Frequency of lactose malabsorption among healthy southern and northern Indian populations by genetic analysis and lactose hydrogen breath and tolerance tests

Association of dietary patterns and health outcomes by spatial regression analysis of nationally representative survey data from India

Background

Our aim was to study the regional differences in dietary patterns in India and their association with population-level nutrition-related health indicators such as the prevalence of anemia, overweight, undernutrition, and hyperglycemia.

Objectives

To identify and characterize the dietary patterns from publicly available nationally representative survey data on food consumption conducted by the National Sample Survey Office (NSSO) to study the regional differences in dietary patterns.

Methods

Dietary patterns were identified by factor analysis of per capita food consumption data from the household consumer expenditure survey (2011). Mean factor scores of dietary patterns were calculated for each district separately for urban and rural regions. Ecological association of factor scores with the district-level percentage prevalence of health indicators from the National Family Health Survey-4 (2015-2016) data was done by the Spatial Durbin Model of spatial regression analysis.

Results

Factor analyses revealed four dietary patterns which were similar in terms of the food items that characterized the factors for both rural and urban regions. Direct effects of dietary patterns by spatial regression analyses were observed with several health outcomes after adjusting for differences in socioeconomic development. Prevalence of anemia was positively associated with "Milk and wheat-rich diet" among men in the rural regions but negatively associated with other dietary patterns. Prevalence of overweight and high blood glucose was positively associated with "Rice and meat-rich diet" and "Coconut and seafood rich diet" in the rural regions. "Refined oil and tur dal-rich diet" was positively associated with the prevalence of overweight and hypertension in urban regions and negatively associated with underweight and anemia in men in rural and urban regions.

Conclusions

Spatial regression analyses revealed several important associations between dietary patterns and health outcomes, mostly in rural regions and some in urban regions. These results suggest the role of the major food items consumed in different regions and their impact on health outcomes in India and may have implications in tailoring dietary modifications accordingly.

Indian consensus statements on irritable bowel syndrome in adults: A guideline by the Indian Neurogastroenterology and Motility Association and jointly supported by the Indian Society of Gastroenterology

The Indian Neurogastroenterology and Motility Association (INMA), earlier named the Indian Motility and Functional Diseases Association developed this evidence-based practice guidelines for the management of irritable bowel syndrome (IBS). A modified Delphi process was used to develop this consensus containing 28 statements, which were concerning diagnostic criteria, epidemiology, etiopathogenesis and comorbidities, investigations, lifestyle modifications and treatments. Owing to the Coronavirus disease-19 (COVID-19) pandemic, lockdowns and mobility restrictions, web-based meetings and electronic voting were the major tools used to develop this consensus. A statement was regarded as accepted when the sum of "completely accepted" and "accepted with minor reservation" voted responses were 80% or higher. Finally, the consensus was achieved on all 28 statements. The consensus team members are of the view that this work may find use in teaching, patient care, and research on IBS in India and other nations.

Probiotic potential of β‑galactosidase‑producing lactic acid bacteria from fermented milk and their molecular characterization

Probiotics have attained significant interest in recent years as a result of their gut microbiome modulation and gastrointestinal health benefits. Numerous fermented foods contain lactic acid bacteria (LAB) which are considered as GRAS and probiotic bacteria. The present study aimed to investigate indigenous LAB from homemade fermented milk samples collected in remote areas of Karnataka (India), in order to isolate the most potent and well-adapted to local environmental conditions bacteria, which were then evaluated using a step-by-step approach focused on the evaluation of probiotic traits and β-galactosidase-producing ability. LAB were screened using 5-bromo-4-chloro-3-indole-D-galactopyranoside (X-Gal) and O-nitrophenyl-β-D-galactopyranoside (ONPG) as substrate, and exhibited β-galactosidase activity ranging from 728.25 to 1,203.32 Miller units. The most promising isolates were selected for 16S rRNA gene sequence analysis and identified as Lactiplantibacillus plantarum, Limosilactobacillus fermentum, Lactiplantibacillus pentosus and Lactiplantibacillus sp. Furthermore, these isolates were evaluated by in vitro, viz., survival in gastrointestinal tract, antibiotic susceptibility, antimicrobial activity, cell surface characteristics, and haemolytic activity. All eight isolates demonstrated strong adherence and prevented pathogen penetration into HT-29 cells, indicating potential of the bacteria to scale up industrial level production of milk products for lactose intolerants.

The challenges of implementing low fermentable oligo-, di-, mono-saccharides and polyol diet in India: An analysis of available data

BACKGROUND

Low fermentable oligo-, di-, monosaccharides, and polyols (FODMAP) diet is used in irritable bowel syndrome (IBS). However, data on the utility and challenges of implementing such a diet in India are scanty. Since dietary practices in India are different from other Asian and Western countries, the existing Indian data were analyzed.

METHODS

This study attempted to analyze the existing Indian data on the frequency of vegetarianism, cereal (wheat vs. rice), milk/milk product consumption, and lactose malabsorption (LM). A 5-point scale (quiet easy, easy, moderately easy, not easy, difficult) for implementation of low FODMAP diet for IBS patients was proposed based on regional dietary diversity and LM in India.

RESULTS

Our analysis showed that vegetarianism is high in India with regional differences in frequency. Similarly, there is regional variation in frequency of LM though it is quite high in most parts of India where data are available. While southern, eastern, and north-eastern [corrected] parts of the country have rice as the staple cereal, wheat is consumed more in other parts. We suggest that implementing a low FODMAP diet in north-eastern India may be most easy compared to northern India, where it may be most difficult. Implementing a low FODMAP diet in southern and eastern India may be easy, moderately easy in western India, and not easy in central India.

CONCLUSIONS

The variation in the difficulty in implementing a low FODMAP diet in India may stem from the regional food preference and differences in vegetarianism, as well as frequency of LM.

Prevalence of lactose intolerance and malabsorption among children of two ethnic groups from the urban areas of Malaysia and its relation to calcium intake and bone health status

Lactase insufficiency could develop into lactose intolerance (LI) and disrupt the intake of calcium, which is a core nutrient for bone development in children. However, data regarding the prevalence of LI and bone health status (BHS) among Malaysian children are scarcely reported.

PURPOSE

This study aimed to determine the prevalence of LI and lactose malabsorption (LM) in Malay and Chinese children and examine its relationship with calcium intake (CI) and BHS.

METHODS

A total of 400 children participated in this study. The prevalence of lactose tolerance (LT) was assessed using hydrogen breath test, LT test, and visual analogue scales. Assessment of CI was performed using a 24-h dietary recall interview (24-h DR) and food frequency questionnaire (FFQ). Calcaneal broadband ultrasound attenuation (BUA) was measured using a quantitative ultrasonometer.

RESULTS

The prevalence of LI among Chinese children (37%) was significantly higher (p = 0.002) than among Malay children (22.5%). However, 61.5% of Malay and 54.5% of Chinese children were found to have LM. CI of the children fulfilled 30.5% and 33.9% of the Malaysian recommended CI (1300 mg/day) for 24-h DR and FFQ, respectively. The BUA score of Malay children was significantly higher (p < 0.001) than that of Chinese children. However, LT and CI were not correlated with BHS (p > 0.05, respectively).

