The 5 Ws of a gluten challenge for gluten-related disorders

FODMAP Content Like-by-like Comparison in Spanish Gluten-free and Gluten-containing Cereal-based Products

Gluten-free foods (GF) availability on supermarket shelves is growing and it is expected to continue expanding in the years ahead. These foods have been linked to a lower content of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), molecules that trigger gastrointestinal symptoms in sensitive persons. In this study, the FODMAP content of 25 cereal-based GF foods in Spain (breakfast cereals, pasta, bread, biscuits, bakery products, and dough and puff pastry) and 25 gluten-containing equivalents (GC) available in the same supermarket were analysed and compared. Lactose, fructose, glucose, sorbitol, mannitol, raffinose, stachyose and fructans were quantified. In a like-by-like analysis, GF foods were found to generally contain fewer FODMAPs than their GC counterparts. The ingredients used in the manufacture of GF cereal-based foods may contribute to this fact. When the individually wrapped size was considered, the proportion of samples classified as high-FODMAPs in GC and GF foods showed a trend towards fewer samples in the GF. However, not all the GF samples were low-FODMAP. Altogether, our findings provide essential information for FODMAP content databases of GF products in Spain.

Evaluation of Gluten Protein Profiles in Hydrolyzed Food Products by a Multiplex-Competitive Enzyme-Linked Immunosorbent Assay

The apparent gluten concentration profiles of 47 hydrolyzed foods (barley malt, sprouted grains, and hydrolyzed wheat proteins (HWP)) were evaluated using a multiplex-competitive ELISA that utilizes the G12, R5, 2D4, MIoBS, and Skerritt antibodies from commercial sources. Cluster analysis was conducted to evaluate similarities or differences in the gluten protein/peptide response profiles among the hydrolyzed foods and their similarities or differences with fermented foods analyzed previously by the ELISA. The gluten protein/peptide response profiles of the hydrolyzed foods mainly depended on the grain source (wheat, rye, or barley) of gluten. Some hydrolyzed foods presented profiles similar to those of certain fermented foods (e.g., barley malt and gluten reduced barley beers), whereas others presented unique profiles (e.g., HWP and sprouted wheat). Additional analysis using wheat gluten-incurred yogurts indicated that while not suitable for the barley- or rye-containing foods tested, a newly developed gluten-incurred yogurt calibrant shows promise for the possible use in the quantitation of several wheat-containing fermented and hydrolyzed foods.

Dietary wheat gluten induces astro- and microgliosis in the hypothalamus of male mice

Gluten, which is found in cereals such as wheat, rye and barley, makes up a major dietary component in most western nations, and has been shown to promote body mass gain and peripheral inflammation in mice. In the current study, we investigated the impact of gluten on central inflammation that is typically associated with diet-induced obesity. While we found no effect of gluten when added to a low-fat diet (LFD), male mice fed high fat diet (HFD) enriched with gluten increased body mass and adiposity compared with mice fed HFD without gluten. We furthermore found that gluten, when added to the LFD, increases circulating C-reactive protein levels. Gluten regardless of whether it was added to LFD or HFD led to a profound increase in the number of microglia and astrocytes in the arcuate nucleus of the hypothalamus, as detected by immunohistochemistry for ionised calcium binding adaptor molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP), respectively. In mice fed LFD, gluten mimicked the immunogenic effects of HFD exposure and when added to HFD led to a further increase in the number of immunoreactive cells. Taken together, our results confirm a moderate obesogenic effect of gluten when fed to mice exposed to HFD and for the first-time report gluten-induced astro- and microgliosis suggesting the development of hypothalamic injury in rodents.

Evaluation of a Single Determination of Gluten Immunogenic Peptides in Urine from Unaware Celiac Patients to Monitor Gluten-Free Diet Adherence

INTRODUCTION AND AIM

Usually, adherence to the gluten-free diet (GFD) in celiac patients is indirectly assessed through serological analysis, questionnaires, or invasive methods such as intestinal biopsy. The detection of gluten immunogenic peptides in urine (urinary gluten immunogenic peptides-uGIP) is a novel technique that directly evaluates the ingestion of gluten. The aim of this study was to evaluate the clinical efficacy of uGIP in the follow-up of celiac disease (CD).

METHODS

From April 2019 to February 2020, CD patients reporting complete adherence to the GFD were prospectively enrolled but were unaware of the reason for the tests. Urinary GIP, the celiac dietary adherence test (CDAT), symptomatic visual analog scales (VAS), and tissue transglutaminase antibodies (tTGA) titres were evaluated. Duodenal histology and capsule endoscopy (CE) were performed when indicated.

