Adult Lactose Intolerance Research Articles

Validation of a Modified Cow’s Milk-Related Symptom Score (CoMiSS) for Screening of Lactose Intolerance in Adults

Abstract Introduction Lactose intolerance is the failure to digest foods and beverages containing the lactose present in milk. Lactose intolerance can be presented by many digestive symptoms. Objective To validate the modified CoMiSS score for the prediction of lactose intolerance, that was confirmed by a stool acidity test. Patients and Methods A crosssectional study, conducted on Ain Shams University Hospitals/ Gastrointestinal Clinics, enrolled100 adult participants during the period from December 2018 to December 2019, with the presence of one or more gastrointestinal symptoms, and subjected to a stool acidity test as a reference test and modified CoMiSS as index test. Results The mean age of participants was 35.30 ± 10.714 years old; 55% were females, and mean BMI was 23.08 ± 2.080 kg/m2, with no statistically significant difference between lactose intolerance and patients gender or body mass index BMI, 24% of participants had positive stool PH, lactose Intolerance diagnosed according to modified CoMISS Score among 19% of study participants, the mean of modified CoMISS Score in positive cases (12.37) were highly statistically significant than those negative lactose intolerance (2.33) as p < 0.001, Area under ROC Curve was 0.998, with cut-off value >8. Sensitivity 89.5% and specificity was 100%. Conclusion Modified CoMiSS is a simple, fast, and easy-to-use tool that can predict lactose intolerance, with a cut-off value of > 8, the Area under the ROC Curve was 0.998, sensitivity 89.5%, and specificity was 100%.

Effects of probiotics administration on lactose intolerance in adulthood: A meta-analysis

This meta-analysis aimed to investigate the effect of probiotic administration on adults with lactose intolerance. Twelve studies were identified from databases such as PubMed, Cochrane Library, and Web of Knowledge based on the inclusion and exclusion criteria. The effect size was estimated using the standardized mean difference (SMD), and Cochrane's Q test was used to evaluate the statistical heterogeneity of the effect size. Moderator analysis, including meta-ANOVA and meta-regression, were performed to determine the cause of heterogeneity in the effect size using a mixed-effect model. Egger's linear regression test was conducted to evaluate publication bias. The results showed that probiotic administration alleviated the symptoms of lactose intolerance, including abdominal pain, diarrhea, and flatulence. Among them, the area under the curve (AUC) showed the greatest decrease following probiotic administration (SMD, -4.96; 95% confidence interval, -6.92 to -3.00). In the meta-ANOVA test, abdominal pain and total symptoms decreased with monostrain probiotic administration. This combination was also effective for flatulence. The dosage of probiotics or lactose was significantly associated with a reduction in the total symptom score, and the linear regression models between the dosage and SMD were found to be Y = 2.3342 × dosage - 25.0400 (R2 = 79.68%) and Y = 0.2345 × dosage - 7.6618 (R2 = 34.03%), respectively. Publication bias was detected for most items. However, even after effect size correction, the probiotic administration effect for all items remained valid. The administration of probiotics was effective at improving adult lactose intolerance, and it is expected that the results of this study could help improve the nutritional status of adults by increasing their consumption of milk and dairy products in the future.

Validation of a modified cow’s milk-related symptom score (CoMISS) for screening of lactose intolerance in adults

