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Objectives Lactose malabsorption is generally assessed by hydrogen breath testing (HBT). However, this test is not recommended in patients with high baseline hydrogen concentrations (H2B). In addition, breath testing is not recommended in the current situation created by the COVID-19 pandemic, due to the potential infectiveness of the samples. The objective is to assess concordance between HBT and lactose tolerance test (LTT) depending on H2B concentrations. Methods A total of 430 patients (40 years, Q1–Q3 = 28–54 years; 66.7% women) suspected of lactose malabsorption were included in the study. Breath and heparinized blood samples were collected at baseline and sequentially after the intake of 50 g of lactose, to measure hydrogen in breath and glycemia in blood, respectively. Results H2B was 20 ppm in 15.8% of subjects. In patients with H2B 2B levels obtained in HBT. Conclusions LTT emerges as an alternative to HBT to assess lactose malabsorption in the presence of high H2B levels or when breath testing is not recommended by the circumstances. The best concordance was obtained when the cut-off for LTT was set at 15 mg/dL.

Lactose is the most important source in mammalian milk. In normal children, Lactose is hydrolyzed by lactase, and directly absorbed into bloodstream by an active transport mechanism. The term of lactose malabsorption is reserved to patients in whom impaired intestinal lactose hydrolysis and uptake has been proven by an appropriate test. The severity of lactose malabsorption and the extent of symptoms vary widely and are the results of several factors such as the amount of ingested lactose, gastric emptying time, intestinal transit time, and colonic flora. The diagnosis of lactose malabsorption is based on clinical findings and the results of appropriate tests. The breath hydrogen test has obvious advantages for pediatric population because it is painless, non-invasive, sensitive and specific. In the absence of bacterial colonization in the small intestine, the elevation of the concentration of hydrogen in the expired air implies the arrival of lactose in the colon. The increasing respiratory excretion of hydrogen is indicative of a deficit of lactase in enterocyte brush border. This test can also be used to show the existence of bacterial growth. Dietary fiber, some drugs, preparation for colonoscopy, colonic pH, and diarrhea can influence the result of breath hydrogen test.

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/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.

Background The prevalence of lactose malabsorption varies widely throughout the world. Only people of Caucasian genetic background continue to produce high amount of lactase throughout adulthood. Previous studies in Indonesia revealed that the prevalence of lactose malabsorption was 21-58% in children aged 3-11 years. Objective To determine the prevalence of lactose malabsorption in the older age group and whether a change in milk drinking habit can affect it. Methods A cross sectional descriptive study was conducted on 98 children aged between 12 and 14 years (junior high school) in Jakarta. Lactose malabsorption was evaluated with Lactometer Breath Hydrogen Test (Hoek Loes, Amsterdam). Milk drinking habit was recorded, and drinking at least 1 glass of milk everyday since 6 months or more before the study was considered as regular milk drinking. Results This study showed 73% of the children had lactose malabsorption. Regular milk drinking habit was found in 32 (33%) children and lactose malabsorption occurred in 26. From 66 children who were irregular milk drinkers, lactose malabsorption was found in 46 (70%). Lactose intolerance was about the same in both groups. Conclusion There was an increasing prevalence of lactose malabsorption in older children. Milk drinking habit is a major concern to review the practical implications of lactose malabsorption.

The lactose hydrogen breath test is a commonly used, non-invasive method for the detection of lactose malabsorption and is based on an abnormal increase in breath hydrogen (H₂) excretion after an oral dose of lactose. We use a combined (13)C/H₂ lactose breath test that measures breath (13)CO₂ as a measure of lactose digestion in addition to H₂ and that has a better sensitivity and specificity than the standard test. The present retrospective study evaluated the results of 1051 (13)C/H₂ lactose breath tests to assess the impact on the diagnostic accuracy of measuring breath CH₄ in addition to H₂ and (13)CO₂. Based on the (13)C/H₂ breath test, 314 patients were diagnosed with lactase deficiency, 138 with lactose malabsorption or small bowel bacterial overgrowth (SIBO), and 599 with normal lactose digestion. Additional measurement of CH₄ further improved the accuracy of the test as 16% subjects with normal lactose digestion and no H₂-excretion were found to excrete CH₄. These subjects should have been classified as subjects with lactose malabsorption or SIBO. In conclusion, measuring CH₄-concentrations has an added value to the (13)C/H₂ breath test to identify methanogenic subjects with lactose malabsorption or SIBO.

