Health ConditionsCeliac disease is defined as an autoimmune disorder originating from an aberrant adaptive immune response against gluten-containing grains in susceptible individuals. More specifically, celiac disease, also known as "celiac sprue," is a chronic inflammatory disorder of the small intestine, produced by the ingestion of dietary gluten products in susceptible people. From a systems perspective, celiac disease is an autoimmune and multisystem gluten-related disorder that causes symptoms involving the gastrointestinal tract and other organs.
Celiac disease is unique among autoimmune diseases in that its key genetic elements (human leukocyte antigen (HLA)-DQ2 and HLA-DQ8), the autoantigen involved (tissue transglutaminase, tTG), and the environmental trigger (gluten) are all well defined. A 2018 systematic review and meta-analysis noted that celiac disease is a global public health concern. The overall prevalence of this condition is 1.4% on the basis of serologic findings and 0.7% on the basis of biopsy findings. Its prevalence in the general population is approximately 1%, with female predominance. The disease can occur at any age, with a variety of symptoms and manifestations.
The classic gastrointestinal symptoms of celiac disease include diarrhea, abdominal pain, and malabsorption. The immune response to gluten fragments occurs at the small intestinal epithelium, involving both innate and adaptive immune responses. The results are characteristic autoantibodies, histologic changes (intraepithelial lymphocytosis, crypt hyperplasia, and villous atrophy), and clinical symptoms such as diarrhea, weight loss, and iron deficiency anemia.
The Oslo classification system provides a useful clinical typology: classical celiac disease presents with signs and symptoms of malabsorption including failure to thrive, weight loss, and diarrhea with or without steatorrhea; non-classical celiac disease presents without signs or symptoms of malabsorption, but with extra-intestinal manifestations including iron deficiency anemia, constipation, bloating, neurologic symptoms, abnormal liver biochemistry, infertility, delayed puberty, and fatigue. Subclinical celiac disease is below the clinical detection threshold, with no signs or symptoms sufficient to prompt routine testing.
Adults have diarrhea as a major symptom of celiac disease in approximately 50% of cases. They may also be diagnosed in the setting of anemia or osteoporosis. Adults may be symptomatic for years prior to their diagnosis or have short stature (suggesting long-standing celiac disease). They are often initially misdiagnosed with irritable bowel syndrome and may have had multiple procedures and/or hospital admissions that can ultimately be traced to their undiagnosed celiac disease.
Extraintestinal manifestations (EIM) are common in celiac disease and include: abnormal liver enzymes, arthralgia/arthritis, dermatitis herpetiformis, alopecia, fatigue, headache, anemia, stomatitis, myalgias, psychiatric disorders, rashes, seizures, neuropathy, short stature, delayed puberty, and infertility.
The production of anti-neuronal antibodies and the breakdown of the blood-brain barrier driven by pro-inflammatory cytokines, such as interleukin (IL)-1, IL-6, IL-8, and tumor necrosis factor (TNF)-Ξ± produced in the small bowel, contribute to the development of peripheral neuropathy, headache, cognitive impairment, "brain fog," epilepsy, psychiatric symptoms, or states of neurological low chronic inflammation.
Celiac disease is often associated with a number of extraintestinal manifestations such as osteoporosis, anemia, and dermatitis herpetiformis, among others. The clinical picture in some patients can also include other autoimmune diseases, including type 1 diabetes, autoimmune thyroiditis, and autoimmune hepatitis, likely due in part to shared mechanisms.
Although rarely lethal, celiac disease is a significant and often debilitating maldigestion and malabsorption syndrome affecting multiple organ systems. Patients with celiac disease are at an increased risk for complications, such as lymphomas and adenocarcinomas of the intestinal tract. Untreated pregnant women are at risk of miscarriage and at risk of having a baby with a congenital malformation. Short stature often results when celiac disease prevents nutrient absorption during the childhood years when nutrition is critical to growth and development.
Celiac disease is an autoimmune disorder characterized by small intestinal inflammation triggered by gluten ingestion in genetically predisposed individuals. A frequent extra-intestinal manifestation of celiac disease is metabolic bone disease, which contributes to an increased risk of fracture. Pathologic bone alterations include osteopenia and osteoporosis due to malabsorption (leading to calcium and vitamin D deficiencies) and chronic inflammation with the secretion of pro-inflammatory cytokines. Hence, celiac disease is considered a secondary osteoporosis risk factor.
Celiac disease has been associated with increased risk for fracture and osteoporosis, although the degree of the association varies from strong (with an odds ratio for fractures of 5β7 compared to controls) to relatively minor (with an odds ratio of 1.9 for fracture). Bone mineral density is noted to be decreased in patients with celiac disease, and there is at least some improvement in bone mineral density with institution of a gluten-free diet. However, it has been shown that a gluten-free diet instituted late in childhood or adolescence may not be associated with normalized bone mineral density.