CONCLUSIONS

LI was diagnosed among Malay and Chinese children. However, the higher prevalence of LM is rather worrying as it could develop to LI. The prevalence possibly has been worsened by insufficient CI. Thus, effective approaches to increase CI are highly needed as bone development occurs rapidly at this age and is important for the attainment of the optimum peak bone mass during late adolescence.

Prevalence, overlap, and risk factors for Rome IV functional gastrointestinal disorders among college students in northern India

BACKGROUND/PURPOSE

There is scarcity of data on prevalence, overlap, and risk factors for functional gastrointestinal disorders (FGID) by Rome IV criteria. We evaluated these factors among medical, nursing, and humanities students.

METHODS

Rome IV Diagnostic Questionnaire (for all FGIDs), Rome III questionnaire (for irritable bowel syndrome [IBS], functional diarrhea [FDr], and functional constipation [FC]), and questionnaires assessing demography, physical activity, anxiety, and depression were used.

RESULTS

A total of 1309 college students were included (medical 425, nursing 390, humanities 494; mean age 20.5 ± 2.1 years; 36.5% males). Prevalence of Rome IV FGIDs was 26.9% (n = 352), significantly higher among females compared with males (32.3% vs. 17.6%; p < 0.001) and significantly higher among medical (34.4%) and nursing students (29.2%) compared with humanities students (18.6%) (p < 0.05). Most common FGIDs were functional dyspepsia (FD) (15.2%), IBS (6.2%), reflux hypersensitivity (3.5%), FDr (2.9%), FC (2.1%), and unspecified functional bowel disorder (2.1%). FGID overlap was present in 9.3%, most common being FD-IBS overlap (4.4%). With Rome III criteria, prevalence of IBS was higher (9.5%), while that of FDr (0.92%) and of FC (1.3%) were lower. On multivariate analysis, independent predictors for FGIDs were female gender, medical student, non-vegetarian diet, junk food, tea/coffee, poor physical activity, anxiety, and insomnia.

CONCLUSION

Rome IV FGIDs were present among one-fourth of college students with preponderance among females and medical students. FD, IBS, and reflux hypersensitivity were the most common FGIDs. Rome IV criteria led to a reduction in IBS prevalence and increase in FDr and FC prevalence. Dietary factors, physical activity, anxiety, and insomnia affected FGID prevalence.

Effect of lactase on symptoms and hydrogen breath levels in lactose intolerance: A crossover placebo-controlled study

Background and Aim

The absence of lactase in the intestinal villi due to mucosal injury or genetic factors causes undigested lactose to reach the colon where it is fermented. Lactose intolerance is diagnosed based on clinical symptoms like bloating, abdominal pain and flatulence, lactose hydrogen breath test (HBT), and lactose tolerance test. No Indian studies are available on the use of lactase supplements. The aim was to study the effect of lactase chewable tablets on clinical symptoms and hydrogen breath excretion in patients with lactose intolerance.

Methods

This was a randomized, double‐blind, crossover placebo‐controlled trial to study the effect of lactase tablets on symptoms and hydrogen breath levels in adults with lactose intolerance, confirmed by Lactose HBT. Clinical symptom severity was recorded using a visual analog scale, and HBT was performed every 30 min for 180 min. As it was a crossover design, the same patients were tested with both lactase and placebo, acting as their own controls with a washout period of 1 week between visits.

Results

Forty‐seven patients (mean age 33.6 years; 30 males) with lactose intolerance formed the study group. Clinical symptoms, mean clinical score (P < 0.05), and mean hydrogen breath levels (P < 0.05) were improved when the patients were given lactase. Reduction in cumulative hydrogen breath level over 180 min was 55% when patients received lactase compared to placebo.

Conclusions

Orally supplemented lactase enzyme significantly reduced the clinical symptoms and hydrogen breath excretion in patients with lactose intolerance.

Association of calcium intake, lactose intolerance and physical activity with bone health assessed via quantitative ultrasound among young adults of a Malaysian university

Lactose intolerance has been proposed to cause poor bone health. This study found the prevalence of lactose intolerance was high among Malaysian young adults, but not associated with bone health status, unlike calcium intake. This is the first study that investigated the association of lactose intolerance and bone health status in Malaysia.

PURPOSE

The aims of this study were to determine the prevalence of lactose intolerance, calcium intake and physical activity level and to investigate the association between these variables with bone health status among young adults.

METHODS

This cross-sectional study consisted of 300 Malay, Chinese and Indian students from Universiti Kebangsaan Malaysia with mean age of 22.5 ± 3.2 years. Determination of lactose tolerance status was performed using hydrogen breath test, lactose tolerance test and visual analogue scales. Calcium intake and physical activity level were evaluated using Food Frequency Questionnaire and International Physical Activity Questionnaire, respectively. Bone health status was assessed on calcaneal bone, using quantitative ultrasound.

RESULTS

Lactose intolerance was highly reported among the Malay subjects (72%) followed by Chinese (59%) and Indians (42%). The mean calcium intake was 542.9 ± 365.2 mg/day whilst the mean physical activity was 2757.6 ± 2007.2 MET-min/week. The bone assessment showed that 91% of the subjects had a low risk of developing osteoporosis. Only calcium intake showed a significant association with bone health status (β = 0.006; p = 0.033), whilst no association was shown for lactose intolerance and physical activity level.

CONCLUSIONS

Malaysian young adults showed a high prevalence of lactose intolerance. Calcium intake is associated with increased bone health status. In contrast, lactose intolerance and physical activity level did not directly influence bone health status. Nutrition education promoting adequate calcium intake should be implemented among young adults due to high lactose intolerance prevalence and low calcium intake among subjects.

Genetics of Lactose Intolerance: An Updated Review and Online Interactive World Maps of Phenotype and Genotype Frequencies

In humans the ability to digest milk lactose is conferred by a β-galactosidase enzyme called lactase-phlorizin hydrolase (LPH). While in some humans (approximately two-thirds of humankind) the levels of this enzyme decline drastically after the weaning phase (a trait known as lactase non-persistence (LNP)), some other individuals are capable of maintaining high levels of LPH lifelong (lactase persistence (LP)), thus being able to digest milk during adulthood. Both lactase phenotypes in humans present a complex genetic basis and have been widely investigated during the last decades. The distribution of lactase phenotypes and their associated single nucleotide polymorphisms (SNPs) across human populations has also been extensively studied, though not recently reviewed. All available information has always been presented in the form of static world maps or large dimension tables, so that it would benefit from the newly available visualization tools, such as interactive world maps. Taking all this into consideration, the aims of the present review were: (1) to gather and summarize all available information on LNP and LP genetic mechanisms and evolutionary adaptation theories, and (2) to create online interactive world maps, including all LP phenotype and genotype frequency data reported to date. As a result, we have created two online interactive resources, which constitute an upgrade over previously published static world maps, and allow users a personalized data exploration, while at the same time accessing complete reports by population or ethnicity.

