The number of adults who complain of digestive problems such as pain, bloating, constipation, excessive gas, burping, heartburn, and nausea is quite high. Some estimates are as high as 50% of adults complaining in any 3-month period. Up to a third of adults in the United States complain of constipation or gastroesophageal reflux disease (GERD), and about 20% complain of irritable bowel syndrome (IBS).1 Although the prevalence of constipation has remained stable,2 the rise in obesity may be contributing to the increasing prevalence of GERD.3

Most signs and symptoms are perceived as medically insignificant, although there can be important medical consequences if left untreated. The specific causes are often identifiable. Patients often believe that their conditions are affected by the consumption of certain foods or beverages, even though current evidence to support these assumptions is limited. Movie stars tout diets, dietary supplements, "colon cleansers," and other products for weight management and prevention of colon cancer and ailments such as IBS. Many individuals do not seek medical care even if their condition is chronic and relapsing but respond to these messages about gastrointestinal (GI) health on the Web, in pharmacies, and from friends. We discuss the usual nonpharmacological approaches to the common complaints of chronic constipation, IBS, and GERD in this article.

Case 1: Chronic Constipation

A 72-year-old generally healthy woman, accompanied by her husband, presents to establish care with a gerontologist. They agree that she has a long history (at least 10 years) of constipation that she has treated in a variety of ways including use of a stool softener, mineral oil, and a daily can of cola. Until recently, Mrs N. felt that these strategies were sufficiently effective. However, with her recent move upon retirement, Mrs N. reports that her constipation has become more frequent. She has 3 to 4 hard stools per week with straining and continually has a sensation of incomplete evacuation. During the interview, her husband interjects that Mrs N. has always been preoccupied with her bowel habits, and her recent focus is interfering with their daily life. He said that Mrs N. is grumpy if she does not have a bowel movement every morning.

Mrs N. also reports a history of hypertension, chronic mild anemia, hyperlipidemia, and osteoporosis. She is adherent to her prescribed medication regimen that includes amlodipine besylate (Norvasc; Pfizer Inc, New York), hydrochlorothiazide or HCTZ (Microzide; Watson Pharma Inc, Morristown, New Jersey), simvastatin (Zocor; Merck, Whitehouse Station, New jersey), baby aspirin, 1000 mg calcium carbonate with 500 IU vitamin D, and a daily iron supplement. Her medical records show her hemoglobin level within the reference range. At registration, Mrs N. was asked to complete a REAP (Rapid Eating and Physical Activity Assessment) questionnaire.4 During the interview, Mrs N. confirmed that she ate whatever she wanted but disliked the flavor and texture of most vegetables and so ate few of them. She limits her fluids to 1 cup of tea in the morning and a 16-oz cola during the day. She worked as a traveling sales representative and developed the habit of limiting her fluid intake to avoid "pit stops." She denies being thirsty. At her daughter's insistence, she tried eating vegetables and drinking 8 glasses of water every day to relieve her constipation but said that strategy did not work for her. A friend has suggested a "colon cleansing" product, but she wonders if that is safe and effective.

Background: Chronic Constipation

Constipation is experienced more often by women than men and by older than younger individuals, although the aging process itself does not cause it. Some medications are known to have constipation as an adverse effect. Changes in lifestyle and routine may either contribute to constipation or alleviate the symptoms. Normal laxation, the elimination of feces, varies widely among individuals, ranging from 3 bowel movements per day to 3 per week.5 The American College of Gastroenterology (ACG) guidelines6 for constipation state that unsatisfactory defecation is characterized by infrequent stools, difficult stool passage, or both; difficult stool passage includes straining, a sense of difficulty evacuation, hard/lumpy stools, prolonged time to expel stool, need for manual maneuvers to pass stool, and less than 3 defecations per week. Chronic constipation must include at least 2 of the following: during at least 25% of defecations, loose stools are rarely present without the use of laxatives; there are insufficient criteria for the diagnosis of IBS; and criteria are met for the last 3 months, with symptom onset at least 6 months prior to diagnosis.

A patient seeking medical help for constipation may be asked to keep a stool diary and advised to schedule time for an undisturbed visit to the toilet.7 Health care professionals usually encourage patients to increase their fluid, dietary fiber intake, and physical activity7 and warn they may experience adverse effects such as abdominal bloating, gas, and cramping if they increase fiber intake too quickly and without increasing fluid intake. A Google search yields a plethora of products, processes, books, and advice to treat constipation.