Both the adaptive and innate immune systems are dysregulated in celiac disease pathophysiology. The primary site of damage is the small intestine, specifically its proximal segments, where gluten is broken down into smaller peptides such as gliadin, which are deamidated by the enzyme transglutaminase-2 (tTG2). This modification enhances their binding affinity to HLA-DQ2 and HLA-DQ8 molecules, triggering T-cell activation and an inflammatory response that leads to small intestinal enteropathy.
The following organ systems are meaningfully implicated:
The pathogenesis of celiac disease involves a combination of predisposing genes, dietary gluten, and environmental factors. The predominant genetic factors are HLA-DQ2 and/or HLA-DQ8 haplotypes, while dietary gluten is the major trigger for disease. Many other environmental factors influence the development of celiac disease but are less well-defined than gluten.
The HLA-DQ2 haplotype is expressed in the majority of affected patients (approximately 90%), the DQ8 haplotype in approximately 5%, and 5% carry at least one of the two DQ2 alleles. An increased risk of celiac disease has been observed among persons who carry two DQB1*02 alleles.
However, while HLA-DQ2 or DQ8 are necessary for disease development, they are not sufficient, implicating other genetic or environmental factors. Approximately 25β30% of individuals of European descent carry HLA-DQ2 susceptibility, but only about 4% of these individuals will develop celiac disease in their lifetime, underscoring the role of additional factors.
Multiple lines of evidence favor a genetic contribution to the pathogenesis of celiac disease: a familial aggregation is found in 5%β15% of celiac disease patients, and a striking 83%β86% concordance rate was observed among monozygotic twin pairs.
Environmental factors implicated in disease pathogenesis include gluten, commensal and pathogenic microorganisms, timing of gluten introduction, mode of delivery, and length of breast-feeding; however, the mechanisms underlying these associations are incompletely understood.
As with many other autoimmune diseases, researchers have witnessed an epidemic of celiac disease, questioning the previous paradigm that gluten is the only key element dictating disease onset in genetically at-risk subjects. Improved hygiene and lack of exposure to various microorganisms have also been linked with a steep increase in autoimmune disorders in industrialized countries during the past 40 years.
Epidemiological and clinical data suggest that other environmental factors, including infections, alterations in the intestinal microbiota composition, and early feeding practices, might also play a role in disease development.
Several known environmental triggers promote the onset of celiac disease at any age after gluten introduction in individuals with a genetic background, such as viral infections and intestinal dysbiosis. Recent publications have described the interference of the intestinal microbiome in gluten metabolism, modulation of local immune reactions, and in maintaining normal gut permeability.
The presence or absence of gluten in the diet can change the diversity and proportions of the microbial communities constituting the gut microbiota. There is an intimate relation between gluten metabolism and celiac disease pathophysiology and gut microbiota; their interrelation defines intestinal health and homeostasis. Environmental factors modify the intestinal microbiota and, in turn, its changes modulate the mucosal and immune responses.
Current evidence from studies of young and adult patients with celiac disease increasingly supports that dysbiosis (i.e., compositional and functional alterations of the gut microbiome) is present in celiac disease, but to what extent this is a cause or consequence of the disease, and whether different intestinal diseases have specific change patterns, is not yet clear.
Three main pathways are implicated in celiac disease: the environmental trigger (gluten), genetic susceptibility, and unusual gut permeability. Intestinal permeability is frequently abnormal in patients with celiac disease. Intestinal permeability was elevated in newly diagnosed celiac disease and in individuals on a gluten-free diet for less than one year. Intestinal permeability was normal in 80% of individuals at one visit and 87% at a second visit in those with celiac disease who had been on a gluten-free diet for more than a year.
Reduced levels of iron, folate, vitamin B12, vitamin D, zinc, and magnesium are common in untreated celiac disease patients, probably due to loss of brush border proteins and enzymes needed for the absorption of these nutrients. In the majority of patients, removal of gluten from the diet leads to histological recovery and normalization of iron, vitamin, and mineral levels.
In a Dutch study of 80 newly diagnosed adult celiac patients, almost all (87%) had at least one value below the lower limit of reference. Specifically, for vitamin A, 7.5% of patients showed deficient levels, for vitamin B6 14.5%, folic acid 20%, and vitamin B12 19%. Zinc deficiency was observed in 67% of patients, 46% had decreased iron storage, and 32% had anemia.
The slow and incomplete intestinal recovery in celiac disease patients on a gluten-free diet may contribute to nutrient deficiencies. The degree of histological damage has been shown to correlate with the severity of iron deficiency at time of diagnosis. Folic acid levels are generally depressed in patients with severe villous atrophy compared to patients with milder lesions.
Iron deficiency anemia is the most common extra-intestinal sign of celiac disease and usually resolves with adherence to a gluten-free diet. However, deficiencies of both folate and vitamin B12 may persist in some patients on a gluten-free diet, thus requiring vitamin supplementation to improve subjective health status. Data from over 20 studies showed that patients with treated celiac disease had an increased risk for vitamin A, vitamin D, iron, folate, and copper deficiency compared to non-celiac controls.
