Gastrointestinal (GI) complications are commonly seen with anorexia, bulimia and binge eating disorder. Heartburn, gas, bloating, early fullness, nausea, abdominal distention, rectal pain, constipation or diarrhea might be considered simply “irritable bowel syndrome” – potentially delaying rapid diagnosis and treatment of an underlying eating disorder. Often referred to as functional gut disorders, there is an impairment in the body’s normal “functioning,” such as delayed movement of food through the digestive tract, hypersensitivity of intestinal nerve cells, and the way in which a person’s brain responds to these stimuli (1). Re-feeding and in turn, recovery, is difficult physically as well as emotionally.
Anorexia Nervosa, Restricting-Type
Prolonged food restriction causes muscular atrophy of the entire digestive tract. This leads to slow stomach emptying (called gastroparesis) and is a direct cause of the trapped gas, bloating and abdominal distention seen with anorexia. Post-meal pain, pressure and constipation can be quite severe.
Consumption of sugar-free products and high fiber fruits and vegetables to blunt hunger can add to GI discomfort. Sorbitol – found in sugar-free gums and mints, and fructose – found in many fruits – can increase gas production. Psychological factors such as depression and/or anxiety, as well as pelvic floor dysfunction, can lead to heightened awareness of pain sensations in the gut, making the problem feel even worse (2,3).
A rare but documented cause of severe abdominal pain can be seen in extremely malnourished individuals. It is called Superior mesenteric artery (SMA) syndrome and is caused by compression of the artery by the first portion of the intestines called the duodenum (4). This is a medical emergency and therefore is imperative that individuals struggling with overcoming any type of eating disorder work with medical professionals to safely guide and monitor them.
Purging can lead to a condition known as acute sialadenosis, in which the parotid glands become swollen and painful. This condition will cause an individual to have a characteristic “chipmunk-like” appearance. Treatment involves warm compresses, tart candies, and anti-inflammatory medication (5). Individuals struggling with bulimia also experience gas, bloating, indigestion and constipation as well as gastritis, an inflammation of the lining of the stomach causing upper abdominal pain.
Upper GI symptoms of acid reflux occur due to repeated bouts of self-induced vomiting. The valve (called a sphincter) that controls the connection between the stomach and esophagus becomes floppy, allowing stomach acids and partially digested foods to back up through the esophagus and into the throat. This is involuntary and may cause erosion of the mucosa of the esophagus, leading to a condition known as Barrett’s esophagus, a precursor to esophageal cancer (3). Repeated bouts of self-induced vomiting can ultimately cause tears in the esophagus, referred to as a Mallory Weiss Tears. Vomiting blood is a very frightening experience and requires emergency medical care. Daily vomiting can put tremendous strain on the heart muscle resulting in arrhythmias, palpitations and death (4).
Bloodwork may show characteristic abnormalities more commonly seen when purging becomes frequent and habitual. The pancreas and liver enzymes may be elevated without other symptoms and electrolyte levels may be abnormal (5,6).
Difficulty swallowing is another problem commonly seen in anorexia and bulimia and may be related to the loss of muscle tone in the esophagus. It is important to see a physician when a patient complains of difficulty swallowing while increasing nutrition.
Other purging disorders – Laxatives, Diuretics and Exercise
Laxative abuse has been reported in more than 1/3 of patients with eating disorders. Patients believe they are purging calories to stay thin, when in fact, most absorption of calories occurs in the small intestine. Most commonly (though not exclusively) seen in patients with bulimia, laxative abuse causes the bowel to become dependent on laxative stimulation to pass a bowel movement. Individuals who use laxatives, diuretics or both (to purge calories) become severely and chronically dehydrated. Kidney function can then suffer impairment from chronic depletion of blood flow due to dehydration. Stimulant laxatives work by irritating the nerves that stimulate the colon to cause frequent watery stools, while bulk-forming laxatives work by increasing stool mass to the point the bowels force it out.
This chronic overstimulation can cause complete bowel shutdown which is referred to as cathartic colon. Once a patient’s colon becomes incapable of transporting fecal material, they may require partial or complete colon resection, or even require a colostomy bag (7,8). Additionally, stopping these behaviors ‘cold turkey’ can cause extreme fluid shifts, renal shutdown and life threatening electrolyte imbalance. This is referred to as Pseudo-Bartters syndrome (5,6). Medical practitioners need to carefully monitor patients as they wean off laxatives and diuretics for this reason. Over exercise is another form of purging behavior.
Rectal prolapse occurs when the rectum protrudes outside the opening of the anus. Although not a common feature, rectal prolapse has been seen in patients who binge and purge, and in patients suffering from severe constipation and/or laxative abuse.