Unfortunately, there is limited evidence to document the factors that contribute to and effectively treat constipation.8,9 Dietary fiber does increase stool bulk and frequency in healthy people, but patients with chronic and severe constipation and those with either slow transit or pelvic floor dysfunction may respond poorly and potentially even get worse on high-fiber diets.10 Although the optimal dosage is unknown, consuming cellulose, polydextrose and psyllium has been shown to prevent or treat constipation. The efficacy of other intact fibers such as inulin and resistant maltodextrin in managing laxation is unknown and may contribute to other GI symptoms such as gas and bloating. The available literature supports the use of fiber supplementation and laxative use rather than increasing dietary fiber intake from food.7

Colon cleansing products are again popular as celebrities tout their benefits. There are many different kinds of products and processes that claim to rid the body of toxins by clearing the colon of its contents. Some products contain significant calories. Instructions that accompany these products may include the following: drink plenty of water, eliminate caffeine, and encourage bowel motility by drinking extra virgin olive oil or castor oil and using calcium magnesium and "natural laxatives." A recent review of the literature identified little quality evidence to support the claims of benefit.11 The literature does, however, support the efficacy of increasing physical activity for preventing constipation.

The Case Revisited

Like many people, Mrs N. does not meet the criteria for chronic constipation, and she needs education about laxation and colon cleansing. Her sense of infrequent and incomplete emptying could be a result of her lifestyle and medication regimen. Four products on her mediation list (amlodipine, simvastatin, calcium bicarbonate with vitamin D, and iron) are known to contribute to constipation. Her physician may be able to prescribe different medications as well as recommend that she discontinue the unnecessary supplemental iron; her blood work has been within reference range.

Mrs N. has recently retired and moved, which may have led to changes in her hydration, physical activity, and dietary intake. It would be appropriate to request a diary of her fiber and fluid intake and her physical activity. Increasing hydration would help her laxation, but only if Mrs N. is dehydrated. The Dietary Reference Intake for Mrs N. is 12 cups of fluid per day, with 9 cups coming from beverages. Although her verbal report of intake is far less than the recommended amount, it is difficult to assess hydration in older adults because of confounders such as her medications. She does not report any of the signs and symptoms of dehydration such as confusion, weakness, dark urine, decreased skin elasticity, headache, dry mouth, fatigue, or lethargy. Thirst is an unreliable indicator, as is the color of her urine, which may be affected by the medications she is taking.12 She states she is unlikely to consume the recommended number of servings of vegetables and instead could be encouraged to find cereal and dietary supplement products with polydextrose or psyllium listed as ingredients, increasing their use gradually. Unless she changes her habit of restricting fluids, she would likely experience abdominal bloating, gas, and cramping with increased fiber intake. She should be encouraged to follow the 2008 Physical Activity Guidelines for Americans. A review of her REAP suggests she could benefit from medical nutrition therapy. If she had met the criteria for chronic constipation and her condition did not change with lifestyle adjustments, the medical management of constipation could include use of osmotic or stimulant laxatives.10 There is less risk of dehydration or electrolyte imbalance with the use of osmotic laxatives, but to avoid impaction, the individual must be well hydrated.

Case 1 Continued: Irritable Bowel Syndrome

Mrs N. also says she believes she has IBS. She reports an episode of abdominal cramps and watery stools every 2 to 3 months. She believes there are foods that trigger the reaction. For example, this occurs immediately after eating a tuna sandwich or marinated burger. These symptoms usually last a few hours and abate without treatment.

Background: IBS

Irritable bowel syndrome is a common functional GI disorder. Patients complain about abdominal pain and altered bowel habits, either constipation or diarrhea or both. Because IBS is a syndrome and not a disease, there are more opinions13-15 than evidence to describe the role of diet in both aggravating and managing IBS symptoms. Up to 70% of individuals with IBS attribute the onset or exacerbation of their symptoms to food. They may avoid foods they believe trigger the symptoms. Some individuals seek food allergy or food sensitivity testing to identify trigger foods. However, the ACG 2009 IBS Task Force15 suggests that there are few data to suggest that testing or exclusion diets are efficacious. The ACG did, however, acknowledge that a restrictive diet might provide a modest benefit for some individuals.

Patients with IBS are advised to increase their dietary fiber to as much as 35 g/d. Recent studies show that the advice should be more specific. The evidence indicates that increasing soluble fiber, especially psyllium by 10 to 20 g/d, may help patients with IBS and constipation.15,16 Some experts claim that the soluble or prebiotic fibers ferment in the colon, changing the composition or activity of gut microflora such as Bifidobacterium and Lactobacillus species, thereby providing benefit. The evidence also suggests that increasing insoluble fibers such as wheat and corn bran may worsen the condition.15,17 Studies using increased amounts of prebiotic dietary fibers, such as partially hydrolyzed guar gum, fructo-oligosaccharides/oligosaccharides, and calcium polycarbophil, have yielded mixed results.18,19 The term oligosaccharide refers to short-chain polysaccharides. Fructo-oligosaccharides and inulin are found in many vegetables and consist of short chains of fructose molecules.

