moving, bacteria have greater access to nutrients. Essentially, stagnation due to ileal braking promotes small intestinal bacterial overgrowth, or SIBO.
Another problem with chronic “braking” is that both the ileal and jejunal brakes halt motility AND gastric acid secretion in the stomach. This allows food to sit in the the stomach longer causing delayed gastric emptying, which may contribute to gastroparesis.
Other problems due to chronic ileal braking may include dyspepsia, H. pylori overgrowth, and diarrhea from increased bacterial metabolites drawing water in to the gut.
Potential solutions to chronic constipation due to ileal braking
Obviously, the solution to chronic activation of the ileal brake is to improve digestion. Factors that contribute to poor digestion include:
- Poor bile output(Essential to fat digestion and absorption)
- Pancreatic insufficiency(PI)
- Obesity/T2D(due to PI & GP)
- Poor sleep
- Being sedentary
- Overeating(By exceeding digestive capabilities)
- Circadian disruption(All mechanisms, especially poor bile output)
- Excessive fat intake
- Eating too quickly/Not chewing adequately
- Poor meal spacing
Steps to correcting excessive ileal braking include addressing the behavioral factors mentioned above, Prioritize sleep, be more active, pace out your meals, etc.
Correcting Type 2 diabetes is also essential. Chronic hyperglycemia damages the enteric nerves and the vagus nerve. Damaging these nerves prevents receptors in the gut from sensing nutrients and muscles in the gut from contracting.
For acute help, pancreatic enzymes provide some benefit. I’m not a fan of using these things long term simply because they shouldn’t be in the stomach. People with gastritis and/or gastroparesis are more likely to have problems using pancreatic enzymes due to prolonged exposure to the stomach.
Poor digestion and absorption of nutrients deprives us of the things we need to survive. The anatomy and physiology of our gut make sure that we effectively breakdown our food and absorb those nutrients.
When this system breaks down, back up systems give our gut more time. Unfortunately, chronically relying on these system causes problems. Relying on the ileal and jejunal brakes promote conditions such as SIBO, IBS, gastroparesis, and gastritis.
The first step in addressing these issues is to correct behavioral issues that promote them. This includes being more active, prioritizing sleep, eating more slowly, and properly spacing your meals. Start here and you may be well on your way to correcting chronic constipation and other gut issues.