Enhancing our understanding of small bowel function using modern imaging techniques

Small intestinal function is critical to digestive health and patients believe an abnormal reaction to food is responsible for many of their symptoms. Despite this, our ability to assess disturbed function in clinical practice has been limited, particularly after ingestion of the complex nutrients which make up normal food. Recent advances in both wireless capsules and magnetic resonance imaging have provided new insights. This review will briefly describe the limitations of past techniques and focus on how these newer techniques are changing our understanding, particularly of how patients' gastrointestinal tracts respond to food.

Lactase deficiency and lactose intolerance in a multiracial Asian population in Malaysia

Background and Aims

There have been few reports on lactase deficiency (LD) and lactose intolerance (LI) in Malaysia, which has a peculiar mix of three distinct major Asian races-Malay, Chinese, and Indian. The aim of this study was to determine the prevalence of LD and LI in a young multiethnic Malaysian population.

Methods

Lactase activity was measured with a ¹³CO₂ lactose breath test using an infrared spectrometer. Each subject took 25 g of lactose naturally enriched in ¹³CO₂ together with 250 mL of water after an overnight fast. Breath samples were collected at baseline and at 15-min intervals for 180 min. Subjects were asked to report gastrointestinal (GI) symptoms following ingestion of the lactose test meal.

Results

Of the 248 subjects tested, 216 (87.1%) were lactase deficient. We found no significant differences in the presentation of LD between gender and races. LD was found in 87.5% of males and 86.8% of females (P = 0.975) and in different races: Chinese (88.5%) versus Malay (83.1%) (P = 0.399), Indian (90.5%) versus Malay (P = 0.295), and Chinese versus Indian (P = 0.902). LI was diagnosed in only 49 (19.8%) subjects; 35 patients had diarrhea, while the remainder had at least two other GI symptoms after the lactose meal.

Conclusion

The prevalence of LD was high in all three major ethnic groups-Malays, Chinese, and Indians. Ironically, the prevalence of LI was low overall.

Epidemiological and clinical perspectives on irritable bowel syndrome in India, Bangladesh and Malaysia: A review

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder, common in clinic and in the community. It has a significant impact on both society and patients' quality of life. The epidemiology, clinical presentation, and management of IBS may vary in different geographical regions due to differences in diet, gastrointestinal infection, socio-cultural and psycho-social factors, religious and illness beliefs, symptom perception and reporting. Although previous reviews and consensus reports on IBS in Asia have been published, Asia is quite diverse socio-demographically. In this context, India, Bangladesh and Malaysia share some similarities, including: (1) large proportion of the population living in rural areas; (2) rapid development and associated lifestyle changes in urban areas; and (3) dietary, cultural and religious practices. The present review explores the clinical and epidemiological data on IBS from these three major nations in South and South-East Asia. In-depth review of the literature revealed important differences between IBS in the East, as revealed by studies from these three countries, and the West; these include a predominantly rural profile, differences in bowel habit and symptom profile, raising concern with regards to diagnostic criteria and subtyping of IBS, higher dietary fiber consumption, frequent lactose malabsorption, parasitosis, and possible overlap between post-infectious IBS and tropical sprue. Moreover, the current perception on difference in prevalence of the disorder in these countries, as compared to the West, might be related to variation in survey methods.

Association of LCT-13910 C/T Polymorphism and Colorectal Cancer

PURPOSE

The activity of epithelial lactase (LCT) is associated with a polymorphism 13910 bp upstream in the lactase encoding gene. Because the association between the LCT-13910 polymorphism and the risk for colorectal cancer is not clear, we investigated the role of the LCT-13910 polymorphism as a potential risk factor for colorectal cancer and colorectal polyps in the Turkish population.

METHODS

One hundred sixty-six subjects (74 with polyps, 44 with colorectal cancer, 48 controls), who had undergone a total colonoscopy between January 2012 and November 2012 in our endoscopy unit were genotyped for the LCT-13910 polymorphism by using the polymerase chain reaction and minisequencing.

RESULTS

The CC genotype in the lactose gene 13910 locus, which is accepted as the genetic indicator of lactase deficiency, was determined as 83.7%. The CC genotype rate was determined as 89.1% in patients who had a history of lactose intolerance and 81.5% in those without a history of lactose intolerance (P = 0.236). No difference was detected between the patients who had colorectal polyp(s) and/or cancer and the controls with regard to the LCT-13910 polymorphism. No differences were determined between groups when they were compared with regard to the C or the T allele.

CONCLUSION

No differences were detected between the patients who had colorectal polyp(s) and/or cancer and those with normal colonoscopy findings with regard to lactase gene polymorphisms. No differences were determined between the groups when they were compared with regard to the C or the T allele.

Chronic constipation in Rome IV era: The Indian perspective

Chronic constipation (CC) is a common problem in the community and in gastroenterology practice all over the world including India. After release of Rome IV guidelines in April 2016, there is increasing interest among gastroenterologists and physicians in India to look into special issues on CC in the Indian perspective. There are important differences in the bowel habit, definition, epidemiology, and pathophysiology including dietary factors and management of CC in India as compared to the West. As severity and frequency of abdominal pain, a symptom essential to diagnose constipation-predominant irritable bowel syndrome (IBS-C) rather than functional constipation (FC), is less common among Indian patients, FC is commoner than IBS-C in India. The pathophysiological mechanisms of CC may include slow colon transit, fecal evacuation disorder (FED), or a combination of these; though CC in a third to half of patients presenting to tertiary care facilities may result from these pathophysiological mechanisms, most patients presenting to primary care may have lifestyle and dietary issues. The current Rome IV algorithm dictates to explore the underlying physiological factors in the pathogenesis of functional gastrointestinal disorders including CC, which may translate to its personalized management. However, the availability of the methods to explore pathophysiological factors and manage CC caused by FED non-pharmacologically (using biofeedback) in India is limited. Though several pharmacological agents are available in India to manage CC, there are several unmet needs in its treatment. This review explores CC in India in relation to these issues, some of which are unique in the Indian perspective.

Lactose and Fructose Intolerance in Turkish Children with Chronic Abdominal Pain

OBJECTIVE

To investigate the prevalence of lactose and fructose intolerance in children with chronic abdominal pain.

METHODS

Hydrogen breath tests were done to detect lactose and fructose malabsorption in 86 children with chronic abdominal pain (44 irritable bowel syndrome, 24 functional abdominal pain and 17 functional abdominal pain syndrome as per Rome III criteria) presenting to a Pediatric Gastroentreology department.

RESULTS

14 (16.3%) of patients were diagnosed with lactose intolerance and 11 (12.8%) with fructose intolerance.

CONCLUSION

Lactose and fructose intolerance in children can lead to chronic abdominal pain and symptoms improve with dietary modifications.

Frequency and risk factors of functional gastro-intestinal disorders in a rural Indian population

BACKGROUND AND AIM

As best estimates on functional gastrointestinal disorders (FGIDs) prevalence are expected from community studies, which are scanty from Asia, we evaluated the prevalence and risk factors of FGIDs in a rural Indian community.

