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Background Adult lactase non-persistence (LNP) is due to low lactase expression, resulting in lactose malabsorption (LM). LNP is a genetic trait, but is typically determined by LM markers including breath H2, blood glucose, and urinary galactose after a lactose tolerance test. Known validity of these markers using milk is limited, despite being common practice. Compositional variation, such as β-casein variants, in milk may impact diagnostic efficacy. This study aimed to evaluate the diagnostic accuracy to detect LNP using these commonly measured LM markers after both lactose and milk challenges. Methods Fourty healthy young women were challenged with 50 g lactose then randomized for separate cross-over visits to ingest 750 mL milk (37.5 g lactose) as conventional (both A1 and A2 β-casein) and A1 β-casein-free (a2 Milk™) milk. Blood, breath and urine were collected prior to and up to 3 h following each challenge. The presence of C/T13910 and G/A22018 polymorphisms, determined by restriction fragment length polymorphism, was used as the diagnostic reference for LNP. Results Genetic testing identified 14 out of 40 subjects as having LNP (C/C13910 and G/G22018). All three LM markers (breath H2, plasma glucose and urinary galactose/creatinine) discriminated between lactase persistence (LP) and LNP following lactose challenge with an area under the receiver operating characteristic (ROC) curve (AUC) of 1.00, 0.75 and 0.73, respectively. Plasma glucose and urinary galactose/creatinine were unreliable (AUC 2 remained high (100%) when milk was used, but sensitivity was reduced with conventional (92.9%) and a2 Milk™ (78.6%) compared to lactose (sensitivities adjusted for lactose content). The breath H2 optimal cut-off value was lower with a2 Milk™ (13 ppm) than conventional milk (21 ppm). Using existing literature cut-off values the sensitivity and specificity of breath H2 was greater than plasma glucose to detect LNP following lactose challenge whereas values obtained for urinary galactose/creatinine were lower than the existing literature cut-offs. Conclusion This study showed accurate diagnosis of LNP by breath H2 irrespective of the substrate used, although the diagnostic threshold may vary depending on the lactose substrate or the composition of the milk. Trial registration ACTRN12616001694404. Registered prospectively on December 9, 2016.

Background. Lactose malabsorption (LM) is a frequent clinical problem associated with several digestive and extra-digestive diseases. The aim of this manuscript was to clarify the real clinical impact of LM on these disorders. Methods. A literature search for digestive and extra-digestive disorders related to LM was carried out using PubMed, Medline and Cochrane. Results. A transient lactase deficiency is present in celiac disease (CD) on a normal diet. The persistence of symptoms in CD on a gluten-free diet may be instead, in part, attributed to a primary LM. Similar circumstances are present in inflammatory bowel diseases (IBD), in which LM can be responsible for a part of persistent symptoms in IBD on clinical remission. LM and irritable bowel syndrome (IBS) are instead independent conditions. On the other hand, a lactose-restricted diet may be useful for some IBS patients. A reduced lactose intake can lead to low bone mass and limited risk of fragility fractures. Finally, the absorption of levothyroxine could be conditioned by LM. Conclusions. LM can be responsible for persistent symptoms in CD and IBD. The association with IBS seems to be casual. Bone mass and levothyroxine absorption can be affected by LM.

Background/aims Self-reported lactose intolerance (LI) is frequent in patients with functional bowel disorders (FBD) that could be interpreted as irritable bowel syndrome (IBS). The present study aims to characterize the responses of patients with FBD, without small intestinal bacterial overgrowth (SIBO), and LI, in terms of lactose malabsorption (LM) and lactose sensitivity (LS) according to psychological and clinical features. Methods One hundred and fifty-eight consecutive FBD outpatients with LI, and no SIBO, were classified according to the Rome III questionnaire and filled Beck Depression Inventory, and State and Trait Anxiety questionnaires. They underwent a lactose tolerance test in which glycemia during 60 minutes and digestive symptoms for 3 hours were recorded. Results Abnormal lactose tolerance tests were found in 110 patients (70%), 44 (28%) with LM, 96 (61%) with LS, and 30 (19%) having both LM and LS. LM patients had a higher frequency of functional diarrhea (P = 0.040) and a lower frequency of dysphagia (P = 0.031). LS patients had a higher depression score (P = 0.007), higher frequency of globus (P = 0.042), irritable bowel syndrome (IBS) (P = 0.027) and mixed IBS (P = 0.049), and lower frequency of abdominal pain (P = 0.040). LS was significantly associated with a higher depression score (P = 0.002), and a higher frequency of globus (P = 0.046). Conclusions Thirty percent of LI patients have normal lactose absorption and normal LS. In the other 70% of patients, LI could be associated with LM and/or LS.

Lactose malabsorption (LM) is caused by the incomplete hydrolysis of lactose due to lactase deficiency [...]

BACKGROUND Lactose malabsorption is a common condition that affects a broad segment of the population. Clinical diagnosis based on symptom recall can be unreliable and conventional testing can be inconvenient, requiring expensive laboratory-based equipment and conduction of the testing in a clinical setting. OBJECTIVE The aim of this study is to assess the performance of a digital handheld hydrogen breath monitor (GIMate) in diagnosing lactose malabsorption compared to a US Food and Drug Administration (FDA)–cleared device (H2 Check) for the same indication. METHODS An interventional crossover study was performed in adult participants with a prior confirmed diagnosis of lactose malabsorption or a suspected history of lactose intolerance. RESULTS A total of 31 participants (mean age 33.9 years) were enrolled in the study. There was 100% positive percent agreement and 100% negative percent agreement between the GIMate monitor and the H2 Check. Correlation between gastrointestinal symptoms and hydrogen values was positive at 0.82 (P CONCLUSIONS The digital handheld GIMate breath monitor achieved equivalent diagnostic performance to that of an FDA-cleared device in the diagnosis of lactose malabsorption. CLINICALTRIAL ClinicalTrials.gov NCT04754724; https://clinicaltrials.gov/ct2/show/NCT04754724

