The Specific Carbohydrate Diet

 

by Tali Guday

The specific carbohydrate diet (SCD) is a strict grain-free, lactose-free and sucrose-free diet therapy.

Originally designed for people with Celiac disease over one hundred years ago, SCD evolved and became known amongst patients as an effective dietary therapy for inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), as well as other gut disorders and other autoimmune conditions. It is also used successfully to help children on the autism spectrum.

Until recently the link between diet, gut bacteria and disease had been ignored by mainstream medicine.  The basic assumption of the SCD was “revolutionary” and ahead of its time with the notion that the food we eat affects our gut bacteria and our gut bacteria effects our immune system and our health. Only in the last decade, as the human microbiome took center stage in scientific research and attention to diet therapies began to grow, the SCD gained the attention of the medical community. Lately it has been investigated in multiple studies as a legitimate medical option for managing disease.

The exact biochemical process occurring in the gut is still being researched, but the basic scientific theories behind SCD may be explained as the following cycle:

1. An internal or external source (a viral illness, antibiotics, MAP, stress…) causes damage to the gut.
2. A damaged gut cannot fully digest complex carbohydrates.
3. When complex carbohydrates are not easily digested and absorbed, they remain in the gut and nourish certain types of the natural gut bacteria. This creates a microbial imbalance in the gut, dysbiosis, as certain types of bacteria crowd-out other types of “good” bacteria.
4. The undigested carbohydrates are consumed by gut microbes in a process of fermentation. The waste products of fermentation, gases like methane, carbon dioxide & hydrogen, together with other toxins, irritate the gut and cause further gut damage.

How the diet addresses this cycle

“By altering the nutrition we take in, we can affect the constitution of our intestinal flora, and bring it back into balance, healing our digestive tracts and restoring proper absorption.”
Elaine Gottschall

The SCD separates allowed and forbidden foods based on the molecular chemical structure of the carbohydrates in each food. Monosaccharides (single molecule structure) are allowed, while disaccharides (double molecules) and polysaccharides (chain molecules) are forbidden.

The base assumption is that monosaccharides are simple structured and therefore easy to digest, but disaccharides and polysaccharides are not easily digested and as a result they end up feeding harmful bacteria in the intestines, causing them to overgrow, and eventually trigger inflammation of the intestine wall.

Eliminating these hard to digest carbohydrates allows the gut time and resources to repair itself and heal. The diet is focused on healthy, natural, unprocessed foods, free of harmful additives. Allowed foods include non-starchy vegetables, meats, fish and eggs, and reasonable quantities of fruits, nuts, honey and some lentils and beans. Forbidden foods are termed illegals, and include all grains, sugar, milk, and artificial additives. A comprehensive list of allowed and forbidden foods on the SCD can be found here: http://pecanbread.com/p/legal_illegal_a.htm

While SCD appears to be similar to current popular grain-free diets, SCD is an older and well-chronicled diet therapy with an interesting history. The roots of the specific carbohydrate diet began over one hundred years ago, but the diet was notably developed by doctor Sydney Valentine Haas, who wrote about it in 1951 in his book ‘Management of Celiac Disease’.

Elaine Gottschall helped to popularize the diet after using it to help her daughter recover from ulcerative colitis. Gottschall continued research on the diet and later wrote her own book which was published in 1994. Today, SCD is best known due to her book, ‘Breaking the Vicious Cycle: Intestinal Health Through Diet’.

A detailed history of the SCD can be found here: https://www.nimbal.org/education/the-specific-carbohydrate-diet-/definition-and-history

Helpful resources for those who are interested to learn more

SCD Official site: Breaking the Vicious Cycle http://www.breakingtheviciouscycle.info/
This site lays out the fundamentals of SCD, but it has not kept updated to reflect the growing body of accumulated knowledge and the constant updates that stem from diet users. It is managed by the family of Elaine Gottschall, which owns the copyrights and the SCD trademark.

