Wheat starch intolerance in patients with celiac disease

Detection of gluten in duplicate portions to determine gluten intake of coeliac disease patients on a gluten-free diet

This study determined the gluten content of foods and meals consumed by coeliac disease (CD) patients who adhere to a gluten-free diet, and to estimate the total daily intake of gluten of these patients. CD patients fulfilling defined inclusion criteria were preselected and approached for participation in the study. Duplicate portions (DP) of foods and mixed dishes were collected from the CD patients for evaluating complete daily food intake during two individual days. Also, for these days, written food records were completed by the participants. From each DP, a laboratory sample was prepared and analysed for its gluten concentration and total daily gluten intake was calculated. Each individual's total daily intakes of energy and macronutrients were calculated using the Dutch food composition database. In total, twenty-seven CD patients participated, seven males and twenty females, aged between 21 and 64 years. In thirty-two (6 %) of 499 food samples collected in total, more than 3 mg/kg gluten was present. In four of these thirty-two samples, the gluten concentration was above the European legal limit of 20 mg/kg and three of the four samples had a gluten-free label. The maximal gluten intake was 3·3 mg gluten/d. The gluten tolerance for sensitive CD patients (>0·75 mg/d) was exceeded on at least six out of fifty-four study days. To also protect these sensitive CD patients, legal thresholds should be re-evaluated and the detection limit of analytical methods for gluten analysis lowered.

Should the Glu Be Ten or Twenty? An Update on the Ongoing Debate on Gluten Safety Limits for Patients with Celiac Disease

The only currently accepted and recommended treatment for individuals diagnosed with celiac disease (CD) is a strict life-long gluten-free diet (GFD). While the use of the GFD is well-established, strict adherence to diet is not easy to accomplish. In addition, the administration of a GFD may be compromised by inadvertent exposure to small amounts of gluten. International guidelines define a gluten-free product as one containing less than 20 parts per million (ppm), (20 milligrams of gluten per 1 kg of food) gluten. A number of reports have assessed the safe upper limit for gluten exposure for patients with CD, with general consensus that patients with CD should limit their daily intake to less than 50 mg.

"Inactive" ingredients in oral medications

Oral forms of medications contain "inactive" ingredients to enhance their physical properties. Using data analytics, we characterized the abundance and complexity of inactive ingredients in approved medications. A majority of medications contain ingredients that could cause adverse reactions, underscoring the need to maximize the tolerability and safety of medications and their inactive ingredients.

Gluten in Celiac Disease-More or Less?

To date, the only known effective treatment for celiac disease is a strict gluten-free diet for life. We reviewed the literature to evaluate the upper limit for gluten content in food, which would be safe for patients with celiac disease. Patients with celiac disease should limit their daily gluten intake to no more than 10-50 mg. Most health authorities define gluten-free products as containing less than 20 parts per million gluten.

Oat safety for celiac disease patients: theoretical analysis correlates adverse symptoms in clinical studies to contaminated study oats

Inclusion of oats in a gluten-free (GF) diet can provide whole grain nutritional benefits to celiac disease (CD) patients, but there has been debate regarding oat safety for these individuals. This is because of conflicting research findings, with inconsistencies attributed to varying CD subject's sensitivities to "pure" oats. Clinical trials to date have assumed oats provided to subjects to be lightly contaminated, if at all. This assumption is challenged here since oat's propensity to be "kernel" contaminated with gluten sources like wheat and barley has recently been shown to significantly complicate confirmation of a GF state. We therefore hypothesize that clinical studies may have inadvertently provided pill-like gluten kernels intermittently to study subjects, leading to adverse outcomes that could potentially explain inconsistencies between study conclusions. To test this theory, potential gluten contamination of oats used in a cross-section of 12 important oat feeding studies has been estimated, done according to descriptions of oats used, published contamination rates for various oat types, and study oat dosages. Expected gluten exposures were found to be at levels to elicit clinical effects in a large portion of CD patients, correlating with observed clinical reaction rates in those studies (P value = .0006). Estimated gluten doses were found insufficient, however, to affect morphological outcomes, whereas only 1 study had 1 case. Our analysis provides a new perspective with which to view oat safety study conclusions and justifies new clinical trials using today's higher-purity GF oats to settle the oat safety for CD patient debate.