Introduction Coeliac disease (CD) is a frequent cause of secondary lactose malabsorption. Many methods are available for the diagnosis of lactose malabsorption. The aim of this study was to assess the prevalence of lactose malabsorption in individuals with CD, as well as symptom correlation with test results. Methods Patients were prospectively recruited between February 2018 and October 2019. Individuals with a potential new diagnosis of CD (positive IgA-EMA/IgA-TTG) or established CD had a duodenal biopsy to assess for lactose malabsorption (Lactose Intolerance Quick Test [LIQT], BIOHIT Oyj, Helsinki, Finland) at time of gastroscopy. Subsequent to this, individuals had a lactose hydrogen breath test (LHBT). Symptoms around the time of gastroscopy were assessed, to allow assessment of symptom correlation with lactose malabsorption (e.g. abdominal pain, bloating, diarrhoea, borborygmi). Results 97 patients were prospectively recruited; out of these 24 had a LHBT suggestive of small intestinal bacterial overgrowth (SIBO) and were excluded. Of the remaining 73 patients (n= 54 female, median age = 47 years), 50 patients had a potential new diagnosis of CD and 23 had established CD. The total prevalence of a positive duodenal lactase test was 43.8%, compared to 15.1% for a positive LHBT. The prevalence of lactose malabsorption was significantly higher in individuals with villous atrophy compared to those without, when using the duodenal lactase test (p Conclusions The prevalence of lactose malabsorption was higher in individuals with CD using the lactase test compared to the LHBT. The prevalence of lactose malabsorption was significantly higher in those with villous atrophy (VA) compared to those without. Although symptom correlation was poor there may be value in using LIQT when assessing CD patients with persisting symptoms.

Lactose intolerance (LI) is characterized by the presence of symptoms, mainly gastrointestinal, due to the colonic fermentation of lactose not absorbed by lactase enzyme deficiency. Lactase deficiency can be primary, congenital, or adult type lactase deficiency, and secondary to other pathologies that involve a loss of enzyme activity. The prevalence of adult type lactose malabsorption varies depending on ethnicity and geographic location. In Europe it is related to the presence of two single nucleotide polymorphisms (SNP C / T-13910 and G / A-22018). What is the best technique for its diagnosis, especially with what dose the provocation should be done and for how long it should be performed, is still under discussion. The clinical symptomatology in lactose intolerance is modified by the load of the lactose substrate, the activity of the lactase enzyme, the speed of intestinal transit, the rate of gastric emptying and colonic compensation. Some LI do not present symptoms after usual amounts of milk intake, mainly of yogurt and cheese. In addition, the intestinal microbiota will also modify the presence and severity of symptoms. So the modification of this with biotics could be a possibility of treatment and to promote dairy products consumption.

Background Lactose malabsorption is a common condition that affects a broad segment of the population. Clinical diagnosis based on symptom recall can be unreliable and conventional testing can be inconvenient, requiring expensive laboratory-based equipment and conduction of the testing in a clinical setting. Objective The aim of this study is to assess the performance of a digital handheld hydrogen breath monitor (GIMate) in diagnosing lactose malabsorption compared to a US Food and Drug Administration (FDA)–cleared device (H2 Check) for the same indication. Methods An interventional crossover study was performed in adult participants with a prior confirmed diagnosis of lactose malabsorption or a suspected history of lactose intolerance. Results A total of 31 participants (mean age 33.9 years) were enrolled in the study. There was 100% positive percent agreement and 100% negative percent agreement between the GIMate monitor and the H2 Check. Correlation between gastrointestinal symptoms and hydrogen values was positive at 0.82 (P Conclusions The digital handheld GIMate breath monitor achieved equivalent diagnostic performance to that of an FDA-cleared device in the diagnosis of lactose malabsorption. Trial Registration ClinicalTrials.gov NCT04754724; https://clinicaltrials.gov/ct2/show/NCT04754724

Additional File 2: Figure S1. Pre and postprandial concentration of A) breath H2, B) plasma glucose and C) urinary galactose/creatinine between lactase persistent and lactase non-persistent individuals following ingestion of lactose, CON milk, and A2M. A) and B) show the timecoure change in breath H2 and plasma glucose respectively pre and post lactose and milk ingestion. C) shows the urinary galactose/creatinine concentration pre and post lactose and milk ingestion. Comparisons computed by generalised linear mixed model. Interaction between group and time are shown on each plot. * p

Additional File 3: Figure S2. The receiver operating characteristic (ROC) curve for breath H2, plasma glucose, and urinary galactose/creatinine ratio.

Additional File 1: Table S1. Response to lactose and milk ingestion. Table showing group means (lactase persistent and lactase non-persistent) means of breath H2 concentration, plasma glucose concentration, and urinary galactose/creatinine ratio following lactose (50 g), conventional milk (750 mL), or a2 Milk™ (750 mL).

Food lactose and lactose intolerance are today hot topics in the field of food and nutrition. About 70% of the adult world population is lactose-intolerant, due to low levels of intestinal lactase, also called lactase-phlorizin hydrolase (LPH), a β-d-galactosidase found in the apical surface of the intestinal microvilli. This may be due to the loss of intestinal lactase in adulthood, a condition transmitted by an autosomal recessive gene, which differs in humans according to race. According to the cultural-historical hypothesis, the mutation that allows the metabolization of lactose appeared about 10 000 years ago in the inhabitants of Northern Europe where mammalian milk continued in the diet after weaning, and lactase-persistent populations were genetically selected in some areas. Many intolerant individuals can tolerate low levels of lactose in their daily diet. Probiotics have also been proposed as an alternative that could avoid some symptoms of lactose intolerance. Many products are marketed nowadays as alternatives to dairy products for lactose-intolerant individuals. However, the rules for low-lactose foods are currently not harmonised in the European Union. As scientific knowledge on lactose intolerance has notably advanced in recent decades, the aim of this work was to review the current state of the knowledge on lactose and lactose intolerance, its diagnosis and clinical management, and the various food products that are offered specifically for non-tolerant individuals.

Consumption of foods can be suppressed by two feeding system defense mechanisms: conditioned taste aversion (CTA) or taste avoidance learning (TAL). There is a debate in the literature about which form of intake suppression is caused by various aversive stimuli. For instance, illness-inducing stimuli like lithium chloride are the gold standard for producing CTA and external (or peripheral) painful stimuli, such as footshock, are the traditional model of TAL. The distinction between CTA and TAL, which have identical effects on intake, is based on differential effects on palatability. That is, CTA involves a decrease in both intake and palatability, whereas TAL suppresses intake without influencing palatability. We evaluated whether lactose, which causes gastrointestinal pain in adult rats, produces CTA or TAL. Using lick pattern analysis to simultaneously measure intake and palatability (i.e., lick cluster size and initial lick rate), we found that pairing saccharin with intragastric infusions of lactose suppressed both the intake and palatability of saccharin. These results support the conclusion that gastrointestinal pain produced by lactose malabsorption produces a CTA, not TAL as had previously been suggested. Furthermore, these findings encourage the view that the CTA mechanism is broadly tuned to defend against the ingestion of foods with aversive post-ingestive effects.

