Lactose Intolerance in Bulgaria: A Preliminary Study

<h3>Background</h3> Microscopic colitis (MC) remains an elusive cause of chronic diarrhea. Histopathology is a gold standard with variable yield. The OCTT and concomitant lactose intolerance in these cases may aid to understand the complex symptoms. We used Hydrogen(H2) breath tests (H₂BT) for detecting SIBO (Small Intestinal Bacterial Overgrowth), Lactose intolerance and calculation of oro-cecal transit time (OCTT). <h3>Methods</h3> 43 MC patients [mean age - 45.83(±15.92] and 10 controls were studied. Among these, 37(86%) patients with MC &amp; 9 (90%) controls underwent breath tests. SIBO was diagnosed with glucose H₂BT. For confirmation, we took rise ≥12 ppm over fasting value in H2 concentration within 2hours of glucose ingestion Lactulose H₂BT was done to calculate OCTT. Time taken for rising in breath hydrogen by ≥12ppm over baseline value in two consecutive readings was considered as OCTT. For lactose breath test, 15 minutes samples were taken up to 4 hours. A ≥20 ppm rise over fasting value in H₂concentration in two consecutive readings was considered intolerance <h3>Results</h3> Four(9.5%) patients of SIBO in Glucose H₂BT were enrolled in controls. Mean (+ SD) OCTT in cases of MC vs controls was 130.38±47.95 mins and 97.14±48.55 mins (p= 0.109) respectively. Thus OCTT increased in 73% cases of MC vs 43% controls. Also, in the MC group, 9(28.1%) patients were lactose intolerant while vs 3(42.9%) controls (p= 0.654). Thus a significant 28% MC patients were lactose intolerant possibly aggravating symptoms <h3>Conclusions</h3> Lactose intolerance has lesser prevalence in cases of microscopic colitis. These patients were also detected to have paradoxically prolonged OCTT excluding the role of small bowel in diarrheal symptoms

Purpose: to determine lactose intolerance (LI) prevalence in women with Hashimoto’s thyroiditis (HT) and assess the impact of LI on LT4 replacement dose. Methods. consecutive patients with HT underwent Lactose Breath Test and clinical/laboratory data collection. Unrelated gastrointestinal disorders were carefully ruled out. Lactose-free diet and shift to lactose-free LT4 were proposed to patients with LI. Results: we enrolled 58 females (age range, 23–72 years) with diagnosis of HT. In total, 15 patients were euthyroid without treatment, and 43 (74%) euthyroid under LT4 (30 of them with a LT4 formulation containing lactose). Gastrointestinal symptoms were present in 84.5% of patients, with a greater prevalence in change in bowel habits in lactose-intolerant patients (p < 0.0001). The cumulative LT4 dose required did not differ in patients with or without LI. No significant difference in both TSH values and LT4 dose were observed in patients shifted to lactose-free LT4 and diet at 3 and 6 months compared to baseline. Conclusion: the prevalence of LI in patients with HT was 58.6%, not different from global prevalence of LI. In the absence of other gastrointestinal disorders, LI seems not to be a major cause of LT4 malabsorption and does not affect the LT4 required dose in HT patients.

Clinical manifestations of lactase (LCT) deficiency include intestinal and extra-intestinal symptoms. Lactose hydrogen breath test (H2-BT) is considered the gold standard to evaluate LCT deficiency (LD). Recently, the single-nucleotide polymorphism C/T(-13910) has been associated with LD. The objectives of the present study were to evaluate the agreement between genetic testing of LCT C/T(-13910) and lactose H2-BT, and the diagnostic value of extended symptom assessment. Of the 201 patients included in the study, 194 (139 females; mean age 38, range 17-79 years, and 55 males, mean age 38, range 18-68 years) patients with clinical suspicion of LD underwent a 3-4 h H2-BT and genetic testing for LCT C/T(-13910). Patients rated five intestinal and four extra-intestinal symptoms during the H2-BT and then at home for the following 48 h. Declaring H2-BT as the gold standard, the CC(-13910) genotype had a sensitivity of 97% and a specificity of 95% with a κ of 0.9 in diagnosing LCT deficiency. Patients with LD had more intense intestinal symptoms 4 h following the lactose challenge included in the H2-BT. We found no difference in the intensity of extra-intestinal symptoms between patients with and without LD. Symptom assessment yielded differences for intestinal symptoms abdominal pain, bloating, borborygmi and diarrhoea between 120 min and 4 h after oral lactose challenge. Extra-intestinal symptoms (dizziness, headache and myalgia) and extension of symptom assessment up to 48 h did not consistently show different results. In conclusion, genetic testing has an excellent agreement with the standard lactose H2-BT, and it may replace breath testing for the diagnosis of LD. Extended symptom scores and assessment of extra-intestinal symptoms have limited diagnostic value in the evaluation of LD.

