Causes & Risk Factors
Dietary & Lifestyle Considerations
Constipation is defined as having infrequent bowel movements, often fewer than three per week, and difficulty passing stools. Most people experience occasional constipation, but about 14% of adults suffer from chronic constipation. Many people turn to laxative medications, but these can lead to dependence and troubling side effects.
Signs & Symptoms
- Infrequent stools, often fewer than three per week, and difficulty passing them.
- Abdominal bloating and discomfort
- Hard or lumpy stools that require straining to pass, or
- A sensation that there is a blockage or some other problem preventing complete emptying of the bowels (UMMC 2013a; Jamshed 2011; Mayo Clinic 2013a).
- Hemorrhoids, which are swollen, inflamed veins in the anal or rectal region, may occur as a result of constipation. Hemorrhoids can cause itching, bleeding, and a sensation of swelling around the anus (NIDDK 2013; Mayo Clinic 2013b).
The large intestine, or colon, is the final major segment of the digestive tract (CCS 2015). Waves of muscular contractions called peristalsis propel fecal material through the colon (Leung, Riutta 2011). These muscular activities are coordinated by signals from the nervous system and neuro-hormones like histamine and serotonin (Lee 2014; Wood 2007). Colonic peristalsis is naturally strongest upon waking in the morning and after meals, and insufficient peristalsis leads to constipation (Yu 2014; Hendricks 1997).
Most people experience occasional constipation, but about 14% of adults suffer from chronic constipation (Basilisco 2013; Rao 2014; Quigley 2011; Jamshed 2011). These people often turn to laxative medications, but these drugs are sometimes ineffective and can cause troubling side effects such as bloating, diarrhea, and loss of bowel control. Moreover, laxative overuse may lead to dependence (Wang 2013; Leung, Rao 2011; Basilisco 2013; Pare 2014; Mayo Clinic 2014a).
For some, constipation can often be relieved without harsh laxatives by increasing fibre and fluid intake as well as physical activity (Rao 2014; Rush 2002; Attaluri 2011).
Many older people dismiss declining bowel function as a normal part of the aging process and learn to live with unsatisfactory evacuation. But constipation should not be ignored. Severe chronic constipation can lead to problematic complications like fecal impaction and fissures (Basilisco 2013; Jamshed 2011; Rogers 2013; Mayo Clinic 2012).
The Gut-Brain Axis
The network of nerves that controls gut activity, known as the enteric nervous system, contains as many nerve cells as the spinal cord (Wood 2007; Daulatzai 2014). The enteric nervous system and central nervous system are functionally interdependent. In other words, dysfunction originating in the central nervous system can give rise to problems in the enteric nervous system, and dysfunction originating in the enteric system may compromise central nervous function (De Palma 2014).
This reciprocal relationship between the gastrointestinal tract and the nervous system has been called the “gut-brain axis” (Daulatzai 2014; O'Malley 2011; Lee 2014; De Palma 2014). Functional (primary) constipation is thought to involve gut-brain axis dysfunction (De Palma 2014). Bi-directional dysfunction of this axis also contributes to irritable bowel syndrome (Daulatzai 2014; O'Malley 2011; De Palma 2014).
- Adequate fluid and fibre are first-line treatments, and regular exercise is also an important intervention
- Laxatives (osmotic and stimulant), suppositories, and enemas
Note: Chronic use of stimulant laxatives may damage the neuromuscular system of the colon, worsening constipation and leading to dependence. They may also cause potentially dangerous electrolyte and fluid imbalances, especially when combined with diuretics.
Emerging Novel Strategies
- Fecal microbiota transplantation, which involves the transfer of colonic microorganisms from a healthy donor to a symptomatic person. Five case reports of patients with chronic constipation-predominant IBS treated with fecal microbiota transplant describe immediate remission in all five cases and stable improvement in follow-up.
- Biofeedback therapy, where patients learn to coordinate muscular activity, is a behavioral treatment that has demonstrated superiority to laxatives in several controlled clinical trials.