SummaryPatients with anomalies of the inferior vena cava (IVC) are rare, are usually asymptomatic and this developmental anomaly is detected during radiologic evaluation of deep vein thrombosis or incidentally during abdominal radiologic evaluation. We report on time resolved three-dimensional magnetic resonance angiography (4D MRA) in a patient with congenital anomaly of the IVC and nonspecific abdominal complaints. 4D MRA is shown for evaluation and detailed diagnosis in vascular venous anatomy. However, due to continuing bloating and irregular bowel movements we investigated carbohydrate malabsorption and a lactose malabsorption was diagnosed. The nonspecific abdominal complaints in this patient with IVC anomaly were due to lactose malabsorption and were treated successfully with a lactose-free diet.@Supplementary material online: www.phlebologieonline.de: http://dx.doi.org/10.12687/phleb2285-1-2016

Background Lactase deficiency may lead to gastrointestinal symptoms after milk ingestion, known as lactose intolerance. Studies showed that lactose intolerant individuals avoid milk consumption, but they eat other dairy. Most of these studies were conducted on healthy people. Aim The aim of present study was to evaluate the impact of lactose malabsorption and lactose intolerance on dairy consumption in children with gastrointestinal diseases. Material and methods Hydrogen breath test was conducted on pediatric patients aged from 2 to 19 years. Data regarding consumption of milk, plain fermented dairy products (FDP), flavored FDP, cheese and cottage cheese were collected. Differences in dairy consumption were analyzed between lactose absorbers and lactose malabsorbers, as well as between lactose intolerant and lactose tolerant individuals. Results Two hundred and three children were selected to the study (82 males, mean age 11.39 years). There was no relationship between dairy products consumption and age. However, the frequency of lactose intolerance increased significantly with age. The type of gastrointestinal disease influenced only the cottage cheese consumption. Lactose intolerance decreased significantly milk consumption, but not other dairy products consumption. Lactose intolerants consumed dairy products (excluding milk) more often than lactose tolerants (38.2% and 23.6% respectively). Positive relationship between milk consumption and the consumption of FDP and cottage cheese was observed only in lactose absorbers and lactose tolerants. Conclusions Lactose intolerance decreases milk consumption, but does not affect other dairy consumption. Dietary preferences play a key role in dairy consumption in lactose absorbers and lactose tolerant children.

Background Recurrent abdominal pain (RAP) is common among school-age children. Previous studies found that lactose malab- sorption has an important role in RAP in children. Up to date, data on the prevalence of lactose malabsorption in children with RAP in Indonesia has not been available. Objective To elicit the prevalence of RAP and lactose malabsorption in children with RAP, and to determine associated foods that cause RAP in children with and without lactose malabsorption, the frequency of lactose intolerance during breath hydrogen test (BHT), and also the onset and duration of the symptoms after a lactose load. Methods This was a cross-sectional study conducted on junior high school students who suffered from recurrent abdominal pain. Results Of 1054 students screened, 157 (14.9%) fulfilled the Apley’s criteria for RAP. Of 157, 85 children were enrolled and underwent BHT. Fifty five of them (65%) were girls. Lactose malabsorption was found in 68 (80%) subjects. Milk and yogurt were the most frequent products that cause symptoms of RAP in our subjects who mostly (80%) were malabsorber. Lactose intolerance during BHT was found in 69 (81%) children. Symptoms appeared in 30 minutes after lactose ingestion, and the most frequent symptom was abdominal pain (44%). Lactose intolerance symptoms disap- peared in about 15 hours. Conclusions The prevalence of RAP in children aged 12-14 years was 14.9%. The prevalence of lactose malabsorption in children with RAP was 80%. Milk and yogurt were the most frequent products that cause symptoms of RAP in our subjects who mostly were malabsorbers. The frequency of lactose intolerance during BHT was 81%, and the symptoms lasted within approximately 15 hours

Summary Background Studies have shown wide variation in the prevalence of lactose malabsorption across the world, but no systematic reviews or meta-analyses have recently assessed the prevalence of lactose malabsorption in different geographical areas. We aimed to present an updated systematic review and meta-analysis on the prevalence of lactose malabsorption in adults, by countries and regions, and to assess the variation between different testing methods. Methods Studies reporting on prevalence of lactose malabsorption and lactase persistence were identified by searching MEDLINE and Embase from database inception to Nov 2, 2016. We evaluated studies presenting lactose malabsorption or lactase persistence prevalence data in adults and children aged 10 years or older, including cross-sectional and prospective studies, using genotyping, hydrogen breath tests, lactose tolerance tests, and other testing methods. We excluded studies in children younger than 10 years, studies using self-reported data, and studies including inpatients and outpatients at gastroenterological wards. Studies were screened by two authors (CLS and SKF) and data values were extracted by two authors (CLS and SKF) independently. The primary outcome was the prevalence of lactose malabsorption. This study is registered with PROSPERO, number CRD42017064802. Findings We screened 2665 records, and 306 study populations from 116 full-text articles were included (primary sources); data for 144 additional study populations from 59 articles were obtained from review articles, because full-text primary articles could not be obtained (secondary sources). Of the 450 study populations included, 231 were assessed by genotyping, 83 by hydrogen breath tests, 101 by lactose tolerance tests, and 35 by other methods or methods that were not described sufficiently. The studies included 62 910 participants from 89 countries (covering 84% of the world's population). When standardising for country size, the global prevalence estimate of lactose malabsorption was 68% (95% CI 64–72), ranging from 28% (19–37) in western, southern, and northern Europe to 70% (57–83) in the Middle East. When assessing the global prevalence using genotyping data only, the estimate was 74% (69–80), whereas prevalence was 55% (46–65) using lactose tolerance test data, and 57% (46–67) using hydrogen breath test data. Risk of bias was assessed based on ten indicators; 12 of the articles had a score of ten, indicating low risk of bias, 76 had a score of nine, 26 a score of eight, and two articles a score of seven (indicating higher risk of bias). There was substantial heterogeneity between studies within most of the assessed countries. Interpretation Lactose malabsorption is widespread in most of the world, with wide variation between different regions and an overall frequency of around two-thirds of the world's population. Acknowledging regional patterns of lactose malabsorption is important to guide management of gastrointestinal symptoms. Funding None.