The Gluten-Free Diet: Can Oats and Wheat Starch Be Part of It?

Objective and Conclusion: Uncertainty still exists about the use of oats and wheat starch as part of a gluten-free diet in patients with celiac disease (CD). This review should help to clarify the issues at hand. Whereas uncontaminated (from gluten/gliadin) oats and oats from cultivars not containing celiac-activating sequences of proline and glutamine can be used without risk of intestinal damage, wheat starch should not be used, unless it is free of gluten-that is, deglutinized-because even small amounts of gluten over time are able to induce small intestinal mucosal damage.

Gluten contamination in foods labeled as "gluten free" in the United States

Gluten is the main storage protein in grains and consists of gliadin and glutenin occurring in the same ratio. Persons suffering from intolerances, including celiac disease, must avoid foods containing gluten or products containing wheat, barley, and rye. Accordingly, gluten detection is of high interest for the food safety of celiac patients. This study was designed to determine the concentrations of gluten in foods labeled "gluten free" available in the United States. Seventy-eight samples labeled gluten free were collected and analyzed using a gliadin competitive enzyme-linked immunosorbent assay. The gluten content was calculated based on the assumption of the same ratio between gliadin and glutenin. Forty-eight (61.5%) of the 78 samples contained less than the limit of quantification of 10 mg/kg for gluten. In addition, 14 (17.9%) of the 78 samples labeled gluten free contained less gluten than the guidelines established by the Codex Alimentarius for gluten-free labeling (20 mg/kg). However, 16 samples (20.5%) did contain gluten levels of ≥20 mg/kg, ranging from 20.3 to 60.3 mg/kg. In particular, five of eight breakfast cereal samples showed gluten contents higher than 20 mg/kg. These results may be of concern, as gluten sensitivity is known to vary among celiac disease patients.

Pepsin digest of wheat gliadin fraction increases production of IL-1β via TLR4/MyD88/TRIF/MAPK/NF-κB signaling pathway and an NLRP3 inflammasome activation

Celiac disease (CD) is a gluten-responsive, chronic inflammatory enteropathy. IL-1 cytokine family members IL-1β and IL-18 have been associated with the inflammatory conditions in CD patients. However, the mechanisms of IL-1 molecule activation in CD have not yet been elucidated. We show in this study that peripheral blood mononuclear cells (PBMC) and monocytes from celiac patients responded to pepsin digest of wheat gliadin fraction (PDWGF) by a robust secretion of IL-1β and IL-1α and a slightly elevated production of IL-18. The analysis of the upstream mechanisms underlying PDWGF-induced IL-1β production in celiac PBMC show that PDWGF-induced de novo pro-IL-1β synthesis, followed by a caspase-1 dependent processing and the secretion of mature IL-1β. This was promoted by K+ efflux and oxidative stress, and was independent of P2X7 receptor signaling. The PDWGF-induced IL-1β release was dependent on Nod-like receptor family containing pyrin domain 3 (NLRP3) and apoptosis-associated speck like protein (ASC) as shown by stimulation of bone marrow derived dendritic cells (BMDC) from NLRP3(-/-) and ASC(-/-) knockout mice. Moreover, treatment of human PBMC as well as MyD88(-/-) and Toll-interleukin-1 receptor domain-containing adaptor-inducing interferon-β (TRIF)(-/-) BMDC illustrated that prior to the activation of caspase-1, the PDWGF-triggered signal constitutes the activation of the MyD88/TRIF/MAPK/NF-κB pathway. Moreover, our results indicate that the combined action of TLR2 and TLR4 may be required for optimal induction of IL-1β in response to PDWGF. Thus, innate immune pathways, such as TLR2/4/MyD88/TRIF/MAPK/NF-κB and an NLRP3 inflammasome activation are involved in wheat proteins signaling and may play an important role in the pathogenesis of CD.