In celiac patients, exposure to even a small amount of gluten can lead to malabsorption of important nutrients including calcium, iron, folic acid, and fat-soluble vitamins because of small-intestine inflammation. Studies on micronutrient circulating levels in long-term gluten-free diet patients over two years with good compliance demonstrated that vitamin D deficiency was detected in up to 25% of subjects. The largest body of evidence found in systematic reviews investigated micronutrients related to bone metabolism, such as vitamin D and calcium in celiac disease.
Participants who had previously undiagnosed celiac disease had lower levels of vitamin B-12 and folate in their blood, likely reflecting a deficiency in the uptake of these nutrients because of intestinal damage. This deficiency was not observed in participants with diagnosed celiac disease, underscoring the importance of diagnosing the disease and undergoing proper treatment (i.e., avoiding gluten).
Research highlights the significance of folate intake, suggesting the consumption of pseudo-cereals like quinoa and amaranth, in addition to typical sources found in vegetables and pulses. Low B-group vitamin levels are linked to lower quality of life, and supplementation is associated with improved overall well-being.
The literature shows that nutritional deficiencies in celiac subjects on long-term gluten-free diet with good compliance relate to vitamin B12, folic acid, vitamin D, calcium, iron, magnesium, zinc, selenium, thiamine, riboflavin, niacin, and vitamin K.
Common mineral deficiencies in celiac disease patients include iron, calcium, magnesium, iodine, potassium, and zinc, though deficiencies in selenium, sodium, and manganese have also been reported. While a suitable gluten-free diet can normalize deficiencies like zinc, it may not be sufficient for others such as magnesium, as gluten-free products have lower mineral content than their gluten-containing counterparts.
Children and adolescents with celiac disease are at risk for suboptimal bone health at time of diagnosis and after 1 year on a gluten-free diet. This could be due in part to suboptimal vitamin D/K status.
Traditional use: The use of fermented foods containing lactic-acid bacteria has a long history across many food cultures worldwide. Fermented dairy, vegetables, and beverages were traditional vehicles for these organisms, though their use was not historically linked specifically to celiac disease, which was only characterized in modern medicine.
Scientific evidence:
Lactobacilli and Bifidobacterium species may be used as a probiotic supplement in celiac disease patients based on their shared possession of the most extensive peptidolytic and proteolytic activity thought to be engaged in the breakdown of gluten among all potential bacterial genera present in the gut microbiota.
In children with celiac disease autoimmunity, a daily oral dose of Lactobacillus plantarum HEAL9 and Lactobacillus paracasei 8700:2 was found to modify the peripheral immune response. Bifidobacterium breve strains have demonstrated a beneficial effect on reducing pro-inflammatory cytokine TNF-Ξ± production in celiac disease children on gluten-free diets.
One trial prospectively and randomly evaluated a probiotic mix composed of Lactobacillus casei, Lactobacillus plantarum, Bifidobacterium animalis, and two strains of Bifidobacterium breve. This mixture, administered daily for 6 weeks, proved effective in improving the severity of gastrointestinal symptoms, and demonstrated modifications to the composition of the microbiota up to 6 weeks after the interruption of supplementation.
A double-blind RCT of 85 participants randomized patients to receive either placebo or a probiotic blend of Bifidobacterium lactis CCT 7858 and Lactobacillus rhamnosus CCT 7863 at 1Γ10βΉ CFU/day over 90 days. Gastrointestinal Symptom Rating Scale (GSRS) scores improved significantly in the probiotic group compared to placebo.
In a systematic review and meta-analysis by Seiler and colleagues, the authors identified six randomized clinical trials (four on celiac adults and two on celiac children) and found that probiotic supplementation ameliorated gastrointestinal symptoms. However, evidence is still considered preliminary: most of the evidence on the effect of probiotics in celiac disease comes from animal models. Some mouse models demonstrate immunomodulatory effects of probiotics and reduced gliadin-induced inflammation. Studies regarding probiotics and celiac disease in humans are very scarce.
Traditional use: Curcumin is a polyphenol extracted from the root of the East Indian rhizomatous perennial Curcuma longa (Zingiberaceae). The rhizomes of C. longa are used to produce turmeric, which is an ingredient in curries and other Indian dishes, and is also used as a yellow pigment. Turmeric has been used for centuries in Ayurvedic and traditional Chinese medicine as a digestive, anti-inflammatory, and hepatoprotective remedy.
Scientific evidence:
Curcumin has been shown to have antioxidant, anti-inflammatory, and anti-cancer effects, and to be effective against enteritis in vitro and in vivo. Curcumin reduces local production of cytokines and chemokines, and inhibits infiltration of neutrophils into the mucous membrane. It also controls inflammation by regulating genes associated with oxidative stress and fibrosis. The anti-inflammatory effect of curcumin is mediated by interference with arachidonic acid synthesis and blocking NF-ΞΊB activity associated with the synthesis of cyclooxygenase-2, 5-lipoxygenase, and inducible nitric oxide.
