Food allergy in irritable bowel syndrome: The case of non-celiac wheat sensitivity

Table 2 Identification of foods triggering symptoms in irritable bowel syndrome patients

Ref.	Patients	Diagnostic methods	Foods	Comment
Nanda et al[13], 1989	91 of 200 IBS patients reported symptomatic improvement after 3 wk of elimination diet	Open challenge	Cheese 35.2% Onions 35.2% Milk 31.9% Wheat 29.7% Chocolate 27.5% Butter 25.3% Yoghurt 24.7% Coffee 24.2% Eggs 23.3% Nuts 18.0% Others 34.1%	73 of the 91 improved patients were able to identify one or more foods responsible for their symptoms in the open challenge. All except one remained well on clinical follow-up
Carroccio et al[71], 2011	160 IBS patients	DBPCFC to wheat and milk	Wheat and milk 18.75% Only milk 3.75% Only wheat 2.5%	40 (25%) patients were found to suffer from food hypersensitivity. These patients had increased levels of fecal eosinophil cationic protein and tryptase, indicating that they might cause inflammation in patients with IBS
Dainese et al[112], 1999	128 IBS patients	Self-reported intolerance questionnaires vs SPT	Milk (28.8% vs 3%) Wheat (17.5% vs 1.5%) Pepper (2.5% vs 6%) Peanut (6.3% vs 6%) Pear (5% vs 7.5%) Tomato (12.5% vs 9%) Onion (3.8% vs 9%) Celery (2.5% vs 9%) Banana (2.5% vs 9%) Carrot (0% vs 10.5%) Garlic (0% vs 10.5%) Parsley (0% vs 16%) Walnut (6.3% vs 18%) Apple (10% vs 18%)	More than 50% of IBS patients were found sensitized to some food or inhalant without any symptom. There is a substantial lack of correlation between self-perceived food intolerance and SPT sensitization
Locke et al[115], 2000	76 IBS patients of 643 subjects from Olmsted County general population	Self-reported intolerance questionnaires	Beans 22.3% Chocolate 23.6% Dairy products 52.6% Eggs 21.0% Nuts 23.6% Onions 57.8% Spicy food 81.5%	Among the 643 subjects, IBS symptoms were reported by 12% (76). IBS was significantly associated with use of analgesics, food allergy or sensitivity
Farah et al[116], 1985	13 of 49 patients suspected of food intolerance after elimination diet	DBPCFC	1/13 peas 1/13 coffee 1/13 eggs	After DBPCFC 3 patients were confirmed to suffer from food intolerance. Authors found that 10 patients reacted to placebo, suggesting a psychogenic cause for their disturbances
Carlson et al[121], 2014	25 children suffering from gastrointestinal disorders and their parents	Child-reported intolerance questionnaires vs parent- reported intolerance questionnaires	Spicy food 68% vs 60% Pizza 52% vs 48% Cow’s milk 56% vs 48% Fired foods 48% vs 36% Fast Foods 40% vs 40% Sodas 40% vs 36% Cheese 40% vs 36%	Specific foods are perceived to exacerbate gastrointestinal symptoms in children with functional gastrointestinal disorders. No differences were found in severity or frequency of symptoms with ingestion of the foods between children and parents with respect to the 10 most frequent foods/food types
Böhn et al[126], 2013	197 IBS patients	Self-reported intolerance questionnaires	Dairy products 49.2% Beans 36.0% Apple 27.9% Wheat 24.4% Fried foods 52.3% Plum 23.4% Peas 19.3% Chocolate 16.8% Foods rich in biogenic amines (58%) Histamine-releasing foods (43%)	Most IBS patients believe that certain foods could be triggers of their symptoms. They identified FODMAP containing foods, histamine-releasing foods, fried foods and foods rich in biogenic amines as the main culprits. Self-reported food intolerance seems to be associated with high symptom burden and reduced quality of life
Monsbakken et al[127], 2006	84 IBS patients	Self-reported intolerance questionnaires	Milk 41.7%	70% of subjects perceived a food intolerance (mean 4.8 food items related to symptoms), 62% limited or excluded food items from their daily intake (mean 2.5 food items reduced or eliminated), and 12% made drastic changes in their diet potentially causing nutritional deficiencies in the long run
			Cheese 14.3%
			Eggs 11.9%
			Peas 21.4%
			Onions 35.7%
			Cabbage 34.5%
			Wheat 14.3%
			Coffee 26.2%
			Chocolate 25.0% Beer 16.9%
Parker et al[130], 2001	122 IBS patients	LHBT, lactose elimination diet and DBPCFC (with 5/10/15 g of lactose)	33/122 (27%) positive to LHBT 9/33 (27.7%) improved on lactose elimination diet 5/9 (55.5%) worsened on DBPCFC with 15 g of lactose	Lactose intolerance was demonstrated in IBS patients with positive (33/122) or negative (13/122) LHBT. DBPCC were inconclusive
Yang et al[131], 2013	60 IBS patients vs 60 controls	LHBT and self-reported lactose intolerance	18% vs 3% with 10 g LHBT 47% vs 22% with 20 g LHBT 85% vs 68% with 40 g LHBT 63% vs 22% with self- reported intolerance	The risk of lactose intolerance is related to the dose ingested and is higher in IBS patients than in controls. Self-reported intolerance is associated with avoidance of dairy products
Dainese et al[132], 2014	51 IBS patients	LHBT (50 g) and self-reported lactose intolerance	21/51 (41.1%) self-perceived lactose intolerance 24/51 (47%) positive LHBT 14/51 (27.4%) reported symptoms during LHBT	Patients who experienced symptoms during LHBT had more severe IBS symptoms and higher anxiety, depression, and fatigue scores. Increase in hydrogen production and in the severity of IBS influenced the symptoms of lactose intolerance during LHBT
Carroccio et al[145], 2010	24/120 IBS patients who underwent DPBCFC after elimination diet	DBPCFC and flow-CAST	12.5% cow milk only on DBPCFC 8.3% wheat only on DBPCFC 79.1% both cow milk and wheat on DBPCFC 86.3% cow milk on Flow-CAST 85.7% wheat on Flow-CAST	Flow-CAST had higher sensitivity than serum total IgE and serum food-specific IgE, both in the diagnosis of cow’s milk allergy and wheat protein allergy. Flow-CAST diagnostic accuracy proved higher than the two traditional techniques both for cow’s milk allergy and for wheat protein allergy diagnoses

DBPCFC: Double blind place controlled food challenge; FODMAP: Fermentable Oligo-, Di-, and Monosaccharides And Polyols; IBS: Irritable bowel syndrome; LHBT: Lactose hydrogen breath test; SPT: Skin prick tests.