Probiotics or live microorganisms themselves are thought to provide health benefits by the suppression of growth or epithelial binding/invasion by pathogenic bacteria; improvement of intestinal barrier function; and modulation of the immune system and of pain perception. It is not known which species and what dosages are needed for benefit. Bifidobacteria, bacteria that can be grown outside the body and then consumed, are thought to be effective as are lactobacilli.15,17,18 There are no known absolute contraindications to their use, and they do not interact with medications. However, marketers may overstate the health benefit of probiotics as the 2008 Federal Trade Commission's successful suit demonstrated. The company claimed improved digestion and regularity with consumption of a probiotic yogurt. "Bacillus regularis" is a marketing term and not a genus or species of bacteria. It remains for future research to support claims about probiotics.

There is evidence to support recommending the use of peppermint oil, as it acts like an antispasmodic, providing short-term relief of abdominal pain and discomfort.15,16

There are several lifestyle changes that are recommended but have little evidence to support their effectiveness. These include restricting some foods, beverages, or ingredients such as caffeine or alcohol after keeping a food diary and linking substances with symptoms such as gas, constipation, or diarrhea.14 However, under study conditions, subjects are unable to correctly link symptoms to trigger foods or beverages. Therefore, the use of such diaries remains uncertain. Two other strategies that have few risks include eating small frequent meals and reducing fat consumption, which may be beneficial to health even if they are ineffective.

Recent studies suggest that a diet rich in poorly absorbed carbohydrates such as fructose, sugar alcohols, and fructo-oligosaccharides may contribute to IBS symptoms, and restricting them could provide relief. Heizer and coworkers18 outlined dietary changes, including restriction of poorly digested carbohydrates, and a process for deciding if the changes have a beneficial effect on IBS symptoms. They note the importance of ensuring that the individual's eating approach should be reviewed for its nutritional adequacy. There is growing interest in the role of fructose in health. Consumption of fructose, a simple sugar, has been postulated to have a role in inducing IBS symptoms.18,20 Fructose released from the hydrolysis of sucrose is generally completely absorbed. However, the absorption of free fructose varies. Some individuals may experience symptom relief with dietary manipulation. Foods with high fructose content include watermelon, pineapple, orange, honey dew melon, honey, peach, Asian pear, mango, apple, and pear. Foods and beverages with added sugars or high-fructose corn syrup, too, contain some fructose. When fructose and glucose, the components of added sugars, are studied separately, it appears that excess fructose, and not glucose, could be responsible for ill effects.

As discussed earlier, there is evidence that consuming prebiotic dietary fibers may provide benefit. However, one group20 argues that consuming these fibers causes signs and symptoms. Their work shows that consumption of FODMAPs, or fermentable oligosaccharides, disaccharides, and monosaccharides, and polyols, contributes to diarrhea, gas, and bloating. Oligosaccharides and inulin are nondigestible and are increasingly being added to foods as sweeteners, as prebiotics or as dietary fiber. Very high amounts clearly do have effects as laxatives, but smaller amounts may not. Polyols or sugar alcohols, such as sorbitol, xylitol, mannitol, isomalt, and erythritol, are used as sweeteners and are known to be poorly absorbed, contributing to bloating and diarrhea. Barrett and Gibson20 describe a low-FODMAP diet and checklist. They suggest the oligosaccharides fructan and galactan are malabsorbed, and individuals who consume a diet rich in these soluble fibers found in wheat-based foods, in foods from the onion family, and in legumes may experience IBS. Barrett and Gibson20 suggest reducing FODMAPs; a very restrictive diet can lead to symptom improvement in as short as 1 week. A longer randomized clinical trial may be needed to determine the efficacy of this eating approach before it is recommended for patients.

The Case Revisited

Mrs N. believes she knows what foods trigger her symptoms, and avoiding these foods would not appear to impact the nutritional adequacy of her diet. She might benefit from the addition of a probiotic to her diet as well as soluble fiber. However, there are many different hypotheses for the cause of IBS, and so it is possible that increasing soluble or prebiotic fibers to improve her laxation might make her IBS symptoms more frequent or severe. If Mrs N. suffered daily with IBS symptoms that interfered with the quality of her life, she might be interested in a trial of the FODMAP diet. Diets that exclude large numbers of foods and beverages can result in nutritional insufficiency and should be monitored by a registered dietitian. Overall, the evidence to support the use of dietary strategies to manage the symptoms of IBS is not very strong, and if the strategies described above show little benefit and her symptoms worsen, medical management may include the use of anticholinergics, which have antispasmodic effects and lead to decreased fecal urgency and pain. Antidiarrheal medications are useful to inhibit peristalsis and slow intestinal motility, which improve stool frequency and consistency and reduce abdominal pain and fecal urgency. However, the long-term use of these medications can cause dizziness, constipation, or dry mouth.