Evidence for curcumin specifically in celiac disease is indirect and limited. Recent research has shown promising new insights into herbal-based treatments of celiac disease. Several herbs and botanical extracts have demonstrated anti-inflammatory, immunomodulatory, and gut-healing properties that make them potential candidates for management. However, no adequately powered, placebo-controlled clinical trials of curcumin in celiac disease have been published as of the time of this writing. Evidence for curcumin's anti-inflammatory properties in general gastrointestinal inflammation is preliminary and is primarily from in vitro and animal studies, with limited human data from IBD research.
Traditional use: Slippery elm has been used traditionally to treat coughing, diarrhea, and gastrointestinal tract diseases by Native Americans. Its inner bark contains mucilaginous compounds that were prepared as a gruel or decoction. Marshmallow root, similarly rich in mucilage, has been used in European and Middle Eastern herbal traditions for soothing inflamed mucous membranes of the digestive tract.
Scientific evidence:
The bark of slippery elm was suggested to be effective for treating IBD patients owing to its antioxidant effects. However, further studies are needed to confirm its efficacy. No clinical trials specific to celiac disease for either slippery elm or marshmallow root have been identified in the peer-reviewed literature. Their soothing properties in gastrointestinal conditions are acknowledged in traditional and integrative contexts, but the evidence base for these herbs in celiac disease specifically remains absent.
Traditional use: Green tea has been consumed for thousands of years in East Asian traditions as both a beverage and medicinal plant, with applications extending to digestive health, immune support, and inflammation.
Scientific evidence: Several herbs and botanical extracts have demonstrated anti-inflammatory, immunomodulatory, and gut-healing properties. Green tea is produced from the leaves of Camellia sinensis and contains a wide array of organic compounds including polyphenols. The polyphenols in green tea, particularly epigallocatechin gallate (EGCG), have been studied for anti-inflammatory and immunomodulatory properties in general, and are referenced in the herbal-based celiac disease treatment literature. However, direct clinical trial evidence in celiac patients is lacking; available research is preclinical or indirect.
Traditional use: The use of plant-derived digestive enzymes such as bromelain (from pineapple) and papain (from papaya) has a history in folk medicine for digestive complaints. Their use in celiac disease is a modern concept based on understanding of gluten's proline-rich structure.
Scientific evidence: New treatments being investigated include degrading immunodominant gliadin peptides using probiotics with endopeptidases or transglutaminase inhibitors. Gliadin peptides are resistant to complete digestion due to their high proline content; prolyl endopeptidases capable of cleaving these residues have been studied. This is an active research area, but evidence from human clinical trials on commercially available enzyme supplements specifically for celiac disease is preliminary and insufficient to support recommendations beyond the gluten-free diet.
Complete elimination of gluten-containing food from the diet is currently the only effective and safe treatment for celiac disease. In celiac patients, exposure to even only a small amount of gluten can lead to malabsorption of important nutrients including calcium, iron, folic acid, and fat-soluble vitamins because of small-intestine inflammation. A strictly followed gluten-free diet throughout the patient's lifetime is the only effective treatment for celiac disease.
Up to 30% of patients may continue to experience symptoms or exhibit laboratory abnormalities or intestinal inflammation suggestive of active celiac disease, despite following a gluten-free diet. This challenge, which encompasses various diagnoses, is known as nonresponsive celiac disease (NRCD).
A gluten-free diet enables celiac patients to control their symptoms and avoid various complications associated with this condition. However, while the quality of gluten-free foods has significantly improved during recent decades, maintenance of a gluten-free diet does not necessarily ensure adequate nutritional intake.
Individuals on a gluten-free diet need to replace wheat, barley, rye, and their derivatives with foods derived from naturally gluten-free cereal grains such as rice, corn, and buckwheat; however, the recommended amounts of fiber, iron, and calcium can be more difficult to obtain on such a diet, and good planning is required.
Studies assessing dietary intakes of children and adolescents on gluten-free diets concluded that these children seem to follow the same trends as healthy children on a common diet, with high intakes of sucrose and saturated fat, and low intakes of dietary fiber, vitamin D, and magnesium.
The quality of gluten-free food alternatives is often still inferior to gluten-containing products. Furthermore, the gluten-free diet has demonstrated benefits in managing some gluten-related disorders, though nutritional imbalances have been reported.
Nutritional qualities such as high protein content, the presence of biologically active and beneficial substances (fiber, beta-glucans, polyunsaturated fatty acids, essential amino acids, antioxidants, vitamins, and minerals), and tolerance by the majority of celiac patients make oats popular for use in a gluten-free diet. The health risk of long-term consumption of oats by celiac patients is a matter of debate. The introduction of oats into the diet is only recommended for celiac patients in remission. Furthermore, not every variety of oat is appropriate for a gluten-free diet. The risk of sensitization and an adverse immunologically mediated reaction is a real threat in some celiac patients.
