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Introduction: Diagnosing lactose malabsorption is usually based on hydrogen excretion in breath after a lactose challenge. However, a proportion of subjects with lactose malabsorption will not present a rise in hydrogen. Measuring excretion of methane or stable isotope labeled 13CO2 after ingestion of 13C-lactose has been proposed to mitigate this problem. Objective: The aim of the study was to assess the performance of measuring methane and 13CO2 in individuals with normal hydrogen excretion compared to a genetic lactase non-persistence test. Methods: Individuals referred for lactose breath testing and healthy controls were included. Participants received 13C-enriched lactose, performed breath testing, and underwent genotyping for a marker of lactase non-persistence (13910C*T). Using genotype as gold standard, the performance of measuring methane and 13CO2 excretion was assessed. Results: 151 subjects participated in the study, 50 of which presented a lactase non-persistent genotype. Of these, 72% were correctly diagnosed through hydrogen excretion of ≥ 20 ppm above baseline. In subjects with normal hydrogen excretion, cumulative 13C excretion had an area under the curve (AUC) of the receiver operating characteristics (ROC) curve of 0.852. Sensitivity was 93% and specificity was 51% for the current cutoff of 14.5%. The optimal cutoff was 12.65% (sensitivity 93%, specificity 70%). The ROC curve of peak methane had an AUC of 0.542 (sensitivity of 14%, specificity of 91% for cutoff ≥ 10 ppm). Conclusions: In individuals with genetically demonstrated lactase non-persistence and negative hydrogen breath test, the use of 13C-lactose with measurement of 13CO2 excretion and hydrogen is a well-performing test to detect the lactose malabsorption and performs better than methane in our cohort. [ABSTRACT FROM AUTHOR]

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.

Abstract 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

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 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

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.

BackgroundLactose 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. ObjectiveThe 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. MethodsAn interventional crossover study was performed in adult participants with a prior confirmed diagnosis of lactose malabsorption or a suspected history of lactose intolerance. ResultsA 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

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.

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.

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.

Exhaled breath tests (BTs) are the main diagnostic method for fructose and lactose malabsorption/intolerance (FI and LI, respectively) and for detecting small intestine bacterial or methanogen overgrowth (SIBO/IMO). Although FI/LI-BTs may provide evidence of the presence of SIBO/IMO, there is limited literature evaluating their reliability for this purpose. The objective of this study was to assess the sensitivity and specificity of FI/LI-BTs in detecting SIBO and their concordance with SIBO-BTs in the identification of IMO.

BACKGROUND: The hydrogen breath test (H2BT) is the most widely used procedure in the diagnostic workup of lactose malabsorption and lactose intolerance.

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−13910 polymorphism) results in lactose malabsorption testing. In total 263 consecutive patients with suspected lactose malabsorption were included in this study. They underwent the H2/CH4 breath test following the ingestion of 50 g lactose and were tested for the C/T−13910 polymorphism. In total 51 patients (19.4%) had a C/C−13910 genotype, indicating primary lactose malabsorption. Only 19 patients (7.2%) also had a positive H2/CH4 breath test. All in all 136 patients (51.69%) had a C/T−13910 and 76 patients (28.91%) a T/T−13910 genotype, indicating lactase persistence. Four patients (1.5%) with the C/T−13910 genotype and one patient (0.4%) with the T/T−13910 genotype had a positive H2/CH4 breath 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/CH4 peak 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/CH4 breath test procedure can cause discrepant results. This trial is registered with K-42-13.

Introduction and Purpose: Hydrogen breath tests serve the crucial purpose of evaluating the absorption of nutrients in the small intestine, particularly when carbohydrates are not properly absorbed, leading to bacterial overgrowth. These tests are non-invasive, cost-effective, and widely accessible diagnostic tools used to assess various gastrointestinal disorders. The objective of this review is to evaluate the effectiveness and methodology of Hydrogen breath testing (HBT). State of knowledge: The disposal of hydrogen gas is essential for maintaining efficient microbial fermentation processes in the gut. Hydrogenotrophic microbes, including acetogens, methanogenic archaea, and sulfate-reducing bacteria, are responsible for this process. Hydrogen breath tests, conducted with substrates like glucose and lactulose, aid in diagnosing conditions such as small intestinal bacterial overgrowth (SIBO), lactose and fructose intolerance, and other carbohydrate absorption disorders. These tests generate a large volume of data, which can be analyzed using data mining techniques to uncover new hypotheses. Conclusions: Hydrogen breath tests, using various substrates, are effective in diagnosing gastrointestinal disorders such as SIBO and carbohydrate malabsorption. They offer valuable insights into microbial processes in the gut and can inform individualized treatment strategies. However, careful consideration of contraindications and proper test administration protocols is essential for accurate diagnosis and interpretation of results.