Dr. Darwin Deen is one of the nation’s foremost authorities on nutrition. Currently Professor of Clinical, Family and Social Medicine and Director of Medical Student Education at the Albert Einstein College of Medicine in New York, he has trained a generation of physicians on the connection between nutrition and health. He has played a leading role in revising medical school curricula to incorporate nutrition training. An award-winning teacher and noted author, he serves as Chair of the Task Force on Medical Nutrition Education of the American College of Nutrition and co-chairs the Group on Nutrition of the Society of Teachers of Family Medicine. His years of experience as a family physician make him perfectly suited to advise clinicians on counseling their patients on diet and lifestyle.

Dr. Lisa Hark is a renowned family nutrition expert, with more than 20 years of experience in nutrition counseling and promoting the benefits of healthy eating in children and adults. As Director of the Nutrition Education Program at the University of Pennsylvania School of Medicine in Philadelphia, she developed a model medical school curriculum and textbook, Medical Nutrition and Disease, which has become one of the most widely used texts in nutrition education. She was given the Excellence in Medical/Dental Nutrition Education award from the American Society for Nutrition. Dr. Hark was also the host of the TV show, “Honey, We’re Killing the Kids,” which airs on TLC, and is a widely sought after speaker who communicates nutrition concepts effectively to health professionals, patients, and the media.

Specific carbohydrate diet

Conventional medicine has typically had little to offer in terms of dietary ad- vice for patients with inflammatory bowel disorders including diverticulitis, Crohn's disease (CD), and ulcerative colitis. There is, however, a therapeutic diet which can be extremely helpful to certain patients with this type of con- dition: The Specific Carbohydrate Diet (SCD). The SCD, described in detail in Elaine Gottschall's book "Breaking the Vicious Cycle," [18]is a low disaccharide diet, in which almost all foods containing disaccharides and polysaccharides are eliminated - including lactose-containing dairy, all grains, and all legumes.

The theory behind the use of the SCD diet in these disorders centers on the concept that part of the cause of diseases characterized by inflammation of the gastrointestinal tract may be a hypersensitive cellular immune response to certain components of the intestinal flora. Several studies have shown that specific foods can trigger symptoms in patients with both ulcerative colitis an CD - and it may be that this is linked to the way in which these foods influence the intestinal flora. Carbohydrates have the greatest influence on the intestinal microbial population - much more than do proteins and fats. Certain types of carbohydrates - monosaccharides in particular - are easily digested and absorbed, leaving behind minimal residue for potentially pathogenic intestinal bacteria to feed on. Disaccharides and other more complex sugars tend to be more difficult to digest and absorb, leaving behind more breakdown products in the gut.

In the "vicious cycle" of carbohydrate malabsorption promoted by the dis- accharides in susceptible individuals, pathogenic microbes proliferate due to their preference for the breakdown products of the complex sugars. This re- sults in changes in intestinal pH, accompanied by disruption of digestion. The pathogenic bacteria also promote a "leaky gut" through their impact on intestinal mucosa, leading to the inappropriate absorption of certain food par- ticles and their presentation to the gut-associated lymphoid tissue. This in turn leads to systemic inflammation and immune dysfunction. The pathogenic bac- teria also promote fermentative degradation of certain hard-to-digest foods, leading to excessive gas, mucous in the stool, and bloating. According to SCD proponents, the main dietary culprits in this "vicious cycle" are disaccharides, polysaccharides, and other enzymatically-resistant carbohydrates found in grains, certain starchy vegetables, fruits, table sugar, and lactose-rich dairy products. These foods are therefore the main targets for elimination in the SCD diet (see Table 14.2). In fact some studies do confirm that carbohydrate consumption is significantly higher in inflammatory bowel disease (IBD) patients than in healthy controls [19-21], although the signif- icance of these findings in the pathogenesis of the disease remains unclear. Many patients with CD do have a higher dietary intake of sucrose, refined carbohydrates and omega-6 fatty acids, and reduced intake of fruit and veg- etables.

Specific carbohydrate diet research

Research on the SCD diet to date is limited. In one study of 204 patients with CD, 69 were randomized to a low carbohydrate diet (84 g/ day). Fifty-four percent of these benefited significantly for as long as they maintained the diet [22]. Elemental and exclusion diets have also been shown to be effective in some patients with CD [23],lending credence to the exclusion of disaccharides and polysaccharides. In a study of 33 patients with CD, 29 patients reported specific food intolerances, and 21 of these remained in remission on diet alone (elimination diet or elemental diet), with the mean length of remission being 15.2months [24].The most important foods provoking symptoms were wheat and dairy products. In another study a group of 20 patients with CD were followed for several years using variations on the SCD approach; all of these patients demonstrated a decrease in symptoms and reduction in medication use [25],and six patients experienced complete clinical remission, discontinued all medication, and maintained remission for five to 80 months.

In addition to its uses in patients with inflammatory bowel disease, the SCD is also often used for treating irritable bowel syndrome, celiac disease, diarrhea, and other digestive disorders. It has also recently become popular as one of the dietary approaches to autistic spectrum disorders. While a significant body of research evidence for the SCD in the management of IBD is lacking, anecdotal evidence is overwhelmingly positive.
Pages 298-301

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There is a lot of discussion about the scientific merit of SCD on pages 140-141.
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