The aim of this study was to compare the impact of whole milk supplementation on gut microbiota and cardiometabolic biomarkers between lactose malabsorbers (LM) and absorbers (LA). We performed a pair-wise intervention study of 31 LM and 31 LA, 1:1 matched by age, sex, body mass index, and daily dairy intake. Subjects were required to add 250 mL/day whole milk for four weeks in their routine diet. At the beginning and the end of the intervention period, we collected data on gut microbiota and cardiometabolic biomarkers. Whole milk supplementation significantly increased Actinobacteria (P &lt, 0.01), Bifidobacterium (P &lt, 0.01), Anaerostipe (P &lt, 0.01), and Blautia (P = 0.04), and decreased Megamonas (P = 0.04) in LM, but not LA. Microbial richness and diversity were not affected. The fecal levels of short-chain fatty acids (SCFAs) remained stable throughout the study. Body fat mass (P &lt, 0.01) and body fat percentage (P &lt, 0.01) reduced in both groups, but the changes did not differ between groups. No significant differences in other cardiometabolic markers were found between LM and LA. When compared with LA, whole milk supplementation could alter the intestinal microbiota composition in LM, without significant changes in fecal SCFAs and cardiometabolic biomarkers.

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.

Background: Sheep milk (SM) is a possible alternate dairy source for those who experience digestive symptoms with cow milk (CM). While both the milks contain lactose, one of the causes for self-reported intolerance to CM, the composition of SM and CM also differs across proteins and fats, which have been shown to impact digestive processes.Objective: To compare the acute digestive comfort and lactose malabsorption of SM to CM in female dairy avoiders.Method: In a double-blinded, randomized cross over trial, 30 dairy-avoiding females (aged 20–30 years) drank 650 mL of SM or CM (each reconstituted from spray dried powder) following an overnight fast, on two separate occasions at least 1 week apart. Blood samples were collected for glucose and insulin assessment, and single nucleotide polymorphisms of the lactase (LCT) gene (C/T13910 and G/A22018). Breath H2 and visual analog scale (VAS) digestive symptom scores were recorded at fasting and regular intervals over 4 h after ingestion.Results: Eighty percentage of study participants were lactase non-persistent (LNP; CC13910 and GG22018 genotype). Digestive symptoms, including abdominal cramps, distension, rumbling, bloating, belching, diarrhea, flatulence, vomiting, and nausea, were similar in response to SM and CM ingestion (milk × time, P > 0.05). Breath H2 was greater after CM than SM (72 ± 10 vs. 43 ± 6 ppm at 240 min, P < 0.001), which may be due to greater lactose content in CM (33 vs. 25 g). Accordingly, when corrected for the lactose content breath H2 did not differ between the two milks. The response remained similar when analyzed in the LNP subset alone (n = 20).Conclusions: Despite a higher energy and nutrient content, SM did not increase adverse digestive symptoms after ingestion, relative to CM, although there was a reduced breath H2 response, which could be attributed to the lower lactose content in SM. The tolerability of SM should be explored in populations without lactose intolerance for whom underlying trigger for intolerance is unknown.

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.

OBJECTIVES: Sheep milk (SM) is compositionally different from cow milk (CM), but maintains the nutritional benefits of CM, making it a potential alternative for CM avoiders. While dairy avoidance is often due to intolerance to lactose, which is also found in SM, there are consumer anecdotal reports that SM is better tolerated than CM. Thus, this clinical trial was undertaken to assess acute digestive comfort and lactose malabsorption comparing SM and CM in female dairy avoiders. METHODS: In a double-blinded, randomized cross over trial, 30 dairy avoiding females (aged 20–30 years) drank 650 mL of SM or CM (reconstituted from spray dried powder) following an overnight fast, on separate occasions at least one week apart. Blood samples were collected for single nucleotide polymorphisms of the LCT gene (lactase gene; C/T(13910) and G/A(22018)). Breath H(2) and visual analog scale (VAS) digestive symptom scores were recorded at fasting and regular intervals over 4 h after ingestion. RESULTS: Genotyping showed 80% of the dairy avoiders were lactase non-persistent (CC(13910) and GG(22018) genotype), hence lactose malabsorbers. Digestive symptoms were similar in response to SM and CM, with increased symptoms; abdominal cramps, rumbling, bloating, belching, flatulence, and nausea, after the ingestion of either milk (P

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

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.

Lactose is the main source of calories in milk, an essential nutriedigestion, patients with visceral hypersensitivity nt in infancy and a key part of the diet in populations that maintain the ability to digest this disaccharide in adulthood. Lactase deficiency (LD) is the failure to express the enzyme that hydrolyses lactose into galactose and glucose in the small intestine. The genetic mechanism of lactase persistence in adult Caucasians is mediated by a single C→T nucleotide polymorphism at the LCTbo -13'910 locus on chromosome-2. Lactose malabsorption (LM) refers to any cause of failure to digest and/or absorb lactose in the small intestine. This includes primary genetic and also secondary LD due to infection or other conditions that affect the mucosal integrity of the small bowel. Lactose intolerance (LI) is defined as the onset of abdominal symptoms such as abdominal pain, bloating and diarrhoea after lactose ingestion by an individual with LM. The likelihood of LI depends on the lactose dose, lactase expression and the intestinal microbiome. Independent of lactose digestion, patients with visceral hypersensitivity associated with anxiety or the Irritable Bowel Syndrome (IBS) are at increased risk of the condition. Diagnostic investigations available to diagnose LM and LI include genetic, endoscopic and physiological tests. The association between self-reported LI, objective findings and clinical outcome of dietary intervention is variable. Treatment of LI can include low-lactose diet, lactase supplementation and, potentially, colonic adaptation by prebiotics. The clinical outcome of these treatments is modest, because lactose is just one of a number of poorly absorbed carbohydrates which can cause symptoms by similar mechanisms. ispartof: GUT vol:68 issue:11 pages:2080-2091 ispartof: location:England status: published

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.