Bifidobacteria inhibit the inflammatory response induced by gliadins in intestinal epithelial cells via modifications of toxic peptide generation during digestion

Celiac disease (CD) is a chronic enteropathy triggered by intake of gliadin, the toxic component of gluten. This study aims at evaluating the capacity of different Bifidobacterium strains to counteract the inflammatory effects of gliadin-derived peptides in intestinal epithelial (Caco-2) cells. A commercial extract of several gliadin (Gld) types (alpha, beta, gamma, [symbol: see text] ) was subjected to in vitro gastrointestinal digestion (pepsin at pH 3, pancreatin-bile at pH 6), inoculated or not with cell suspensions (10(8) colony forming units/ml) of either B. animalis IATA-A2, B. longum IATA-ES1, or B. bifidum IATA-ES2, in a bicameral system. The generated gliadin-derived peptides were identified by reverse phase-HPLC-ESI-MS/MS. Caco-2 cell cultures were exposed to the different gliadin peptide digestions (0.25 mg protein/ml), and the mRNA expression of nuclear factor kappa-B (NF-kappaB), tumor necrosis factor alpha (TNF-alpha), and chemokine CXCR3 receptor were analyzed by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) in stimulated cells. The production of the pro-inflammatory markers NF-kappaB p50, TNF-alpha, and IL-1beta (interleukine 1beta) by Caco-2 cells was also determined by ELISA. The peptides from gliadin digestions inoculated with bifidobacteria did not exhibit the toxic amino acid sequences identified in those noninoculated (alpha/beta-Gld [158-164] and alpha/beta-Gld [122-141]). The RT-PCR analysis evidenced a down-regulation in mRNA expression of pro-inflammatory biomarkers. Consistent with these results the production of NF-kappaB, TNF-alpha, and IL-1beta was reduced (18.2-22.4%, 28.0-64.8%, and abolished, respectively) in cell cultures exposed to gliadin digestions inoculated with bifidobacteria. Therefore, bifidobacteria change the gliadin-derived peptide pattern and, thereby, attenuate their pro-inflammatory effects on Caco-2 cells.

Gliadins induce TNFalpha production through cAMP-dependent protein kinase A activation in intestinal cells (Caco-2)

Celiac disease is an autoimmune enteropathy caused by a permanent intolerance to gliadins. In this study the effects of two gliadin-derived peptides (PA2, PQPQLPYPQPQLP and PA9, QLQPFPQPQLPY) on TNFalpha production by intestinal epithelial cells (Caco-2) and whether these effects were related to protein kinase A (PKA) and/or -C (PKC) activities have been evaluated. Caco-2 cell cultures were challenged with several sets of gliadin peptides solutions (0.25 mg/mL), with/without different activators of PKA or PKC, bradykinin (Brdkn) and pyrrolidine dithiocarbamate (PDTC). The gliadin-derived peptides assayed represent the two major immunodominant epitopes of the peptide 33-mer of alpha-gliadin (56-88) (LQLQPFPQPQLPYPQPQLPYPQPQLPYPQPQPF). Both peptides induced the TNFalpha production triggering the inflammatory cell responses, the PA2 being more effective. The addition of the peptides in the presence of dibutyril cyclic AMP (cAMP), Brdkn or PDTC, inhibited the TNFalpha production. The PKC-activator phorbol 12-myristate 13-diacetate additionally increased the PA2- and PA9-induced TNFalpha production. These results link the gliadin-derived peptides induced TNFalpha production through cAMP-dependent PKA activation, where ion channels controlling calcium influx into cells could play a protective role, and requires NF-kappaB activation.