During the last decade, lactose-free diets have become increasingly popular in the general population, either isolated or as a part of a cow's milk-free diet. However, health-related benefits from a lactose-free diet are only documented for individuals with clinical lactose intolerance due to decreased intestinal lactase activity and subsequent lactose malabsorption. In this paper we summarize the current knowledge of lactose intolerance regarding diagnostic procedures and treatment.

Background Lactase is an enzyme involved in the hydrolysis of lactose. Deficiency of the enzyme (hypolactasia) may be determined genetically or arise secondarily to disease of small intestine. Under this condition, lactose enters the colon where it is fermented by intestinal microflora and turns to gases and short-chain fatty acids, causing gastrointestinal symptoms known as lactose intolerance (LI). Objectives To investigate the incidence of lactose malabsorption (LM), LI and the coexistence of these two conditions in children with upper gastrointestinal tract diseases (UGTD), malabsorption syndrome, inflammatory bowel disease (IBD) and functional gastrointestinal disorders (FGID). Material and methods Hydrogen breath test (HBT) was conducted in 387 pediatric patients in years 2010-2013. Two hundred thirty two children with gastrointestinal tract diseases were selected and assigned to groups - UGTD, malabsorption syndrome, IBD or FGID. For each group the frequency of LM, frequency and severity of LI and the frequency of their co-occurrence were calculated. Results Lactose malabsorption was observed in 37.08% of patients with gastrointestinal diseases. Positive HBT result was the most common in children with malabsorption syndrome (52.50%) and less common in UGTD (30.85%), especially in ulcer disease (23.53%). Symptoms after lactose ingestion affected 36.64% of the subjects, and were more specific to lactose malabsorbers than to lactose absorbers (72.10% vs. 15.75%). The higher frequency of LI was noted in children with FGID, especially in irritable bowel syndrome (IBS) (65.22%). The lowest incidence of symptoms was obtained in children with UGTD, especially in those with ulcer disease (27.44%). The incidence of LM with LI was noted in 27.16% of all patients and was the highest in IBS (47.83%) and the lowest in ulcer disease (15.78%). Conclusions Lactose malabsorption is a common problem in children with gastrointestinal diseases, especially in children with bowel diseases. Lactose intolerance is related to LM, but does not affect all malabsorbers.

Background: Milk is the major food in the diet of the infant mammal and consequently has always attracted considerable interest from the physician, the industrialist and the mother. The concentration of lactose in milk varies from species to species. Main objective is to study the prevalence of malabsorption in malnutrition.Methods: Sixty-seven children ranged between ages of 6 months to 3 years, of both sex and varying grades of malnutrition, were studied. Study conducted between July 1979-December 1979. All children were grouped into 4 grades of malnutrition according to Indian Academy of Pediatrics recommendation.Results: Out of 67 cases, 50 were followed up. Severe malnutrition of grades III and IV (less than 60 percent of expected body weight) comprises 58.2 percent (39 out of 67) in first seen group, and 52 percent (26 out of 50) in follow up group. 59.7 percent Males and 40.3 percent females in first seen cases. 58 percent males and 42 percent females in follow up cases. 24 cases (53.33 percent) of lactose malabsorbers were males and 21 cases (46.67 percent) were females.Conclusions: Lactose malabsorption is common in protein-energy malnutrition. This can be determined by simple ward tests and abnormal lactose tolerance curve after oral lactose load. Lactose malabsorption increases with the severity of malnutrition. Malnutrition leads to lactose malabsorption and lactose malabsorption is an important contributory factor in production of malnutrition.

Objectives Recently, an intermediate lactose intolerance (LI) phenotype based on the lactase gene (LCT) C/T-13910 polymorphism was proposed. However, a multifactorial genesis of LI phenotypic variation including endogenous and exogenous factors cannot be ruled out. Therefore, this study was conducted to investigate a possible association between serum diamine oxidase (DAO) and LI phenotypes in individuals with lactose malabsorption (LM). Design and methods A total of 121 ambulatory patients with LM were included in this retrospective study. The lactose hydrogen breath test (LHBT) and serum DAO activity measurements were performed on the same day. A thorough anamnesis with respect to gastrointestinal symptoms was carried out at the initial consultation. Results In total, 44 (36.4%) patients with a serum DAO activity

Primary adult-type lactose malabsorption (PALM) is a widespread inherited autosomal recessive condition, which is considered to be associated with osteoporosis. This prospective study aimed at assessing the 25-hydroxy-vitamin D (25(OH)D) status and serum CrossLaps levels in individuals with PALM and normal controls.All participants (n=210) underwent genotyping for the LCT C/T-13910 polymorphism, 25(OH)D and CrossLaps measurements and clinical examinations. In addition, the anthropometric data (that is, height, weight and body mass index) were determined.Fifty-five individuals with PALM (that is, LCT C/C-13910 homozygotes) showed lower 25(OH)D (mean: 24.95±10.04 vs 28.59±9.56 ng/ml, P=0.018) and higher CrossLaps serum levels (mean: 0.46±0.31 vs 0.43±0.49 ng/ml, P=0.251) compared with 155 normal controls (that is, LCT C/T-13910 hetero- or T/T-13910 homozygotes). Anthropometric data were similar between PALM probands and controls.Individuals with PALM were found to have lower 25(OH)D and higher CrossLaps serum levels compared with normal controls. In order to preserve life-long bone health, routine 25(OH)D and CrossLaps serum measurements should be performed in individuals with PALM.

Background/Aims: Lactose malabsorption (LM) consists in the incomplete absorption of lactose, due to lactase deficiency. According to previous studies, headache can be triggered by food intolerance. We investigated the onset and severity of headache during the LBT and a correlation with LM. Patients and Methods: We enrolled 93 (74F/19M; mean-age 42 ± 16 yrs) outpatients who performed a LBT according to the guidelines. Patients reported on a Visual-Analogue-Scale the intensity of headache before and at the end of the test. We considered as significant an increase of headache in VAS peak >10mm. Results: 67/93 (72%) resulted LM, while 53% (49/93) referred a headache worsening. Within the group of LM headache worsened in 50.7%, compared to 57.7% in non-malabsorbers (p=0.36). In the subgroup of patients with habitual headaches there is a significant worsening compared to non-habitual ones (70.7% vs 38.5%; p=0.003) regardless of the LBT result. Conclusion: The present study denies the existence of an association between LM and headache. We found that headache significantly worsened in patients usually suffering from headache, regardless LM. We think that this data should be considered, since we suppose that the onset of headache during a LBT could affect the correct execution of the test.

