About 40% of Americans who report constipation use laxatives regularly. The relationship between laxatives and constipation is only a short-term solution and doesn’t get to the root cause of constipation. If you experience frequent constipation, the underlying cause is often small intestinal bacterial overgrowth (SIBO). Anytime I had a patient experiencing regular constipation, I immediately tested them for SIBO. 

In functional medicine, we view the body as a whole instead of a specific disease or a symptom of a particular organ. Conventional medicine will tell you it’s OK to take over-the-counter laxatives and stool softeners to find quick relief from constipation. However, these can have long-term effects ranging from electrolyte imbalances, dehydration, reliance, and even more constipation. 

As a functional medicine physician, I advocate for getting to the root cause of constipation and supporting healthy bowel patterns with natural laxative supplements. I will tell you about my No. 1 tool to support healthy bowel patterns, how SIBO contributes to constipation, and the seven common causes. First, let’s talk more about the issue with over-the-counter laxatives. 

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The Problem with Most Laxatives

As I mentioned, nearly half the people that experience constipation turn to over-the-counter laxatives for fast relief. While they can be effective for occasional constipation, there are substantial problems with using them.  

One of the biggest issues with laxatives is that you can become reliant on them to have a bowel movement. This is known as laxative dependency. Long-term use of laxatives can lead to other potential problems. Here are the risks of laxative dependency:1

  • Constipation– The irony is that many people use laxatives to relieve constipation. They work by stimulating the nerves in the large intestine to move stool through the colon. Long-term use can damage these nerves and lead to chronic constipation. 
  • Dehydration– Laxatives remove water from the body, which can cause diarrhea. Diarrhea increases the amount of water your body is losing. This vicious cycle often leads to dehydration, which can affect your kidney function and make you feel fatigued. 
  • Electrolyte imbalances– Moderate to severe diarrhea cause the loss of electrolytes such as sodium, potassium, and magnesium. Your body needs electrolytes to regulate your heartbeat and muscle contraction. In extreme cases, imbalanced electrolytes can lead to serious complications such as kidney damage.
  • Irritable Bowel SyndromeIBS gets defined by a group of symptoms, including abdominal pain or discomfort and changes in bowel movement patterns. Long-term laxative use is associated with IBS. Over time, laxatives cause your large intestine to lose normal muscle function and nerve response, meaning the colon cannot eliminate waste effectively, causing it to sit in the intestine for longer than usual. 

The good news is that there is a solution to constipation without using over-the-counter laxatives. Before we get into the best solution for constipation, let’s talk about the causes of constipation. The most common cause of constipation is small intestinal bacterial overgrowth or SIBO. 

How SIBO Contributes To Constipation

SIBO occurs when the bacteria in your colon and large intestine increase and move into the small intestines. Most of your gut bacteria are meant to be in your large intestine and colon. Here they help break down food, synthesize vitamins, and eliminate waste. 

However, medications such as laxatives or a poor diet can cause your gut microbiome to become unbalanced. When this happens, the bacteria typically found in the large intestine and colon overgrow and colonize in your small intestine. Moreover, the overgrown bacteria feeds off undigested carbohydrates, which leads to fermentation and the release of hydrogen, which feeds archaea, producing methane gas. 

Methane-producing SIBO is more common than hydrogen-producing SIBO. Excess methane slows motility or movement of waste in the colon, contributing to constipation.2

If you suspect you have SIBO, there is a breath test you can take to determine if SIBO is causing your constipation.

7 Common Causes Constipation

Optimally, you’ll have at least one bowel movement each day. It’s even better if it’s two or three because your body is moving out of waste consistently and efficiently. Generally, conventional medicine describes constipation as less than three weekly bowel movements. I consider a minimum of once per day to be “regular.”

Constipation is chronic if the condition persists for more than several weeks. “Motility” refers to the digestive system moving what you eat from the beginning (esophagus) to the end of the GI, or gastrointestinal, tract (colon and rectum). Here are seven common reasons this process gets backed up.3

laxatives and constipation – infographic – Amy Myers MD®laxatives and constipation - infographic - Amy Myers MD® https://content.amymyersmd.com/article/laxatives-sibo/laxatives and constipation – infographic – Amy Myers MD®

Dehydration

Like the plumbing in your home, our internal flushing system requires adequate water to to move waste through your pipes (your intestines). You should be drinking half your bodyweight in ounces of water daily. For example, if you weigh 150 pounds, you should be drinking 75 ounces each day. 