- Neurotrophin-3, a growth factor produced by the body, may be able to combat age-related neurodegeneration in the gut, which could help relieve constipation.
CAUSES & RISK FACTORS
- Slow transit-constipation – impaired regulation of peristalsis by the enteric nervous system; dietary factors such as a low-fibre diet.
- Normal-transit constipation – no known cause for this type of constipation beyond its association with psychosocial stress.
- Pelvic floor dysfunction – there is faulty coordination of the muscles that facilitate expulsion of stool from the rectum. Psychological causes have been proposed, and physical trauma plays a role in some cases (Leung, Riutta 2011; Lembo 2003; Rao 2014; Jamshed 2011).
- Blockages. These include colorectal cancer, bowel stricture (narrowing), abdominal tumor pressing on the colon, and any other cause of bowel obstruction (Basilisco 2013).
- Neurological causes. Conditions that disrupt intestinal neuromuscular signaling can cause secondary constipation (eg, multiple sclerosis, Parkinson’s disease, spinal cord injury, diabetic neuropathy, and stroke) (Basilisco 2013; Rao 2014).
- Hormonal causes. Endocrine conditions, such as hypothyroidism, can cause or contribute to constipation (Basilisco 2013; Rao 2014). Diabetes is associated with constipation; this is thought to be through eventual damage of enteric nerves, altered intestinal muscle contractility and function, and disrupted intestinal microbiota (Yarandi 2014).
- Muscular causes. For some individuals, constipation is caused by difficulty controlling the muscles of the pelvic floor and the external anal sphincter. Injury or trauma to the pelvic muscles can be responsible (Roque 2015; Leung, Riutta 2011).
- Medications. Medications, notably opioid pain relievers, can cause secondary constipation, particularly in the elderly. Other medications less commonly cause secondary constipation: acetaminophen (Tylenol), anticholinergics, antidepressants, antihistamines, antipsychotics, calcium-channel blockers, beta-blockers, diuretics, and non-steroidal anti-inflammatory drugs (Jamshed 2011; Rao 2014; Leung, Riutta 2011).
Female gender. Women are 2 – 3 times as likely as men to have chronic constipation (Jamshed 2011; Roque 2015). This may be due to the influence of hormones on digestive function, since many women experience constipation during the luteal phase (last two weeks) of the menstrual cycle (Chu 2014; Oh 2013; Jamshed 2011). Pelvic floor injuries sustained during childbirth may be to blame in another segment of women with chronic constipation (Leung, Riutta 2011; Roque 2015).
Older age. Constipation is more common in older age, with the greatest prevalence among those 70 or older. As many as 70% of institutionalized elderly report daily use of laxatives (Leung, Riutta 2011).
Other complications of chronic constipation include:
- Anal fissures are small tears in the delicate lining of the anus (Mayo Clinic 2012).
- Rectocele is a bulging of the rectum toward the vaginal wall (Mayo Clinic 2014b).
- Rectal prolapse is a collapse and telescoping of the rectum through the anal canal (UMMC 2015b; MUSC 2015).
- Fecal impaction occurs when a mass of dry, hard stool becomes lodged in the rectum, usually in individuals who have been constipated for an extended period of time (UMMC 2015a).
- Fecal incontinence is involuntary passage of stool associated with chronic constipation. It can occur due to general anorectal muscular weakness as a result of chronic constipation, laxative use, severe hemorrhoids, rectal prolapse, or fecal impaction (UMMC 2014).
- Acquired megacolon is an extremely enlarged colon that can result from prolonged severe constipation and that may require surgical treatment. Acquired megacolon occurs due to weakness and collapse of chronically stretched walls of the colon (Vieira 1996; Sparberg 1990; Pereira 1987).
- Bowel perforation as a result of constipation is a very rare medical emergency that can cause the bowel contents to enter the abdomen (Leung, Riutta 2011; NLM 2014a).