METHODS

House-to-house survey was undertaken by trained interviewers using translated-validated Rome III and hospital anxiety and depression questionnaires.

RESULT

Among 3426 subjects ≥ 18 years old from 3 villages in Uttar Pradesh, 84% participated, of whom 80% were finally analyzed. Of these 2774 subjects (age 38.4 ± 16.5 years, 1573 [56.7%] male), 2654 [95.7%] were vegetarian and 120 [4.3%] non-vegetarian. Socioeconomic classes were upper (16.7%), upper middle (15.1%), lower middle (22%), upper lower (22.2%), and lower (24%) using Prasad's Classification; 603 (21.7%) had FGIDs (413 [14.9%] dyspepsia, 75 [2.7%] irritable bowel syndrome (IBS) and 115 [4.1%] dyspepsia-IBS overlap), by Rome III criteria. In subjects with dyspepsia, 49/528 (9%) had epigastric pain, 141 (27%) postprandial distress syndromes (EPS, PDS) and 338 (64%) EPS-PDS overlap. IBS was more often diarrhea than constipation-predominant subtype. On univariate analysis, chewing tobacco, aerated drink, tea/coffee, disturbed sleep, vegetarianism, and anxiety parameters and presence of dyspepsia predicting occurrence of IBS were associated with FGIDs. On multivariate analysis, chewing tobacco, aerated soft drink, tea/coffee, vegetarianism, anxiety parameters, and presence of dyspepsia predicting IBS were significant.

CONCLUSION

Functional gastrointestinal disorders, particularly dyspepsia-IBS overlap, are common in rural Indian population; the risk factors included chewing tobacco, aerated soft drink, tea/coffee, vegetarian diet, disturbed sleep, anxiety, and dyspepsia predicting occurrence of IBS.

Lactose Intolerance and Symptom Pattern of Lactose Intolerance among Healthy Volunteers

Aims

To see the prevalence of lactose intolerance (LI) and related symptoms following oral lactose challenge in healthy volunteers.

Materials and methods

Symptoms of abdominal pain, nausea, borborygmi, flatulence, and diarrhea were noted for 24 hours and blood glucose was estimated at 0 hour and 30 minutes after 25 gm oral lactose load to healthy volunteers. Failure to rise blood glucose level ≥ 1.1 mmol/l at 30 minutes after lactose intake from fasting level was taken as lactose malabsorption (LM), i.e., LI.

Results

A total of 166 volunteers (123 males, 43 females) with a mean age 34.78 ± 11.45 years participated in this study. Lactose intolerance was found among 85.54% (n = 142, M = 104, F = 38). The main symptoms of LI were diarrhea (n = 83, 58.4.0%), borborygmi (n = 81, 57.04%), abdominal pain (n = 35, 24.65%), and flatulence (n = 27, 19.0%).

Conclusion

Lactose intolerance among healthy adults may be common in Bangladesh. Diarrhea and borborygmi were mostly associated symptoms of LI.

How to cite this article

Saha M, Parveen I, Shil BC, Saha SK, Banik RK, Majumder M, Salam MU, Nazmul Islam ASM. Lactose Intolerance and Symptom Pattern of Lactose Intolerance among Healthy Volunteers. Euroasian J Hepato-Gastroenterol 2016;6(1):5-7.

A study of the molecular variants associated with lactase persistence in different Ecuadorian ethnic groups

OBJECTIVE

Lactase persistence (LP) is an adaptive trait that certain human populations have acquired in response to lactose consumption in adulthood. The T-13910 variant has been reported as a causal polymorphism in Europeans. The Ecuadorian population has been described as multicultural and multiethnic, comprised of three main ethnic groups (Mestizo, Native Amerindian, and Afro-Ecuadorian). The aim of the study was to identify the molecular basis of LP in these admixed populations for the first time and determine the association between the T-13910 marker and the European ancestry proportion of each ethnic group.

METHODS

Genotyping was performed in 741 Ecuadorian individuals by sequencing a 576 bp region around the -13910 position upstream of the LCT gene. The ancestry proportions of Mestizo, Afro-Ecuadorian, and Native Amerindians were calculated using Ancestry Informative Markers and were compared with the diversity panel of the Human Genome Diversity Project.

RESULTS

LP prevalence calculated from T-13910 allele frequency in Mestizo, Afro-Ecuadorian, and Native Amerindians was 24.4%, 16%, and 12.5%, respectively. The ancestry percentage correlated to the admixture proportion of each ethnic group, and the C/T-13910 genotype frequency was influenced by the European ancestry proportion.

CONCLUSIONS

The presence of the T-13910 polymorphism in the Ecuadorian population suggested that LP was a trait introduced by European migration and inherited by admixture that occurred during the colonization of South America. This variant was not fixed in a population with a history of admixture, and its allele frequency was proportional to the ancestry proportion of each Ecuadorian ethnic group. Am. J. Hum. Biol. 28:774-781, 2016. © 2016Wiley Periodicals, Inc.

Clinical evaluation, biochemistry and genetic polymorphism analysis for the diagnosis of lactose intolerance in a population from northeastern Brazil

OBJECTIVE

This work aimed to evaluate and correlate symptoms, biochemical blood test results and single nucleotide polymorphisms for lactose intolerance diagnosis.

METHOD

A cross-sectional study was conducted in Fortaleza, Ceará, Brazil, with a total of 119 patients, 54 of whom were lactose intolerant. Clinical evaluation and biochemical blood tests were conducted after lactose ingestion and blood samples were collected for genotyping evaluation. In particular, the single nucleotide polymorphisms C>T-13910 and G>A-22018 were analyzed by restriction fragment length polymorphism/polymerase chain reaction and validated by DNA sequencing.

RESULTS

Lactose-intolerant patients presented with more symptoms of flatulence (81.4%), bloating (68.5%), borborygmus (59.3%) and diarrhea (46.3%) compared with non-lactose-intolerant patients (p<0.05). We observed a significant association between the presence of the alleles T-13910 and A-22018 and the lactose-tolerant phenotype (p<0.05). After evaluation of the biochemical blood test results for lactose, we found that the most effective cutoff for glucose levels obtained for lactose malabsorbers was <15 mg/dL, presenting an area under the receiver operating characteristic curve greater than 80.3%, with satisfactory values for sensitivity and specificity.

CONCLUSIONS

These data corroborate the association of these single nucleotide polymorphisms (C>T-13910 and G>A-22018) with lactose tolerance in this population and suggest clinical management for patients with lactose intolerance that considers single nucleotide polymorphism detection and a change in the biochemical blood test cutoff from <25 mg/dL to <15 mg/dL.

Correlation Between Capillary and Venous Blood Glucose in the Lactose Tolerance Test

BACKGROUND

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.

AIM

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Small Intestinal Bacterial Overgrowth in Patients with Refractory Functional Gastrointestinal Disorders

Background/Aims

Small intestinal bacterial overgrowth (SIBO) is considered to be involved in the pathogenesis of functional gastrointestinal disorders (FGID). However, the prevalence and clinical conditions of SIBO in patients with FGID remain to be fully elucidated. Here, we examined the frequency of SIBO in patients with refractory FGID.

