Specific Carb Diet vs. Low-fiber

Crohn’s and other inflammatory bowel diseases (IBDs) can be frustrating and hard manage. 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 people find that a diet with relatively little fiber helps ease symptoms of cramping and diarrhea, by reducing the volume of stool.

But experts generally advise people with Crohn’s to try 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 choice for treating IBDs?

Are Carbohydrates the Villain?

Dr. Sidney V. Haas is credited with first introducing the idea of the specific carbohydrate diet in 1923 when he presented eight case studies to the New York Academy of Medicine in his paper titled “The Value of the Banana in the Treatment of Celiac Disease.” He presented his research and the full diet in the 1951 book he co-authored with his son, Merrill Patterson Haas, titled “Management of Celiac Disease.”

The diet was introduced to the general public in the early 1990s by biochemist 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.

 Gotschall studied how the inflammatory process affects the lining of the intestines. On the advice of her daughter’s doctors, Gotschall’s daughter followed the strict low-carbohydrate, gluten-free diet. When her daughter’s symptoms resolved completely, allowing her go back to a normal diet, Gotschall promoted the highly restrictive diet, called the specific carbohydrate diet, as an answer to IBDs.

According to Gotschall, undigested carbohydrates promote the activity of certain microorganisms, or bacteria, living in the gut lining. This activity encourages the release of toxins and acids that damage the tissue of the digestive tract lining. This action in turn damages enzymes that ordinarily help break down carbohydrates. In this way, a vicious cycle begins preventing the digestion and absorption of nutrients from carbohydrates.

The diet is even more demanding than a gluten-free diet. Gluten is a protein found in certain grains, including:

  • wheat
  • rye
  • barley

People who are allergic to this protein have an illness called Celiac disease, which often goes undiagnosed. Avoiding gluten helps people with Celiac disease manage symptoms and return to health. 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, sucrose, and starchy foods such as pasta, bread and potatoes.

The goal is to eliminate virtually all carbohydrates. Critics note that it’s 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 fructose, a form of sugar. Some people with IBDs have fructose malabsorption. This means they have difficulty absorbing this type of sugar. As a result, they 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, contain carbohydrates that even many healthy people have difficulty digesting.

There is also growing interest in “intestinal microflora.” These are microscopic life-forms living in the digestive tract, including:

  • bacteria
  • viruses
  • fungi

Researchers are interested in the possible role these organisms play in promoting or reducing inflammation associated with IBD. Some research suggests that the body overreacts to the presence of certain microbes. Reducing their number through a restrictive diet might reduce symptoms of inflammation.

Specific Carbohydrate vs. 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.

One study, published in the Journal of the Academy of Nutrition and Dietetics in 2015, surveyed 50 people with IBDs in remission who followed the specific carbohydrate diet. The survey found that this diet could potentially help manage IBDs, specifically cases of colonic and ileocolonic Crohn’s disease. Participants generally reported some improvement in symptoms after about 30 days on the diet, while 33 of them said their symptoms resolved completely after about 10 months. The researchers noted that participants took an average of 10.8 hours each week to prepare food, and about 40 percent did not have full-time jobs. On a scale of 0 to 100 percent, subjects rated the difficulty of following this diet at 40 percent.

Doctors with experience in IBD patients say 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. Some doctors express concern that its highly restrictive nature might encourage weight loss among 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. They emphasize that while vitamins and minerals can be obtained through supplements, 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.

You Asked, We Answered

  • Are there any things a person with IBS or Crohn’s should always have in their cabinet or bag?
  • Always keep on hand a very concentrated probiotic supplement, such as Vitamin D and VSL #3, a probiotic food available over the counter. Good research supports the daily intake of these supplements for IBD sufferers.

    - Natalie Butler, RD, LD