Background. Insufficient vitamin D and calcium intake associated with the restricted intake of milk and dairy products can lead to poor health outcomes like malnutrition and abnormal bone mineralization. The aim of the study was to estimate the prevalence of primary and secondary lactose intolerance in children with IBD. Methods. The study included 107 patients (mean age 14.07±3.58 years; 46.7% boys) which includes 43 patients with Crohn’s disease (CD), 31 with ulcerative colitis (UC), and 33 children with functional abdominal pain (AP-FGID). We analysed the result of the hydrogen breath test with lactose loading, two single nucleotide polymorphisms of the LCT gene (LCT-13910CC and LCT-22018GG). The results were analysed with MedCalc Statistical Software. Results. Adult-type hypolactasia (ATH) was found in 31% of patients with IBD and 42.4% of AP-FGID (p=0.2). Lactose malabsorption (LM) was found in 27.9% of patients with CD, in 22.6% with UC, and in 24.2% with AP-FGID (p=0.8). Lactose intolerance (LI) was diagnosed in a similar percentage of patients in each group (p=0.9). Secondary LI in IBD patients does not depend on the location, duration, and activity of the disease and the number of relapses (p>0.05). The median time of lactose-free diet in CD was 10 months and in CU 24 months. Conclusions. The incidence of LI, LM, and ATH does not differ among children with IBD from the population.

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 Current literature proposes associations between homocysteine (HCY), folic acid (FA), vitamin B12 metabolism and depression. However, the exact underlying biological mechanisms remain unclear. This study aimed at evaluating a possible link between primary adult-type lactose malabsorption (PALM), HCY, FA and vitamin B12 metabolism and depressive disorder. Methods Plasma levels of HCY, FA and vitamin B12 were determined in 78 patients with PALM and 160 individuals with lactase persistence sub-grouped by the presence or absence of major depression. Results In 78 patients with PALM, the subgroup of 22 individuals with major depression showed significantly higher median (interquartile range) HCY (10.10 [8.46–12.03] vs. 8.9 [7.54–9.86] μmol/L, p = 0.029) and lower plasma FA levels (5.7 [4.68–9.14] vs. 6.95 [5.24–10.56] μmol/L, p = 0.272) compared to the subgroup of 56 individuals without depression, respectively. No such associations could be observed for those 160 individuals without PALM (i.e., lactase persistence) Plasma HCY levels were positively correlated with depressive symptoms (p = 0.052), and showed negative correlations with FA (p = < 0.001) and vitamin B12 (p = 0.029), respectively. Conclusion Depressed individuals with PALM were found with significantly higher HCY and lower FA levels compared to non-depressed individuals with PALM, however, this association was absent in the subgroup of lactase persistent individuals. These findings suggest an association between increased HCY levels, lactose malabsorption and depression.

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.

WOS:000323601900005; International audience; Background: Lactose malabsorption occurs frequently and the variable consequent intolerance may seriously impair quality of life. No reliable and convenient test method is in routine clinical practice. A recent animal study showed that the respiratory quotient changed significantly after ingestion of sucrose and lactose in naturally lactase-deficient rats. Aims: This exploratory study evaluated the relevance of monitoring the respiratory quotient after lactose ingestion to detect malabsorption. Methods: Healthy volunteers were identified and classified lactose absorbers and malabsorbers by a lactose tolerance test (25 g). After an overnight fast, a second lactose challenge was performed to monitor hydrogen excretion and respiratory quotient kinetics over 4 h. Participants also completed questionnaires to score and localise their gastrointestinal symptoms. Results: 20 subjects were enrolled (10 per group, 60% males, mean age 34 +/- 4 years). Respiratory quotient kinetics were different between absorbers and malabsorbers during the first 100 min after lactose ingestion (p \textless 0.01) and during the initial 30-50 min period. Respiratory quotient was significantly, positively correlated to peak glycaemia (R = 0.74) and negatively correlated to hydrogen excretion (R = -0.51) and symptoms score (R = -0.46). Conclusions: Indirect calorimetry could improve the reliability of lactose malabsorption diagnosis. Studies on larger populations are needed to confirm the validity of this test and propose a simplified measurement. (c) 2013 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

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.