When lactose malabsorption gives rise to symptoms, the result is called 'lactose intolerance'. Although lactose intolerance is often bothersome for patients, once recognized it may be managed by simple dietary adjustments. However, diagnosing lactose intolerance is not straightforward, especially in primary care. To summarize available evidence on the diagnostic performance of gastrointestinal symptoms and self-reported milk (lactose) intolerance in primary care, and the relationship between lactose malabsorption and intolerance. PubMed, EMBASE and reference screening. Studies were selected if the design was a primary diagnostic study; the patients were adults consulting because of non-acute abdominal symptoms; the diagnostic test included gastrointestinal symptoms and/or self-reported milk intolerance. A total of 26 primary diagnostic studies were included in the review. Quality assessment and data extraction were performed by two reviewers independently. They adhered to the most recent guidelines for conducting a diagnostic review as described in the Cochrane Diagnostic Reviewers' Handbook. The diagnostic performance of diarrhea, abdominal pain, bloating, flatulence and self-reported milk intolerance was highly variable. A non-Caucasian ethnic origin was associated with the presence of lactose malabsorption. Both lactose malabsorbers and lactose absorbers reported symptoms during the lactose hydrogen breath test. Our review shows that high-quality studies on the diagnosis of lactose malabsorption and intolerance in primary care are urgently needed. An important prerequisite would be to clearly define the concept of lactose intolerance, as well as how it should be assessed.

The prevalence of lactose intolerance is one of the factors driving consumers toward plant-based milk alternatives (PBMA). This study aimed to analyze the carbohydrate profile of cows' milk (regular and lactose-free from both pasteurized and UHT milks; n = 80) and PBMA (n = 60) by HPLC. The study revealed that there was no significant difference in the energy content and total carbohydrate content between regular milk and lactose-free milk. Although milk and PBMA are entirely different food matrices, some PBMA types, as soya and coconut, may have energy contents and total carbohydrate contents comparable to those of milk. Furthermore, the variability observed in total carbohydrate content, as well as in carbohydrate profile, both between PBMA types and within samples of the same type, arises not only from variations in raw materials but also from the number of dilutions of the vegetable extract and the addition of different types and levels of carbohydrates, such as sucrose, fructose, or sorbitol, during PBMA manufacture. Although, milk presents a regular carbohydrate composition, differing solely between presentations (regular/lactose-free), the PBMA differs significantly between types and among the same type, not being for that reason regarded as a milk substitute.

Prevalence of Lactose Intolerance in Healthy Medical Students

The hydrogen (H2) breath test is a non-invasive investigation used to diagnose lactose intolerance (LI). Patients with LI may also expire increased amounts of methane (CH4) during a lactose test. The aim of this study is to evaluate the contribution of CH4 measurements. We tested 209 children (1–17 years old) with symptoms suggesting LI with lactose H2 and CH4 breath tests. The result was positive when the H2 excretion exceeded 20 parts per million (ppm) and the CH4 was 10 ppm above the baseline. A clinician, blinded for the results of the breath test, registered the symptoms. Of the patient population, 101/209 (48%) were negative for both H2 and CH4; 96/209 (46%) had a positive H2 breath test result; 31/96 (32%) were also positive for CH4; 12/209 (6%) patients were only positive for CH4. The majority of hydrogen producers showed symptoms, whereas this was only the case in half of the H2-negative CH4 producers. Almost all patients treated with a lactose-poor diet reported significant symptom improvement. These results indicate that CH4 measurements may possibly be of additional value for the diagnosis of LI, since 5.7% of patients were negative for H2 and positive for CH4, and half of them experienced symptoms during the test.

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...