Research highlights the significance of folate intake, suggesting the consumption of pseudo-cereals like quinoa and amaranth, in addition to typical sources found in vegetables and pulses, as a strategy to address micronutrient gaps on the gluten-free diet.
Diet is a major environmental factor influencing gut microbiota diversity and functionality, which might be relevant to subjects following dietary therapies. Celiac disease is an enteropathy caused by an aberrant immune response to cereal gluten proteins, and the only therapy is adherence to a gluten-free diet. A preliminary study established whether the gluten-free diet in itself could modify the composition and immune properties of the gut microbiota. The trial included 10 healthy subjects who were submitted to a gluten-free diet over one month. Analysis of fecal microbiota and dietary intake indicated that numbers of healthy gut bacteria decreased, while numbers of unhealthy bacteria increased, parallel to reductions in the intake of polysaccharides after following the gluten-free diet.
Studies exploring the role of intestinal microbiota in nonresponsive celiac disease found an association between the persistence of symptoms and changes in mucosal integrity biomarkers, with different gut microbiome structures among nonresponsive celiac disease patients, indicating a significant role of the microbiome. Strict dietary adherence is therefore a key lifestyle determinant of outcomes.
The 2013 American College of Gastroenterology guidelines reported that micronutrient deficiencies (in particular iron, folic acid, vitamins B6 and B12, vitamin D, copper, and zinc) are frequent in celiac patients at the time of diagnosis. Therefore, in patients with newly diagnosed celiac disease, micronutrient deficiencies should be found and integrated. These tests should include iron, folic acid, vitamin D, vitamin B12, and more.
Following the United Kingdom 2015 National Institute for Health and Care Excellence guidelines, it was reported that some patients with celiac disease may need additional nutritional supplements, mainly in the early stages after diagnosis, suggesting, however, that this should be identified through appropriate ongoing monitoring and that integration should begin after a full evaluation.
Celiac disease is often a silent but significant contributor to bone loss across the lifespan. Missed or delayed diagnosis, particularly in children, can have lasting consequences for skeletal development and peak bone mass. Optimal bone health requires a coordinated approach to care that includes gastroenterologists, endocrinologists, and dietitians to address nutrient deficiencies, monitor bone density, and implement individualized nutrition interventions.
Recent publications have described the interference of the intestinal microbiome in gluten metabolism, modulation of local immune reactions, and in maintaining the gut barrier's normal permeability. These results have promoted further lines of research on the benefit of probiotic administration in celiac disease patients in order to prevent disease onset or alleviate clinical symptoms along with a gluten-free diet.
The literature shows that nutritional deficiencies in celiac subjects on long-term gluten-free diet with good compliance relate to vitamin B12, folic acid, vitamin D, calcium, iron, magnesium, zinc, selenium, thiamine, riboflavin, niacin, and vitamin K, indicating that the overall diversity and quality of the diet warrants careful attention beyond gluten exclusion alone.
Aspergillopepsin (ASP) from Aspergillus niger is a food-grade acid protease studied for gluten detoxification relevant to celiac disease. In vitro research (Ehren et al., PLOS ONE 2009) showed ASP markedly enhanced gluten digestion relative to pepsin, cleaving Ξ±2-gliadin at multiple sites; combined with DPP-IV, it achieved more complete clearance of immunotoxic epitopes.
AN-PEP (A. niger prolyl endoprotease) has been studied in celiac disease patients in a pilot study, demonstrating significantly reduced gluten reaching the duodenum. The National Celiac Association acknowledges preliminary data on AN-PEP as promising. However, current evidence does not support AN-PEP as a replacement for a gluten-free diet in diagnosed celiac patients.
Bifidobacterium genus strains are the most extensively studied probiotics in celiac disease. A 2025 PubMed review confirmed multiple in vitro and animal studies showing Bifidobacterium strains reduce gliadin-induced inflammatory cytokines, degrade gliadin peptides, and inhibit intestinal permeability in CeD models, with human clinical trials showing improvements in GI symptoms. The PMC 2020 systematic review concluded Bifidobacteria administration may restore gut microbiota composition and pre-digest gluten in CeD patients.
Bifidobacterium bifidum IATA-ES2 is specifically identified in in vitro studies as protecting against gliadin-induced inflammatory response and mucosal damage in celiac disease models, reducing IFN-Ξ³ and TNF-Ξ± while increasing IL-10. These findings are cited in the PMC 2020 systematic review and the 2025 PubMed review of Bifidobacteria in CeD. IATA-ES2 is among the most mechanistically characterized strains in celiac disease probiotic research.