The aim of this study was to establish a retrospective evaluation and comparison of the hydrogen/methane (H2/CH4) breath test and genetic test (C/T−13910polymorphism) results in lactose malabsorption testing. In total 263 consecutive patients with suspected lactose malabsorption were included in this study. They underwent the H2/CH4breath test following the ingestion of 50 g lactose and were tested for the C/T−13910polymorphism. In total 51 patients (19.4%) had a C/C−13910genotype, indicating primary lactose malabsorption. Only 19 patients (7.2%) also had a positive H2/CH4breath test. All in all 136 patients (51.69%) had a C/T−13910and 76 patients (28.91%) a T/T−13910genotype, indicating lactase persistence. Four patients (1.5%) with the C/T−13910genotype and one patient (0.4%) with the T/T−13910genotype had a positive H2/CH4breath test result, indicating secondary lactose malabsorption. Cohen's Kappa measuring agreement between the two methods was 0.44. Twenty patients (7.6%) with a positive H2/CH4peak within 60 minutes after lactose ingestion were classified as patients with lactose-dependent small intestinal bacterial overgrowth (SIBO). In conclusion, only moderate agreement between the breath test and the genetic test was shown. Secondary lactose malabsorption as well as preanalytical limitations of the combined H2/CH4breath test procedure can cause discrepant results. This trial is registered with K-42-13.

Commentary on: A Shaukat, MD Levitt, BC Taylor, et al.. Systematic review: effective management strategies for lactose intolerance. Ann Intern Med2010;152:797–803.

Objective.To establish whether supplementation with a standard oral dose of Beta-Galactosidase affects hydrogen breath excretion in patients presenting with lactose malabsorption.Methods.Ninety-six consecutive patients positive to H2 Lactose Breath Test were enrolled. Mean peak H2 levels, the time to reach the peak H2, the time to reach the cut-off value of 20 ppm, the cumulative breath H2 excretion, the areas under the curve, and a Visual Analogical 10-point Scale for symptoms were calculated. Genotyping of the C/T-13910 variant was carried out.Results.Following the oral administration of Beta-Galactosidase, in 21.88% of the cases, H2 Lactose Breath Test became negative (Group A), while mean peak H2 levels (74.95 ppm versus 7.85),P<0.0000, in 17.71% (Group B) were still positive, with the H2 level 20 ppm above the baseline, but the peak H2 levels were significantly lower than those observed at the baseline test (186.7 ppm versus 66.64),P<0.0000, while in 60.41% (Group C) they were still positive with the peak H2 levels similar to those observed at the baseline test (94.43 versus 81.60 ppm). All 96 individuals tested presented the C/C-13910 genotype nonpersistence.Conclusions.The response to oral administration of Beta-Galactosidase in patients with symptoms of lactose malabsorption presents a significant variability.

Objetivo: determinar a prevalência de má absorção de lactose e sua associação com a cor da pele e com a idade em crianças e adolescentes de escolas públicas do município de Porto Alegre. Métodos: foi realizado um estudo transversal, que incluiu 225 indivíduos de 8 a 18 anos, alunos de duas escolas públicas do município de Porto Alegre. A seleção dos alunos ocorreu através de sorteio. Os participantes foram classificados segundo a cor da pele (brancos e não-brancos), e a faixa etária (8 a 12 e 13 a 18 anos). A má absorção de lactose foi diagnosticada através do teste do hidrogênio expirado após ingestão de 250ml de leite de vaca integral industrializado. O teste teve duração de 3 horas, com coletas em jejum e aos 60, 120 e 180 minutos após a ingestão do leite. Foi considerado como critério de positividade o aumento > 20 ppm na concentração de hidrogênio em relação ao nível basal. Resultados: foram estudados 225 alunos, com uma média e desvio-padrão de idade de 12,2 ± 2,0 anos. Cento e trinta e quatro indivíduos eram do sexo feminino (59,6%). Cento e cinqüenta e quatro alunos eram de cor branca (68,4%) e os restantes, de cor nãobranca. A má absorção de lactose foi evidenciada em 19/225 casos (8,4%). Ela foi diagnosticada em 8/154 alunos de cor branca (5,2%) e em 11/71 alunos de cor não-branca (15,5%) (p= 0,02). Em relação à faixa etária, ocorreram 15/143 casos de má absorção nos alunos entre 8 a 12 anos (10,5%), e 4/82 casos entre 13 e 18 anos (4,9%) (p= 0,227). Conclusões: a prevalência de má absorção de lactose encontrada em alunos de escolas públicas de Porto Alegre é significativa, especialmente se considerarmos que foram utilizadas doses fisiológicas do dissacarídeo (250 ml de leite) para o diagnóstico. A taxa de má absorção foi maior entre as crianças de cor não-branca em relação às crianças de cor branca, confirmando a influência racial na hipolactasia primária do tipo adulto. Não foi encontrada associação entre má absorção de lactose e faixa etária. Objective: to determine the prevalence of lactose malabsorption and its association with skin color and age in children and teenagers attending public schools in Porto Alegre, Brazil. Methods: a cross-sectional study was performed with 225 subjects between 8 and 18 years attending two public schools in Porto Alegre, Brazil. Patients were randomly selected. Subjects were classified according to skin color (white and nonwhite) and age group (8 to 12 and 13 to 18 years). Lactose malabsorption was diagnosed using the breath hydrogen test after ingestion of 250 ml of whole cow milk. The test lasted for 3 hours, with collections after fasting and 60, 120, and 180 minutes after milk ingestion. Malabsorption was determined in the presence of increase of >20 ppm in hydrogen concentration regarding the basal levels. Results: two-hundred and twenty-five students were studied, with a mean age ± standard deviation of 12.2 ± 2.0 years. The subjects consisted of 134 females (59.6%); 154 white (68.4%); and 71 nonwhite. Lactose malabsorption was observed in 19/225 cases (8.4%). It was diagnosed in 8/154 white patients (5.2%) and in 11/71 nonwhite patients (15.5%) (P= 0.02). Regarding the age group, we found 15/143 cases of malabsorption in students between 8 and 12 years (10.5%), and 4/82 cases in students between 13 and 18 years (4.9%) (P = 0.227). Conclusions: the prevalence of lactose malabsorption in students attending public schools in Porto Alegre is significant, especially if we consider that the physiological doses (250 ml of milk) were used for diagnosis. The malabsorption rate was higher among nonwhite children, which confirms the influence of race on primary adult type hypolactasia. No association was observed between lactose malabsorption and age group.

