Digestion, Diet, and Disease

Digestion, Diet, and Disease


Digestion, Diet, and Disease: Irritable Bowel Syndrome and Gastrointestinal Function


Janice M. Vickerstaff Joneja.


Rutgers University Press, Piscataway, New Jersey, U.S.A.





From the publisher:

Malfunction in the digestive tract can arise from a variety of causes, and it requires the sciences of immunology, physiology, biochemistry, microbiology, and nutrition to fully explain the basis of the dysfunction as well as effective treatment options. Now Dr. Janice Vickerstaff Joneja has written the first book that:

  • Applies current research data in all of the relevant sciences into a practical resource for the management of gastrointestinal disease, in particular irritable bowel syndrome (IBS).
  • Supplies complete scientific references for the research scientist, the clinician, and the student.
  • Provides specific dietary management strategies for IBS and related dysfunction in the gastrointestinal tract, based on scientific data.
  • Includes meal plans, recipes, and dietary advice for balanced nutrition, while avoiding the foods most likely to trigger or exacerbate IBS.

These unique qualities make DIGESTION, DIET, AND DISEASE the ideal choice for practitioners, educators, and researchers in the field of nutritional medicine, as well as nurses, alternative medicine professionals, and the educated general public suffering from IBS.

Excerpt from the Introduction

Disorders of the digestive tract, designated “functional gastrointestinal disorders” (FGID), are considered by most physicians to be exceedingly common (Thompson et al. 2002). A telephone survey of households in the United States estimated a prevalence of 70 percent in the population surveyed (Drossman et al. 1993). The most frequently diagnosed FGID is irritable bowel syndrome.

Irritable bowel syndrome (IBS) is defined as “a functional bowel disorder in which abdominal pain is associated with defecation or a change in bowel habit, with features of disordered defecation and distention” (Camilleri 2001). This chronic disorder is much more prevalent in women than in men, and has been estimated to affect as many as 22 million people (Drossman 1989). Everhart (1991) found that IBS accounts for 20–50 percent of outpatient gastroenterology referrals in the United States. A 1990 report estimates that in the United States between 2.4 and 3.5 million visits to physicians per year are due to irritable bowel syndrome (Sandler 1990). Symptoms of IBS affect up to 20 percent of the general population, although only a minority seeks treatment (Talley et al. 1995).

The symptoms of IBS include diarrhea, constipation, excessive gas, abdominal pain, and bloating. Sometimes the pain is relieved by defecation, or there is a feeling of incomplete evacuation of the bowels. After other disorders have been excluded, treatment is usually directed at the predominant symptoms and gauged to their severity. “A careful balance between a thoughtful investigation and the expense and dangers of overtesting must always be considered. Most patients continue to have persistent symptoms several years after the original diagnosis” (Bonis and Norton 1996).

Professor David L. Wingate, in his foreword to the book Treating IBS (1995), succinctly summarizes the medical status of IBS: “the disorder is a constellation of symptoms lacking an agreed and objective pathophysiology. A doctor examining a patient with IBS will find no consistent physical changes. There are no accepted diagnostic tests. Finally, there is no therapy that is accepted as effective in even the majority of cases.” He goes on to point out that “IBS is the source of much frustration between patients and doctors. The patient describes the symptoms to the physician and awaits a response; often, there is virtually none, because, while the physician agrees with the diagnosis (which is often already known to the patient), there seems nothing more to be done. Patients are frustrated by what seems to be the inertia or even indifference of physicians, while physicians are irritated by the reiteration of complaints that sometimes sound trivial” (Wingate 1995, xi–xii).

Lamentably, as Christensen (1994) points out, “After more than fifty years of study, the only agreement about the irritable bowel syndrome is the idea that it occurs in the absence of demonstrable organic disease of the colon.” Even more disconcerting for both patient and health care provider (Bonis and Norton 1996) is that “the challenge of irritable bowel syndrome is treating a symptom complex without having a clear understanding of the cause.” An added confounding factor in the treatment of IBS is that the placebo response seems inordinately high: It has been estimated that improvement can be due to the placebo response in as much as 71 percent of cases (Drossman and Thompson 1992). This inescapably leads many physicians to suspect that psychological factors predominate in patients presenting with symptoms of IBS.

Changing Approach to Irritable Bowel Syndrome

Recent advances in basic and clinical sciences indicate that many factors may contribute to a patient’s symptoms. Whereas previously IBS was considered to be a purely psychosomatic illness, research in the past several years has revealed that several distinct, but interacting mechanisms play a role in the clinical picture. Irregularities in intestinal motility, sensory changes, and abnormalities in the processing of visceral pain in the central nervous system (CNS) are being recognized as important factors in the development of symptoms (Mertz 1999). Several attempts have been made to characterize the symptoms of IBS for purposes of clinical trials and epidemiological studies. The most widely accepted protocols for identification of IBS are known as the Rome II diagnostic criteria (Thompson et al. 1999). For epidemiological studies, a questionnaire was developed from these criteria (Drossman et al. 2000). The Rome criteria and the ancillary questionnaire are the basis for most studies of IBS at the present time.