Clinical trial: gluten microchallenge with wheat-based starch hydrolysates in coeliac disease patients - a randomized, double-blind, placebo-controlled study to evaluate safety

BACKGROUND

Wheat-based starch hydrolysates such as glucose syrups, dextrose and maltodextrins are found in more than 50% of European processed food. These products contain low amounts of residual gluten and it has been questioned whether they are safe for coeliac disease patients.

AIM

To investigate whether coeliac disease patients can safely consume wheat-based starch hydrolysate products.

METHODS

This randomized, double-blind, placebo-controlled, prospective follow-up study involved 90 coeliac disease patients in remission randomized to consume glucose syrups, maltodextrins or placebo for 24 weeks. Small bowel mucosal morphology and inflammation, symptoms, coeliac serology and malabsorption laboratory data were evaluated at baseline and at the end of the study.

RESULTS

Daily ingestion of wheat-based starch hydrolysates, glucose syrups and maltodextrins, had no deleterious effect on small-bowel mucosal villous architecture or inflammation in coeliac disease patients when compared to the placebo group. Neither were there any significant differences in gastrointestinal symptoms, serology or malabsorption parameters after 24 weeks.

CONCLUSIONS

Wheat-based starch hydrolysates, glucose syrups and maltodextrins did not have harmful effect on coeliac disease patients. Coeliac patients can thus safely continue to consume these products.

Systematic review: tolerable amount of gluten for people with coeliac disease

BACKGROUND

The threshold amount of gluten in 'gluten-free' products that can be tolerated by people with coeliac disease is unclear.

AIM

To investigate the threshold amount of gluten and the threshold concentration of gluten in food products that can be tolerated by people with coeliac disease.

DESIGN

Systematic review of studies published between 1966 and May 2007.

METHODS

The data sources used were MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, CINAHL, and reference lists of retrieved articles. We included studies that evaluated the amount of dietary gluten or the concentrations of gluten in food products that can be tolerated by people with coeliac disease whatever their design, method or language of publication.

RESULTS

Thirteen studies (three randomized controlled, one cohort, two crossover, and seven cross-sectional) met the inclusion criteria. The daily amount of tolerable gluten varied widely between studies. Whilst some patients tolerated an average of 34-36 mg of gluten per day, other patients who consumed about 10 mg of gluten per day developed mucosal abnormalities. The effect of the consumption of 'gluten-free' products with different degrees of gluten contamination was also inconsistent.

CONCLUSIONS

The amount of tolerable gluten varies among people with coeliac disease. Although there is no evidence to suggest a single definitive threshold, a daily gluten intake of <10 mg is unlikely to cause significant histological abnormalities.

Consumption of gluten-free products: should the threshold value for trace amounts of gluten be at 20, 100 or 200 p.p.m.?

OBJECTIVE

The threshold of gluten contamination in gluten-free products of both dietary and normal consumption is under debate. The objective of this study was to gather information on consumption of gluten-free products intended for dietary use of people under a gluten-free diet. This information is essential to ascertain the exposure of coeliac patients to gluten through their diet and deduce the maximum gluten content that these products should contain to guarantee a safe diet.

METHODS

A diet diary of consumption of gluten-free products intended for dietary use was distributed to the coeliac societies of two typical Mediterranean countries (Italy and Spain) and two Northern countries (Norway and Germany). The diet diary included a self-weigh table of the selected food items and a 10-day consumption table. Results were reported in percentiles as distributions were clearly right skewed.

RESULTS

The respondents included in the study accounted for 1359 in Italy, 273 in Spain, 226 in Norway and 56 in Germany. Gluten-free products intended for dietary use contributed significantly to the diet of coeliac patients in Italy, Germany and Norway and to a lesser degree in Spain. The most consumed gluten-free product in all countries was bread, and it was double consumed in the Northern countries (P<0.001). Mediterranean countries showed consumption of a wider variety of gluten-free foods and pasta was eaten to a large degree in Italy.