Methods

We prospectively enrolled patients with refractory FGID based on Rome III criteria. A glucose hydrogen breath test (GHBT) was performed using a gas analyzer after an overnight fast, with breath hydrogen concentration measured at baseline and every 15 minutes after administration of glucose for a total of 3 hours. A peak hydrogen value ≥ 10 ppm above the basal value between 60 and 120 minutes after administration of glucose was diagnosed as SIBO.

Results

A total of 38 FGID patients, including 11 with functional dyspepsia (FD), 10 with irritable bowel syndrome (IBS), and 17 with overlapping with FD and IBS, were enrolled. Of those, 2 (5.3%) were diagnosed with SIBO (one patient diagnosed with FD; the other with overlapping FD and IBS). Their symptoms were clearly improved and breath hydrogen levels decreased to normal following levofloxacin administration for 7 days.

Conclusions

Two patients initially diagnosed with FD and IBS were also diagnosed with SIBO as assessed by GHBT. Although the frequency of SIBO is low among patients with FGID, it may be important to be aware of SIBO as differential diagnosis when examining patients with refractory gastrointestinal symptoms, especially bloating, as a part of routine clinical care.

Lactose Hydrolysis in Milk and Dairy Whey Using Microbial β-Galactosidases

This work aimed at evaluating the influence of enzyme concentration, temperature, and reaction time in the lactose hydrolysis process in milk, cheese whey, and whey permeate, using two commercial β-galactosidases of microbial origins. We used Aspergillus oryzae (at temperatures of 10 and 55°C) and Kluyveromyces lactis (at temperatures of 10 and 37°C) β-galactosidases, both in 3, 6, and 9 U/mL concentrations. In the temperature of 10°C, the K. lactis β-galactosidase enzyme is more efficient in the milk, cheese whey, and whey permeate lactose hydrolysis when compared to A. oryzae. However, in the enzyme reaction time and concentration conditions evaluated, 100% lactose hydrolysis was not reached using the K. lactis β-galactosidase. The total lactose hydrolysis in whey and permeate was obtained with the A. oryzae enzyme, when using its optimum temperature (55°C), at the end of a 12 h reaction, regardless of the enzyme concentration used. For the lactose present in milk, this result occurred in the concentrations of 6 and 9 U/mL, with the same time and temperature conditions. The studied parameters in the lactose enzymatic hydrolysis are critical for enabling the application of β-galactosidases in the food industry.

Adult lactose digestion status and effects on disease

BACKGROUND

Adult assimilation of lactose divides humans into dominant lactase-persistent and recessive nonpersistent phenotypes.

OBJECTIVES

To review three medical parameters of lactose digestion, namely: the changing concept of lactose intolerance; the possible impact on diseases of microbial adaptation in lactase-nonpersistent populations; and the possibility that the evolution of lactase has influenced some disease pattern distributions.

METHODS

A PubMed, Google Scholar and manual review of articles were used to provide a narrative review of the topic.

RESULTS

The concept of lactose intolerance is changing and merging with food intolerances. Microbial adaptation to regular lactose consumption in lactase-nonpersistent individuals is supported by limited evidence. There is evidence suggestive of a relationship among geographical distributions of latitude, sunhine exposure and lactase proportional distributions worldwide.

DISCUSSION

The definition of lactose intolerance has shifted away from association with lactose maldigestion. Lactose sensitivity is described equally in lactose digesters and maldigesters. The important medical consequence of withholding dairy foods could have a detrimental impact on several diseases; in addition, microbial adaptation in lactase-nonpersistent populations may alter risk for some diseases. There is suggestive evidence that the emergence of lactase persistence, together with human migrations before and after the emergence of lactase persistence, have impacted modern-day diseases.

CONCLUSIONS

Lactose maldigestion and lactose intolerance are not synonymous. Withholding dairy foods is a poor method to treat lactose intolerance. Further epidemiological work could shed light on the possible effects of microbial adaptation in lactose maldigesters. The evolutionary impact of lactase may be still ongoing.

Review article: the aetiology, diagnosis, mechanisms and clinical evidence for food intolerance

BACKGROUND

Food intolerance is non-immunological and is often associated with gastrointestinal symptoms.

AIM

To focus on food intolerance associated with gastrointestinal symptoms and critically appraise the literature in relation to aetiology, diagnosis, mechanisms and clinical evidence.

METHODS

A search using the terms and variants of food intolerance, lactose, FODMAP, gluten, food chemicals within Pubmed, Embase and Scopus was carried out and restricted to human studies published in English. Additionally, references from relevant papers were hand searched for other appropriate studies.

RESULTS

Food intolerance affects 15-20% of the population and may be due to pharmacological effects of food components, noncoeliac gluten sensitivity or enzyme and transport defects. There have been significant advances in understanding the scientific basis of gastrointestinal food intolerance due to short-chain fermentable carbohydrates (FODMAPs). The most helpful diagnostic test for food intolerance is food exclusion to achieve symptom improvement followed by gradual food reintroduction. A low FODMAP diet is effective, however, it affects the gastrointestinal microbiota and FODMAP reintroduction to tolerance is part of the management strategy.

CONCLUSIONS

There is increasing evidence for using a low FODMAP diet in the management of functional gastrointestinal symptoms where food intolerance is suspected. Exclusion diets should be used for as short a time as possible to induce symptom improvement, and should be followed by gradual food reintroduction to establish individual tolerance. This will increase dietary variety, ensure nutritional adequacy and minimise impact on the gastrointestinal microbiota.

Fortification of foods with vitamin D in India

Vitamin D deficiency is widely prevalent in India, despite abundant sunshine. Fortification of staple foods with vitamin D is a viable strategy to target an entire population. Vitamin D fortification programs implemented in the United States and Canada have improved the vitamin D status in these countries, but a significant proportion of the population is still vitamin D deficient. Before fortification programs are designed and implemented in India, it is necessary to study the efficacy of the American and Canadian vitamin D fortification programs and then improve upon them to suit the Indian scenario. This review explores potential strategies that could be used for the fortification of foods in the Indian context. These strategies have been proposed considering the diverse dietary practices necessitated by social, economic, cultural and religious practices and the diverse climatic conditions in India. Fortification of staple foods, such as chapati flour, maida, rice flour and rice, may be more viable strategies. Targeted fortification strategies to meet the special nutritional needs of children in India are discussed separately in a review entitled, "Fortification of foods with vitamin D in India: Strategies targeted at children".

