A diet rich in multiple carbohydrate sources, including sugars, starchy carbohydrates, and dietary fiber, is a likely perpetrator of inflammatory bowel disease (IBD), two researchers believe. They say the diet may promote immune imbalances, and disrupt the gut’s natural barrier and microbiome.
They propose that a “carbohydrate monotony” diet may have greater benefits for IBD patients.
“We believe our hypothesis is novel, thought-provoking and well-substantiated. Therefore, we are confident that this viewpoint has a significant opportunity to advance the field,” they stated.
The opinion piece, “Carbohydrate Monotony as Protection and Treatment for Inflammatory Bowel Disease,” was published in the Journal of Crohn’s and Colitis.
IBD, which includes Crohn’s disease and ulcerative colitis, causes chronic and inflammatory diseases that affect the digestive tract. The physiological cause of these conditions is unclear, and no cure for IBD has been found.
Less-developed countries that are adopting a Western-type lifestyle are showing an increase in IBD cases, albeit with a lower incidence. This illustrates the importance of understanding the environmental factors behind IBD.
Researchers believe IBD is influenced by genetics, defective immunological responses of the host, problems in the gut’s natural barrier and in its microbiome (the natural, beneficial community of microbes living in the gut). But dietary changes associated with industrialization have also received great attention from the scientific community.
Processed food, emulsifiers, refrigeration, low fiber intake, high fat or sugar intake, and carbohydrate-dominated food consumption characteristic of Western diets could be a possible cause of IBD development.
The two researchers at the Texas Children’s Hospital Baylor College of Medicine hypothesized that a nutritional theory of IBD could lead to valuable treatment for these patients. They examined world trends of carbohydrate consumption to understand whether a higher intake rate correlates with an increased incidence of IBD.
They saw that most of the 10 countries with the highest consumption are in Africa, where the primary energy source is carbohydrates with lower intake of protein and fat. However, these countries also present a low IBD incidence, meaning that the amount of carbohydrate intake may not contribute to IBD.
“It seems that the populations with lower IBD incidence and prevalence are some of the highest consumers of carbohydrates, leading us to believe that it is not the amount of carbohydrate intake that leads to an increased risk of developing IBD,” the authors wrote.
They looked for common factors among dietary regimens that are showing promising results in IBD symptom management. Exclusive enteral nutrition (EEN) — the use of a complete liquid diet, with the exclusion of normal dietary components for a defined period of time — the specific carbohydrate diet (SCD), and Paleo diet all restrict the variety of carbohydrates a person eats.
The intake of only a few carbohydrate types, especially simple sugars (monosaccharides) such as glucose, fructose, and galactose in SCD, has been shown to improve the diversity of microorganisms or microbiome in an IBD patient’s gut. Changes in the microbiome could promote a transition to a non-inflammatory gut microenvironment.
A gluten-free diet, famous for its use among celiac patients, has also been adopted in IBD. However, any symptom relief is most likely because of a reduction in the intake of low fermentable, poorly absorbed, short-chain carbohydrates or FODMAPs responsible for increasing gut permeability, a known predisposing factor for Crohn’s disease.
Beyond the impact on microbiome, other effects of these diets on inflammatory dysfunction and mucosal barrier have not been shown. Nevertheless, the intake of consistent and not diverse carbohydrates holds promise for IBD.
“It is our viewpoint, based on assessing similarities between EEN, SCD, and other exclusion diets that have been successfully used in patients with IBD, that it is the monotonous nature of these diets, specifically with respect to carbohydrates, that is the common and key factor for success,” they concluded.