Introduction Lactose intolerance (LI) is the failure to digest foods and beverages containing the lactose present in milk. LI can present by many digestive symptoms. Objective To validate the modified CoMiSS score for prediction of LI, that was confirmed by a stool acidity test. Patients and methods A cross-sectional study, was conducted at Ain Shams University Hospitals/Gastrointestinal Clinics, and included one hundred adult participants during the period from December 2018 to December 2019. Enrolled patients had one or more gastrointestinal symptoms and were subjected to a stool acidity test (fecal PH test) as a reference test and modified CoMiSS as an index test. Results The mean age of participants was 35.30 ± 10.714 years old; 55% were females, and their mean body mass index (BMI) was 23.08 ± 2.080 kg/m2, with no significant relation between LI and patients` gender or BMI. Out of the studied participants 24% had positive stool PH, LI diagnosed according to modified CoMISS was present among 19% of them. The mean value of modified CoMISS Score was significantly higher in positive cases (12.37) compared to negative LI participants (2.33) as p < .001. Area under ROC Curve was 0.998, at the selected cut-off value 8, the sensitivity was 89.5% and specificity was 100% thus, levels of questionnaire scoring of 8 or higher would indicate presence of lactose intolerance. Conclusion Modified CoMiSS is a simple, fast, and easy-to-use tool that can predict LI, with a cut-off value of >8, the Area under the ROC Curve was 0.998, sensitivity 89.5%, and specificity was 100%.

Adult lactose intolerance, calcium intake, bone metabolism and bone density in German-Turkish immigrants.

Adult lactose intolerance (ALI) significantly alters calcium intake and absorption, and thus may promote osteoporosis. ALI is a recessive condition with a geographical north-south gradient characterised by decreased levels of intestinal lactase. PCR-based genotyping of lactase (LCT) gene polymorphisms is a safe and easy way to diagnose ALI and may complement diagnostic procedures to identify individuals at risk for reduced calcium intake and subsequently osteoporosis due to lactose malabsorption. Therefore, we investigated the frequency of ALI and its influence on calcium intake, markers of bone metabolism and bone mineral density (BMD) in a cohort of Turkish immigrants living in Germany. We investigated single nucleotide polymorphisms of the LCT gene, calcium intake, markers of bone metabolism and BMD in 183 Turkish immigrants. ALI was diagnosed in 154 out of 183 (81%) probands. ALI was significantly associated with self-reported lactose intolerance (p < 0.001) and dislike for dairy products (p < 0.01). Osteopenia was diagnosed in 59 out of 183 (32%) and osteoporosis in 15 out of 183 (8%) probands. Probands with reduced BMD had ALI in 86%. All probands had a decreased calcium intake [mg/week]. There was no significant association between ALI, calcium intake, markers of bone metabolism or BMD. Turkish immigrants mostly have ALI and overall show a reduced calcium intake per week. However, ALI did not significantly influence calcium intake, markers of bone metabolism or BMD in this cohort. Therefore, ALI in Turkish immigrants does not seem to be a risk factor for osteoporosis.

Real-time PCR based detection of the lactase non-persistence associated genetic variant LCT-13910C>T directly from whole blood.

Primary hypolactasia is the main cause of lactose intolerance in adults. It is strongly associated with the single genetic variant LCT-13910C>T, located upstream of the lactase encoding gene. Consequently, analysis of LCT-13910C>T has been recommended as a direct genetic test for the trait. The aim of our study was to develop a TaqMan probe based real-time PCR protocol for the detection of the LCT-13910C>T variant directly from whole blood, circumventing DNA isolation. The LCT-13910C>T variant was determined using the DirectBlood Genotyping PCR Kit (myPOLS Biotec, Konstanz, Germany) together with an in-house TaqMan primer-probe assay. Validity and specificity of the assay was evaluated using EDTA anti-coagulated whole blood samples and corresponding DNA samples. Results from real-time PCR were compared with results obtained by Sanger sequencing from 105 blinded whole blood samples. Validity and specificity of the assay using whole blood were comparable to those using purified genomic DNA as substrate in PCR. Genetic analysis of blood samples were in complete agreement with results obtained by Sanger sequencing. In conclusion, we present a reliable real-time PCR protocol for the detection of the LCT-13910C>T variant directly from whole blood further facilitating diagnosis of primary hypolactasia in symptomatic patients.