RESULTS

A total of 280 patients were enrolled. Thirty-two (11.4%) had a positive uGIP test (uGIP+). uGIP+ patients did not show significant differences in demographic parameters, CDAT, or VAS scores. The tTGA+ titre was not related to the positivity of uGIP (14.4% vs. 10.9% in patients with tTGA+ and tTGA-). Regarding histology, 66.7% of the GIP+ patients had atrophy compared to 32.7% of the GIP patients (p-value 0.01). However, the presence of atrophy did not correlate with tTGA. Mucosal atrophy was detected in 29 (47.5%) out of 61 patients by CE. With this method, no noticeable dependence on uGIP results (24 GIP- vs. 5 GIP+) was observed.

CONCLUSIONS

The single uGIP test was positive in 11% of CD cases referring a correct GFD adherence. Furthermore, uGIP results significantly correlated with the duodenal biopsy, formerly considered the gold standard for assessing CD activity.

A Highly Sensitive Method for the Detection of Hydrolyzed Gluten in Beer Samples Using LFIA

Most gluten analysis methods have been developed to detect intact gluten, but they have shown limitations in certain foods and beverages in which gluten proteins are hydrolyzed. Methods based on G12/A1 moAbs detect the sequences of gluten immunogenic peptides (GIP), which are the main contributors to the immune response of celiac disease (CD). Immunogenic sequences with tandem epitopes for G12/A1 have been found in beers with <20 mg/kg gluten, which could be consumed by CD patients according to the Codex Alimentarius. Therefore, an accurate method for the estimation of the immunogenicity of a beer is to use two moAbs that can recognize celiac T cell epitopes comprising most of the immunogenic response. Here, a specific and sensitive method based on G12/A1 LFIA was developed to detect GIP in beers labeled gluten-free or with low gluten content, with an LOD of 0.5 mg/kg. A total of 107 beers were analyzed, of those 6.5% showed levels higher than 20 mg/kg gluten and 29% showed levels above the LOD. In addition, G12/A1 LFIA detected gluten in 15 more beer samples than competitive ELISA with another antibody. Despite their labeling, these beers contained GIP which may cause symptoms and/or intestinal damage in CD patients.

Assessment of activated gut-homing CD8+ T cells in blood by flow cytometry during a 3-day gluten challenge

Accurate celiac disease (CD) diagnosis must be performed in individuals following a gluten containing diet. Diagnostic procedures for individuals already on a gluten-free diet (GFD) avoiding long gluten reintroductions are still challenging. To deal with this issue, we developed an accurate but simple method that requires only a 3-day gluten challenge and circumvents the main limitations of previously suggested proposals such as requirement of specific peptides and unusual specialized lab facilities or high cost. In an attempt to standardize this methodology to be used in daily clinical practice, we describe here an optimized protocol for assessing activated gut-homing CD8+ T cells in blood combined with a short gluten challenge. Details about the amount and type of gluten antigen and the starting material are included, as well as the strategy to easily characterize and identify the cells of interest using flow cytometry. This methodology constitutes a diagnostic tool for CD diagnosis of high specificity and sensitivity for seropositive disease (>95%) as an alternative to long-term gluten challenge and open new possibilities to test the response to gluten in research and clinical trials.

No Difference in Tolerance between Wheat and Spelt Bread in Patients with Suspected Non-Celiac Wheat Sensitivity

Individuals with suspected non-celiac wheat sensitivity (NCWS) often report better tolerance of spelt (Triticum aestivum ssp. spelta) compared to wheat (Triticum aestivum ssp. aestivum) bakery products. This experience has neither been validated nor explained on a molecular level. Therefore, we performed blinded wheat and spelt bread challenge in this patient group. Twenty-four adults with a history of NCWS but suspected spelt tolerance were challenged in a single-blinded crossover design over six weeks with six different study breads each at 300 g per day for 4 days followed by a washout phase of 3 days. Study breads comprised spelt and wheat breads made either after a traditional (T) or a current (C) recipe, resulting in four bread types plus a gluten-free bread with 1.5% added oligosaccharides (+FODMAP) and a gluten-free bread with 5% added wheat gluten (+Gluten). The main outcome parameter was the Irritable Bowel Syndrome—Severity Scoring System, which was higher than self-estimated by the participants after spelt bread consumption (p = 0.002 for T; p = 0.028 for C) and lower for wheat bread (p = 0.052 for T; p = 0.007 for C), resulting in no difference between wheat and spelt bread tolerance. The +FODMAP bread was better tolerated than both T breads (p = 0.003 for spelt; p = 0.068 for wheat) and equally well tolerated as both C breads and +Gluten breads after normalization to the washout scores. Neither signs of inflammation nor markers for intestinal barrier integrity were influenced. Our data do not confirm, on an objective basis, the differences in expected symptoms resulting from wheat and spelt products, suggesting a strong nocebo effect for wheat and a placebo effect for spelt.