Case 2: Gastroesophageal Reflux Disease

Mr J. is a 56-year-old man who complains of gas, bloating, heartburn, burping, and constipation. His body mass index (BMI) is 32 kg/m², and waist circumference is 41 in and meet the criteria for abdominal obesity. He is a retired teacher who enjoys reading, golfing, and gardening. He sleeps late in the morning and enjoys a large cup of strong coffee. He eats most of his meals alone because his wife works and travels 3 to 5 days per week. When she is gone, he eats fast and convenience foods, often late at night, and drinks up to 12 oz of wine each evening. He drinks 2 to 4 L of soda, mostly diet, per day. He likes chocolate candy as a snack. He smoked 3 packs of cigarettes a day for 20 years but now smokes 1/2 pack per day. He had been taking a prescription medicine that provided relief, but a change in copay has made it very expensive, and he wonders if there are lifestyle changes that would have the same benefit.

Background: GERD

Gastroesophageal reflux disease is a chronic digestive disease that occurs when stomach acid or, occasionally, bile flows back (refluxes) into the esophagus. The backwash of acid irritates and without treatment may erode the lining of the esophagus. This causes GERD signs and symptoms individuals call heartburn or acid reflux. If these symptoms occur more than twice each week or interfere with daily life, it is considered GERD. Although there are no generally accepted evidence-based diet recommendations for patients with GERD, there are different dietary strategies, such as avoiding acidic foods that have been reported to help some patients. It is unlikely that following these recommendations will cause harm even if no symptom relief is achieved. However, if the patient's symptoms are not aggravated by, for example, eating a highly acidic food, there is no reason to exclude those foods from the diet.

Usual care for GERD includes 4 nutrition goals. First, avoid decreases in lower esophageal sphincter pressure by limiting the intake of dietary fat, alcohol, chocolate, peppermint, and coffee. Second, decrease the reflux frequency and volume by losing weight if overweight, eating small and more frequent meals, drinking fluids between rather than with meals, and consuming adequate fiber to avoid constipation because straining increases intra-abdominal pressure. Third, decrease esophageal irritation by limiting citrus, tomato products, spicy foods, onions, carbonated beverages, and foods and beverages that the patient reports regularly cause heartburn. And finally, improve esophageal clearing time by sitting upright or walking after meals, avoiding eating 2 to 3 hours before bed time and elevating the head of the bed, smoking cessation, and losing weight if overweight.14,21

In our review of the literature, we found evidence that a few strategies can effectively reduce symptoms. There appears to be a strong relationship between increased BMI, but not necessarily abdominal obesity, and reflux. A weight loss of about 20 lb appears to reduce GERD symptoms for many obese patients.22-24 A recent study demonstrated that total fiber intake is significantly inversely associated with the risk of any Barrett esophagus, a complication of chronic GERD.25 On the other hand, a recent systematic review26 suggested no direct evidence that carbonated beverages promote or exacerbate GERD.

The Case Revisited

Several lifestyle recommendations can be made to Mr J. He is overweight, and because of the strong relationship between GERD and increased BMI, he could benefit from weight loss. Increasing his dietary fiber intake may aid both in weight loss and improve symptoms. He can be counseled for smoking cessation and reducing intakes of chocolate and alcohol. He may want to try some of the other lifestyle strategies described and adhere to those that provide him relief. If he does not find relief, medical management might include the use of over-the-counter antacids or a return to the use of a proton pump inhibitors or an H-2 blocker. Long-term use of these approaches may be costly and could impact the absorption of some nutrients including vitamins B₁₂ and D and calcium. Dietary supplements may be needed if they are used chronically.

Final Observation

There are surprisingly few studies to support or disprove the role of foods and beverages in causing or treating chronic constipation, IBS, or GERD. It is clear that advising a patient to "eat more dietary fiber" without being more specific about the type of fiber will yield mixed results. Clinicians need to pay attention to the rapidly changing understanding of the role of various dietary fibers in health and the kind and amounts of fibers being added to foods, beverages, and dietary supplements. Giving a patient a recommendation to restrict selected foods, beverages, or ingredients to prevent or relieve GI symptoms may be more effective than no treatment at all. However, it may take a trial of different dietary strategies to find the effective approach, and the evidence is not strong on the efficacy of these dietary strategies. Patients should be informed that there is misinformation about GI health on the World Wide Web. An excellent source of easy-to-read publications on this subject is the National Digestive Diseases Information Clearinghouse (http://www.digestive.niddk.nih.gov).

Acknowledgments

The authors thank Katherine Rickett, MSEd, MSLS, Laupus Library, East Carolina University; Jonathon Firnhaber, MD, Department of Family Medicine, Brody School of Medicine, East Carolina University; and Carolyn Lackey, PhD, NC State University Emeritus, for their assistance in the literature search and preparation of the manuscript.

REFERENCES