Annotated Abstracts

The lactose tolerance test is a classic method for the study of lactose malabsorption. However, the methodology used has not been standardized, and this leads to differences in results. The aim of this report was to analyze whether capillary blood glucose measurement is in agreement with venous blood glucose when performing lactose tolerance test. This is a prospective study of consecutive patients with suspected lactose malabsorption who had lactose tolerance test performed in venous and capillary blood simultaneously, using a load of 50 g lactose. Agreement was measured using the concordance correlation coefficient of Lin (95 % CI) and Bland-Altman plots. The degree of agreement was measured using the Kappa index. A value of p < 0.05 was considered statistically significant. Eighty-four patients (68 % women) were included. The concordance correlation coefficient showed very poor agreement between the two techniques: 0.68 (0.58-0.77), 0.72 (0.62-0.8), and 0.77 (0.69-0.83) for baseline, 30, and 60 min, respectively. The Bland-Altman plots showed that capillary blood glucose measurements result in higher levels than venous blood glucose measurements, with mean differences of 0.39, 0.77, and 1.1 mmol/L at baseline, 30, and 60 min, respectively. The degree of agreement was low, with a Kappa index of 0.59 (p < 0.001). The test measured in venous blood is not in agreement with the measurement obtained from capillary blood. It is likely that the diagnostic accuracy attributed without distinction to lactose tolerance test in different studies for lactose malabsorption is incorrect, making it necessary to specify the analysis method.

To study the relation between dietary-induced increase of intestinal lactase activity and lactose absorption, 11-wk-old rats were fed either a high-starch (70 cal%), low-fat (7 cal%) diet or a low-starch (5 cal%), high-fat (73 cal%) diet for 7 days. Food intake and body weight changes were similar in the two dietary groups. In the first experiment, lactose absorption was studied in vivo after oral administration of 600 mg lactose (10% solution in water with added [3H]PEG) to rats fasted for 16 h. Groups of rats were killed at time 0 and at 1-h intervals for the next 3 h. Lactase activity and lactose absorption were significantly higher (P less than 0.01) in the high-starch group than in the low-starch group. In the subsequent experiment, 9-wk-old rats were fed the two isocaloric diets for 3 days. By use of the everted sac technique, we have demonstrated a significantly higher absorption of monosaccharides from lactose in the high-starch diet group; also, glucose transport was higher in the high-starch diet-fed animals. When Tris, an inhibitor of lactase, was added into the mucosal fluid, absorption of lactose was abolished and no effect was seen on glucose absorption (in vivo and in vitro). In both experiments, significant linear regression was established between lactase activity and lactose absorption. Our results thus show that the increase in lactase activity, induced by feeding a high-starch diet to adult rats, is accompanied by an increased capacity to hydrolyze lactose and absorb the constituent monosaccharides.

ObjectiveDairy intake has been reported to be both pro-inflammatory and anti-inflammatory; this inconsistency has led to uncertainty in the field. We aimed to address this using genetic data to perform a causal analysis of the link between lactose intolerance, rheumatoid arthritis (RhA) and body mass index (BMI). Lactose intolerance necessarily leads to reduced dairy intake. RhA is an autoimmune disease, which has been linked to both increased and reduced dairy intake. Dairy intake has also been associated with elevated BMI, which is itself pro-inflammatory and is associated with increased risk of RhA.MethodsWe separately considered congenital lactose intolerance, and adult-onset lactose intolerance where a prolonged period of dairy intake has already occurred. We combined Mendelian randomisation (MR) and rare genetic variant association testing to determine the relationship between genetic liability to lactose intolerance, risk of RhA and BMI. As a positive control to optimise instruments for measurement of lactose intolerance, we used the causal link between lactose intolerance and osteoporosis. Rare variant analysis was performed under a recessive model. Conditional analysis of the effect of lactose intolerance on the risk of RhA via BMI used multivariable MR.ResultsWe observed an opposite effect of congenital and adult-onset lactose intolerance on RhA risk. Congenital lactose intolerance increases the risk of RhA, but adult-onset lactose intolerance reduces the risk of RhA. The protective effect of adult-onset lactose intolerance on RhA is conditional on reduced BMI.DiscussionWe conclude that dairy intake is anti-inflammatory, which explains why congenital lactose intolerance and lifetime avoidance of dairy foods increases the risk of RhA. However, adult-onset lactose intolerance can reduce the risk of RhA because of an association with reduced BMI, which is also anti-inflammatory.