CONCLUSIONS

The differences between Northern and Mediterranean countries were not in the total amount of gluten-free products but in the type of products consumed. The observed daily consumption of gluten-free products results in the exposure to rather large amounts of gluten, thus the limit of 200 p.p.m. should be revised. A limit of 20 p.p.m. for products naturally gluten-free and of 100 p.p.m. for products rendered gluten-free is proposed to guarantee a safe diet and to enable coeliac patients to make an informed choice. These limits should be revised as new data become available.

Review article: safe amounts of gluten for patients with wheat allergy or coeliac disease

For both wheat allergy and coeliac disease the dietary avoidance of wheat and other gluten-containing cereals is the only effective treatment. Estimation of the maximum tolerated amount of gluten for susceptible individuals would support effective management of their disease. Literature was reviewed to evaluate whether an upper limit for gluten content in food, which would be safe for sufferers from both diseases, could be identified. When setting gluten limits for coeliac disease sufferers, the overall potential daily intake should be considered, while for wheat allergy limits should be based on single servings. For coeliac disease sufferers this limit should lie between 10 and 100 mg daily intake. For wheat allergy, lowest eliciting doses for children lie in the lower milligram range, while for adults they are most significantly higher. Gliadins (part of the gluten proteins) not only trigger coeliac disease, but are also major allergens in wheat allergy. Therefore, measurement of gliadins with validated enzyme-linked immunosorbent assay methods provides an appropriate marker for assessing gluten and/or wheat protein contents in food. Available data suggest that a maximum gluten content for 'gluten-free' foods could be set, which protects both wheat allergy sufferers and coeliac patients.

Gliadin fragments induce phenotypic and functional maturation of human dendritic cells

Celiac disease is a chronic inflammatory disease developing in genetically predisposed individuals. Ingested gliadin, the triggering agent of the disease, can cross the epithelial barrier and elicit a harmful T cell-mediated immune response. Dendritic cells (DC) are supposed to play a pivotal role in shaping the immune response. The direction of the immune response toward immunity or tolerance depends on the stage of maturation and the functional properties of the DC. DC become fully functional APC upon maturation by various stimuli. We investigated the effect of a peptic digest of gliadin on the maturation of human monocyte-derived DC. Stimulation of cells with gliadin, in contrast with other tested food proteins, led to enhanced expression of maturation markers (CD80, CD83, CD86, and HLA-DR molecules) and increased secretion of chemokines and cytokines (mainly of IL-6, IL-8, IL-10, TNF-alpha, growth-related oncogene, MCP-1, MCP-2, macrophage-derived chemokine, and RANTES). Maturation was accompanied by a greater capacity to stimulate proliferation of allogeneic T cells and significantly reduced endocytic activity. Furthermore, gliadin-induced phosphorylation of members of three MAPK families (ERK1/2, JNK, and p38 MAPK) was demonstrated. The largest contribution of p38 MAPK was confirmed using its inhibitor SB203580, which markedly down-regulated the gliadin-triggered up-regulation of maturation markers and cytokine production. Gliadin treatment also resulted in increased NF-kappaB/DNA binding activity of p50 and p65 subunits. Taken together, gliadin peptides can contribute to overcoming the stage of unresponsiveness of immature DC by inducing phenotypic and functional DC maturation, resulting in more efficient processing and presentation of gliadin peptides to specific T lymphocytes.

Dietary guidelines and implementation for celiac disease

Medical nutrition therapy is the only accepted treatment for celiac disease. This paper summarizes a review of scientific studies using the gluten-free diet, nutritional risk factors, controversial elements of the diet, and its implementation in treating celiac disease. Treatment for celiac disease requires elimination of the storage proteins found in wheat, rye, and barley. The inclusion of oats and wheat starch is controversial. Research supports that oats may be acceptable for patients with celiac disease and can improve the nutritional quality of the diet. However, use of oats is not widely recommended in the United States because of concerns of potential contamination of commercial oats. Studies assessing the contamination of commercial oats are limited. Research indicates no differences in patients choosing a strict wheat starch-containing, gluten-free diet vs. a naturally gluten-free diet. Factors other than trace gluten may be the cause of continued villous atrophy in some patients. The impact of nutrient malabsorption caused from untreated celiac disease is well documented. The diet and gluten-free products are often low in B vitamins, calcium, vitamin D, iron, zinc, magnesium, and fiber. Few gluten-free products are enriched or fortified, adding to the risk of nutrient deficiencies. Patients newly diagnosed or inadequately treated have low bone mineral density, imbalanced macronutrients, low fiber intake, and micronutrient deficiencies. Also troubling is the increased incidence of obesity seen in persons with celiac disease following a gluten-free diet. Because of the nutritional risks associated with celiac disease, a registered dietitian must be part of the health care team that monitors the patient's nutritional status and compliance on a regular basis.