Increased intraabdominal pressure from vomiting, among other factors such as medication, poor diet and low fiber intake contribute to this condition. Surgical treatment is the definitive treatment for recurring prolapse but steps to prevent further constipation are essential (5,6).
Binge Eating Disorder
Individuals who binge-eat tend to have erratic and irregular eating patterns around all meals, in turn causing a host of GI symptoms including constipation, gas, bloating and diarrhea.
Patients with anorexia who binge eat are at risk for acute gastric dilatation. This is due to slow gastric emptying and overeating large volumes in the face of weakened stomach musculature. The large quantity of food exceeds the stomach’s ability to empty which obstructs of blood flow to the stomach and intestines. The result is potential rupture of the stomach (4). Symptoms include vomiting, severe abdominal distention and pain.
Practical Suggestions to Reduce GI Discomfort While Recovering
It is advisable to see a physician to evaluate the many causes of gastrointestinal distress. Although many symptoms mentioned resolve with normal eating, it is important to rule out the potentially serious GI issues we see commonly with eating disorders.
The best long term relief for the discomfort accompanying normalized eating at the start of recovery is to schedule meals, snacks and fluids at regular intervals, and to sit calmly and mindfully while eating. Often referred to as “the rule of threes” (7,8) it is advisable to consume three meals and three snacks, at least three hours apart. Re-introducing foods as well as any type of nutritional supplementation should be done under the proper care and guidance of a physician and the dietitian to collaboratively treat these problems in a multidisciplinary approach.
For people with eating disorders, adequate fluids and fiber are the first line treatment for chronic constipation. It is advisable to increase fiber intake slowly to avoid additional gas and bloating. Examples of fiber-rich foods include whole grain breads and cereals, bran, nuts and seeds, lentils, beans and some fruits and vegetables.
Patients who are continuing to struggle with constipation should consult with their physicians for any potential medication needs. The fact remains that with continued good eating over time, many of these GI complains will resolve.
Gas, Bloating and Cramping
Physicians will recommend simethicone (Gas-X) to help with gas pain, and recent clinical guidelines by the American College of Gastroenterology suggest the use of metoclopramide (Reglan) to help with slow gastric emptying (9). Metoclopramide increases muscle contractions in the upper digestive tract and speeds up the rate at which the stomach empties into the intestines. This medication must be given with caution, however, as it can affect the heart rate of someone with anorexia.
One of the main goals in treating the GI symptoms of bulimia is to reduce and eliminate purging behavior. In cases where associated heartburn is frequent doctors will recommend a protein-pump inhibitor, a medication that protects the esophageal wall by reducing the stomach’s production of gastric acid.
In some cases, therapies to calm the gut including meditation or anti-anxiety meds, can be quite helpful. It is important to note that “special” diets, or eliminating certain foods in an attempt to alleviate symptoms is not wise to try while in recovery. Dietitians need to individualize meal plans for the specific needs of each client.
If you are in recovery or caring for someone in recovery, the abdominal discomfort with eating is very real. The body has gotten used to eating smaller amounts of food and the additional anxiety of increasing intake is truly distressing. As long as you’ve consulted a medical professional, the best treatment for GI upset is to continue following a plan of regular meals and snacks. Some patients have found heat pads or hot water bottles placed directly on the belly after meals to be helpful when pain is severe.
New Research Ahead – The Role of the Intestinal Microbiota
New research on the role of the intestinal microbiota in anorexia and other eating disorders is exciting. This research looks at the enteric nervous system, comprised of more than 100 million nerve cells lining your entire GI tract. This neural complex is thought to be equivalent to “a second brain” affecting digestion, weight regulation and even mood. Entirely new treatments are on the horizon as we begin to understand the interactive regulation that now clearly exists between the gut and the brain (10). Hopefully, we will continue to find new treatments for the gastric distress that eating disorder sufferers encounter as they work towards meaningful recovery.
About The Author:
Erica Leon, MS, RDN, CDN, CEDRD is the founder of Erica Leon Nutrition. She specializes in nutrition counseling for eating disorders and unhealthy eating patterns, as well as intuitive eating coaching.
Thank you so much to the following clinicians who kindly (and generously) reviewed this paper for accuracy of content:
Marcia Herrin, EdD, MPH, RDN, LD, FAED
Fellow, Academy of Eating Disorders
Author: The Parent’s Guide to Eating Disorders (Gurze Press, 2007) & Nutrition Counseling in the Treatment of Eating Disorders (Brunner-Routledge, 2013)
Patsy Catsos, MS, RDN, LD
Digestive Health Expert
Author: IBS—Free at Last! (2012)
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