Dehydration is one of the most common causes of constipation and is the easiest to avoid. Drinking coffee, soda, and alcohol can also lead to dehydration if you aren’t drinking enough water to counterbalance it. Providing your digestive tract with water is an easy and inexpensive step to support regularity and motility.

Not Eating Enough Dietary Fiber

Your body doesn’t digest dietary fiber. Instead, dietary fiber travels relatively intact through the stomach and intestines, absorbing water to add bulk to stool and helping move waste through your system.4

Eating high-fiber foods such as prunes, beans, and flax seeds can support a healthy bowel pattern. However, many prebiotic foods are difficult to digest and/or high in sugar, which could make SIBO worse. Leafy green vegetables, cauliflower, and zucchini are high-fiber foods that support a healthy digestive pattern, even if you have SIBO. 

Disruption of the Gut Flora

Your digestive system is home to a rainforest of good bacteria that help break down, absorb food, and eliminate waste. Many factors, such as taking antibiotics or oral contraceptives, stress, or inflammation, can disrupt the natural gut flora leading to yeast overgrowth, SIBO, and leaky gut, all of which cause constipation.

Hypothyroidism and Hashimotos’s

Hypothyroidism, an underactive thyroid, slows down many of the body’s systems, including elimination. For your body to eliminate waste, your colon must contract, and slow or weak colon contractions can be a symptom of hypothyroidism. It’s estimated that 27 million Americans have an underactive thyroid, and most don’t know they do. 

Even if your doctor does order a complete thyroid function test panel, they’re usually relying on “normal” thyroid test results reference ranges that are too broad and often inaccurate. When lab reference ranges for a healthy thyroid were created, it was later discovered that people who already had thyroid dysfunction were included in those ranges. Learn more about thyroid testing in this article.

Food Sensitivities

Constipation can be a common symptom of general digestive mayhem related to food sensitivity as the body struggles to digest and eliminate the foods at the root of inflammation. However, many foods can trigger food sensitivity. Gluten and dairy are the most common culprits.

Autoimmune Disease 

Autoimmune diseases are born when your body is working hard to defend itself against something potentially dangerous, such as an allergen, a toxin, an infection, or even a food, and it fails to differentiate between the intruder and parts of your own body. This leads your immune system to attack your own organs. These diseases can cause constipation because they attack the intestinal tissue itself, and the intestines stop moving food properly through the digestive system. 

Bowel Obstruction

A more acute cause of constipation can be an obstruction in the small or large intestine that prevents stool from moving through. Common causes of intestinal obstructions are scar tissue or adhesions caused by abdominal surgery, hernias, or Crohn’s disease (which can narrow or twist the intestine).

There are, of course, many other potential causes for constipation, such as not getting enough exercise, excessive stress, or taking over-the-counter painkillers such as ibuprofen or acetaminophen.

It is best to take a comprehensive view of your health and what factors might contribute to your constipation. Once you understand what is causing your constipation, you can properly find relief for it without laxatives. Before I get into how you can support healthy bowel patterns, let’s discuss over-the-counter laxatives a bit more. 

How Laxatives Impact Constipation

Laxatives come in the form of pills, liquids, foods, suppositories, and enemas. As I mentioned, the most significant risk with taking laxatives is becoming reliant on them to have a bowel movement. There are several types of laxatives, including bulking-agent laxatives, osmotic laxatives, emollient laxatives, and stimulant laxatives.  

Bulking Agents

Bulk-forming laxatives draw water into the stool to increase its mass with water to allow easier movement through the intestinal tract. Fiber supplements are a type of bulking agent to promote healthy bowel patterns. Typical examples are psyllium (Metamucil®) and methylcellulose (Citrucel.®). However, fiber supplements should be avoided if you have SIBO because fiber feeds the bacteria in your gut and could cause the bacteria overgrowth to worsen. 