The safe threshold for gluten contamination in gluten-free products. Can trace amounts be accepted in the treatment of coeliac disease?

BACKGROUND

Gluten contamination in gluten-free products cannot totally be avoided. The safe threshold for gluten remains obscure.

AIM

The purpose was to estimate a reasonable limit for residual gluten, based on current literature and measurement of gluten in gluten-free products on the market.

METHODS

The gluten content of 59 naturally gluten-free and 24 wheat starch-based gluten-free products were analysed by enzyme-linked immunosorbent assay. The daily intake of flours was calculated in 76 adults on gluten-free diet, and the intake compared with mucosal histology.

RESULTS

A number of both naturally gluten-free (13 of 59) and wheat starch-based gluten-free (11 of 24) products contained gluten from 20 to 200 ppm (=mg/kg). The median daily flour consumption was 80 g (range: 10-300). Within these limits, the long-term mucosal recovery was good.

CONCLUSIONS

The threshold for gluten-contamination can safely be set at 100 ppm. Provided that the daily flour intake is even 300 g, a level of 100 ppm results in 30 mg of gluten intake. This has been shown to be safe, when correlated to histology, in clinical and challenge studies. The level can be achieved by the industry, and does not make the diet too cumbersome.

Wheat-starch-based gluten-free products in the treatment of newly detected coeliac disease: prospective and randomized study

BACKGROUND

The safety of wheat-starch-based gluten-free products in the treatment of coeliac disease is debatable. Prospective studies are lacking.

AIM

: To compare the clinical, histological and serological response to a wheat-starch-based or natural gluten-free diet in patients with newly detected coeliac disease.

METHODS

Fifty-seven consecutive adults with untreated coeliac disease were randomized to a wheat-starch-based or natural gluten-free diet. Clinical response, small bowel mucosal morphology, CD3+, alphabeta+ and gammadelta+ intra-epithelial lymphocytes, mucosal human leucocyte antigen-DR expression and serum endomysial, transglutaminase and gliadin antibodies were investigated before and 12 months after the introduction of the gluten-free diet. Quality of life measurements were performed by standardized questionnaires and the bone mineral density was analysed.

RESULTS

In both groups, abdominal symptoms were alleviated equally by a strict diet. There were no differences between the groups in mucosal morphology, the density of intra-epithelial lymphocytes, serum antibodies, bone mineral density or quality of life tests at the end of the study. Four patients on a natural gluten-free diet and two on a wheat-starch-based gluten-free diet had dietary lapses; as a result, inadequate mucosal, serological and clinical recovery was observed.

CONCLUSIONS

The dietary response to a wheat-starch-based gluten-free diet was as good as that to a natural gluten-free diet in patients with newly detected coeliac disease.

Adult coeliac patients do tolerate large amounts of oats

OBJECTIVE

The aim of the present study was to investigate whether adult patients with coeliac disease in remission could include large amounts of oats in their daily gluten-free diet for an extended period of time without adverse effects.

DESIGN, SUBJECTS AND METHODS

Twenty adult coeliac patients in remission included large amounts of uncontaminated rolled oats in their daily diet for a prolonged period. The examinations, performed four times during the study period, included small bowel endoscopy with biopsies, blood samples (nutritional status, serological analysis), height and body weight, gastrointestinal symptoms and dietary records. Gastrointestinal symptoms and diet were also investigated through unannounced telephone interviews once a month during the study period.