Changes in Diet and Anthropometric Parameters in Children and Adolescents with Celiac Disease-One Year of Follow-Up

Celiac disease (CD) may cause numerous nutrient deficiencies that a proper gluten-free diet (GFD) should compensate for. The study group consists of 40 children, aged 8.43 years (SD 3.5), on average, in whom CD was diagnosed on the basis of clinical symptoms, immunological and histopathological results. The patients' height, weight, diet and biochemical tests were assessed three times: before diagnosis, after six months, and following one year of GFD. After one year, the patients' weight and height increased but nutritional status (body mass index, BMI percentile) did not change significantly. The children's diet before diagnosis was similar to that of the general Polish population: insufficient implementation of the dietary norm for energy, fiber, calcium, iodine, iron as well as folic acid, vitamins D, K, and E was observed. Over the year, the GFD of the children with CD did not change significantly for most of the above nutrients, or the changes were not significant for the overall assessment of the diet. Celiac patients following GFD may have a higher risk of iron, calcium and folate deficiencies. These results confirm the need for personalized nutritional education aimed at excluding gluten from the diet, as well as balancing the diet properly, in patients with CD.

Celiac disease in children: A review of the literature

Celiac disease is an immune-mediated systemic disease triggered by intake of gluten in genetically susceptible individuals. The prevalence of celiac disease in the general population is estimated to be 1% in the world. Its prevalence differs depending on geographical and ethnic variations. The prevalence of celiac disease has increased significantly in the last 30 years due to the increased knowledge and awareness of physicians and the widespread use of highly sensitive and specific diagnostic tests for celiac disease. Despite increased awareness and knowledge about celiac disease, up to 95% of celiac patients still remain undiagnosed. The presentations of celiac disease have significantly changed in the last few decades. Classical symptoms of celiac disease occur in a minority of celiac patients, while older children have either minimal or atypical symptoms. Serologic tests for celiac disease should be done in patients with unexplained chronic or intermittent diarrhea, failure to thrive, weight loss, delayed puberty, short stature, amenorrhea, iron deficiency anemia, nausea, vomiting, chronic abdominal pain, abdominal distension, chronic constipation, recurrent aphthous stomatitis, and abnormal liver enzyme elevation, and in children who belong to specific groups at risk. Early diagnosis of celiac disease is very important to prevent long-term complications. Currently, the only effective treatment is a lifelong gluten-free diet. In this review, we will discuss the epidemiology, clinical findings, diagnostic tests, and treatment of celiac disease in the light of the latest literature.

Mediterranean Gluten-Free Diet: Is It a Fair Bet for the Treatment of Gluten-Related Disorders?

Gluten-free diet (GFD) is the current treatment of gluten-related disorders. It eliminates wheat, barley, and rye, while the exclusion of oats is still under debate. GFD is based on a combination of naturally gluten-free foods and gluten-free substitutes of cereal-based foods. Although effective as treatment of gluten-related disorders, today there is concern about how to improve GFD's nutritional quality, to make it not only gluten-free, but also healthy. The "Mediterranean diet" (MedD) refers to the dietary pattern and eating habits typical of populations living in the Mediterranean basin, which have been associated with low prevalence of several diet-related pathologies. Here we present a narrative review of the current knowledge about GFD and MedD, their characteristics and central food components. Based on the Mediterranean diet pyramid developed by the Italian pediatric society, we propose a combination between the MedD and the GFD, an attractive alternative to reach a gluten-free state that at the same time is healthy, with a clear benefit to those who practice it.

An updated overview of spectrum of gluten-related disorders: clinical and diagnostic aspects

The incidence of gluten-related disorders (GRDs) continues to increase and its global prevalence is estimated at approximately 5% of the population. Celiac disease (CD), dermatitis herpetiformis (DH), gluten ataxia (GA), wheat allergy (WA), and non-celiac gluten sensitivity (NCGS) are the five major GRDs that present with a wide range of clinical manifestations. The diagnosis of GRDs can be challenging because the typical and atypical clinical manifestations of the GRDs overlap. In this review, the current definitions of gluten-related disorders, focusing on their clinical features, diagnostic and therapeutic approaches are presented. We concluded that GRDs are usually diagnosed using a combination of clinical features, serological tests, and histopathological findings. Treatment usually involves dietary modification.