Bifidobacterium breve BR03 and B632 were evaluated in a 2018 double-blind placebo-controlled trial in 40 celiac disease children, showing microbiota modulation correlating with TNF-Ξ± reductions and short-chain fatty acid changes. B. breve was also included in the VSL#3 blend tested in an RCT for celiac disease. The 2025 PubMed review includes B. breve among evidence-supported Bifidobacterium strains for CeD.
Bifidobacterium infantis NLS super strain was evaluated in a randomized double-blind placebo-controlled trial in active celiac disease patients (Smecuol et al., J Clin Gastroenterol 2013). It has also been studied in a registered ClinicalTrials.gov RCT (NCT03271138) specifically for persistent GI symptoms in CeD patients on GFD. In vitro data support its capacity to reduce gliadin-induced intestinal permeability and inflammatory markers.
Bifidobacterium lactis NLS-SS was studied in a 2013 double-blind RCT in active celiac disease patients. A 2025 RCT in 85 CeD patients used B. lactis CCT 7858 with L. rhamnosus for 90 days, concluding probiotics are beneficial adjunct therapy for CeD symptom relief. A 2008 study demonstrated B. lactis inhibits the toxic effects of wheat gliadin in epithelial cell cultures.
Bifidobacterium longum IATA-ES1 has demonstrated in vitro capacity to degrade gliadin-derived peptides and reduce gliadin-induced inflammatory cytokines in CeD cell models. B. longum ATCC 15707 reduces IFN-Ξ³ and TNF-Ξ± and increases IL-10 in response to gliadin peptides in vitro. B. longum was included in the VSL#3 blend evaluated in a randomized controlled trial in celiac disease.
Exocrine pancreatic insufficiency is a recognized co-morbidity in celiac disease, estimated to occur in 12% or more of non-responsive celiac patients. Pancreatic enzyme supplementation has been investigated in a randomized, double-blind, placebo-controlled crossover trial for non-responsive celiac disease (NRCD). Clinical guidelines suggest a trial of PERT for celiac patients with persistent malabsorption or weight loss despite a gluten-free diet. Evidence quality for this specific application is limited and considered low to moderate.
Calcium deficiency and reduced bone mineral density affect over 50% of newly diagnosed celiac disease patients due to malabsorption in the damaged proximal intestine and concurrent vitamin D deficiency. The ACG 2013 and UK NICE 2015 guidelines recommend calcium supplementation, especially combined with vitamin D, when GFD does not normalize bone mineral density. Calcium supplementation at β₯1,200 mg/day is specifically referenced in CeD management literature.
DHA deficiency is documented in celiac disease due to fat malabsorption. A 2026 University of Chile clinical trial (NCT07585669) specifically uses 2,000 mg DHA/day (plus 400 mg EPA) in newly diagnosed CeD patients alongside GFD to evaluate reduction of intestinal and systemic inflammation. DHA's anti-inflammatory mechanisms are directly relevant to CeD intestinal pathology.
Dipeptidyl peptidase IV (DPP-IV) from Aspergillus oryzae is an X-Pro amino-exopeptidase studied for its ability to release proline-containing dipeptides from gluten N-termini, complementing prolyl endopeptidases in reducing immunotoxic gluten fragments. It has been studied in combination with aspergillopepsin for gluten detoxification in celiac disease and is present in the majority of commercial glutenase supplements.
EPA is among the omega-3 fatty acids that are deficient in celiac disease due to fat malabsorption. A 2026 University of Chile clinical trial (NCT07585669) uses 400 mg EPA + 2,000 mg DHA/day in newly diagnosed CeD patients alongside GFD to evaluate reduction of intestinal inflammation. EPA's anti-inflammatory properties are directly relevant to the chronic intestinal inflammation characteristic of CeD.
Celiac disease is caused by an aberrant immune response to incompletely digested gluten peptides that resist normal gastrointestinal proteolysis. Exopeptidase supplementation has been specifically developed and clinically tested as a potential adjunct therapy to degrade these peptides before immune activation. A human crossover clinical trial demonstrated that the exopeptidase combination AMYNOPEP significantly improved in-vivo degradation of the immunodominant 33-mer gluten peptide, warranting further investigation in celiac patients.
Folate (folic acid) deficiency is one of the most common and persistent nutritional deficiencies in celiac disease, arising from malabsorption in the proximal small intestine, and may persist on long-term GFD. The 2013 ACG guidelines list folic acid among the first micronutrients to screen and supplement at diagnosis. A 2002 study by Hallert et al. demonstrated poor folate status persisting in coeliac patients after 10 years on GFD.
Iron deficiency anemia is the most common extra-intestinal manifestation of celiac disease, arising from malabsorption in the damaged duodenum and proximal jejunum. The ACG 2013 guidelines list iron as among the first micronutrients to screen and supplement at diagnosis. Iron deficiency usually resolves with strict GFD, but supplementation is warranted when deficiency persists.