RESULTS

No adverse effects of a large intake of oats were seen in small bowel histology, serology nor in nutritional status in the 15 subjects who completed the whole study period. Two of the subjects dropped out because of gastrointestinal symptoms and three for non-medical reasons. The median intake of oats was 93 g/day and the compliance to the oat diet was found to be good. Examinations of the patients after drop-out did not show any deterioration in small bowel histology or nutritional status nor raised levels of antibodies.

CONCLUSION

Results from this study indicate that adult patients with coeliac disease in remission can include large amounts of controlled wheat-free rolled oats for an extended period of time without adverse effects.

Wheat starch, gliadin, and the gluten-free diet

Individuals with celiac disease generally are advised to follow a lifelong gluten-free diet and avoid consumption of the prolamins gliadin (wheat), secalin (rye), and hordein (barley). Although the designation of the diet as glutenfree may imply that the diet contains zero gluten, this is not necessarily true. In some countries (eg, United States, Canada), the gluten-free diet is completely devoid of gluten and is based on foods such as rice and corn that are naturally gluten free. In others (eg, Scandinavia, United Kingdom), the gluten-free diet may include foods such as wheat starch that have been rendered gluten free but nonetheless contain small amounts of toxic prolamins. The discrepancy in the use of foods rendered gluten free exists because the amount of toxic prolamins that individuals with celiac disease may consume without damaging the mucosa of the small intestine is unknown. Minimal research has been conducted on the toxicity of foods rendered gluten free, and there are no definitive data about whether the small amount of prolamin found in these products is safe to consume. Nonetheless, the Codex Alimentarius Standard for gluten-free foods allows a certain amount of prolamin in foods designated gluten free, and these products have been used in many countries for several decades. Well-designed, scientifically sound studies are needed to help determine the amount of toxic prolamins, if any, that may be safely consumed by individuals with celiac disease. Until this research is conducted, dietitians in the United States should continue to advise their patients against the use of wheat starch and other foods rendered gluten free.

Analysis and clinical effects of gluten in coeliac disease

The prolamin working group coordinates research on laboratory gluten analysis in food and on clinical evaluation of patient sensitivity to prolamins. As an observer organization to the Codex Alimentarius Commission, the group summarizes current data on analysis and effects of gluten in coeliac disease. All types of gliadin, the ethanol-soluble fraction of gluten, contain the coeliac-active factor. However, coeliac toxicity and immunogenicity (humoral and cellular) of various prolamins are not identical in coeliac patients. There are no conclusive data on the threshold of gluten sensitivity of coeliac patients. Information as to the long-term risk to coeliac patients exposed to small doses of gliadin is lacking. Therefore, every effort should be made to keep the diet of coeliac patients as gluten-free as possible. The prolamin group is currently evaluating a new enzyme-linked immunosorbent assay (ELISA) protocol for gluten analysis that could serve as a basis for further Codex regulations. The group recommends adherence to a single Codex limit for gluten-free foods. The current limit of 200 ppm gluten is questionable and requires reconsideration based on new information that will be available soon.

Gastrointestinal symptoms rating scale in coeliac disease patients on wheat starch-based gluten-free diets

BACKGROUND

A wheat starch-based gluten-free diet is widely adopted in the treatment of coeliac disease, even though the products contain trace amounts of gluten. The aim here was to establish whether such a diet sustains abdominal symptoms.

METHODS

The Gastrointestinal Symptom Rating Scale (GSRS) was applied to 58 coeliac disease patients on gluten-free diets and 110 non-coeliac controls. An estimate was made of daily dietary fibre and wheat starch-derived gluten. Psychological well-being was evaluated by a structured interview. Twenty-three coeliac patients consented to small-bowel biopsy.