A Gluten-Free Meal Produces a Lower Postprandial Thermogenic Response Compared to an Iso-Energetic/Macronutrient Whole Food or Processed Food Meal in Young Women: A Single-Blind Randomized Cross-Over Trial

Consumption of ultra-processed food (PF) is associated with obesity risk compared with whole food (WF) intake. Less is known regarding the intake of gluten-free (GF) food products. The purpose of this study was to directly compare the thermic effect (TEM), substrate utilization, hunger/taste ratings, and glucose response of three different meals containing PF, WF, and GF food products in young healthy women. Eleven volunteers completed all three iso-caloric/macronutrient test meals in a single-blind, randomized crossover design: (1) whole food meal (WF); (2) processed food meal (PF); or (3) gluten-free meal (GF). TEM was significantly lower following GF compared with WF (−20.94 kcal/meal, [95% CI, −35.92 to −5.96], p = 0.008) and PF (mean difference: −14.94 kcal/meal, [95% CI, −29.92 to 0.04], p = 0.04), respectively. WF consumption resulted in significantly higher feelings of fullness compared to GF (mean difference: +14.36%, [95% CI, 3.41 to 25.32%], p = 0.011) and PF (mean difference: +16.81%, [95% CI, 5.62 to 28.01%], p = 0.004), respectively, and enhanced palatability (taste of meal) compared to PF meal (mean Δ: +27.41%, [95% CI, 5.53 to 49.30%], p = 0.048). No differences existed for substrate utilization and blood glucose response among trials. Consumption of a GF meal lowers postprandial thermogenesis compared to WF and PF meals and fullness ratings compared to a WF meal which may impact weight control and obesity risk over the long-term.

Living with Gluten and Other Food Intolerances: Self-Reported Diagnoses and Management

People suffering from a food intolerance (FI) tend to initiate restrictive diets such as a gluten-free diet (GFD), to alleviate their symptoms. To learn about how people live with these problems in daily life (independent of their medical diagnoses), 1203 participants answered a previously validated questionnaire and were divided into: G1 (those self-reporting symptoms after gluten consumption) and G2 (those informing no discomfort after gluten consumption). Self-reported clinical characteristics, diagnoses and diets followed were registered. Twenty nine percent referred some FI (8.5% in G1). In G1, self-reported diagnoses were more frequent (p < 0.0001), including a high proportion of eating and mood disorders. Diagnoses were reported to be given by a physician, but GFD was indicated by professional and nonprofessional persons. In G2, despite declaring no symptoms after gluten consumption, 11.1% followed a GFD. The most frequent answer in both groups was that GFD was followed “to care for my health”, suggesting that some celiac patients do not acknowledge it as treatment. Conclusion: close to one third of the population report suffering from some FI. Those perceiving themselves as gluten intolerant report more diseases (p < 0.0001). A GFD is followed by ~11% of those declaring no symptoms after gluten ingestion. This diet is perceived as a healthy eating option.

Impact of FODMAP Content Restrictions on the Quality of Diet for Patients with Celiac Disease on a Gluten-Free Diet

Restrictive diets as gluten-free (GFD) or reduced in Fermentable, Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAP) are used to improve gastrointestinal (GI) symptoms in sensitive individuals. Aiming at comparing the nutritional quality and effects of a regular GFD regimen (R-GFD) and a low-FODMAP GFD (LF-GFD), in 46 celiac patients with persistent GI symptoms we conducted a randomized, double-blind intervention-controlled study. Patients received a personalized diet, either a strict GFD (n = 21) or a LF-GFD (n = 25) for 21 days. A validated food-frequency questionnaire before intervention and a 7-day weighed-food record after the intervention assessed the diets. Patients were 41.1 ± 10.1 years (mean ± SD), 94% women, with mean BMI 21.8 ± 2.9 kg/m². On day 21, patients on R-GFD still showed poor nutritional adequacy compared to dietary recommendations, with decreased energy intake, even though an improvement in carbohydrates and folates was observed (all p < 0.025). In both groups, intake of iron, calcium, vitamin D, sodium and folates did not meet daily recommendations. As expected, consumption of legumes and grains was lower and that of fruits was higher in the LF-GFD group than in the R-GFD one (all p < 0.05). The nutritional quality of both diets was not different. When restrictive diets are useful to improve the persistent GI symptoms, careful nutritional surveillance and counseling is mandatory.

