Editorial

Low-Disaccharide Diet Effective Against Crohn’s Disease

Nowadays the airways are being bombarded by commercials for Humira, a drug that has been approved by the FDA for the treatment of Crohn’s disease. This drug costs about $19,000 per year, and can cause serious side effects, including life-threatening infections, neurologic disorders, and cancer. With sales of $10.7 billion last year (it is also approved for several other autoimmune diseases), Humira is the largest-selling drug in the world. It is one of the latest examples of obscenely expensive, frightfully dangerous drugs being advertised to desperate patients with serious diseases.

Fortunately, a safe and effective dietary treatment for Crohn’s disease – the Specific Carbohydrate Diet – has been available for more than 20 years. Although it has not been as widely publicized as drug treatments, a growing number of Crohn’s-disease suffers have experienced dramatic improvements, and in many cases apparent cures, from this diet. It is called the Specific Carbohydrate Diet because it only allows foods that are free of or contain negligible amounts of disaccharides (a specific type of dietary carbohydrates) or disaccharide precursors.

Low-Disaccharide Diet

Lactose, sucrose, maltose, and isomaltose are the major disaccharides present in the human diet. These nonabsorbable disaccharides are hydrolyzed to absorbable monosaccharides by disaccharidase enzymes present in the small-intestinal mucosa: lactase, sucrase, maltase, and isomaltose, respectively.

Lactase deficiency has been observed in 30% to 40% of patients with Crohn’s disease.¹ In addition, a significant reduction in total disaccharidase activity was found in the jejunum of patients with Crohn’s disease who had no radiologic evidence of small-bowel involvement.² It is well known that malabsorbed lactose is fermented by intestinal bacteria, which leads to the production of gases that can cause various gastrointestinal symptoms. Patients with lactose intolerance complicating Crohn’s disease often experience an improvement in their intestinal symptoms when they avoid cow’s milk and other lactose-containing foods. Similarly, patients with congenital sucrase deficiency experience an improvement in gastrointestinal symptoms when they avoid sucrose-containing foods.³

Elaine Gottschall, in her 1994 book, Breaking the Vicious Cycle, hypothesized that the consumption of disaccharide-containing foods not only exacerbates symptoms in many patients with Crohn’s disease but also plays an important role in the pathogenesis of the disease.⁴ According to this hypothesis, the presence of undigested disaccharides encourages bacterial proliferation in the normally sterile small bowel. The byproducts of bacterial fermentation, in addition to triggering gastrointestinal symptoms, further damage the small-intestinal mucosa and further decrease disaccharidase activity, which leads to a vicious cycle of more bacterial overgrowth and more pronounced intestinal damage. This vicious cycle can be broken by avoiding all foods that contain either disaccharides or starches that are metabolized to disaccharides (such as amylopectin).

Gottschall reported that consumption of a low-disaccharide diet frequently results in marked clinical improvement or complete remission in patients with Crohn’s disease. Moreover, many patients who strictly adhere to the diet for 2 years or more are apparently “cured,” in that they are able to relax the dietary restrictions without experiencing a recurrence of the disease.

The Specific Carbohydrate Diet excludes all grains (including wheat, oats, barley, rye, corn, rice, millet, buckwheat, spelt, and triticale), milk and other lactose-containing foods, potatoes, soybeans and certain other beans, corn syrup, foods that contain sucrose, and a number of other foods. It is described in detail in Gottschall’s book. In my experience, the Specific Carbohydrate Diet has been highly beneficial for several patients with Crohn’s disease.

Other investigators have recently confirmed Gottschall’s observations. In a new report, researchers reviewed the medical record of 7 children (aged 7–16 years) with Crohn’s disease who had followed the Specific Carbohydrate Diet and had not received immunosuppressive medication. The mean duration of dietary therapy was 14.6 months (range, 5–30 months). All symptoms were resolved in all cases at a follow-up visit 3 months after the start of the diet. Each patient’s laboratory tests, including serum albumin, C-reactive protein, hematocrit, and stool calprotectin (an indicator of intestinal inflammation), either became normal or improved significantly. All patients had an increase in height and weight.⁵

Many of the foods prohibited on this diet (such as wheat, corn, and milk) are among the most frequently allergenic foods, so it is not clear how much of the improvement is due to allergen avoidance and how much to the avoidance of disaccharides. In addition, it is not clear how the proposed vicious cycle of small-bowel bacterial overgrowth and disaccharidase deficiency begins. Studies in infants recovering from enteritis have shown that ingestion of cow’s milk protein can cause a marked reduction in lactase, sucrase, and maltase activity (isomaltase activity was not measured), accompanied by histologic changes in jejunal mucosa.⁶ That finding suggests that consumption of allergenic foods may in some cases be the initial insult that leads to disaccharide intolerance. In other cases, the initial insult might be disruption of the intestinal flora secondary to antibiotic therapy.⁷

Alan R. Gaby, MD

Notes

1. Kirschner BS et al W. Lactose malabsorption in children and adolescents with inflammatory bowel disease. Gastroenterology. 1981;81:829–832.

2. Arvanitakis C. Abnormalities of jejunal mucosal enzymes in ulcerative colitis and Crohn’s disease. Digestion. 1979;19:259–266.

3. Harms HK et al. Enzyme-substitution therapy with the yeast Saccharomyces cerevisiae in congenital sucrase-isomaltase deficiency. N Engl J Med. 1987;316:1306–1309.

4. Gottschall E. Breaking the Vicious Cycle. Kirkton, ON: Kirkton Press; 1994.

5. Suskind DL et al. Nutritional therapy in pediatric Crohn disease: the specific carbohydrate diet. J Pediatr Gastroenterol Nutr. 2014;58:87–91.

6. Iyngkaran N et al. Acquired carbohydrate intolerance and cow milk protein-sensitive enteropathy in young infants. J Pediatr. 1979;95:373–378.

7. Hildebrand H et al. Early-life exposures associated with antibiotic use and risk of subsequent Crohn’s disease. Scand J Gastroenterol. 2008;43:961–966.