Lactose Intolerance in Adults: Biological Mechanism and Dietary Management

Lactose intolerance related to primary or secondary lactase deficiency is characterized by abdominal pain and distension, borborygmi, flatus, and diarrhea induced by lactose in dairy products. The biological mechanism and lactose malabsorption is established and several investigations are available, including genetic, endoscopic and physiological tests. Lactose intolerance depends not only on the expression of lactase but also on the dose of lactose, intestinal flora, gastrointestinal motility, small intestinal bacterial overgrowth and sensitivity of the gastrointestinal tract to the generation of gas and other fermentation products of lactose digestion. Treatment of lactose intolerance can include lactose-reduced diet and enzyme replacement. This is effective if symptoms are only related to dairy products; however, lactose intolerance can be part of a wider intolerance to variably absorbed, fermentable oligo-, di-, monosaccharides and polyols (FODMAPs). This is present in at least half of patients with irritable bowel syndrome (IBS) and this group requires not only restriction of lactose intake but also a low FODMAP diet to improve gastrointestinal complaints. The long-term effects of a dairy-free, low FODMAPs diet on nutritional health and the fecal microbiome are not well defined. This review summarizes recent advances in our understanding of the genetic basis, biological mechanism, diagnosis and dietary management of lactose intolerance.

Diagnóstico de intolerancia a la lactosa en adultos: rendimiento comparativo de la clínica, test de hidrógeno espirado y test genético

Genetically programmed adult-type hypolactasia affects 56% of Chilean population. Ideally, diagnosis should be confirmed. To compare diagnostic yield of genetic test, hydrogen (H2) expiratory test and a validated symptomatic structured survey (SS). Patients submitted to H2 test answered a historic (anamnestic) and current SS (after the ingestion of 25 g of lactose). A blood sample was obtained for determination of genetic polymorphisms C/T_13910, C/G_13907 and G/A_22018 by polymerase chain reaction. The gold standard for diagnosis of lactose intolerance (LI) was the agreement of at least two of three tests. Sixty-one participants aged 39 ± 12 years (21 males), were studied. Anamnestic SS was diagnostic of LI in all cases (score > 7), while current SS detected LI in 27/61 (46%). H2 test (an increase > 15 ppm after ingestion of 25 g of lactose) showed LI in 31/61 (51%). The locus C/G_13907 showed no polymorphism and locus G/A_22018 was in complete linkage disequilibrium with C/T_13910. Genotype C/C_13910, associated to hypolactasia, was present in 30/58 (52%). According to the gold-standard, 32/61 (52.5%) patients were diagnosed as LI. Sensitivity and specificity were, respectively, 79% and 69% for current SS, 93% and 93% for H2 test and 97% and 93% for the genetic test. The last two showed a positive likelihood ratio (LR) > 10 and a negative LR < 0.1, figures within the range considered clinically useful. Genotype C/C_13910 is responsible for hypolactasia in this population. Anamnestic report of symptoms after milk ingestion and symptoms after lactose ingestion, are not accurate enough. H2 and genetic tests are simple and similarly accurate to diagnose lactose intolerance in adults.

Milk Consumption and Lactose Intolerance in Adults

Objective To investigate relations between milk consumption and lactose intolerance (LI) in adults and to explore the effect of milk consumption on lactase activity. Methods Total of 182 subjects aged 20–70 years were recruited and interviewed by questionnaires, and their accumulative cow's milk intake (AMI) was calculated. LI was evaluated by hydrogen breath test (HBT). Results A negative correlation was found between AMI and severity of observed LI symptom ( r=–0.2884; P<0.05). Binary logistic regression analysis showed a negative correlation between LI and duration and frequency of milk consumption (OR, 0.317 and 0.465, respectively; both P<0.05) and a positive correlation between LI and amount of milk consumed per sitting (OR, 6.337; P<0.05). Conclusion LI is related to various milk consumption behaviors. Most Chinese adults with LI may tolerate moderate milk consumption <160 mL.