The lactose breath test (LBT) is the standard technique for diagnosis of lactose malabsorption. However, it is time-consuming, strenuous for the patient and has been reported to have low sensitivity. The lactose intolerance quick test (LIQT) measures lactase activity in duodenal biopsies and may be performed as part of upper gastrointestinal endoscopy. The purpose of this study was to assess the role of the LBT and LIQT in the case management of suspected lactose malabsorption. The study group included 69 consecutive patients evaluated by the LBT followed by the LIQT. The test results were compared, and the sensitivity, specificity, and predictive values of the LBT were calculated. Mean age of the patients was 54.4 years, male/female ratio was 1:3, and mean body mass index was 25.2. None had celiac disease on duodenal biopsy. The LIQT was positive for hypolactasia in 55 patients (80 %): mild in 14 (25 %) and severe in 41 (75 %); 10 (18 %) were symptomatic during the LBT. The LBT was positive for lactose malabsorption in 32 patients (46 %). Of the 37 patients with normal findings on the LBT, 24 (65 %) had positive findings on the LIQT: 11 (30 %) mild hypolactasia, 13 (35 %) severe hypolactasia. In one case, the LBT was positive and the LIQT was negative. The LBT had a sensitivity of 56 %, specificity 93 %, positive predictive value 97 %, and negative predictive value 35 %. The LBT may serve as a diagnostic screening tool for lactose malabsorption. Symptomatic patients with negative LBT results should be referred for second-line testing with the LIQT.

The majority of the world's adult population and an estimated 80 million Americans are hypolactasic and hence malabsorb ingested lactose. Although lactose malabsorption is easily identified, less readily assessed is the clinically important question of how often does this malabsorption induce symptoms. This review summarizes: (1) knowledge concerning the etiology and diagnosis of hypolactasia and the pathophysiology of the symptoms of lactose malabsorption and (2) the results of well-controlled trials of the symptomatic response of lactose malabsorbers to varying dosages of lactose and the efficacy of therapeutic interventions to alleviate these symptoms. We conclude that the clinical significance of lactose malabsorption has been overestimated by both the lay public and physicians in that commonly ingested doses of lactose (ie, the quantity in a cup of milk) usually do not cause perceptible symptoms when ingested with a meal. Symptoms occur when the lactose dosage exceeds that in a cup of milk or when lactose is ingested without other nutrients. Simple dietary instruction, rather than the use of commercial products to reduce lactose intake, is recommended for the vast majority of lactose-malabsorbing subjects.

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.

Objectives The objective of the present study was to evaluate the calcium intake and bone mass in children and early adolescents in accordance with their absorption capacity to lactose. Patients and methods A transversal study was conducted on a sample composed of 76 individuals. Lactose malabsorption status was determined with hydrogen breath test. The hydrogen breath test was applied using 2 g of lactose per kilogram of weight up to a maximum of 50 g. A hydrogen increment ≥20 pm in relation to fasting was used to characterize lactose malabsorption. Two 24-hour recalls were applied for the evaluation of food consumption. Bone mineral content and bone mineral density were evaluated in the lumbar spine by dual-energy x-ray absorptiometry. Results The prevalence of lactose malabsorption was 61.8%. The participants were divided into 2 groups: lactose malabsorbers (n = 47) and lactose absorbers (n = 29). There was no statistically significant difference (P > 0.05) between the groups with respect to the intake of total calcium, milk calcium, milk, cheese, yogurt, ice cream, and calcium density of the diet. Additionally, there was no difference with respect to the bone mineral content and the bone mineral density of the lumbar spine. Independent from lactose absorption capacity, it was observed that the majority of the children and early adolescents showed calcium intake lower than the recommended value. Conclusions There was no relation among lactose malabsorption and bone densities, bone mineral content, or calcium intake within the present study.