Secondary lactose intolerance is highly prevalent in newly diagnosed celiac disease patients because intestinal villous damage reduces brush-border lactase enzyme levels. Oral lactase supplementation is recommended by CeD specialists while the gut heals on a gluten-free diet. Beth Israel Deaconess Medical Center, the National Celiac Association, and Beyond Celiac all explicitly cite oral lactase tablets as a management tool for CeD patients with concurrent lactose intolerance.
Lactobacillus genus strains have been studied in multiple clinical trials for celiac disease. The PMC 2020 systematic review concluded Lactobacilli may pre-digest gluten, reduce intestinal permeability, and modulate cytokine and antibody production in CeD. The VSL#3 blend containing multiple Lactobacillus strains was tested in an RCT for CeD microbiome effects.
Lactobacillus acidophilus was included in the VSL#3 probiotic blend evaluated in a randomized controlled trial in celiac disease patients (PMC4972910). L. acidophilus strains modulate humoral immune responses via TGF, IL-10, and IL-6 expression relevant to CeD. The PMC 2020 systematic review includes L. acidophilus among Lactobacilli with potential for gluten-induced immune response modulation in CeD.
Lactobacillus paracasei 8700:2 was evaluated in a 2021 randomized placebo-controlled trial in children with celiac disease autoimmunity (PMID 34249990) alongside L. plantarum HEAL9. L. paracasei was also included in the VSL#3 blend tested in an adult CeD RCT. Celiac.com (2017) reported trial data on L. paracasei 8700:2 for immune support and potential delay of CeD immune activation.
Lactobacillus plantarum HEAL9 was evaluated in a 2021 randomized placebo-controlled trial in children with celiac disease autoimmunity (PMID 34249990). L. plantarum was also included in the VSL#3 blend tested in an adult CeD RCT. Some L. plantarum strains have gluten-degrading protease activity. Celiac.com (2017) reported trial data on L. plantarum HEAL9 for immune support in CeD.
Lactobacillus rhamnosus CCT 7863 was used in a 2025 randomized controlled trial (PMID 40699044, 85 CeD patients) in combination with Bifidobacterium lactis, concluding probiotics are beneficial adjunct therapy for CeD providing symptom relief and quality of life improvement. L. rhamnosus strains are noted in CeD literature for gut barrier integrity enhancement properties relevant to the increased intestinal permeability in CeD.
Pancreatic exocrine insufficiency (PEI) is a recognized possible cause of persistent symptoms in celiac disease despite a gluten-free diet. A prospective, randomized, double-blind, placebo-controlled crossover trial of pancrelipase (lipase-containing preparation) in non-responsive celiac disease found no significant improvement in gastrointestinal symptom scores compared to placebo.
Magnesium deficiency is common in celiac disease and may persist even on long-term, compliant gluten-free diet because gluten-free cereal products contain lower magnesium than conventional counterparts. The 2013 ACG guidelines and a 2013 systematic review explicitly recognize magnesium deficiency as relevant in CeD and recommend a magnesium-enriched diet or supplementation for persistent deficiency.
Millet seed is naturally gluten-free and is documented as a safe, nutritionally superior alternative grain for individuals with celiac disease. PMC-indexed reviews confirm millets are non-allergenic and do not provoke the autoimmune intestinal response that characterizes celiac disease. Millet introduction into gluten-free diets is recommended for celiac patients.
Omega-3 fatty acid deficiency is documented in celiac disease due to gluten-induced fat malabsorption. A 2026 clinical trial at the University of Chile (NCT07585669) is evaluating 2,400 mg/day omega-3 PUFAs alongside GFD initiation in newly diagnosed CeD adults to reduce intestinal inflammation. The Gluten Free Society identifies omega-3 deficiency as more common in CeD than in the general population.
Prolyl endopeptidases (PEPs), especially the Aspergillus niger-derived AN-PEP, cleave proline-rich immunogenic gluten peptides that human gut proteases cannot fully digest. Multiple clinical trials have evaluated AN-PEP in celiac disease patients as an adjunct to a gluten-free diet; a 2024 double-blind RCT observed a significantly lower prevalence of severe symptoms in the AN-PEP arm.
Exogenous peptidase supplementation, specifically prolyl endopeptidases, has been directly studied as a potential therapy for celiac disease. Gliadin peptides are resistant to normal digestion, and prolyl endopeptidase (PEP) has been shown to cleave the immunodominant 33-mer gliadin peptide to non-toxic fragments in vivo. Research is at preclinical and early clinical trial stage.
Quinoa is naturally gluten-free and is formally recommended by dietetic guidelines (Academy of Nutrition and Dietetics) as a whole-grain alternative for celiac disease patients. Clinical dietetic guidelines recommend it as one of the preferred enriched gluten-free grains. Human studies in celiac patients consuming quinoa-containing cereal bars showed changes in cholesterol and triglycerides. Its complete nutritional profile (iron, fiber, protein) addresses common nutrient gaps in the gluten-free diet.