DIETARY & LIFESTYLE CONSIDERATIONS
Eat a High-Fibre Diet
Surprisingly, many people do not consume the recommended daily amount of fibre. The suggested intake is 22 g for women over 50 and 28 g for men over 50 (USDA 2010; King 2012; Schmier 2014; Chiba 2015; McRorie 2015). Increasing fibre intake is a simple, cost-effective solution in many cases of constipation (Schmier 2014).
In a trial in 117 people with chronic constipation, a diet containing 25 g of fibre per day for two months resulted in increased stool frequency and decreased laxative use. The improvement was more pronounced in a subgroup of participants instructed to drink 2 L of mineral water per day compared with those told to drink as much water as they wanted (Anti 1998). Another preliminary trial found that eating a breakfast cereal containing 5.4 g of fibre (mainly from wheat bran) daily for two weeks had beneficial effects on bowel function in people whose regular diets included less than 15 g of fibre per day; improvements in constipation, bloating, sluggishness, and digestive discomfort were noted (Lawton 2013). Many other trials of various forms of supplemental dietary fibre have demonstrated improved bowel movement frequency and clinical benefit in constipation (Xu 2014; Yang 2012; Woo 2015; Quartarone 2013; Dahl 2003; Rao 2015).
Specific Foods to Help with Constipation
In addition to consuming plenty of dietary fibre and staying adequately hydrated, a few specific foods may improve bowel regularity.
Prunes (dried plums) have long been used to treat constipation. It is thought that their laxative effect is in part due to their high concentration of sorbitol, a slowly digested sugar that has an osmotic effect and holds water in the intestines (Stacewicz-Sapuntzakis 2001).
Kiwifruit is a traditional laxative food. Several clinical trials have found that eating kiwifruit can relieve constipation (Rush 2002; Chan 2007; Chang 2010).
- Olive and flaxseed oil
A preliminary study tested the effects of mineral oil, olive oil, and flaxseed oil in 50 dialysis patients with constipation. The participants were given one of these three oils to take daily for four weeks, at a dose of about 1 tsp per day. All three oils reduced constipation scores, with olive oil demonstrating some superiority to flaxseed oil. These results suggest edible oils might be a useful alternative to mineral oil for the treatment of constipation (Ramos 2015).
Increase Water Consumption
Increasing fluid intake is an effective treatment for constipation (Markland 2013). In addition, water and fibre appear to work best together (Anti 1998). Water restriction has been demonstrated to rapidly reduce bowel movements in healthy people (Klauser 1990), and low fluid consumption has been associated with an increased risk of chronic constipation (Markland 2013).
High-mineral-content water may be more helpful in treating constipation than typical lower-mineral water. In a four-week study, women with chronic constipation were given 1.5 L of drinking water per day. They were divided into three groups based on the composition of the water received, which contained either 1 L, 0.5 L, or none of a high-mineral natural spring water. By week two of the study, the women whose daily water included 1 L of mineral water had better stool consistency and less use of laxatives than women in the other two groups. Response to treatment corresponded to concentrations of magnesium and sulfate in the mineral water (Dupont 2014).
Increase Physical Activity
A sedentary lifestyle is a major contributor to many chronic diseases, including constipation (Booth 2012; Sandler 1990; Khatri 2011), and a recommendation of regular exercise is part of standard management of constipation in adults (Rao 2014; Borre 2015). In a study in which experimental bed rest was imposed on healthy men for 35 days, 60% developed constipation (Iovino 2013).
Other studies have found that exercise interventions can successfully improve chronic constipation (Beradze 2011). In one such study in 43 participants with chronic constipation, 30 minutes of brisk walking twice weekly plus a daily 11-minute strength and flexibility program for 12 weeks led to significant reductions in most constipation symptoms (De Schryver 2005).