Background Lactose malabsorption (LM), diagnosed currently using lactose hydrogen breath and tolerance tests (LHBT, LTT) with a high, nonphysiological dose (50-g), may mimic irritable bowel syndrome (IBS). In LM-endemic areas, clinically significant malabsorption (lactose intolerance) may be better diagnosed using a lesser dose, and positive results so obtained may predict response to milk withdrawal more effectively. Methods Fifty patients each with IBS (Rome III) were evaluated using LHBT and LTT with 50-g, 25-g, and 12-g lactose. Sensitivity and specificity of LHBT and LTT with different dosages (gold standard: lactase gene C/T-13910 polymorphism) and symptom development were evaluated. Effect of milk withdrawal was studied. Result Of 150 patients, 37/50 (74%) and 28/50 (56%) had LM by LHBT and LTT using 50-g lactose; 41/50 (82%) and 31/50 (62%) had LM using 25-g lactose, and 14/50 (28%) and 29/50 (58%) using 12-g lactose, respectively. Sensitivity and specificity of LHBT using 50-g, 25-g, and 12-g lactose were 92.6%, 52.0%, and 94%, 60%, and 36.4%, 88.2%, and those of LTT, 92%, 80.0%, and 84.8%, 82.4%, and 66.7%, 58.8%, respectively. Breath hydrogen correlated with lactose dose. Though patients developing symptoms with 50-g lactose exhaled more hydrogen than those remaining asymptomatic, hydrogen levels did not differ following 25-g and 12-g dosages in relation to symptom development. Patients' milk intake was 335 ± 92 mL/d (≈ 16.7 ± 9.6-g lactose). Positive LHBT using 25-g dose better predicted symptom resolution than by 50-g and 12-g lactose. Conclusion Twenty-five gram is the ideal dose of lactose for LHBT and LTT in LM-endemic areas.

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.

Summary Background Fructose malabsorption, lactose malabsorption and an early rise in breath hydrogen after lactulose (ERBHAL) may play roles in induction of symptoms in gastrointestinal conditions. Aim To compare prevalence and interactions of fructose malabsorption, lactose malabsorption and ERBHAL among healthy subjects and those with chronic intestinal disorders using consistent breath hydrogen testing methodologies. Methods Consecutive series of Caucasian patients with Crohn’s disease (n = 91), ulcerative colitis (56), functional gastrointestinal disorders (FGID) (201), coeliac disease (136) and 71 healthy volunteers underwent breath hydrogen testing using lactulose, fructose and lactose. Results Early rise in breath hydrogen after lactulose occurred more commonly in healthy controls (39%) than in Crohn’s disease (20%) and untreated coeliac disease (14%; P

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.

As decreased bone mineral density (BMD) is a common problem in cystic fibrosis (CF) and milk products may have pivotal dietary role affecting BMD, we aimed to assess the potential influence of adult-type hypolactasia (ATH) and lactose malabsorption (LM) on BMD in adolescent and young adult patients. In 95 CF pancreatic-insufficient patients aged 10–25 years (without liver cirrhosis, steatosis and cholestasis, diabetes mellitus, systemic glucocorticoid therapy), lumbar BMD, the nutritional status, pulmonary function, vitamin D3 concentration, calcium intake and single-nucleotide polymorphism upstream of the lactase gene were assessed. In subjects with the −13910 C/C genotype predisposing to ATH, the presence of LM was determined with the use of a hydrogen–methane breath test (BT). BMD and calcium intake were significantly lower in patients with the C/C genotype (P

Summary Background & aims Lactose malabsorption (LM) is a frequent condition in adults and is often associated with bowel symptoms. Although the diagnostic gold standard is represented by assessment of the tissue lactase activity, LM diagnosis is currently made non-invasively by hydrogen breath test. Alternatively, an accurate clinical and anamnestic evaluation of symptoms can suggest LM in many cases. The aim of the study was to evaluate the diagnostic accuracy of clinical variables for the diagnosis of LM when compared to the hydrogen breath test. Methods Forty consecutive patients with suspected LM performed a hydrogen breath test after oral load of lactose (25 g). Patients were requested to answer five questions on a visual-analogical scale (0–4): subjective correlation milk/symptoms; abdominal pain; bloating; soft stools; response after milk exclusion. Statistical analysis was performed by using the Mann–Whitney U-test and Cohen's k of agreement. Also, a ROC curve was constructed to identify the best diagnostic cut-off for the resulting clinical-anamnestic score. Results Breath test was positive in 16 out of 40 patients (40%). The mean clinical score was significantly higher in patients with LM (14 vs 8.5; p 10 showed a sensitivity of 91%, a specificity of 95%, positive and negative predictive values of 91% and of 95% for LM diagnosis. Additionally, a score >10 presented high concordance with the result of the breath test (k = 0.92). Conclusions Accurate evaluation of five clinical-anamnestic variables, with the use of a simple scoring system, is almost equivalent to the hydrogen breath test for the diagnosis of lactose malabsorption and could avoid breath testing in many cases.