The LCT 13910 C/T polymorphism as a risk factor for osteoporosis, has no impact on metastatic bone disease in breast cancer

To the editorThe most common skeletal complication of breast can-cer is bone metastasis, which occurs in 80% of patientswith advanced disease [1, 2].The maintenance of skeletal integrity in a healthyindividual requires a balanced bone remodeling. Osteo-clast-mediated bone resorption is a common factor in thepathogenesis of osteoporosis and metastatic bone disease[3, 4]. Evidence is given, that tumor mediated osteoclastactivation disrupts the normal equilibrium of boneremodeling, allowing tumor cells to survive and grow inthis microenvironment [4, 5].A functional dimorphism, 13910 C/T (LCT) which isassociated with adult lactose intolerance, has been sug-gested as a possible risk factor for osteoporosis and bonefractures, particularly in postmenopausal women [6].In the present study, we investigated the impact of the13910 C/T LCT polymorphism on the risk of bonemetastasis in 500 breast cancer patients. Patient charac-teristics have been described previously [7]. The study wasperformed according to the Austrian Gene Technology Actand had been approved by the local ethics committee.Written informed consent was obtained from all subjects.LCT -13910 genotypes were determined as describedpreviously [7]. SPSS 14.0 for Windows was used for sta-tistical analysis. Continuous values were analyzed byStudent’s t-test, and proportions of groups compared by the

Genetic Predisposition for Adult Lactose Intolerance and Relation to Diet, Bone Density, and Bone Fractures

Evidence that genetic disposition for adult lactose intolerance significantly affects calcium intake, bone density, and fractures in postmenopausal women is presented. PCR-based genotyping of lactase gene polymorphisms may complement diagnostic procedures to identify persons at risk for both lactose malabsorption and osteoporosis. Lactase deficiency is a common autosomal recessive condition resulting in decreased intestinal lactose degradation. A -13910 T/C dimorphism (LCT) near the lactase phlorizin hydrolase gene, reported to be strongly associated with adult lactase nonpersistence, may have an impact on calcium supply, bone density, and osteoporotic fractures in the elderly. We determined LCT genotypes TT, TC, and CC in 258 postmenopausal women using a polymerase chain reaction-based assay. Genotypes were related to milk intolerance, nutritional calcium intake, intestinal calcium absorption, bone mineral density (BMD), and nonvertebral fractures. Twenty-four percent of all women were found to have CC genotypes and genetic lactase deficiency. Age-adjusted BMD at the hip in CC genotypes and at the spine in CC and TC genotypes was reduced by -7% to -11% depending on the site measured (p = 0.04). LCT(T/C-13910) polymorphisms alone accounted for 2-4% of BMD in a multiple regression model. Bone fracture incidence was significantly associated with CC genotypes (p = 0.001). Milk calcium intake was significantly lower (-55%, p = 0.004) and aversion to milk consumption was significantly higher (+166%, p = 0.01) in women with the CC genotype, but there were no differences in overall dietary calcium intake or in intestinal calcium absorption test values. The LCT(T/C-13910) polymorphism is associated with subjective milk intolerance, reduced milk calcium intake, and reduced BMD at the hip and the lumbar spine and may predispose to bone fractures. Genetic testing for lactase deficiency may complement indirect methods in the detection of individuals at risk for both lactose malabsorption and osteoporosis.

Lactose malabsorption and lactose intolerance in adults - a cause of irritable bowel syndrome?

Gastroenterologists and general practitioners see many patients that have abdominal symptoms which are not explained when the patients are investigated for celiac disease, inflammatory bowel disease, peptic ulcer or tumours. The diagnosis is irritable bowel syndrome (IBS). Many of these patients report intolerance to certain foods including milk, and some develop symptoms after ingestion of lactose during the lactose tolerance test. In Northern European populations, lactose malabsorption is, however, not clearly overrepresented among the adult IBS patients, and subjective lactose intolerance is more common than IBS. Relatively few respond to a low-lactose diet on a long-term basis. Keywords: Irritable bowel syndrome, lactose intolerance, lactose malabsorption

Chemotherapy-induced lactose intolerance in adults.