NIMBAL (Nutrition in Immune Balance) https://www.nimbal.org/education
This site is based on current research of SCD style diet therapy for IBD. It was created by Professor David Suskind of Seattle Children’s Hospital to support patients, families, and healthcare providers. Built upon evidence-based research on the role of diet in Inflammatory Bowel Disease, NIMBAL transforms this data into understandable, applicable and practical approaches to diet in IBD.

Comprehensive list of allowed and forbidden foods on the SCD http://pecanbread.com/p/legal_illegal_a.htm

Reliable SCD Resources for Beginners http://gutharmony.net/index.php/2016/01/01/reliable-resources-for-beginners-of-the-specific-carbohydrates-diet/

To explore ongoing SCD clinical trials around the world, visit ClinicalTrials.gov.

About the Author

Tali Guday is on a mission to make diet therapies for IBD better understood and easier to practice. She established a large international support group for pediatric IBD families, and founded the website Gut Harmony and the corresponding Gut Harmony FB site. She is a member of Dr. Suskind’s NIMBAL Advisory Committee and is currently focused on helping young adults transition to independent practice of restricted diet therapy at college and beyond.

SCD Research Article Summary

by Human Para Moderator

Nutritional Adequacy of the Specific Carbohydrate Diet in Pediatric Inflammatory Bowel Disease. (Nov. 2017)
The goal of this study was to assess the adequacy of the Specific Carbohydrate Diet (SCD). Researchers compared the levels of 20 key nutrients in 8 SCD pediatric IBD patients vs. non-SCD pediatric controls. SCD participants met the recommended daily allowance for vitamins B2, B3, B5, B6, B7, B12, C, A, and E. The daily intake for vitamin D and calcium was not met for most SCD participants, and 42% met the required intake for magnesium. The conclusion was that nutrient intake of SCD patients was adequate when compared to healthy peers, but that close monitoring of patients on SCD is recommended to assure positive outcomes.
Braly K et al, J Pediatr Gastroenterol Nutr. 2017 Nov;65(5):533-538.

Lack of Mucosal Healing From Modified Specific Carbohydrate Diet in Pediatric Patients With Crohn Disease. (Sept. 2017)
This retrospective review examined the effect of mucosal healing on pediatric Crohn’s disease patients who followed a modified SCD protocol (SCD + some “illegal” foods.) The subjects were on the mSCD for an average of 26 weeks, and had no active symptoms when the endoscopies were completed. Of the 7 patients studied, one had complete ileocolonic healing, but mucosal healing in both the ilecolonic and upper gastrointestinal tract was not seen in any of the patients. More study is needed.
Wahbeh GT et al, J Pediatr Gastroenterol Nutr. 2017 Sep;65(3):289-292.

Specific carbohydrate diet for pediatric inflammatory bowel disease in clinical practice within an academic IBD center. (April 2016)
Researchers here reviewed records of 26 pediatric IBD patients (20 with Crohn’s disease, 6 with ulcerative colitis) who were following the SCD. The Crohn’s Disease Activity Index dropped from 32.8 at the start of the SCD to 20.8 at 4 weeks, and to 8.8 by 6 months. For the UC patients, the disease activity went from 28.3 at the start of SCD to 20.0 at 4 weeks, to 18.3 at 6 months. The authors’ conclusion was that SCD could be incorporated into pediatric IBD care centers to improve outcomes for patients.
Obih C et al, Nutrition. 2016 Apr;32(4):418-25.

Response to strict and liberalized specific carbohydrate diet in pediatric Crohn’s disease. (Feb. 2014)
The aim of this study was to look at SCD as a maintenance of remission therapy for pediatric Crohn’s disease patients. Of the 11 patients using SCD, 3 had no other therapy, 2 were on antibiotics or 5-ASA, 3 added a steroid taper and 3 remained on 6MP and 5-ASA. None were on biologics. 3 patients maintained a strict SCD regimen, and the others added “illegal” foods after starting the study. 90% of patients gained weight while on the strict SCD. Improvements were seen in anemia, albumin and inflammatory markers when the patients followed strict SCD. However, mild deviation after strict SCD may provide an option for maintaining remission.
Burgis J et al, World J Gastroenterol. 2016 Feb 14; 22(6): 2111–2117.