AIM: To validate 4-sample lactose hydrogen breath testing (4SLHBT) compared to standard 13-sample LHBT in the clinical setting. METHODS: Irritable bowel syndrome patients with diarrhea (IBS-D) and healthy volunteers (HVs) were enrolled and received a 10 g, 20 g, or 40 g dose lactose hydrogen breath test (LHBT) in a randomized, double-blinded, controlled trial. The lactase gene promoter region was sequenced. Breath samples and symptoms were acquired at baseline and every 15 min for 3 h (13 measurements). The detection rates of lactose malabsorption (LM) and lactose intolerance (LI) for a 4SLHBT that acquired four measurements at 0, 90, 120, and 180 min from the same data set were compared with the results of standard LHBT. RESULTS: Sixty IBS-D patients and 60 HVs were studied. The genotype in all participants was C/C-13910. LM and LI detection rates increased with lactose dose from 10 g, 20 g to 40 g in both groups (P < 0.001). 4SLHBT showed excellent diagnostic concordance with standard LHBT (97%-100%, Kappa​​ 0.815-0.942) with high sensitivity (90%-100%) and specificity (100%) at all three lactose doses in both groups. CONCLUSION: Reducing the number of measurements from 13 to 4 samples did not significantly impact on the accuracy of LHBT in health and IBS-D. 4SLHBT is a valid test for assessment of LM and LI in clinical practice.

Probiotics are living microorganisms that exert scientifically proven health effects. The idea behind probiotics, prebiotics and synbiotics is to produce food or food supplements which, after ingestion, strengthen healthy intestinal microbiota, by either adding probiotic microorganisms, indigestible but fermentable prebiotic carbohydrates, or both constituents combined in synbiotics. This chapter offers a thorough review of evidence for uses of probiotics for a number of medical conditions: gastrointestinai disorders, Helicobacter eradication, lactose malabsorption and inflammatory bowel disease.

BACKGROUND Lactose intolerance is a frequent condition in certain populations. Different methods for diagnosis exist. There is scarce literature regarding Lactose Quick Test (LQT) and concordance with other methods for lactose intolerance diagnosis in children. METHODS Prospectively, we included children who underwent gastroduodenoscopy for evaluation of abdominal pain. We obtained a duodenal sample for LQT and blood sample for genetic test to evaluate LCT C>T-13910 variant. Later, patients underwent breath test with lactose, to evaluate malabsorption. We evaluated the concordance between the three different tests. KEY RESULTS We included 46 patients, 56.5% women. Mean age was 13.2 years (range 9-18 years). 66.6% of patients had lactose malabsorption according to breath test; 64.4% were homozygous CC; and 91.3% had hypolactasia (mild or severe) according to LQT. None of the patients with normolactasia had altered breath test. Genetic test had a substantial agreement (k = 0.675) with breath test and fair agreement (k = 0.301) with LQT. LQT had fair agreement (k = 0.348) with breath test. CONCLUSIONS & INFERENCES Genetic test had better concordance with breath test than LQT to diagnose lactose malabsorption, however, none of the patients with normal LQT had lactose malabsorption. In patients who undergo gastroduodenoscopy to study abdominal pain, it seems reasonable to perform LQT, and, in those with hypolactasia, to perform breath test.

Lactose malabsorption (LM) is caused by insufficient enzymatic degradation of the disaccharide by intestinal lactase. Although hydrogen (H2) breath tests (HBTs) are routinely applied to diagnose LM, false-negative results are not uncommon. Thirty-two pediatric patients (19 females, 13 males) were included in this prospective study. After oral lactose administration (1 g kg(-1) bodyweight to a maximum of 25 g), breath H2 was measured by electrochemical detection. HBT was considered positive if H2 concentration exceeded an increase of ⩾20 ppm from baseline. In addition to H2, exhaled methane (CH4), blood glucose concentrations and clinical symptoms (flatulence, abdominal pain, diarrhea) were monitored. A positive HBT indicating LM was found in 12/32 (37.5%) patients. Only five (41.7%, 5/12) of these had clinical symptoms during HBT indicating lactose intolerance (LI). Decreased blood glucose concentration increments (⩽20 mg dL(-1) (⩽1.1 mmol L(-1))) were found in 3/5 of these patients. CH4 concentrations ⩾10 ppm at any time during the test were observed in 5/32 (15.6%) patients and in 9/32 (28.1%) between 1 ppm and 9 ppm above baseline after lactose ingestion. In patients with positive HBT 10/12 (83.3%) showed elevated CH4 (>1 ppm) above baseline in breath gas, whereas in patients with negative HBT this figure was only 4/17 (23.5%). In addition to determining H2 in exhaled air, documentation of clinical symptoms, measurement of blood glucose and breath CH4 concentrations may be helpful in deciding whether in a given case an HBT correctly identifies patients with clinically relevant LM.

The problem of lactose metabolism remains relevant from the standpoint of various areas of medical research. Clinicians, anthropologists, physiologists and geneticists are engaged in the study of lactose digestion devices and various types of disorders associated with it, including lactose intolerance.Determination of such mechanisms allows us to understand not only the nutritional causes of the development of functional intestinal symptoms, but also the evolution of man and nutrition, culture and lifestyle. Symptoms of lactose intolerance are abdominal pain, flatulence, nausea, bloating, and diarrhea after drinking milk or dairy products. These symptoms may be caused by malabsorption of lactose, which is the result of low levels of lactase in the small intestine. Symptoms also occur after consumption of lactose or lactose products, with no apparent effect on the human microbiota and overall health. Therefore, of particular concern are the strict dairy-free diets commonly prescribed for patients with such complaints.This article discusses modern recommendations for the diagnosis and treatment of lactose malabsorption and lactose intolerance, which largely comply with European recommendations.