Emollient Laxatives 

Emollient laxatives allow fats and water to get absorbed by stool, enabling smoother motility through the digestive system. These are commonly known as stool softeners. Stool softeners are frequently used if you’ve had surgery, given birth, or have hemorrhoids. Examples include Colace® and Diocto.

Enemas/Colonic Irrigation

An enema is inserting a small amount of liquid into the anus to loosen stool. Colonic irrigation involves a lot more water. In this process, a technician flushes up to 16 gallons of water through the colon using a tube inserted into the rectum. Both of these methods induce elimination right away.

Osmotic and Hyperosmolar Laxatives

The purpose of osmotic laxatives is to make the colon wetter. The most common names for osmotic and hypertonic laxatives include Fleet Phospho-Soda, lucatose (Kristalose), magnesium hydroxide (Milk of Magnesia or MOM), lactitol (Pizensy), and polyethylene glycol (Miralax). These draw fluids to the intestine to soften the stools and lubricate the intestinal lining. These are the most common types of laxatives prescribed before a colonoscopy.

Stimulant Laxatives 

Stimulant laxatives are often the last resort when nothing else works to relieve your constipation. They work by stimulating the lining of the intestine, which speeds up the stool’s journey through the colon. The relief is nearly instantaneous. Common examples include Ex-Lax®, Correctol®, and Dulcolax®.

Many people believe that the easiest or the only way to relieve their constipation is to resort to laxatives. If you’re looking for a natural way to relieve constipation, I have great news. 

A Natural Solution to Constipation

As I mentioned, SIBO is often the underlying cause. Addressing your SIBO is the best solution to chronic constipation. Whether or not the issue is SIBO, while you are tackling the root cause of your constipation, you can start to support normal bowel function by incorporating a few simple dietary changes. 

These include drinking plenty of water, adding more leafy greens to your diet, and including artichokes in your meals. However, many traditional foods suggested for constipation, such as prunes, beans, or flax seeds, are high in sugar and/or difficult to digest, making SIBO worse. It’s best to avoid those. For those who need additional support, a great natural option for supporting healthy bowel function and avoiding constipation is Magnesium Citrate.  

Magnesium, specifically Magnesium Citrate, is also an excellent tool for promoting healthy bowel patterns. When I had my colonoscopy a few months ago, I had to take high doses of Magnesium Citrate the day before. This form of magnesium promotes healthy bowel patterns by attracting water to the bowels. Magnesium Citrate is one of the most bioavailable forms of magnesium. 

Magnesium Citrate is a form of magnesium that’s mixed with citric acid. Citric acid is in citrus fruits such as oranges, grapefruit, or lemon. If you are sensitive to citrus, you should talk with your functional healthcare provider before using Magnesium Citrate.5 To find out if you have a citrus sensitivity, I recommend an elimination diet

The Final Word on Laxatives and Constipation

Remember, constipation is never normal, and there’s always an underlying cause, whether dehydration, lack of fiber, hypothyroidism, or bowel obstruction. However, if your constipation occurs often, the cause is likely SIBO. 

Getting rid of SIBO is the first step to relieving chronic constipation. Instead of turning to laxatives for constipation relief, I recommend using Magnesium Citrate to support healthy bowel patterns. You don’t need to accept the bloat and discomfort of constipation from SIBO — or any other cause — as a part of daily life. 


Article Sources

  1. What is Laxative Abuse?. Rosewood Centers for Eating Disorders. 2023.
  2. Slow Transit Constipation Associated With Excess Methane Production and Its Improvement Following Rifaximin Therapy: A Case Report. Uday C Ghoshal, Deepakshi Srivastava, Abhai Verma, and Asha Misra. Journal of Neurogastroenterol Motility. 2011.
  3. Common causes of constipation. Harvard Medical School. 2021.
  4. Dietary fiber: Essential for a healthy diet. Mayo Clinic. 2022.
  5. Mg citrate found more bioavailable than other Mg preparations in a randomized, double-blind study. Ann F Walker, Georgios Marakis, Samantha Christie, and Martyn Byng. Clinical Trial: Magnesium Research. 2003.