Latitude, sunshine, and human lactase phenotype distributions may contribute to geographic patterns of modern disease: the inflammatory bowel disease model

Countries with high lactase nonpersistence (LNP) or low lactase persistence (LP) populations have lower rates of some "western" diseases, mimicking the effects of sunshine and latitude. Inflammatory bowel disease (IBD), ie, Crohn's disease and ulcerative colitis, is putatively also influenced by sunshine. Recent availability of worldwide IBD rates and lactase distributions allows more extensive comparisons. The aim of this study was to evaluate the extent to which modern day lactase distributions interact with latitude, sunshine exposure, and IBD rates. National IBD rates, national distributions of LP/LNP, and population-weighted average national annual ultraviolet B exposure were obtained, estimated, or calculated from the literature. Negative binomial analysis was used to assess the relationship between the three parameters and IBD rates. Analyses for 55 countries were grouped in three geographic domains, ie, global, Europe, and non-Europe. In Europe, both latitude and ultraviolet B exposure correlate well with LP/LNP and IBD. In non-Europe, latitude and ultraviolet B exposure correlate weakly with LP/LNP, but the latter retains a more robust correlation with IBD. In univariate analysis, latitude, ultraviolet B exposure, and LP/LNP all had significant relationships with IBD. Multivariate analysis showed that lactase distributions provided the best model of fit for IBD. The model of IBD reveals the evolutionary effects of the human lactase divide, and suggests that latitude, ultraviolet B exposure, and LP/LNP mimic each other because LP/LNP follows latitudinal directions toward the equator. However, on a large scale, lactase patterns also follow lateral polarity. The effects of LP/LNP in disease are likely to involve complex interactions.

Study on influence of age, gender and genetic variants on lactose intolerance and its impact on milk intake in adult Asian Indians

BACKGROUND

Lactase non-persistence (LNP) has been associated with the CC genotype of -13910C > T and GG genotype of -22018G > A polymorphisms present upstream of the lactase gene. Lactose intolerance (LI) is caused when gastrointestinal symptoms develop in individuals with low lactase activity.

OBJECTIVE

To analyse association of LNP genotype and LI symptoms with milk intake and determine whether factors such as age, gender and genotype affect LI status.

SUBJECTS AND METHODS

Genetic analysis and lactose tolerance test (LTT) were performed on 205 healthy Indian adults. The pattern of milk consumption was recorded using a dietary questionnaire.

RESULTS

LI was strongly associated with -13910CC genotype (OR = 10.28, 95% CI = 2.32-45.55, p = 0.002). Females were found to be at a higher risk of developing LI (OR = 2.47, 95% CI = 1.33-4.59, p = 0.004). The association of the ≥50 years age group with LI was marginally significant (OR = 1.86, 95% CI = 0.995-3.47, p = 0.05). Frequency and quantity of milk intake were lower in subjects belonging to the LNP genotype and LI groups (p < 0.05).

CONCLUSIONS

Subject study suggests that gender and genotype may be associated with development of LI. Association of age with LI was marginal. The data also indicate that LNP genotype and LI may play a role in influencing milk intake in individuals.

Hydrogen breath tests in gastrointestinal diseases

Hydrogen breath tests are widely used to explore pathophysiology of functional gastrointestinal (GI) disorders. Small intestinal bacterial overgrowth (SIBO) and carbohydrate malabsorption are disorders detected by these tests that have been proposed to be of great importance for symptoms of GI diseases. Glucose hydrogen breath test is more acceptable for diagnosis of SIBO whereas lactose and fructose hydrogen breath tests are used for detection of lactose and fructose maldigestion respectively. Lactulose hydrogen breath test is also used widely to measure the orocecal transit time for GI motility. These methods are noninvasive and inexpensive. Many patients with functional gut disorders are unaware of the relationship between diet and GI symptoms they present. In particular, patients with chronic symptoms may regard their condition as normal and may not be aware that their symptoms can be effectively managed following a proper diagnosis. Patients with symptoms of abdominal pain, bloating, flatulence and altered bowel movements (diarrhea and constipation), or with a medical diagnosis of irritable bowel syndrome or celiac disease, may have undiagnosed carbohydrate malabsorption or SIBO. Hydrogen breath tests are specific and sensitive diagnostic tests that can be used to either confirm or eliminate the possibility of carbohydrate malabsorption or SIBO in such patients. Breath tests, though valuable tools, are underutilized in evaluating dyspepsia and functional bloating and diarrhea as well as suspected malabsorption. However, because of their simplicity, reproducibility and safety of procedure they are now being substituted to more uncomfortable and expensive techniques that were traditionally used in gastroenterology.

Vitamin D deficiency in India: prevalence, causalities and interventions

Vitamin D deficiency prevails in epidemic proportions all over the Indian subcontinent, with a prevalence of 70%-100% in the general population. In India, widely consumed food items such as dairy products are rarely fortified with vitamin D. Indian socioreligious and cultural practices do not facilitate adequate sun exposure, thereby negating potential benefits of plentiful sunshine. Consequently, subclinical vitamin D deficiency is highly prevalent in both urban and rural settings, and across all socioeconomic and geographic strata. Vitamin D deficiency is likely to play an important role in the very high prevalence of rickets, osteoporosis, cardiovascular diseases, diabetes, cancer and infections such as tuberculosis in India. Fortification of staple foods with vitamin D is the most viable population based strategy to achieve vitamin D sufficiency. Unfortunately, even in advanced countries like USA and Canada, food fortification strategies with vitamin D have been only partially effective and have largely failed to attain vitamin D sufficiency. This article reviews the status of vitamin D nutrition in the Indian subcontinent and also the underlying causes for this epidemic. Implementation of population based educational and interventional strategies to combat this scourge require recognition of vitamin D deficiency as a public health problem by the governing bodies so that healthcare funds can be allocated appropriately.

Lactose malabsorption diagnosed by 50-g dose is inferior to assess clinical intolerance and to predict response to milk withdrawal than 25-g dose in an endemic area

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.

Association between celiac disease and primary lactase deficiency

Primary lactase deficiency (PLD) is a common inherited condition caused by a reduced activity of lactase. Two single-nucleotide polymorphisms C/T(-13910) and G/A(-22018) upstream of the lactase gene are associated with lactase nonpersistence. In celiac disease (CD) patients, lactose intolerance could be due to secondary lactase deficiency and to PLD. The aim of this study were to evaluate the association of PLD and CD using genetic test, and to define the prevalence of PLD in celiac subjects compared with a control population. A total of 188 controls and 92 biopsy-proven CD patients were included in the study. More than 70% of all subjects were found homozygous for the polymorphisms. Differences in the prevalence of PLD were not found between CD patients and controls.In conclusions, the hereditary lactase deficiency is frequent in Italian CD children as in control population.

Primary Care Management of Chronic Constipation in Asia: The ANMA Chronic Constipation Tool

Chronic constipation (CC) may impact on quality of life. There is substantial patient dissatisfaction; possible reasons are failure to recognize underlying constipation, inappropriate dietary advice and inadequate treatment. The aim of these practical guidelines intended for primary care physicians, and which are based on Asian perspectives, is to provide an approach to CC that is relevant to the existing health-care infrastructure. Physicians should not rely on infrequent bowel movements to diagnose CC as many patients have one or more bowel movement a day. More commonly, patients present with hard stool, straining, incomplete feeling, bloating and other dyspeptic symptoms. Physicians should consider CC in these situations and when patients are found to use laxative containing supplements. In the absence of alarm features physicians may start with a 2-4 week therapeutic trial of available pharmacological agents including osmotic, stimulant and enterokinetic agents. Where safe to do so, physicians should consider regular (as opposed to on demand dosing), combination treatment and continuous treatment for at least 4 weeks. If patients do not achieve satisfactory response, they should be referred to tertiary centers for physiological evaluation of colonic transit and pelvic floor function. Surgical referral is a last resort, which should be considered only after a thorough physiological and psychological evaluation.