Background. Non-alcoholic fatty liver disease (NAFLD) is a leading etiological factor of chronic liver diseases in children in industrialized countries. The high prevalence of small intestinal bacterial overgrowth (SIBO) is common in patients with NAFLD. Therefore, the purpose of our work is to study the impact of SIBO on the structural and functional parameters of the liver in obese/overweight children. Materials and methods. We examined 73 children aged 6 to 17 years, mean age of patients was (11.41 ± 2.68) years. Depending on the presence of overweight/obesity and the results of glucose hydrogen breath test (HBT), patients were divided into 2 groups: group 1 — 30 overweight/obese persons with SIBO, group 2 — 28 overweight/obese children without SIBO. The control group consisted of 15 apparently healthy children with normal weight and without SIBO. The presence of liver steatosis was established by means of transient elastography with controlled attenuation parameter. Additionally, we performed lactose HBT and a biochemical blood test with biochemical hepatogram, determination of lipid and carbohydrate parameters. Results. It was found that 70 % of children in group 1 had NAFLD, compared to 32 % in group 2. Also, erythrocyte sedimentation rate was higher in group 1 than in groups 2 and 3 (p, Актуальность. Неалкогольная жировая болезнь печени (НАЖБП) занимает лидирующие позиции среди хронических заболеваний печени у детей в промышленно развитых странах. Известно, что для пациентов с НАЖБП характерна высокая распространенность синдрома избыточного бактериального роста (СИБР). Цель работы — изучить влияние СИБР на структурно-функциональные показатели печени у детей с избыточным весом и ожирением. Материалы и методы. Обследовано 73 ребенка в возрасте от 6 до 17 лет, средний возраст пациентов составил (11,41 ± 2,68) года. В зависимости от наличия избыточного веса/ожирения и результатов водородного дыхательного теста (ВДТ) с глюкозой пациенты были разделены на 2 группы: 1 группа — 30 детей с избыточным весом/ожирением и наличием СИБР, 2 группа — 28 детей с избыточным весом/ожирением без СИБР. Контрольную группу составили 15 практически здоровых детей с нормальным весом и без СИБР по результатам ВДТ с глюкозой. Наличие стеатоза печени устанавливали при помощи транзиентной эластографии с функцией САР. Дополнительно проводили ВДТ с лактозой и биохимический анализ крови с определением показателей биохимической гепатограммы, липидного и углеводного спектров. Результаты. Установлено, что 70 % детей 1 группы имели сопутствующую НАЖБП по сравнению с 32 % во 2 группе. В 1 группе скорость оседания эритроцитов была выше, чем во 2 и 3 группах (p, Актуальність. Неалкогольна жирова хвороба печінки (НАЖХП) посiдає провідні позиції серед хронічних захворювань печінки в дітей у промислово розвинених країнах. Відомо, що для пацієнтів iз НАЖХП характерна висока поширеність синдрому надмірного бактеріального росту (СНБР). Метою роботи є вивчення впливу СНБР на структурно-функціональні показники печінки в дітей iз надмірною вагою та ожирінням. Матеріали та методи. Обстежено 73 дитини віком від 6 до 17 років, середній вік пацієнтів становив (11,41 ± 2,68) року. Залежно від наявності надмірної ваги/ожиріння i результатів водневого дихального тесту (ВДТ) з глюкозою пацієнти були розподілені на 2 групи: 1 група — 30 дітей iз надмірною вагою/ожирінням та СНБР, 2 група — 28 дітей iз надмірною вагою/ожирінням без СНБР. Контрольну групу становили 15 практично здорових дітей iз нормальною вагою та без СНБР за результатами ВДТ з глюкозою. Наявність стеатозу печінки встановлювали за допомогою транзієнтної еластографії з функцією САР. Додатково проводили ВДТ з лактозою та біохімічний аналіз крові з визначенням показників біохімічної гепатограми, ліпідного й вуглеводного спектрів. Результати. Встановлено, що в 70 % дітей 1 групи була супутня НАЖХП порівняно з 32 % у 2 групі. У 1 групі швидкість осідання еритроцитів була вищою, ніж у 2 і 3 групах (p

Genetic testing is a good predictor of lactase persistence (LP) in specific populations but its clinical utility in children is less clear. We assessed the role of lactose malabsorption in functional gastrointestinal disorders (FGID) in children and the correlation between the lactase non-persistence (LNP) genotype and phenotype, based on exhaled hydrogen and gastrointestinal symptoms, during a hydrogen breath test (HBT). We also evaluate dairy consumption in this sample. We conducted a 10-year cross-sectional study in a cohort of 493 children with suspected FGID defined by Roma IV criteria. Distribution of the C/T-13910 genotype was as follows: CC, 46.0%; TT, 14.4% (LP allele frequency, 34.1%). The phenotype frequencies of lactose malabsorption and intolerance were 36.3% and 41.5%, respectively. We observed a strong correlation between genotype and both lactose malabsorption (Cramér’s V, 0.28) and intolerance (Cramér’s V, 0.54). The frequency of the LNP genotype (p = 0.002) and of malabsorption and intolerance increased with age (p = 0.001 and 0.002, respectively). In 61% of children, evaluated dairy consumption was less than recommended. No association was observed between dairy intake and diagnosis. In conclusion, we found a significant correlation between genotype and phenotype, greater in older children, suggesting that the clinical value of genetic testing increases with age.

Since the early 1990s, Spanish humanitarian associations have welcomed Saharawi children from the refugee camps in Tindouf (Argelia). These children are the most affected by the lack of food, water, hygienic measures and health care. The main objective of this study was to analyze the anthropometric, nutritional and parasitological data of 38 Saharawi boys and girls (from 10 to 13 years old) under a holiday host program in the city of Valencia. Our results confirm that malnutrition and multiparasitism are highly frequent, so it is understood that living conditions in refugee camps continue to be precarious with a lack of proper hygiene and nutrition. Furthermore, biochemical alterations, lactose malabsorption and the risk of celiac disease, also detected in our study as a secondary objective, will complicate nutritional management and restoration of health. For this reason, sustainable feeding alternatives and interventions from a hygienic and nutritional point of view are proposed, emphasizing in an improvement in the education of parents and children.

Since the early 1990s, Spanish humanitarian associations have welcomed Saharawi children from the refugee camps in Tindouf (Argelia). These children are the most affected by the lack of food, water, hygienic measures and health care. The main objective of this study was to analyze the anthropometric, nutritional and parasitological data of 38 Saharawi boys and girls (from 10 to 13 years old) under a holiday host program in the city of Valencia. Our results confirm that malnutrition and multiparasitism are highly frequent, so it is understood that living conditions in refugee camps continue to be precarious with a lack of proper hygiene and nutrition. Furthermore, biochemical alterations, lactose malabsorption and the risk of celiac disease, also detected in our study as a secondary objective, will complicate nutritional management and restoration of health. For this reason, sustainable feeding alternatives and interventions from a hygienic and nutritional point of view are proposed, emphasizing in an improvement in the education of parents and children. This study was part of the project “Promotion of hygienic-health habits for the prevention of intestinal parasites in the Saharawi population” promoted by the University of Valencia in collaboration with the Nutrition Clinic of the University of Valencia (CUNAFF), the Federation of Solidarity Associations with the Saharawi People of the Valencian Country (FASPS-PV) and the Ministry of Sanitat de la Comunitat Valenciana, in addition to being funded by the . Sí