Anorexia and weight loss contribute to the morbidity and mortality from cancer. This study was designed to test the hypothesis that chemotherapy produces lactose intolerance which could have an adverse effect on the nutritional status of patients receiving cytotoxic drugs. Twenty-seven patients were evaluated for the development of lactose intolerance during chemotherapy. Lactose breath hydrogen testing (LBHT) was used to assess lactose malabsorption objectively. This test is based on the principle that in patients with lactase deficiency, lactose is not hydrolyzed in the small intestine and ultimately is degraded by colonic bacteria. This results in the production of hydrogen gas, which is excreted by the lungs and can be quantified with a breath hydrogen analyzer. Of the 27 patients studied, 8 (30%) had an abnormal postchemotherapy LBHT results, and for the population as a whole, postchemotherapy LBHT values were significantly greater than prechemotherapy values (P = 0.04). However, only three patients (11%) showed clinical symptoms of lactose intolerance during the post-chemotherapy LBHT. Five patients had asymptomatic elevations in breath hydrogen excretion on prechemotherapy testing. One of these patients had a further increase in hydrogen excretion on Day 8 after chemotherapy, which was accompanied by symptoms of lactose intolerance. Twenty-two patients had normal prechemotherapy LBHT results. Two of these patients had abnormal post-chemotherapy LBHT results, which were associated with symptoms of lactose intolerance. Although chemotherapy may interfere with lactose metabolism, the development of symptomatic lactose intolerance is uncommon. Dietary restriction of milk products in patients receiving chemotherapy therefore is not warranted unless clinical symptoms of lactose intolerance are observed.

Prevalence of Primary Adult Lactose Malabsorption in the Eastern Province of Saudi Arabia

Although it has been reported that adult lactose malabsorption (ALM) is relatively common among Arabs, data on the prevalence of ALM in the Saudi and Yemeni populations are scant. We have determine...

Biogenesis of intestinal lactase-phlorizin hydrolase in adults with lactose intolerance. Evidence for reduced biosynthesis and slowed-down maturation in enterocytes.

Enzymatic activity, biosynthesis, and maturation of lactasephlorizin hydrolase (LPH) were investigated in adult volunteers with suspected lactose intolerance. Mean LPH activity in jejunal biopsy homogenates of these individuals was 31% compared to LPH-persistent individuals, and was accompanied by a reduced level of LPH-protein. Mean sucrase activity in individuals with low LPH was increased to 162% and was accompanied by an increase in sucrase-isomaltase (SI)-protein. Biosynthesis of LPH, SI, and aminopeptidase N (APN) was studied in organ culture of small intestinal biopsy specimens. In individuals with LPH restriction, the rate of synthesis of LPH was drastically decreased, reaching just 6% of the LPH-persistent group after 20 h of culture, while the rate of synthesis of SI appeared to be increased. In addition, maturation of pro-LPH to mature LPH occurred at a slower rate in LPH-restricted tissue. Immunoelectron microscopy revealed an accumulation of immunoreactive LPH in the Golgi region of enterocytes from LPH-restricted individuals and reduced labeling of microvillus membranes. Therefore, lactose intolerance in adults is mainly due to a decreased biosynthesis of LPH, either at the transcriptional or translational level. In addition, intracellular transport and maturation is retarded in some of the LPH-restricted individuals, and this leads to an accumulation of newly synthesized LPH in the Golgi and a failure of LPH to reach the microvillus membrane.

Primary adult lactose intolerance protects against development of inflammatory bowel disease

The have compared the incidence of inflammatory bowel disease (IBD) to the prevalence of lactose malabsorption (LM) in several countries. Our observations indicate that IBD is rare where LM is highly prevalent. The correlation between incidence of Crohn's disease and LM is −0.93, p < 0.01, the correlation between incidence of ulcerative colities and LM is −0.89, p < 0.01. We, therefore, propose that LM results in the formation of volatile fatty acids which may inhibit multiplication of potentially pathogenic organisms.

Primary adult lactose intolerance in the Kivu Lake area: Rwanda and the Bushi.