In a study designed to determine the ideal posture for ease of defecation, 28 healthy adults adopted three different defecation postures, each for six consecutive bowel movements, and recorded the time and ease of defecation. The first posture was seated on a standard toilet; the second was seated with feet resting on a 10 cm-high footstool; and the third was squatting, using a flat container. For all of the participants, squatting was associated with the shortest time spent moving stool and the easiest sensation of bowel emptying (Sikirov 2003). According to the study authors, the straightening of the recto-anal angle that occurs with squatting is the natural posture for defecation (Sikirov 1989; Sikirov 2003).
Comprehensive Lifestyle Changes
Researchers assessed a chronic constipation education program in 35 chronically constipated women. After three months, measures of constipation symptoms and severity had improved significantly (Ayaz 2014). The program guidelines were:
- Consume 25‒30 g of fibre per day by eating fruits, vegetables, and whole grains;
- Drink 1.5‒2 L of fluids per day, preferring water and avoiding diuretic drinks such as alcohol;
- Incorporate regular exercise in the form of walking, with a goal of 3.5‒5 hours per week;
- Use the toilet at the same time each day whether or not there is an urge;
- Use a squatting posture to promote proper defecation.
Magnesium and Vitamin C
Magnesium supplements can have a laxative effect by drawing water into the intestines (Izzo 1996). Several forms of magnesium (eg, carbonate, oxide, citrate) can be used to treat constipation (Yamasaki 2014; Siegel 2005; Liu 2011; Ranade 2001).
In one study, 3835 women’s diets were assessed for magnesium intake. Compared with women with the lowest magnesium intake, those with higher intake had up to 30% lower risk of constipation. The investigators considered the possibility that some dietary magnesium remains in the digestive tract and attracts water by an osmotic effect (Murakami 2007). Also, high doses of vitamin C can facilitate bowel evacuation (LPI 2014).
There are convenient powdered formulas available that contain magnesium mixed with ascorbic acid that can induce a bowel movement relatively quickly (typically 30‒90 minutes). A teaspoon or more of vitamin C and magnesium crystals will evacuate the bowel within 30‒90 minutes if taken on an empty stomach with several glasses of water. One of these powdered formulas provides 4500 mg of vitamin C and 250 mg of magnesium in each teaspoon. The dose needs to be individually adjusted so it will not cause day-long diarrhea.
Buffered vitamin C powders combined with primarily potassium salts can work as well as magnesium/ vitamin C powders and may be used on alternate days for those needing ongoing relief.
The suggested number of times these nutritional colon cleanses be used is about three times per week. Excess use may create tolerance and require higher dosing.
Soluble fibre supplements absorb water and hold it in the intestines, keeping the stool soft and easy to move, and tend to create a lubricating film when exposed to water; insoluble fibre supplements add bulking particles to the stool and shorten transit time by stimulating peristalsis (Yang 2012; Suares 2011b; Eswaran 2013). Soluble fibres are generally fermentable, which means they can be digested by microbes in the intestines. This quality is referred to as “prebiotic.” Prebiotic fermentable fibres are important for establishing and maintaining healthy colonies of beneficial bacteria in the gut (Quigley 2010). Soluble fibre is present in psyllium husk, legumes, nuts, seeds, and some fruits and vegetables. Sources of insoluble fibre include wheat bran, whole grains, and vegetables (NLM 2014b).
Psyllium. The husk of the psyllium seed, a product of the Plantago ovata plant, is rich in soluble fibre and contains some insoluble fibre (Moreno 2003); many well-designed trials have demonstrated that psyllium fibre supplementation relieves constipation and irritable bowel syndrome (McRorie 1998). Psyllium has also been associated with increased stool frequency in constipated Parkinson’s disease patients (Ashraf 1997). In patients with chronic primary constipation, taking 5 g of psyllium twice daily improved stool consistency and frequency (Ashraf 1995).
Psyllium has several ancillary benefits as well, including improving the lipid profile (Komissarenko 2012; Sartore 2009), glucose metabolism (Ziai 2005; Karhunen 2010), and blood pressure control (Cicero 2007).
