**4. The role of dietary in GI autoimmune diseases: Nutritional implications**

The value of the nutrition in the treatment and the prevention of the diseases has been known for thousands of years before the current modern medicine. The growing interest in the value of nutrition made it clearer that many of the diseases that have boomed in the modernism era are entangled with the poor nutrition and the lifestyle of the individuals. In this section, we aim to explore the role of the nutrition in the GI autoimmune diseases.

### **4.1 Role of dietary interventions in achalasia**

Nutrition in patients with achalasia has often been overlooked. Achalasia is initially characterized by dysphagia when eating solid and liquid foods. Solid food tends to cause more dysphagia than liquids. Most patients modify their eating habits to ease

### *Autoimmune Diseases of the GI Tract Part II: Emergence of Diagnostic Tools and Treatments DOI: http://dx.doi.org/10.5772/intechopen.106185*

the progress of the food bolus: eating more slowly or using certain maneuvers, such as raising the arms or arching the back [102].

The disease is extremely rare and has a high success rate in treatment. The clinicians usually recommend the patients to eat what they can tolerate and usually the patients resume the regular diet after the treatment. An adequate nutrition modification should be a part of the therapy. If the patient experiences swallowing difficulties, they may be advised to reduce their fiber intake as soluble fibers increase the viscosity of the bolus, decreasing its absorption, while insoluble fibers have a high water-binding capacity, increasing the bulk of the bolus. Low-fiber diets would be physiologically advantageous in situations where luminal narrowing is present, such as in achalasia due to high LES pressure. There is a possibility that some patients will have to switch to high-calorie/protein liquids if this is necessary for their condition. Patients with persistent vomiting might also benefit from supplementation with thiamine (and other vitamins and minerals). Achalasia patients who continue to have difficulty meeting their nutritional needs orally may need gastric access for enteral feeding, but this is rarely needed due to the effective treatment options available [103–105].

### **4.2 Role of dietary interventions in AAG**

AAG patients are reported to have the malabsorption of food-bound vitamin B12 due to decreased IF production resulting in hematological, gastroenterological, and neuropsychiatric disorders. In addition, they are reported to have malabsorption of iron resulting in microcytic anemia. They are also reported to have a vitamin C deficiency that leads to decreased antioxidant defense, immunity, and protein synthesis. They are also reported to have calcium deficiency that could lead to osteopenia/osteoporosis. Furthermore, they are reported to have vitamin D deficiency that could lead to secondary hyperparathyroidism, osteopenia/osteoporosis, decreased immunity, and an increased risk of autoimmune disease development [106]. It is recommended that patients with AAG to follow an anti-inflammatory diet and avoid the food that causes inflammatory responses [107]. Some foods in particular such as garlic could be of beneficial use in the anti-inflammatory intake [108–111]. In addition, probiotics that can have positive influence on the gut microbiota have been shown to be good for the diet of AAG patients [112].

### **4.3 Role of dietary interventions in celiac disease (CD)**

Gluten is considered an environmental trigger for CD. Unlike other autoimmune diseases, the progression and chronic dynamics of CD are reversible. The reconstruction of the mucosa is also achievable when accompanied by total gluten avoidance [113]. Hence, a strict gluten-free diet (GFD) results in intestinal and extraintestinal symptoms improvement, intestinal villi regrowth, and autoantibodies negativity. Furthermore, this diet reverses the complications of CD that includes malabsorption, osteopenia, osteoporosis, diarrhea, bloating, constipation, and abdominal pain [114]. Besides a GFD, lactose present in milk and most dairy products should be avoided at the early stages of treatment due to a brush border lactase deficiency that is a secondary result of the surface epithelial cells damage [113]. Another thing to consider is a diet low in fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs). Since irritable bowel syndrome (IBS) symptoms are prevalent in 38% of CD-treated patients, these symptoms

persist even when they are following a strict GFD [115]. Lactose-free milk/yogurt, feta, cheddar, mozzarella, parmesan, brie, butter, and plant-based milk/yogurt are good alternatives that have low lactose content. A variety of dairy products that are low in lactose could provide CD patients with sufficient calcium. However, when choosing nondairy, lactose-free products that are made from soy, rice, and nuts it is crucial to find products that are supported with calcium since plant-based products are poor in calcium. CD individuals should aim for 200 − 300 mg of calcium/250 ml per serving [116].

Oats, rice, corn/quinoa/millet bread, sourdough, starch, corn tortilla, potato, soba/rice sticks/kelp/brown rice noodles, sago, samp, wonton wrapper, rice-based products, quinoa-based products, and quinoa/chickpea/sourdough pasta are all good substitutes that are gluten-free and would help CD patients to have a varied and balanced diet.