Background: Symptoms after intake of milk are common in persons with irritable bowel syndrome (IBS). The aims of this study were to compare the prevalence of lactose malabsorption (LM) and symptoms related to intake of milk and lactose in subjects with IBS with that of healthy volunteers, and to search for symptoms that are characteristic of LM. Methods: A case‐control study in a Norwegian population was initiated. Subjects with IBS were asked for symptoms related to intake of milk and lactose, tested for LM, and compared with a group of healthy volunteers. Results: The study comprised a total of 187 persons (82 with IBS and 105 volunteers), females/males: 138/49, mean age 47 years. In subjects with IBS and in healthy volunteers, LM was present in 3/74 (4.1%) and 4/105 (3.8%), respectively (ns), milk‐related symptoms in 32/79 (40%) and 13/105 (12%), respectively (P < 0.001) and symptoms after intake of lactose in 28/74 (38%) and 21/104 (20%), respectively (P = 0.01). Borborygmi starting within 5 h after intake of lactose and lasting for more than 2 h indicated LM (OR 61 (95% CI:­8–475), P < 0.001). Conclusions: IBS and LM are unrelated disorders in a Norwegian population. Milk‐related symptoms and symptoms after intake of lactose are unreliable predictors for LM. Precise symptom‐based criteria might enhance the diagnostic accuracy for LM.

Research objective: to establish the genotype frequency of single nucleotide polymorphisms rs4988235 and rs182549 of the MCM6 gene depending on the ethnicity of adolescents in Eastern Siberia (Russians, Khakasses, Tuvans) and to identify the relationship between lactase deficiency (LD) and the clinical characteristics of recurrent abdominal pain (RAP). Materials and Methods: 449 adolescents aged 11-18 years old were examined at schools in three cities of Siberia (Krasnoyarsk, Abakan, Kyzyl) and in-patient hospital in Krasnoyarsk. Lactase deficiency (LD) was diagnosed by the hydrogen breath test (HBT) after oral lactose load using the Gastrolyzer apparatus (Bedfont, UK). In schoolchildren, genomic DNA was isolated from saliva samples by the sorption method using the DIAtom DNA Prep kits (IsoGen, Russia). In inpatient children, DNA was isolated from whole blood by the sorption method from 0.1 ml of a suspension of leukocytes using the DNA-Sorb-B kit (103-20, AmpliPrime, Russia). Genotyping for the carriage of allelic variants rs4988235 and rs182549 of the MCM6 gene was performed on the basis of TaqMan allelic discrimination technology using real-time polymerase chain reaction (RT-PCR) on a detecting thermal cycler «Rotor-Gene 6000» (Corbett Life Science, Australia). Results: The CC genotype of the rs4988235 polymorphism of the MCM6 gene occurs almost 5 times more often (93%) with a positive HBT than with a negative HBT (22%), p&lt;0.001. Moreover, carriage of the rs4988235*CC genotype has a high sensitivity for LD diagnostics, i.e. 93 (81-99) %, with a relatively low specificity of 77 (69-85) %, which is likely to be due to the presence of secondary LD. A significantly higher prevalence of CC genotypes of both polymorphisms associated with LD has been observed in Mongoloid adolescents (Khakas - 82% and Tuvans - 91%), compared with Russian adolescents - 49%, p&lt;0.001. There was no relationship between genetic markers of LD and RAP, verified according to the J. Apley and N. Naish criteria. Conclusion: A high diagnostic significance of the rs4988235*CC genotype for LD diagnostics in Siberian adolescents was established. The СС genotype prevalence of both polymorphisms, associated with LD, in Russian adolescents (49%) does not differ from European data, whereas these genotypes were found in the great majority of Mongoloids examined (82-91%), which can be considered to be "paradoxical", given that the southern regions of Central Siberia are characterized by a historically high level of dairy farming development. Keywords: lactase deficiency, adolescents, hydrogen breath test (HBT), genetic polymorphisms, recurrent abdominal pain.

Lactose intolerance is a common pathology that occurs due to the reduced activity of β-galactosidase leaving undigested lactose in the intestine. About 70% of the world population suffers from this condition. The gastro intestinal symptoms associated with this condition are diarrhoea, pain, nausea, bloating, flatulence, etc. It has been reported that these individuals are at a risk of developing several other pathologies like irritable bowel disease, osteoporosis, etc. Hence, proper diagnosis and treatment is essential for dealing with this condition. Various methods are used for providing an accurate diagnosis, such as hydrogen breath test (HBT), lactose intolerance test, genetic test, intestinal biopsy, etc. Depending on the type of intolerance, several methods are adopted for treating it, such as replacing enzyme, using exogenous enzymes, following lactose free diet, as well as consuming prebiotics and probiotics. Different methods are applied to synthesize lactose free dairy products to help lactose intolerant individuals suffering from important vitamins and minerals deprivation. Recently, plant-based milks are also used as a substitute for providing calcium and vitamins. The last few years have seen improvement in the quality and availability of lactose-free dairy products offering tempting foodstuffs to consumers. This narrative article aimed to review the existing science on lactose intolerance, along with its epidemiology, diagnosis, and clinical management.