In order to investigate the ethnic differences of lactose intolerance in the Bantu and Hamitic races, lactose loading tests were performed on the populations living around Kivu Lake in central Africa. In addition to the blood sugar rise the identification of the urinary sugars after the loading test was found to be a useful criterion for the diagnosis of lactose intolerance. Two out of 27 Tutsi (7.8%), 21 out of 36 Hutu (58%), 17 out of 22 Twa (77%), and 27 out of 28 Shi (96%) were lactose intolerant. These frequencies are not linked with the actual milk-drinking habits. Of 3 Twa families, 2 were mostly lactose intolerant, whereas the third was predominantly tolerant. For 11 mixed-bred Hutu-Tutsi the frequency of lactose intolerance was 55%. The results are in favor of a genetic origin of lactose intolerance.

Progress report. New light on ethnic differences in adult lactose intolerance.

Progress report. New light on ethnic differences in adult lactose intolerance.

Lactose tolerance in an Arab population.

Lactose tolerance tests were performed on 67 adult Arab villagers. Fifty-four (80.6%) had a low rise in glucose and most had symptoms during the test. Lactose tolerance was not related to age or sex and did not correlate with milk consumption. A high incidence of adult lactose intolerance has been found in all Mediterranean groups studied to date—Greek Cypriots, Jews, and now Arabs.

Primary adult lactose intolerance and the milking habit: a problem in biologic and cultural interrelations. II. A culture historical hypothesis.

The principal conclusion reached in Part I of this article (1) was that the group differences found in primary adult lactose intolerance among the world's peoples are largely genetic in origin. In this part, after a review of recent research that adds to Part I in important ways, we turn to a consideration of the conditions of genetic selection that may have led some groups of men to have persistently high levels of intestinal lactase throughout life, and others not. Low incidence of intolerance, it is held, would develop over time in a group that has an abundant milk supply, that has alternate foodstuffs inadequate in amount and quality, and that consumes milk in lactose-rich forms. Since such selection cannot have occurred among groups that did not use milk, areas of nonmilking in the modern world are first delimited. The origins and diffusion of dairying are then sketched to determine the length of time that milk was consumed in various regions. With the background thus gained, the present-day occurrence of various Old World groups with high and low incidences of intolerance is explained. All groups studied so far within the traditional areas of nonmilking are found to have high incidences of intolerance. Overseas groups, such as American Negroes, whose ancestors came from nonmilking regions also have high incidences of intolerance. Within the areas of milking in Africa and Europe, moreover, the known group differences in tolerance are found to be in accord with the hypothesis. Then, that the hypothesis may further be confirmed, specific additional research efforts are suggested.

Primary adult lactose intolerance and the milking habit: a problem in biological and cultural interrelations. I. Review of the medical research.

The principal conclusion reached in Part I of this article (1) was that the group differences found in primary adult lactose intolerance among the world's peoples are largely genetic in origin. In this part, after a review of recent research that adds to Part I in important ways, we turn to a consideration of the conditions of genetic selection that may have led some groups of men to have persistently high levels of intestinal lactase throughout life, and others not. Low incidence of intolerance, it is held, would develop over time in a group that has an abundant milk supply, that has alternate foodstuffs inadequate in amount and quality, and that consumes milk in lactose-rich forms. Since such selection cannot have occurred among groups that did not use milk, areas of nonmilking in the modern world are first delimited. The origins and diffusion of dairying are then sketched to determine the length of time that milk was consumed in various regions. With the background thus gained, the present-day occurrence of various Old World groups with high and low incidences of intolerance is explained. All groups studied so far within the traditional areas of nonmilking are found to have high incidences of intolerance. Overseas groups, such as American Negroes, whose ancestors came from nonmilking regions also have high incidences of intolerance. Within the areas of milking in Africa and Europe, moreover, the known group differences in tolerance are found to be in accord with the hypothesis. Then, that the hypothesis may further be confirmed, specific additional research efforts are suggested.