Rye contains secalin, a gluten-related protein that triggers the same autoimmune intestinal damage as wheat gliadin in individuals with celiac disease. Rye must be strictly excluded from the diet of people with celiac disease. This is a well-established, clinically confirmed relationship documented in major guidelines and the StatPearls/NCBI Bookshelf.
Saccharomyces boulardii KK1 reduced CD71 expression, cytokine production, and CeD-like histological changes in a mouse model when fed gluten digested with this yeast. S. boulardii CNCM I-745 reduced gluten immunopathology in immunized NOD/DQ8 mice via AhR pathway activation and synergizes with duodenal microbiota from CeD patients to increase tryptophan and AhR signaling, with researchers calling for clinical trials.
Selenium deficiency is documented in celiac disease patients on long-term gluten-free diet in a 2019 PMC systematic review of micronutrient deficiencies in compliant CeD patients. Whole grains are a primary dietary source of selenium, and their exclusion from the GFD reduces selenium intake. The 2023 Birmingham Gastroenterology Associates guidance identifies selenium deficiency in CeD as contributing to thyroid dysfunction and immune function impairment.
Streptococcus thermophilus was included in the VSL#3 probiotic blend tested in an RCT in celiac disease patients (PMC4972910; 450 billion CFU/day for 12 weeks). S. thermophilus produces lactase, which is directly relevant to the secondary lactose intolerance common in CeD. The PMC 2019 Nutrients review notes S. thermophilus among probiotics that modulate TGF, IL-10, and IL-6 expression relevant to CeD immune pathology.
Thiamine (vitamin B1) deficiency is documented in celiac disease patients on long-term gluten-free diet, identified in a 2019 PMC systematic review of micronutrient deficiencies in CeD patients with good GFD compliance. Whole grains, excluded in GFD, are a primary dietary source of thiamine; gluten-free cereal products are often less thiamine-fortified. Supplementation is included in clinical guidance for CeD nutritional management.
Vitamin B12 deficiency is documented in approximately 30% of celiac disease patients on strict GFD for more than 2 years, as the ileal mucosa where B12 is absorbed can be affected by CeD. The ACG 2013 and UK NICE 2015 guidelines recommend B12 screening and supplementation at CeD diagnosis. B12 deficiency in CeD contributes to anemia, neurological complications, and fatigue.
Riboflavin (vitamin B2) deficiency is documented in celiac disease patients on long-term gluten-free diet, identified in a 2019 PMC systematic review of micronutrient deficiencies in compliant CeD patients. Gluten-free cereal products are often unfortified and lower in riboflavin than their conventional counterparts. Riboflavin supplementation is included in clinical recommendations for CeD-related nutritional management.
Vitamin B6 deficiency is documented in celiac disease patients both at diagnosis and on long-term gluten-free diet, as confirmed by the 2013 ACG guidelines and a 2020 multinational review. A 2025 Scientific Reports cross-sectional study (59 newly diagnosed CeD vs. 59 controls) found significantly lower vitamin B6 levels in CeD patients. Deficiency may persist on established GFD, possibly due to lower B6 content in gluten-free cereal products.
Folate deficiency is among the most common and persistent nutritional deficiencies in celiac disease, resulting from impaired proximal intestinal absorption and possible continuation on long-term GFD. ACG 2013 guidelines recommend folate screening and supplementation at diagnosis. Multiple systematic reviews confirm folate deficiency in both newly diagnosed and treated CeD patients.
Methylfolate (5-MTHF) is the bioactive form of folate increasingly used in celiac disease supplementation because it bypasses intestinal and hepatic conversion steps, making it particularly advantageous in patients with intestinal malabsorption. Folate deficiency is guideline-endorsed as a primary nutritional concern in CeD, and 5-MTHF specifically addresses the absorption challenges inherent to CeD gut damage.
Vitamin D deficiency is among the most common micronutrient deficiencies in both newly diagnosed and treated celiac disease, arising from malabsorption of fat-soluble vitamins. The 2013 ACG guidelines and 2015 UK NICE guidelines recommend screening and supplementing vitamin D in CeD patients. Supplementation combined with calcium is specifically endorsed when GFD alone does not normalize bone mineral density.
Vitamin D3 (cholecalciferol) is the preferred supplemental form used to correct vitamin D deficiency in celiac disease, as endorsed by the ACG 2013 and UK NICE 2015 guidelines. Malabsorption of fat-soluble vitamins including D3 is a hallmark of untreated CeD. Combined D3 and calcium supplementation is specifically recommended when GFD alone fails to normalize bone mineral density.
Zinc deficiency is consistently documented in newly diagnosed celiac disease patients and may persist on long-term gluten-free diet, as confirmed by multiple systematic reviews and the ACG 2013 guidelines. A 2025 Scientific Reports study confirmed significantly lower zinc levels in 59 newly diagnosed CeD patients vs. controls. The ACG 2013 guidelines recommend zinc screening and supplementation at CeD diagnosis.
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