RESULTS

The mean GSRS score in coeliac disease patients did not differ from that in control subjects. Poorer psychological well-being was associated with abdominal symptoms in coeliac patients, whereas the daily amount of wheat starch had no effect on GSRS score. Overall dietary compliance was good, and villous atrophy was found in only 2 out of 23 patients. The average fibre consumption, 13 g per day, was lower than recommended.

CONCLUSIONS

Wheat starch-based gluten-free products are well-tolerated in coeliac disease patients, provided that their diets are otherwise strict.

Dietary analysis in symptomatic patients with coeliac disease on a gluten-free diet: the role of trace amounts of gluten and non-gluten food intolerances

BACKGROUND

Whereas many people with coeliac disease (CD) are asymptomatic when consuming a gluten-free diet (GFD), a proportion continues to experience symptoms. The reasons for this are unclear.

METHODS

Thirty-nine adult members of The Coeliac Society of New South Wales, all of whom had persistent gastrointestinal symptoms despite adhering to a GFD, were evaluated. Dietary analysis indicated that 22 (56%) were consuming a GFD as defined by the WHO/FAO Codex Alimentarius (Codex-GFD), in which foods containing up to 0.3% of protein from gluten-containing grains can be labelled as 'gluten free'. The remaining 17 were following a no detectable gluten diet (NDG)-GFD, as defined by Food Standards Australia. All subjects were required to follow a NDG-GFD during the study. Those in whom symptoms persisted after changing from a Codex-GFD and those who entered the study already on a NDG-GFD began an elimination diet followed by open and double-blind challenges to identify specific non-gluten food or food chemical intolerances.

RESULTS

Of 22 patients who switched to a NDG-GFD symptoms resolved in 5 (23%) and were reduced in 10 others (45%). Thirty-one subjects commenced the elimination diet. Symptomatic improvement was experienced in 24 (77%). Subsequent food or food chemical challenges resulted in a mean of five positive challenges per individual. Diarrhoea was the most commonly provoked symptom, followed by headache, nausea, and flatulence. Symptoms were especially provoked by amine, salicylate and soy.

CONCLUSION

The consumption of trace amounts of gluten, traditionally allowed in a Codex-GFD, may be responsible for the continuing symptoms seen in some patients with CD. Further investigation for non-gluten food intolerances should follow if symptoms persist after adherence to a NDG-GFD.

Wheat starch-containing gluten-free flour products in the treatment of coeliac disease and dermatitis herpetiformis. A long-term follow-up study

BACKGROUND

We investigated whether wheat starch-based gluten-free products are safe in the treatment of gluten intolerance.

METHODS

The study involved 41 children and adults with coeliac disease and 11 adults with dermatitis herpetiformis adhering to a gluten-free diet for 8 years on average. Thirty-five newly diagnosed coeliac patients at diagnosis and 6 to 24 months after the start of a gluten-free diet and 27 non-coeliac patients with dyspepsia were investigated for comparison. Daily dietary gluten and wheat starch intake were calculated. Small-bowel mucosal villous architecture, CD3+, alphabeta+, and gammadelta+ intraepithelial lymphocytes, mucosal HLA-DR expression, and serum endomysial, reticulin, and gliadin antibodies were investigated.

RESULTS

Forty of 52 long-term-treated patients adhered to a strict wheat starch-based diet and 6 to a strict naturally gluten-free diet; 6 patients had dietary lapses. In the 46 patients on a strict diet the villous architecture, enterocyte height, and density of alphabeta+ intraepithelial lymphocytes were similar to those in non-coeliac subjects and better than in short-term-treated coeliac patients. The density of gammadelta(+)cells was higher, but they seemed to decrease over time with the gluten-free diet. Wheat starch-based gluten-free flour products did not cause aberrant upregulation of mucosal HLA-DR. The mucosal integrity was not dependent on the daily intake of wheat starch in all patients on a strict diet, whereas two of the six patients with dietary lapses had villous atrophy and positive serology.

CONCLUSION

Wheat starch-based gluten-free flour products were not harmful in the treatment of coeliac disease and dermatitis herpetiformis.