Background Lactose malabsorption is normally evaluated by measuring exhaled H2 produced by intestinal flora, from unabsorbed lactose. However, differing microbiome composition can lead to the production of CH4 instead of H2; hence, some authors challenge the H2 method sensitivity and favor the evaluation of both intestinal gases. Aim To compare different approaches to usage of a lactose breath test for lactose malabsorption diagnosis, after medical evaluation of gastrointestinal symptoms. Methods In a retrospective observational study, we compared the 2 approaches in a population of 282 subjects in Northern Italy. Following oral lactose administration, exhaled samples were harvested every 30 minutes for 4 hours and prepared for H2 and CH4 analysis. Basal gas levels were subtracted from H2 and CH4 ppm and values at 4 hours and peaks were considered for analysis. Results Applying the standard methodology, which takes separately into consideration H2 and CH4 produced in the intestinal lumen, the results indicated that 11.7% of the patients were diagnosed “positive” for hypolactasia, differently from what was expected. Conversely, taking into consideration the sum of H2 and CH4, the percentage increased to 62.8%, closer to the expected one. No significant differences were found when comparing the 2 groups for age, gender, or symptoms. The sizable difference between the 2 approaches is likely linked to gut microbiome variability, and consequently the different production of the 2 gases, in the population. Conclusion The threshold normally used for lactose breath test should be reconsidered and changed, merging H2 and CH4 stoichiometric values to increase sensitivity.

Background: Carbohydrate malabsorption is a frequent digestive problem associated with abdominal pain, bloating and diarrhea. Hydrogen breath testing (BT) represents the most reliable and validated diagnostic technique. The aim of this manuscript was to clarify the usefulness of BTs in the nutritional management of these disorders. Methods: A literature search for BT related to carbohydrate malabsorption was carried out using the online databases of Pubmed, Medline and Cochrane. Results: Lactose BT showed good sensitivity and optimal specificity for lactose malabsorption. However, an accurate diagnosis of lactose intolerance should require blind lactose challenge although this method is difficult to utilize in clinical practice. Regarding dose-depending fructose and sorbitol malabsorption, BTs could not add diagnostic advantage compared with a direct dietary intervention. In addition, carbohydrates are fundamental components of fermentable oligo-, di- and monosaccharides and polyols (FODMAPs). Before starting a low FODMAP diet, lactose BT should be suggested in a population with low prevalence of hypolactasia. Conclusions: BTs represent a valid and noninvasive technique in many digestive conditions. Regarding the management of carbohydrate intolerance, lactose BT can be recommended with some limitations. No sufficient evidence is available about the usefulness of BTs for other sugars in clinical practice.

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal (GI) disorder characterized by abdominal pain and altered bowel habits. Symptom-based criteria are typically used to diagnose IBS. An estimated 10% of the general population has IBS. Little is known about the prevalence, symptoms, diagnosis, attitude, and referral to specialists of patients with irritable bowel syndrome (IBS) in general practice. This study aimed to determine these characteristics. Keywords: IBS (irritable bowel syndrome), LMA (lactose malabsorption), MMPI (Minnesota Multiphasic Personality Inventory)

Trabajo fin de grado en Enfermería, Cada vez es más frecuente que las personas asocien síntomas gastrointestinales al consumo de determinadas sustancias y las eliminen de su dieta habitual, pudiendo evitar alimentos que aportan nutrientes esenciales y beneficios importantes para la salud. En el caso de la lactosa, el auto-diagnóstico de intolerancia es cada vez más común. Esta revisión pretende analizar la evidencia existente acerca de los efectos de la lactosa sobre la salud y determinar cuál es la aproximación terapéutica más adecuada. Los resultados muestran evidencia de que los sujetos con malabsorción de lactosa pueden tolerar la dosis de lactosa contenida en un vaso de leche sin experimentar síntomas, por lo que los productos “sin lactosa” y los preparados con lactasa resultan innecesarios en la mayoría de los casos. El incremento del auto-diagnóstico puede deberse a numerosos factores psicológicos y los síntomas pueden reducirse normalmente con estrategias dietéticas sencillas. Con respecto a los efectos de la lactosa sobre la salud y el desarrollo de determinadas enfermedades, los resultados son contradictorios, hacen falta más investigaciones que analicen los efectos de la lactosa de forma aislada, aunque sí parece evidente que mejora la absorción del calcio. Es necesario que los profesionales sanitarios dispongan de una mayor información actualizada acerca de este tema para que puedan ayudar a comprender a la población que la intolerancia a la lactosa es una condición mucho menos frecuente de lo que actualmente se cree y que puede tratarse sin necesidad de consumir productos especiales o fármacos., It is becoming more frequent for people to associate gastrointestinal symptoms with the consumption of certain substances and to eliminate them from their habitual diet, avoiding foods that provide essential nutrients and important health benefits. In the case of lactose, self-diagnosis of intolerance is becoming more common. This review aims to analyze the existing evidence about the effects of lactose on health and determine the most appropriate therapeutic approach. The results show ample evidence that subjects with lactose malabsorption can tolerate the dose of lactose contained in a cup of milk without symptoms, so that “lactose free” products and lactase preparations are unnecessary in most cases. Increased self-diagnosis may be due to numerous psychological factors and symptoms can be reduced with simple dietary strategies. Regarding the effects of lactose on health and the development of certain diseases, the results are contradictory and more research is needed to analyze the effects of lactose alone, although it seems to improve the absorption of calcium. It is necessary that health professionals have more up-to-date information on this subject so that they can help to understand the population that lactose intolerance is a much less frequent condition than is currently believed and can be treated without need of consuming special products or drugs.

Lactose intolerance has seen recognized as a clinical syndrome characterized by pain, abdominal distention, flatulence, and diarrhea after the consumption of lactose. Lactose is a common disaccharide found in dairy that requires lactase-phlorizin hydrolase (LPH) to break down into glucose and galactose. A deficiency in this enzyme results in flora bacteria further along in the gastrointestinal tract (GI) tract to metabolize the excess lactose to numerous gases, including H2. Recent studies show that the risk of symptoms after lactose ingestion depends on the dose of lactose, LPH expression, intestinal flora, and sensitivity of the gastrointestinal tract. Currently, there are several diagnostic tests that investigate the biological mechanism of lactose intolerance such as blood, biopsy, genetic, and breath tests. Due to its relatively low cost, availability, and non-invasiveness, the hydrogen breath test (HBT) has become a popular technology to aid in the diagnosis of many gastroenterological diseases, specifically lactose intolerance. Additionally, while administering the HBT there seems to be a lack of uniform criteria amongst the various studies, with many using their own guidelines, which may in turn cause inconsistency with the analysis of the results. With ever improving nanotechnology, novel approaches to expedite and lower the costs of the HBT has become an area of research with significant advancements.