Other fibres. Although psyllium is one of the most common and most thoroughly studied types of supplemental fibre, several other fibres can be used to supplement dietary intake as well:
- Inulin. Inulin is a prebiotic soluble starch that functions as fibre in the digestive tract. Inulin is found in many plant foods, most notably in Jerusalem artichoke and chicory root, but also in more commonly eaten vegetables like onions, garlic, and asparagus (Nishimura 2015). It is considered a prebiotic fibre because of its positive effects on colonies of beneficial bowel bacteria (Kolida 2002). A rigorous analysis of many randomized controlled trials concluded that supplemental inulin can decrease transit time, increase stool frequency, and improve stool softness in people with chronic constipation (Collado Yurrita 2014).
- Partially hydrolyzed guar gum. Guar gum is a product from the guar bean (Cyamopsis tetragonoloba). Partially hydrolyzed guar gum is a soluble, fermentable fibre that is more palatable and less likely to cause adverse effects than whole guar gum (Lewis 1992; Slavin 2003). Preliminary research shows that supplemental guar gum helps relieve constipation symptoms in patients with constipation-predominant irritable bowel syndrome (IBS-C) (Polymeros 2014; Russo 2015; Quartarone 2013; Slavin 2003).
- Glucomannan. Glucomannan is a soluble, fermentable fibre found in many plants, especially the root of the konjac plant (Amorphophallus konjac). It has prebiotic effects, supporting the beneficial bacteria in the large intestine (Tester 2013). Several clinical trials showed that glucomannan improved multiple measures of constipation better than placebo (Marzio 1989; Passaretti 1991; Chen 2008).
- Pea fibre. In a preliminary study that included 114 elderly subjects who lived in nursing homes and had constipation, the addition of 1–3 g of pea fibre powder to other foods three to four times per day for six weeks significantly increased stool frequency and decreased laxative use (Dahl 2003).
- Flaxseed. Flaxseed is a source of both soluble and insoluble fibres. The soluble fibre in the outer coating of the flaxseed is a mucilage that becomes slippery when wet. Mucilages, like all soluble fibres, increase moisture in stool (Kajla 2015) and are thought to have lubricating effects (Hanif Palla 2015).
The gut microbiota is increasingly recognized as a key factor in the functioning, or malfunctioning, of the entire digestive tract. Probiotics are supplements containing live microorganisms that are taken to improve digestive and overall health (Narula 2010). Their effectiveness in treating a wide array of disorders, including chronic constipation and IBS-C as well as myriad gastrointestinal and other disorders, is the subject of intensive research (Quigley 2011; Varankovich 2015; Quigley 2012a).
A thorough analysis of research into probiotic supplements concluded that those made with Bifidobacterium lactis(also called B. animalis ) can effectively shorten intestinal transit time in both constipated and non-constipated people, with the greater effect seen in those with constipation (Merenstein 2015; Miller 2013). Another review of the research found that probiotic supplements with B. lactis and Lactobacillus casei ( L. casei) may have positive effects in adults with chronic constipation (Chmielewska 2010). A number of probiotic supplements, such as those made with L. GG, L. plantarum, L. acidophilus, L. casei, and B. animalis, have been found to alleviate individual IBS-C symptoms, such as bloating, flatulence, and constipation (Quigley 2012a). Trials using B. lactis and B. infantis have demonstrated benefit in patients with IBS-C (Quigley 2011).
Supplemental fibre (eg, psyllium husks): about 6 g daily for women and about 12 g daily for men.
Magnesium and vitamin C (as an effervescent powdered formulation): 4500 mg vitamin C and 250 mg magnesium three times weekly or as needed. Quick relief of constipation can be achieved if this is taken on an empty stomach with a few glasses of water. Dose may be adjusted to individual needs.
Probiotics: 15 billion colony forming units (CFUs) daily
Prebiotics: 1500 mg daily
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