The prevalence and duration of lactose malabsorption was studied in 64 Central Australian Aboriginal children requiring hospitalization for acute enteritis. Lactose malabsorption was determined by the breath‐hydrogen test. Sixty‐nine per cent were shown to malabsorb lactose, a figure similar to that for well nourished urban European children, hospitalized for acute enteritis. Whereas 90 per cent of the European children became lactose‐tolerant 1 month later, only three of 32 aboriginal children were lactose‐tolerant after 3 months. Lactose malabsorption was also associated with more frequent hospitalizations in affected children. Coronavirus‐like particles were the commonest agent isolated from Aboriginal children. The majority of the Aboriginal children were malnourished (< 80% standard weight for age) which may have been contributed to by their lactose malabsorption and explain why this failed to recover in the same way as European children. The possibility of lactose malabsorption must be taken into consideration when managing Aboriginal children with acute diarrhoeal disease and undernutrition. The use of the breath‐hydrogen test allows an accurate diagnosis of lactose malabsorption to be made in Aboriginal children with diarrhoea so that appropriate dietary management can be instituted.

Lactose malabsorption is a syndrome producing constellation of symptoms, including abdominal pain, bloating, flatulence, diarrhea, and sometimes nausea and/or vomiting. Primary causes of lactose malabsorption due to loss of intestinal lactase activity include genetic/racial lactase nonpersistence, congenital lactase deficiency, and developmental lactase deficiency. Secondary lactose malabsorption can be caused by any disorder that injures the small intestinal mucosa, such as viral gastroenteritis, celiac disease, allergic (eosinophilic) gastroenteritis, and radiation enteritis. The diagnosis depends on careful clinical evaluation and is customarily confirmed with a lactose breath hydrogen test. As the symptoms are nonspecific, many adults diagnosed with lactose malabsorption actually have irritable bowel syndrome. Treatment consists of a trial of eliminating lactose-containing dairy foods, with supplementation of alternative calcium and protein sources. Commercial enzyme products containing β-galactosidases can be prescribed to help patients digest dietary lactose. Long-term lactose restriction usually is not necessary and can lead to reduced bone mineral density.

Background: Lactose malabsorption (LM), the inability to break down lactose into glucose and galactose, is due to a deficiency in the small intestinal lactase phlorizin hydrolase enzyme. Ethnic and geographic variations of LM are known. Objective: The aim of this study was to compare the frequency of LM in healthy southern and northern Indian populations. Design: A total of 153 healthy volunteers (76 from southern and 77 from northern India) were evaluated for LM by using a lactose tolerance test (LTT), a lactose hydrogen breath test (lactose HBT), and polymerase chain reaction-restriction fragment length polymorphism to identify the lactase gene C/T-13910 polymorphism (confirmed by sequencing). Results: Volunteers from southern and northern India were comparable in age and sex. The LTT result was abnormal in 88.2% of southern Indians and in 66.2% of northern Indians (P = 0.001). The lactose HBT result was abnormal in 78.9% of southern Indians and in 57.1% of northern Indians (P = 0.003). The CC genotype was present in 86.8% and 67.5% (P = 0.002), the CT genotype was present in 13.2% and 26.0% (P = 0.036), and the TT genotype was present in 0% and 6.5% (P = 0.03) of southern and northern Indians, respectively. The frequency of symptoms after the lactose load (47.4% compared with 15.6%; P < 0.001) and peak concentrations of breath hydrogen (88.5 ± 71.9 compared with 55.4 ± 61.9 ppm; P = 0.003), both of which might indicate the degree of lactase deficiency, were higher in southern than in northern Indians. Conclusion: The frequency and degree of LM is higher in southern than in northern Indian healthy populations because of genetic differences in these populations.

BACKGROUND: The hydrogen breath test (H2BT) is the most widely used procedure in the diagnostic workup of lactose malabsorption and lactose intolerance.AIM: To establish whether a simplified two-or three-sample test may reduce time, costs and staff resources without reducing the sensitivity of the procedure.PATIENTS AND METHODS: Data from 1112 patients (292 men, 820 women) with a positive 4 h, nine-sample H2BT were retrospectively analyzed. Patients were stratified according to the degree of lactose malabsorption, the occurrence and type of symptoms. Loss of sensitivity in the procedure was evaluated taking into account two-sample tests (0 min and 120 min or 0 min and 210 min) or three-sample tests (0 min, 120 min and 180 min or 0 min, 120 min and 210 min).RESULTS: Using a two-sample test (0 min and 120 min or 0 min and 210 min) the false-negative rate was 33.4% and 22.7%, respectively. With a three-sample test (0 min, 120 min and 180 min or 0 min, 120 min or 210 min), lactose malabsorption was diagnosed in 91.2% (1014 of 1112) patients and in 96.1% (1068 of 1112) patients, respectively. Of 594 patients with abdominal symptoms, 158 (26.6%) and 73 (12.2%) would have false-negative results with 0 min and 120 min or 0 min and 210 min two-sample tests, respectively. The three-sample tests, 0 min, 120 min and 180 min or 0 min, 120 min and 210 min, have a false-negative rate of 5.9% and 2.1%, respectively.CONCLUSIONS: A three-sample H2BT is time-and cost-sparing without significant loss of sensitivity for the diagnosis both of lactose malabsorption and lactose intolerance.