Background Relationships between inflammatory bowel disease and lactose containing foods remain controversial and poorly defined regarding symptoms, nutritional outcomes, and epidemiologic associations for lactose maldigestion. Methods A literature review was performed using Pub Med, Cochrane library and individual references, to extract data on lactose maldigestion prevalence in inflammatory bowel diseases. A meta-analysis was done using selected articles, to determine odds ratios of maldigestion. Information was collected about symptoms, impact on pattern of dairy food consumption, as well as the effects of dairy foods on the course of inflammatory bowel diseases. Results A total of 1022 articles were evaluated, 35 articles were retained and 5 studies were added from review articles. Of these 17 were included in meta-analysis which showed overall increased lactose maldigestion in both diseases. However increased risk on sub analysis was only found in Crohn’s in patients with small bowel involvement. Nine additional studies were reviewed for symptoms, with variable outcomes due to confounding between lactose intolerance and lactose maldigestion. Fourteen studies were evaluated for dairy food effects. There was a suggestion that dairy foods may protect against inflammatory bowel disease. Nutritional consequences of dairy restrictions might impact adversely on bone and colonic complications. Conclusions Lactose maldigestion in inflammatory bowel disease is dependent on ethnic makeup of the population and usually not disease. No bias of increased disease prevalence was noted between lactase genotypes. Intolerance symptoms depend on several parameters besides lactose maldigestion. Dairy foods may decrease risks of inflammatory bowel disease. Dairy restrictions may adversely affect disease outcome.

Background. The aim of the study is to investigate the association of expression of galectin-9 (Gal-9) mRNA and lactose malabsorption in obese children with polymorphism (SNP) of the lactase gene (LCT) and to study the efficacy of lactase deficiency therapy using exogenous lactase preparations. Materials and methods. Seventy obese children (BMI > 95 th percentile) and 16 children without obesity aged 6–18 years were examined. There was studied SNP LCT (material for investigation venous blood) by real-time PCR, expression of Gal-9 mRNA (study material buccal epithelium) by real-time PCR with reverse transcription, malabsorption of lactose by hydrogen breath test (HBT). Among obese children, 38 children with genotype C/C 13910 presented the first observation group, 32 children with phenotype identical genotypes C/T 13910 and T/T 13910, p > 0.05, presented the second group. Children from the first observation group also determined the level of expression of Gal-9 mRNA and lactose malabsorption after using exogenous lactase preparations. Results. The genotype C/C 13910 was determined in 38 (54.3 %), genotype C/T 13910 in 22 (31.4 %) and genotype T/T in 10 (14.3 %) patients. Malabsorption of lactose in children with genotype C/C 13910 averaged 32.7 ± 10.4 pmm, in children with genotypes C/T 13910 — 26.3 ± 4.9 pmm (p > 0.05) and with genotype T/T 13910 and was absent in children without obesity (p

Lactose malabsorption and lactose-induced symptoms are poorly correlated, as shown by breath tests and various symptom assessment methods. Validated assessment is the key to overcome the limitations of biased symptom measurements. We characterized lactose-induced symptoms with the population-specific, validated paediatric carbohydrate perception questionnaire (pCPQ) and their correlation with the history of symptoms (HoS).A total of 130 patients with functional gastrointestinal symptoms underwent a lactose hydrogen breath and tolerance test (LBTT) allowing for a diagnosis of malabsorption (M+) and lactose sensitivity (S+). HoS indicative of lactose-induced symptoms (abdominal pain, nausea, bloating, flatulence, diarrhoea) in the 4 weeks preceding the test was determined using a validated questionnaire. The pCPQ was used to score lactose-induced symptoms.The LBTT revealed 41 children (31.5%) with lactose malabsorption (M+), 56 (43.1%) with lactose sensitivity (S+) and 24 (18.5%) were M+/S+. Sensitivity correlated with HoS (P0.001), regardless of whether malabsorption was detectable. Malabsorption status did not correlate with HoS (NS). The odds of lactose sensitivity significantly increased when abdominal pain [odds ratio (OR) 3.5, confidence interval (CI) 1.6-7.8], nausea (OR 2.3, CI, 1.1-4.9) and flatulence (OR 3.1, CI 1.4-6.8) were reported in the 4 weeks preceding the LBTT. Symptoms after the lactose load were similar for M+/S+ and M-/S+, except for flatulence, which was more frequent in malabsorbers (P0.01).Our findings fit well with the emerging view of the important role of a validated symptom assessment after a lactose load. The determination of symptoms may be more relevant than malabsorption for the clinical outcomes of paediatric patients with lactose-related gastrointestinal symptoms.

In patients with hypothyroidism, levothyroxine (LT4) is the treatment of choice, and tablets are the most commonly prescribed formulation. Despite multiple scenarios being reported in the literature with impaired tablet absorption and likely missed TSH targets, it is yet unclear what the implications are for clinical practice and the role of liquid solution (LS) and soft gel (SG) formulations. We have thus conducted a narrative review evaluating the prevalence within the general population of gastrointestinal disorders impacting tablet LT4 absorption. PubMed and Google Scholar were searched until December 2019 for systematic reviews and meta-analyses on the topic. If they could not be retrieved, other types of manuscripts were searched. Lactose malabsorption and Helicobacter pylori infection represented the most common disorders, with a global prevalence of 68% and 48%, respectively. The prevalence of other conditions, including autoimmune gastritis, bariatric surgery, celiac disease, gastroparesis, giardiasis, liver cirrhosis, or ulcerative colitis, was lower than 20%. Data at regional and country levels were found to be heterogeneous, but at least one in five patients was diagnosed with one disorder. The worldwide prevalence of gastrointestinal disorders associated with tablet LT4 malabsorption, including lactose malabsorption and Helicobacter pylori infection, is high. Interactions with drugs or food can further increase this risk. Considering that all studies investigating the impact of switching patients from tablet to LS or SG found an improved thyroid balance, the latter formulations should be considered as first-line therapy for managing hypothyroidism.