Specific Carb Diet vs. Low-fiber

Crohn’s and other inflammatory bowel diseases (IBDs) can be frustrating for patients and their health care providers alike. While food is clearly not the source of the illness, it’s equally clear that diet can play a role in dealing with symptoms and prolonging remission of the disease. Many patients find that a diet with relatively little fiber (the so-called low-fiber/low-residue diet) helps ease symptoms of cramping and diarrhea, by reducing the volume of stool.

But experts generally advise Crohn’s patients to attempt to eat a normal, nutritionally balanced diet to the extent they are able. So what about specialized diets, such as the Specific Carbohydrate Diet, which has been touted in some circles as a superior diet for treating IBD?

Are Carbohydrates the Villain?

The Specific Carbohydrate Diet was developed by doctor Sidney V. Haas, and introduced to the public in the early 1990s by author, Elaine Gotschall, in her book, Breaking the Vicious Cycle: Intestinal Health Through Diet. Gotschall’s interest in promoting the diet arose from her experiences helping her own daughter deal with colonic inflammation as a young child. A biochemist, Gotschall studied how the inflammatory process affects the lining of the intestines. On the advice of her daughter’s physicians, Gotschall’s daughter followed the strict low-carbohydrate, gluten-free diet.

When her daughter’s symptoms resolved completely, allowing her to resume eating a normal diet, Gotschall promoted the highly restrictive diet as an answer to IBDs. According to Gotschall, undigested carbohydrates promote the activity of certain microorganisms (bacteria) living in the gut lining, encouraging the release of toxins and acids that damage the tissue of the digestive tract lining. This in turn damages enzymes that ordinarily help break down carbohydrates, thus perpetuating a “vicious cycle” that prevents the digestion and absorption of nutrients from carbohydrates.

The diet is even more demanding than a standard gluten-free diet. Gluten is a protein found in certain grains, including wheat, rye and barley. People who are truly allergic to this protein have an often-undiagnosed illness called celiac disease. Avoidance of all gluten helps people with celiac disease return to health and resume a normal life. The Specific Carbohydrate Diet goes even further, eliminating all grains from the diet, including corn, oats, rice, soy, and so on. It also eliminates lactose (milk sugar), sucrose (table sugar), and starchy foods such as pasta, bread and potatoes.

The goal is to eliminate virtually all carbohydrates. Critics note that it is an extremely restrictive, difficult-to-follow diet. They also point out that there is very little well-documented scientific evidence to support the effectiveness of the diet.

Additional inconsistencies in the diet bother experts. The diet allows consumption of fruits, for instance, which contain the carbohydrate fructose, a form of sugar. Some IBD patients suffer from fructose malabsorption, meaning they have difficulty absorbing this type of sugar. As a result, such patients are more likely to suffer the intestinal cramps and diarrhea that the diet purports to prevent. Also, while the Specific Carbohydrate Diet prohibits most legumes, it allows others. Critics argue that this is illogical, as some of the allowed legumes, such as white beans, actually contain carbohydrates that even many healthy people have difficulty digesting.

On the other hand, there is growing interest in the possible role of so-called “intestinal microflora” (microscopic lifeforms, including bacteria, viruses and fungi), which live in the digestive tract, in promoting the inflammation associated with IBD. Some recent research suggests that the body overreacts to the presence of certain microbes. Reducing their number through a restrictive diet, therefore, might be expected to reduce symptoms of inflammation.

Specific Carbohydrate Versus Low-Fiber: Which Is Better?

Unfortunately, no large, well-controlled clinical trials have been conducted to investigate the relative merits of the Specific Carbohydrate Diet versus a low-fiber/low-residue diet. For that matter, little credible evidence exists in medical literature to support the effectiveness of the Specific Carbohydrate Diet as a therapy for Crohn’s disease.

Doctors with experience in IBD patients note that some patients have reported success on the Specific Carbohydrate Diet. They also note, however, that patients often find the diet too difficult to stick with, and some worry that its highly restrictive nature might further encourage weight loss among some patients, for whom failure to gain weight is a crucial concern.

Some experts feel that the diet is worth a try, but they caution that it should be followed with the help of a nutritionist, who can ensure that the patient is getting enough calories. Vitamins and minerals can be obtained through supplements, but calories must come from food. Experts also advise against starting the diet and then stopping medications. Patients should always consult with their physician before making any significant changes in their diet or medical treatment.