In Western countries 15–20 percent of the adult population suffers from IBS (Bonis and Norton 1996; Jones and Lydeard 1992; Thompson 1986; Thompson and Heaton 1980). It has been estimated that one quarter of the population of Britain and the United States suffers from irritable bowel syndrome (Thompson 1986) and the disorder seems to occur with equal frequency in the young and the elderly adult (O’Keefe and Talley 1991). Interestingly, it appears that whereas only a third to a half of the sufferers seek medical attention for their problem (Bonis and Norton 1996; Jones and Lydeard 1992), patients with irritable bowel syndrome make up to 50 percent of all outpatients referred to gastroenterologists (Drossman and Thompson 1992; Everhart and Renault 1991).

A recent survey using a random digit dial national survey in Canada of household members eighteen years of age or younger based on the Rome I and II questionnaires (Thompson et al. 2002) indicated that at least one functional gastrointestinal disorder occurred in 61.7 percent of 1,149 respondents. Irritable bowel syndrome prevalence was recorded for 12.1 percent of male respondents and 13.5 percent of female respondents.

Studies of populations in China indicate a prevalence of IBS similar to that in Western countries (Bi-zhen and Qi-Ying 1988). Apparently, IBS occurs less frequently in Southeast Asia and in rural communities of South Africa (Drossman and Thompson 1992).

Female IBS patients greatly outnumber males in Western countries, where 75–80 percent of people seeking medical assistance for IBS are female (Harvey et al. 1983). In contrast, male patients outnumber females in India and Sri Lanka (Drossman and Thompson 1992), where cultural and economic factors may influence the apportionment of health care funds.

Health Care Costs of Irritable Bowel Syndrome

In 1995 Talley and coworkers reported the results of the first population-based study to estimate the direct medical care costs of persons with IBS compared with controls from the same community of 100,000 persons in the United States (Talley et al. 1995). This estimation does not include the costs of medications used in the treatment of the symptoms, indirect costs (such as lost wages), and nonmedical costs (such as home care). In the subject community, the prevalence of IBS was measured at 18 percent. On average, persons with IBS incurred $300 more in direct medical costs per year than control subjects of the same age and gender. In 1992 the costs for IBS alone in the subject community was estimated to be $4 million. The authors of the study estimate by extrapolation that excess charges for health care of IBS patients in the white community of the United States alone would be $8 billion per year. A previous estimation (Sonnenberg and Everhart 1993) indicated that the cost of treating IBS patients was in the region of $1.3 billion annually.

In addition to the direct charges to medical care, prescription drugs used in the treatment of IBS add substantially to the costs of the condition in the general population. Office-based physicians were reported to prescribe medications for 75 percent of their IBS patients (Everhart and Renault 1991) and the over-the-counter sales of laxatives in drugstores in the United States was estimated at $348 million per year in 1995 (Longstreth 1995). This figure is undoubtedly higher now. Interestingly, hysterectomy and ovarian surgery has been reported in 47 percent (Longstreth 1994) and 54 percent (Burns 1986) of patients with IBS, and these procedures have been carried out in sufferers of IBS more frequently than in any other group (Longstreth 1995).

Patients with IBS are reported to have more somatic complaints than people without IBS. Fatigue, headache, backache, pelvic pain, and psychosocial factors leading to psychiatric illness such as anxiety and depression, especially with a history of abuse in childhood and adulthood, often accompany symptoms of IBS. Additional costs accrue from alcohol abuse and use of sedatives and oral narcotics, which appear to be more frequent in persons experiencing IBS (Longstreth 1995). In women, IBS symptoms frequently worsen during menstruation and overlap of IBS with gynecological disorders leads to increased numbers of visits to gynecologists. Because of the frequent association with other organ systems and psychological factors, the severity of IBS waxes and wanes within the population, this determines the number of patients who seek medical help and undergo costly gastrointestinal investigations at any given time (Longstreth 1995). Because IBS remains a diagnosis of exclusion, these expensive investigations are often prerequisites for a final diagnosis of IBS.

The Role of Food in IBS

When all else fails, sufferers from chronic somatic distress tend to blame food for their problems. Since eating causes them to feel ill, presumably not eating will make them feel well. However, without food a person will starve to death. The alternative is choosing the right food. So often, food is the only factor in a person’s life over which they have complete control. Unfortunately, many popular books and magazine articles promise that “the right diet” will solve all problems, and patients frequently blame themselves for “not having enough willpower to stick to my diet,” or worse, blame their previous health care providers for not supplying them with the right formula, because, of course, there is such a thing, if only someone would tell them what it is!

Table of Contents:

Chapter 1 – What is Irritable Bowel Syndrome?
Chapter 2 – Functions of the Gastrointestinal Tract
Chapter 3 – Gastrointestinal Motility
Chapter 4 – Intestinal Mucosal Immunity
Chapter 5 – Inflammation
Chapter 6 – The Role and Functio9n of Microorganisms in the Digestive Tract
Chapter 7 – Microbial Colonization and Fermentation in the Small Intestine
Chapter 8 – Abnormalities in the Large Intestine
Chapter 9 – Infection and Toxicity in the Digestive Tract
Chapter 10 – Food Allergy
Chapter 11 – Food Intolerance
Chapter 12 – Psychological Factors and Stress in IBS
Chapter 13 – Therapeutic Management Strategies for IBS
Chapter 14 – Rationale for Dietary Management of Irritable Bowel Syndrome
Chapter 15 – Determining the Tolerated Foods
Appendix A – Dietary Management of Disaccharidase Deficiency
Appendix B – The Lactose-Free Diet
Appendix C – Meal Plans for the IBS Diet
Appendix D – Challenge Test Check List

What is Irritable Bowel Syndrome?