Background Adult-type hypolactasia is a widespread condition throughout the world, causing lactose malabsorption. The lactose breath test is a simple tool for diagnosis but the need for prolonged monitoring of hydrogen excretion has led to a genetic test proposal. The aim of this study was to compare the genetic test with the lactose breath test in order to give some insights into the clinical value of genetic testing. Methods Thirty-two consecutive functional patients underwent lactose breath test and lactase genetic polymorphism analysis (C/T 13910 and G/A 22018). Intolerance symptoms after lactose load were also monitored. Results All patients with positive lactose breath test showed homozygosis for both polymorphisms. Among the nine patients with a negative breath test result, six showed heterozygosis while three showed homozygosis. Intolerance symptoms were present in 16 homozygotic patients but also in one heterozygotic patient. The k value for the agreement between the genetic test and the lactose breath test was 0.74. Conclusion A positive genetic test for lactase non-persistence indicates whether lactase activity decline may represent a clinical problem for the patient, but does not give information on actual patient symptoms. On the contrary, this information is already available by combining the lactose breath test with intolerance symptom evaluation. Lactose absorption phenotype may be not yet evident until young adult age.

Background and Aim Lactase non-persistence is common in India. We evaluated: (i) frequency of lactase gene (C/T-13910 and G/A-22018) polymorphisms in irritable bowel syndrome (IBS) and healthy controls (HC), (ii) association between these polymorphisms and IBS-subtypes and symptoms. Methods A total of 150 IBS patients (Rome-III criteria) and 252 age and gender-matched HC were evaluated for C/T-13910 and G/A-22018 genotypes using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results Totals of 79 (52%), 52 (35%) and 19 (13%) patients had diarrhea-predominant IBS (D-IBS), constipation predominant IBS (C-IBS) and alternating diarrhea and constipation IBS (A-IBS), respectively (Rome-III). Frequency of C/T-13910 [genotypes: CC 102 (68%), CT 43 (29%), TT 5 (3%) vs CC 155 (61%), CT 83 (33%), TT 14 (6%), P > 0.05] and G/A-22018 [GG 97 (65%), GA 41 (27%), AA 12 (8%) vs GG 154 (61%), GA 78 (31%), AA 20 (8%), P > 0.05] were similar among IBS and HC. Patients with D-IBS more often had C/T-13910 and G/A-22018 genotypes than C-IBS (CC 71 [90%], CT 6 [8%], TT 2 [2%]) versus (24 [46%], 25 [48%], 3 [6%]), A-IBS (7 [39%], 12 [63%], 0, [0%]) and HC (155 [61%], 83 [33%], 14 [6%]), P

The prevalence of lactose malabsorption (LM) is increased in the elderly, although the mechanisms responsible are still a matter of speculation. The objective of this study was to investigate the possible roles of reduced functional small intestinal absorptive area, lactase deficiency and small intestinal bacterial overgrowth (SIBO).Twenty Caucasian (Anglo-Celtic), asymptomatic, well-nourished, elderly volunteers (median age 79 years, range 70-94 years) with no clinically apparent predisposition to SIBO underwent a 50 g lactose breath hydrogen test (LBHT) and mannitol absorption test, the latter as an index of functional small intestinal absorptive area. Those with LM additionally underwent bacteriological assessment of small intestinal secretions and mucosal biopsy, to assess the contribution of SIBO and lactase deficiency, respectively, to the pathogenesis of LM in individual cases. The prevalence of SIBO was also determined in elderly subjects without LM. Twenty asymptomatic younger subjects (median age 29 years, age range 18-35 years) served as controls. All subjects were "hydrogen producers" in response to lactulose.LM was evident in 10/20 (50%) elderly subjects and 1/20 (5%) younger subjects (p=0.003). Mannitol absorption did not differ significantly in elderly and younger subjects or in elderly subjects with and without LM. SIBO was documented in 9/10 (90%) elderly subjects with LM; eradication was associated with resolution of LM. Lactase deficiency was evident in only one elderly subject with LM. SIBO was evident in 2/10 (20%) elderly subjects without LM (p=0.005 compared to those with LM). Lactulose breath hydrogen test identified only 2/11 (18%) elderly subjects with SIBO.Increased prevalence of LM in the elderly is mostly due to clinically non-apparent SIBO, rather than mucosal factors. The lactulose breath hydrogen test cannot be relied upon to identify elderly subjects with SIBO, even in those without an anatomical predisposition.