Frequency of LCT-13910C/T and LCT-22018G/A single nucleotide polymorphisms associated with adult-type hypolactasia/lactase persistence among Israelis of different ethnic groups

Primary lactase deficiency (PLD), the physiological decline of lactase, is associated with the LCT-13910C/T and LCT-22018G/A polymorphisms. PLD is the most common phenotype in humans and varies widely as a function of ethnicity. Israel is a multiethnic country. We analyzed the genetic frequencies of PLD in different Israeli ethnicities. Ethnicity-related frequencies were analyzed in 439 Israelis: Ashkenazi (n=96), Iraqi (n=96), Moroccan (n=96) Jews and Bedouin-Arabs (n=151). DNA was extracted from leukocytes; LCT-13910C/T, -22018G/A and -13915T/G (in Bedouin-Arabs) polymorphisms were analyzed by PCR-restriction fragment length polymorphism analysis. There was a significant association between ethnicity and genotype in both polymorphic LCT SNPs (-13910C/T and -22018). Prevalence of the CC (LCT-13910C/T) genotype associated with adult hypolactasia was 97%, 93%, 83% and 82% among Bedouin-Arabs and Iraqi, Ashkenazi and Moroccan Jews, respectively. The prevalence of the GG (LCT-22018G/A) adult hypolactasia genotype among those groups was identical to that of the CC genotype in each group, except for Iraqi-Jews, of which only 83% carried the GG genotype. The prevalence of heterozygous and homozygous genotypes associated with lactase persistence (CT, TT for -13910C/T and GA, AA for -22018G/A) was 3%, 7%, 17% and 18% and 3%, 17%, 17% and 18% for Bedouin-Arabs, Ashkenazi, Iraqi and Moroccan Jews, respectively. A significant correlation between SNPs was found. PLD prevalence is high among different ethnic groups in Israel and varies between ethnicities. The prevalence of the -13915*G allele, indicative of lactose persistence in African and Arab populations, was 41% in the Bedouin-Arabs group. Lactase persistence genotype prevalence was found to vary between Israeli ethnicities (4-18%). SNPs (-13910C/T and -22018) showed significant correlation in detecting genotype prevalence in Israeli Jews. We suggest adjusting nutritional recommendations accordingly.

Application of molecularly imprinted hydrogel for the preparation of lactose-free milk

BACKGROUND

A variety of lactose imprinted hydrogels were prepared and their binding properties were studied in comparison with blank non-imprinted hydrogel. Methacrylamide and ethylene glycol dimethacrylate were used as functional monomer and cross-linker, respectively. Dimethylsulfoxide was also applied as polymerisation solvent.

RESULTS

Different template/monomer ratios were studied and the optimised imprinted hydrogel (MIP₂), with a lactose/methacrylamide ratio of 1:8, was selected in a rebinding test. In Scatchard analysis of MIP₂-lactose interactions, the dissociation constant and maximum binding sites were 0.33 mmol L⁻¹ and 67.76 µmol g⁻¹ hydrogel, respectively. The selectivity of MIP₂ for lactose in aqueous media was also evaluated in comparison with different mono- and disaccharides. The data showed that the affinity of MIP₂ for lactose is significantly higher than other saccharides. The imprinted hydrogel was finally used as a sorbent for separation of lactose from milk.

CONCLUSIONS

The results indicated that MIP₂, as an optimised imprinted hydrogel, can effectively bind lactose and decrease its concentration in milk.

Lactase persistence/non-persistence genetic variants in irritable bowel syndrome in an endemic area for lactose malabsorption

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 < 0.0001 and (GG 69 [87%], GA 6 [8%], AA 4 [5%]) vs (22 [42%], 24 [46%], 6 [12%]) vs (6 [32%], 11 [58%], 2 [10%]), P < 0.0001. IBS with CC and GG genotypes more often had abdominal pain (P = 0.005), distension (P = 0.031) and higher stool frequency (P = 0.003) and reported symptoms following dairy products than non-CC (P < 0.0001).

CONCLUSION

Though C/T-13910 and G/A-22018 polymorphisms were comparable among IBS and HC, these were more common among D-IBS and reported some symptoms like abdominal pain, bloating and exacerbation by dairy products.

The global perspective on irritable bowel syndrome: a Rome Foundation-World Gastroenterology Organisation symposium

Although irritable bowel syndrome (IBS) is common worldwide, there is uncertainty regarding similarities and differences in geographical regions and cultural groups. For example, are Western diagnostic criteria applicable to other groups? The interaction between culture and health can impact quality of care and health outcomes and, in research, cause methodological shortcomings that lead to bias and inappropriate interpretations of research results. Two central questions are: do physicians have the cross-cultural competence to effect a participatory model of care; and do we have sufficient knowledge and experience in conducting multinational, cross-cultural research? The Rome Foundation and the World Gastroenterology Organisation convened a symposium to foster interest in the global aspects of IBS, foster cross-cultural competence, improve multinational IBS research, foster international networks for IBS research, increase awareness of culture's impact on patient care and research in the functional gastrointestinal disorders (FGIDs), address cross-cultural issues in multinational clinical drug trials, and facilitate the development of patient-reported outcome measures for FGID research across cultures. This review summarizes key points and messages.

Lactose intolerance: diagnosis, genetic, and clinical factors

Most people are born with the ability to digest lactose, the major carbohydrate in milk and the main source of nutrition until weaning. Approximately 75% of the world’s population loses this ability at some point, while others can digest lactose into adulthood. This review discusses the lactase-persistence alleles that have arisen in different populations around the world, diagnosis of lactose intolerance, and its symptomatology and management.

Correlation of G/A -22018 single-nucleotide polymorphism with lactase activity and its usefulness in improving the diagnosis of adult-type hypolactasia among North Indian children

Adult-type hypolactasia (AtH or lactase non-persistence) is the physiological decline in lactase activity that manifests in majority of the world's population after weaning. Recently, various single-nucleotide polymorphisms (SNPs) upstream of lactase gene (LCT) have been suggested to be associated with AtH or the lactase persistent trait in different human populations. C/T -13910 SNP was found be completely associated with AtH in Finnish population, and G/A -22018 SNP was found to be strongly, but not completely, associated with AtH. The aim of this study was to correlate G/A -22018 SNP with intestinal lactase activity in North Indian children. These children were also genotyped for C/T -13910 SNP. We also examined the differences in milk consumption and milk-related clinical symptoms in children with different genotypes of G/A -22018 and C/T -13910 SNPs. Intestinal biopsies were obtained from 231 children aged 2-16 years undergoing routine endoscopy for various abdominal complaints. The biopsies were assayed for lactase, sucrase, and maltase activities and genotyped for G/A -22018 and C/T -13910 SNPs using restriction fragment length polymorphism and DNA sequencing analysis. There was a significant correlation between lactase activity and different genotypes of G/A -22018 SNP. Children with G/G -22018 genotype had low lactase activity. With a reference value of <10 U/g protein (lactase activity) to be indicative of AtH, the sensitivity and specificity of genetic test based on G/A -22018 SNP was 94.4 and 94.1 %, respectively. Furthermore, the consumption of milk was lower in children with G/G -22018 genotype. Flatulence was the only symptom significantly more frequent among the children with G/G -22018 genotype compared to those with G/A and A/A -22018 genotypes. However, most of the children with G/G -22018 genotype seem to tolerate small amounts of milk without any significant difference in gastrointestinal symptoms from those with G/A and A/A -22018 genotypes.