Management of celiac disease in daily clinical practice

Celiac disease (CD) is the most common autoimmune enteropathy worldwide. In CD, dietary gluten triggers a T cell driven small intestinal inflammation in a subset of genetically predisposed subjects, expressing the HLA DQ2 and/or DQ8 genes on their antigen presenting cells. HLA DQ2/DQ8 can bind gluten peptides after their prior modification by the CD autoantigen, tissue transglutaminase (TG2). This process leads to the activation of gluten reactive T cells, small bowel villous atrophy, crypt hyperplasia and intraepithelial lymphocytosis, the histological hallmarks of CD. The clinical picture of CD is extremely heterogeneous including intestinal (especially diarrhea, abdominal pain, bloating) and extraintestinal (especially associated autoimmune diseases, anemia, osteoporosis) manifestations. The prevalence of CD in most parts of the world is estimated at 1:100-1:150 and its diagnosis is based on the presence of circulating autoantibodies (anti-TG2) and the histological detection of villous atrophy. Treatment is a lifelong gluten free diet but adjunctive therapies are in development. Although CD is a well-characterized disease, it is grossly underdiagnosed, despite the severe consequences of long-term gluten ingestion in CD, such as enhanced autoimmunity, refractory CD and intestinal T cell lymphoma. The aim of the presented review is to provide a clinical guide and to summarize the most recent clinical progress in CD research.

Exposure to Different Amounts of Dietary Gluten in Patients with Non-Celiac Gluten Sensitivity (NCGS): An Exploratory Study

It is unclear whether patients with non-celiac gluten sensitivity (NCGS) can tolerate gluten. We have evaluated the changes of both gastrointestinal symptoms and quality of life for NCGS patients after the re-introduction of dietary gluten. Twenty-two NCGS patients reporting functional gastroenterological symptoms and on gluten-free diet (GFD) for the previous three weeks were exposed to incremental gluten-containing diets. Three groups were compared at baseline (immediately after 3-weeks on GFD) and immediately after the return of symptomatology: (i) a group tolerating a low-gluten diet (3.5 g gluten/day, week 1, n = 8), (ii) a group tolerating a mid-gluten diet (8 g gluten/day, week 2, n = 6), and (iii) a group tolerating a high-gluten diet (13 g gluten/day, week 3, n = 8). Their gastrointestinal symptoms and quality of life were assessed at baseline and post-intervention. The most common symptoms were: constipation (46%), abdominal pain (50%) and dyspepsia (38%). A decrease in several short form health survey (SF-36) sub-scores (all p < 0.03) after gluten re-introduction was only observed in the group tolerating the low-gluten diet; the same group showed a lower post-intervention role-emotional SF-36 score (p = 0.01). Most gastrointestinal symptoms remained similar after gluten re-introduction. However, a decrease in the general perception of well-being was only found after gluten re-introduction in the group tolerating a low-gluten diet (p = 0.01); the same was true when comparing the post-intervention general well-being perception among the three groups (p = 0.050). In conclusion, dissimilar responses from patients with NCGS were observed after the re-introduction of gluten, with gluten at a low dosage affecting the quality of life and general well-being of a group of patients, whereas others tolerate even higher doses of dietary gluten.

The Relationship between Body Composition and a Gluten Free Diet in Children with Celiac Disease

The primary and proven therapy, in cases of celiac disease (CD), is a rigorous gluten-free diet (GFD). However, there are reports of its negative effects in the form of nutritional deficiencies, obesity, and adverse changes in body composition. The study aimed to assess the impact of a GFD on the body composition of children with CD. In a case-controlled study (n = 41; mean age 10.81 y; SD = 3.96) children with CD, in various stages of treatment, underwent medical assessment. The control group consisted of healthy children and adolescents, strictly matched for gender and age in a 1:1 case-control manner. More than half of the examined children (n = 26) followed a GFD. CD children had significantly higher mean values of the fat free mass (FFM% = 80.68 vs. 76.66, p = 0.015), and total body water (TBW% = 65.22 vs. 60.47, p = 0.012), and lower mean values of the fat mass (FM% = 19.32 vs. 23.34, p = 0.015). Children who were on a GFD presented slightly higher, but not statistically significant, mean values of FM and FFM, than children who did not follow dietary recommendations (FM [kg] = 7.48 vs. 5.24, p = 0.064; FM% = 20.81 vs. 16.73, p = 0.087; FFM [kg] = 28.19 vs. 22.62, p = 0.110). After minimum one year of a GFD, CD children showed significantly higher values of FFM [kg] (p = 0.001), muscle mass (MM) [kg] (p < 0.001), TBW [L] (p < 0.001) and body cell mass (BCM) [kg] (p < 0.001). Furthermore, CD children who were on a GFD presented a significantly higher increase in weight (p = 0.034) and body mass index (BMI) (p = 0.021). The children adhering to a GFD demonstrate a tendency towards higher indices of selected body composition components.