Nutritional Aid for Non-Infectious Inflammatory Bowel Disease – Does the Low-Carbohydrate Diet Really Work?

The primary symptoms include frequent diarrhea, abdominal pain, blood in stool, weight loss, and chronic fatigue. During the disease course, digestive and absorptive dysfunctions occur, leading to nutrient deficiencies and systemic complications. Both conditions exhibit alternating phases of exacerbation and remission. While a cure is not possible, symptom management can be achieved through targeted medications and dietary adjustments (S. S. Seyedian, F. Nokhostin, M. D. Malamir 2019). Without intervention, surgical resection or stoma creation may become necessary, significantly enhancing patient quality of life (A. L. Komorowski 2017).

The carbohydrate-selective diet was initially devised in the early 20th century by Dr. Sidney Hass as a dietary intervention for celiac disease, an autoimmune condition triggered by gluten consumption. In the late 1980s, Elaine Gottschall popularized the SCD diet as an adjunct therapy for inflammatory bowel diseases. This nutritional approach involves the exclusion of complex carbohydrates, including starch, lactose, and sucrose. Research indicates that individuals with Crohn's disease or ulcerative colitis experience impaired digestion of polysaccharides, leading to their accumulation in the intestines. These polysaccharides serve as nutrients for pathogenic gut microbiota, potentially exacerbating dysbiosis and inflammation. The removal of complex carbohydrates may alleviate dysbiosis and gastrointestinal symptoms (D. L. Suskind et al., 2014). Beyond IBD, this diet has been explored for irritable bowel syndrome, diverticulitis, celiac disease, autism, and cystic fibrosis (NASPGHAN, 2016).

The SCD diet prohibits the following products: processed meat products (liverwurst, sausages, canned goods, low-quality deli meats containing sugar), cereals and their derivatives, potatoes, sweet potatoes, parsnips, legume seeds (except for beans, peas, and chickpeas), seaweed, milk and dairy products (except for homemade yogurt and goat cheese), instant coffee and tea, candied and dried fruits, powdered spices, sugar, and sweeteners – with the exception of honey (E. Gottschall, 1994).

There is limited research on the effectiveness of a carbohydrate-selective diet. Elaine Gottschall, who popularized and described this dietary approach, claims that it prevented her daughter from requiring intestinal surgery and led to remission of inflammatory bowel disease. However, this is only a case report, which does not allow for definitive conclusions. Scientific sources indicate that most studies on the efficacy of the SCD diet have been conducted on children. With long-term use (over 4 weeks), significant improvements in health, intestinal mucosa, well-being, and a reduction in the PCDAI (Pediatric Crohn’s Disease Activity Index) have been observed. Additionally, laboratory test results have improved. However, researchers emphasize that further studies are needed to confirm the diet’s effectiveness in inflammatory bowel diseases. In irritable bowel syndrome (IBS), the primary dietary recommendation is a low-FODMAP diet, which restricts fermentable oligo-, di-, and monosaccharides (fructose, lactose, galactans, fructans) and polyols (e.g., xylitol, sorbitol). The goal is to identify foods that trigger symptoms such as bloating, gas, abdominal pain, constipation, or diarrhea. In the initial phase (2–6 weeks), all high-FODMAP foods, including most fruits, certain vegetables, mushrooms (except oyster mushrooms), artificial sweeteners, honey, milk and dairy products, gluten-containing grains (except sourdough rye bread), legumes, and certain nuts, should be eliminated. In the second phase, individual foods are gradually reintroduced while monitoring the body’s response. The ultimate aim is to reintroduce as many well-tolerated foods as possible (J.J. Sebastián Domingo, 2022). The effectiveness of the SCD diet in IBS has also been investigated. However, results indicate that the low-FODMAP diet is significantly more effective. While the SCD diet also alleviates symptoms, it has been associated with reduced vitamin D and folate levels in the blood (M. Vincenzi et al., 2017).

The SCD diet is initiated during a disease flare-up. In the initial phase, lasting up to five days, only specific foods are permitted: homemade poultry broth, meat, homemade yogurt, diluted juices, cooked apples, berries, and vegetables, as well as eggs if no intolerance exists. Following this period, other SCD-compliant ingredients can be gradually incorporated. During the first two weeks, consistent medical supervision is crucial, along with monitoring for potential side effects and the body's response to the new dietary regimen. Regular blood tests and weight tracking are also recommended. If laboratory parameters improve and weight increases, the frequency of medical visits can be reduced to once every two to four weeks. However, if no improvement occurs or symptoms worsen, the diet must be discontinued. In the second phase, additional foods are introduced incrementally. Initially, all fruits and vegetables must be thoroughly peeled, pitted, and cooked. If no digestive issues arise, new permitted ingredients can be added daily. By the end of this phase, lasting several weeks, raw fruits and vegetables may also be consumed. After at least one year, if the SCD diet is well-tolerated, the introduction of foods outside the approved list can be considered. However, this process should be approached cautiously and ideally under medical or dietary supervision (E. Gottschall 1994).

The carbohydrate-specific diet presents significant challenges, as it is highly restrictive and difficult to sustain over time. On the one hand, such stringent limitations can foster unhealthy eating patterns. On the other hand, individuals with inflammatory bowel diseases experience chronic digestive issues, which often lead them to instinctively avoid numerous food groups, an approach that does not always yield the desired outcomes. Another concern is ensuring adequate energy intake alongside essential macro- and micronutrients. In the case of the SCD diet, deficiencies—particularly in calcium, folate, and vitamins B, E, and D—are commonly observed. Therefore, regular monitoring of nutrient levels and collaboration with a dietitian are crucial (J. C. Burgis et al., 2016).

A carbohydrate-selective diet may offer a promising therapeutic approach for managing inflammatory bowel diseases, though additional research is required to definitively establish its efficacy. Nevertheless, it is an extremely restrictive dietary regimen that may lead to nutritional deficiencies, and thus should only be implemented under medical and dietary supervision. However, healthy individuals should not adopt SCD as a weight-loss diet or a healthy lifestyle choice.