Why am I writing about constipation? Because up to 20% of Americans suffer from constipation. That’s over 60 million people. Since I’m a proponent of colon health, it’s appropriate that I address this common ailment.
Let’s first define constipation. To the layperson, constipation usually means having difficulty having a bowel movement, passing hard stools, or infrequent bowel movements. This is actually very close to the medical definition. The medical definition of constipation revolves around the frequency of bowel movement. The normal frequency of bowel movements is between 3 per day to one every 3rd day. If you have two or fewer bowel movements per week or you have difficulty in evacuating your stool, you fit the definition of constipation. Difficulty with evacuation includes: the inability to initiate defecation; excessive straining; or the feeling of incomplete evacuation.
To inject some levity into the topic of constipation, I thought I’d share some interesting facts:
- one liter of fluid per day enters the colon from the upper digestive tract.
- this consists of food residue, fiber which is indigestible carbohydrate, salt, and water
- it takes 24-30 hours for this material to exit the colon
- most of the salt and water is absorbed by the colon
- most of the fiber is fermented into gas which leads to flatulence
- only about 10% of the original fluid becomes stool
The causes of constipation are usually divided into two categories: (1) idiopathic which means we don’t really know for certain the cause or (2) secondary which means it is due to some other underlying medical condition. Secondary disorders causing constipation include many diseases such as diabetes, low thyroid (hypothyroidism), spinal cord tumor, colon cancer, dehydration, and anal fissures to name a few. Idiopathic causes include slow-transit constipation which probably results from dysfunction of the nerves supplying the colon muscles or due to ineffective function of the muscles of the pelvis and rectum. If you’re still awake at this point, let’s move on from physiology to treatment of constipation.
The initial treatment of constipation involves diet. The main goal of dietary therapy is to eat 20-35 grams of fiber per day. To help you figure out how to reach this goal of fiber intake, check out my dietary fiber guide. Avoiding excesses of rich foods or animal protein can also help. Even though it is recommended to increase fluid intake and exercise, there is actually very little evidence that these measures are of value. Nevertheless, I think it is reasonable to consume 4-6 glasses of water per day and to exercise for 150 minutes per week.
Laxatives can be helpful. There are many laxatives available by prescription or available over-the-counter. My favorite laxative to recommend is polyethylene glycol or PEG which is sold under the product name of Miralax. PEG is a white, tasteless and odorless powder that mixes with any liquid. Taking a daily serving can help maintain regularity. You can adjust the dose of PEG up or down to achieve the desired result. PEG is safe to take long term.
There are prescription medications that also can be helpful. This topic is beyond the scope of this blog. If you are still struggling with constipation after increasing your dietary fiber intake, avoiding excesses of rich foods or animal protein, drinking enough fluids, exercising, and a trial of PEG, then you should see your healthcare provider. If you are 50 years of age or older, you should have a colonoscopy to exclude colon cancer or polyps which might be contributing to constipation.
Here’s to your colon health!
Frank Farrell, MD, MPH, AGAF