Meta-analysis: the diagnostic accuracy of lactose breath hydrogen or lactose tolerance tests for predicting the North European lactase polymorphism C/T-13910

BACKGROUND

  The diagnostic accuracy of two indirect tests of lactose digestion, lactose breath hydrogen and lactose tolerance tests, have not been systematically reviewed for comparison with available publications on genotype.

AIM

  To perform a meta-analysis of available studies that compares the north-European genetic polymorphism C/T-13910 with the lactose breath hydrogen and the lactose tolerance tests, to determine their ability to predict geno/phenotype relationships. We examine the effects of lactose loading dose, inclusion of children and latitudes of study centre on comparative outcome.

METHODS

  An electronic database of the literature as well as individual references in articles were searched with the theme of genetics of lactase and comparisons with breath or lactose tolerance tests were carried out. Random effect and fixed effect models were used for breath and lactose tolerance tests respectively, to report summary accuracy measures with 95% confidence intervals (CI).

RESULTS

  The search revealed 19 studies: 17 evaluated breath hydrogen, five lactose tolerance test (3/17 overlapped). Overall sensitivity was 0.88 (CI, 0.85-0.90), specificity was 0.85 (CI, 0.82-0.87) for breath test. Heterogeneity was explored by adjusting for studies including children, high or low dose lactose and to some extent by site of study. The lactose tolerance test showed sensitivity of 0.94 (0.9-0.97) and specificity of 0.90 (0.84-0.95) with a nonsignificant heterogeneity.

CONCLUSION

  The diagnostic accuracy of both tests individually reflects expected geno/phenotypes when the populations are well defined.

Association of lactose sensitivity with inflammatory bowel disease--demonstrated by analysis of genetic polymorphism, breath gases and symptoms

BACKGROUND

Sensitivity to lactose has been reported in Crohn's disease, but its true role in inflammatory bowel disease (IBD) is unclear. The genetic marker CC₁₃₉₁₀, on chromosome2, with measurement of breath hydrogen and methane, and gut and systemic symptoms, are now the most comprehensive tests for evaluating sensitivity to lactose.

AIM

To investigate, for the first time, the prevalence of lactose sensitivity in IBD, using the most comprehensive tests for diagnosing this condition.

METHODS

Prevalence of CC₁₃₉₁₀ genotype was investigated using RT-PCR in 165 patients (Crohn's disease = 70, ulcerative colitis = 95), and 30 healthy volunteers. Genotype was correlated with breath hydrogen and methane up to 6 h after 50 g of oral lactose, all symptoms being recorded for up to 48 h. Critically, Crohn's disease and ulcerative colitis patients were selected with no record of lactose sensitivity, in remission at the time of the test.

RESULTS

Lactose sensitivity occurred in a much higher proportion of patients, (approximately 70%), with IBD than previously thought. Seventeen per cent had raised methane, without raised breath hydrogen; those with ulcerative colitis exhibiting most symptoms. All CC patients were lactose sensitive. There was no correlation between genetic phenotype and IBD. As substantial numbers of IBD patients were CT or TT, and were lactose sensitive, this polymorphism cannot explain full down-regulation of the lactase gene.

CONCLUSIONS

Our results have implications for the clinical management of IBD. The high breath methane raised the possibility of a pathogenic role for methanogenic archaebacteria (Archaea) in IBD. This needs to be investigated.

Herders of Indian and European cattle share their predominant allele for lactase persistence

Milk consumption and lactose digestion after weaning are exclusively human traits made possible by the continued production of the enzyme lactase in adulthood. Multiple independent mutations in a 100-bp region--part of an enhancer--approximately 14-kb upstream of the LCT gene are associated with this trait in Europeans and pastoralists from Saudi Arabia and Africa. However, a single mutation of purported western Eurasian origin accounts for much of observed lactase persistence outside Africa. Given the high levels of present-day milk consumption in India, together with archaeological and genetic evidence for the independent domestication of cattle in the Indus valley roughly 7,000 years ago, we sought to determine whether lactase persistence has evolved independently in the subcontinent. Here, we present the results of the first comprehensive survey of the LCT enhancer region in south Asia. Having genotyped 2,284 DNA samples from across the Indian subcontinent, we find that the previously described west Eurasian -13910 C>T mutation accounts for nearly all the genetic variation we observed in the 400- to 700-bp LCT regulatory region that we sequenced. Geography is a significant predictor of -13910*T allele frequency, and consistent with other genomic loci, its distribution in India follows a general northwest to southeast declining pattern, although frequencies among certain neighboring populations vary substantially. We confirm that the mutation is identical by descent to the European allele and is associated with the same>1 Mb extended haplotype in both populations.

How to interpret hydrogen breath tests

Hydrogen breath tests using various substrates like glucose, lactulose, lactose and fructose are being used more and more to diagnose small intestinal bacterial overgrowth (SIBO) and lactose or fructose malabsorption. Though quantitative culture of jejunal aspirate is considered as gold standard for the diagnosis of SIBO, hydrogen breath tests, in spite of their low sensitivity, are popular for their non-invasiveness. Glucose hydrogen breath test is more acceptable for the diagnosis of SIBO as conventionally accepted double-peak criterion on lactulose hydrogen breath test is very insensitive and recently described early-peak criterion is often false positive. Hydrogen breath test is useful to diagnose various types of sugar malabsorption. Technique and interpretation of different hydrogen breath tests are outlined in this review.

How to interpret hydrogen breath tests

Hydrogen breath tests using various substrates like glucose, lactulose, lactose and fructose are being used more and more to diagnose small intestinal bacterial overgrowth (SIBO) and lactose or fructose malabsorption. Though quantitative culture of jejunal aspirate is considered as gold standard for the diagnosis of SIBO, hydrogen breath tests, in spite of their low sensitivity, are popular for their non-invasiveness. Glucose hydrogen breath test is more acceptable for the diagnosis of SIBO as conventionally accepted double-peak criterion on lactulose hydrogen breath test is very insensitive and recently described early-peak criterion is often false positive. Hydrogen breath test is useful to diagnose various types of sugar malabsorption. Technique and interpretation of different hydrogen breath tests are outlined in this review.