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Lactose intolerance has a high prevalence worldwide, ranging between 57% and 65%. It is caused by a reduction or loss of the activity of the intestinal enzyme lactase-phlorizin hydrolase, responsible for the digestion of lactose. This alteration determines an increased osmotic load in the small intestine and the fermentation of lactose by the bacterial flora, which leads to a high production of short-chain fatty acids and gas. This is followed by the onset of abdominal pain, diarrhea, and flatulence. In addition to these problems, it was found that subjects with lactose intolerance have an increased risk of developing various extra-intestinal diseases, including cancers. The diagnosis is essential to undertake an adequate treatment and, for this purpose, different methods have been tested. These include genetic test, hydrogen breath test (HBT), quick lactase test, and lactose tolerance test. HBT is the most used method because it is non-invasive, inexpensive, and highly sensitive and specific, as well as easy to perform. In clinical practice, the other methods are mainly used as HBT integration tests. There are also many therapeutic options. An appropriate intervention concerns the dietetic style, such as the consumption of lactose-free foods, but with nutritional characteristics comparable to dairy products. Other valid choices are represented by the use of exogenous enzymes, probiotics, prebiotics, the selection of milk containing specific types of beta-caseins. This review is intended to illustrate the diagnostic methods currently available and the possible therapeutic options for lactose intolerance., (Copyright © 2021. Published by Elsevier Inc.)

Recent discoveries in the "omics" field and the growing focus on preventive health have opened new avenues for personalized nutrition (PN), which is becoming an important theme in the strategic plans of organizations that are active in healthcare, food, and nutrition research. PN holds great potential for individual health optimization, disease management, public health interventions, and product innovation. However, there are still multiple challenges to overcome before PN can be truly embraced by the public and healthcare stakeholders. The diagnosis and management of lactose intolerance (LI), a common condition with a strong inter-individual component, is explored as an interesting example for the potential role of these technologies and the challenges of PN. From the development of genetic and metabolomic LI diagnostic tests that can be carried out in the home, to advances in the understanding of LI pathology and individualized treatment optimization, PN in LI care has shown substantial progress. However, there are still many research gaps to address, including the understanding of epigenetic regulation of lactase expression and how lactose is metabolized by the gut microbiota, in order to achieve better LI detection and effective therapeutic interventions to reverse the potential health consequences of LI.

Acute-feeding and multiple-day studies have demonstrated that milk containing A2 β-casein only causes fewer symptoms of lactose intolerance (LI) than milk containing both A1 and A2 β-caseins. We conducted a single-meal study to evaluate the gastrointestinal (GI) tolerance of milk containing different concentrations of A1 and A2 β-casein proteins. This was a randomized, double-blind, crossover trial in 25 LI subjects with maldigestion and an additional eight lactose maldigesters who did not meet the QLCSS criteria. Subjects received each of four types of milk (milk containing A2 β-casein protein only, Jersey milk, conventional milk, and lactose-free milk) after overnight fasting. Symptoms of GI intolerance and breath hydrogen concentrations were analyzed for 6 h after ingestion of each type of milk. In an analysis of the 25 LI subjects, total symptom score for abdominal pain was lower following consumption of milk containing A2 β-casein only, compared with conventional milk ( p = 0.004). Post hoc analysis with lactose maldigesters revealed statistically significantly improved symptom scores ( p = 0.04) and lower hydrogen production ( p = 0.04) following consumption of milk containing A2 β-casein only compared with conventional milk. Consumption of milk containing A2 β-casein only is associated with fewer GI symptoms than consumption of conventional milk in lactose maldigesters.

Lactose intolerance is a common but poorly understood cause of gastrointestinal symptoms. Contrary to popular belief, there is much more to its diagnosis beyond symptoms with exposure and management beyond milk- and dairy-product avoidance. In this article, we review definitions, genetic basis, pathogenesis, clinical signs, as well as diagnostic and management strategies., (Copyright © 2020 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.)

Background: Lactose malabsorption (LM) is a major cause of digestive discomfort from dairy products. Recently, a role for bovine β-casein A1 has been proposed., Objectives: We examined whether there are distinct symptoms of digestive discomfort due to either lactose or differing bovine β-casein types., Methods: Women (n = 40; age: 25.2 ± 0.5 y) with self-reported varying dairy tolerance underwent a 50-g lactose challenge. Based on postchallenge LM and digestive discomfort, participants were classified as either lactose intolerant (LI; n = 10, self-reported intolerant, diagnosed lactose intolerant), nonlactose dairy intolerant (NLDI; n = 20, self-reported intolerant, diagnosed lactose tolerant), or dairy tolerant (DT; n = 10, self-reported tolerant, diagnosed lactose tolerant). In a double-blinded randomized sequence, participants consumed 750 mL conventional milk (CON; containing A1 and A2 β-casein and lactose), a2 Milk (A2M; exclusively containing A2 β-casein with lactose), or lactose-free conventional milk (LF-CON; containing A1 and A2 β-casein without lactose). Subjective digestive symptoms and breath hydrogen (measuring LM) were recorded regularly over 3 h, and further ad hoc digestive symptoms over 12 h., Results: LI subjects experienced prolonged digestive discomfort with CON milk. A2M reduced (P < 0.05) some symptoms (nausea: A2M 8 ± 3 mm compared with CON 15 ± 3mm; fecal urgency: A2M 4 ± 1 compared with CON 10 ± 3 mm), and attenuated the rise in breath hydrogen over 3 h, relative to CON milk (A2M 59 ± 23 compared with CON 98 ± 25 ppm at 150 min; P < 0.01). In contrast, NLDI subjects experienced rapid-onset, transient symptoms (abdominal distension, bloating, and flatulence) without increased breath hydrogen, irrespective of milk type., Conclusions: In LI individuals, LM and digestive comfort with lactose-containing milks was improved with milk containing exclusively A2 β-casein. Furthermore, self-reported dairy intolerance without LM (NLDI) is characterized by early-onset digestive discomfort following milk ingestion, irrespective of lactose content or β-casein type. This trial was registered at www.anzctr.org.au as ACTRN12616001694404., (Copyright © The Author(s) 2019.)

Postmenopausal osteoporosis is a significant cause of morbidity and mortality. The role of primary lactase deficiency (PLD) in its development is not clear. This meta-analysis showed that PLD is a risk factor for osteoporosis in postmenopausal women. These women need special attention in terms of screening for osteoporosis and its prevention., Introduction: Postmenopausal osteoporosis is an important predictor of bone fractures. The purpose of the study was to conduct a systematic review and meta-analysis of association of PLD and bone mineral density (BMD) in postmenopausal women., Methods: The electronic databases PubMed, Scopus, and Web of Science were searched over the course of July 2017 for any date of publication without language limitation. Studies were included in the meta-analysis if the diagnosis of PLD was made by genetic testing or H-2 breath tests and the diagnosis of osteoporosis was made by a modern reliable method for BMD measurement. Two investigators conducted a comprehensive, independent review of all the papers. Five of the studies initially identified met the inclusion criteria. We used MOOSE guidelines for abstracting data and assessing data quality and validity. Meta-analysis was performed using the random effects model., Results: Five case-control studies with 2223 participants and 763 lactase-deficient cases fulfilled the inclusion criteria. Meta-analysis showed a significantly higher bone density Z-score in absorbers (mean difference 0.20, CI (0.14-0.27), P = 0.000), with no significant heterogeneity among the studies. Moreover, the Z-score in the vast majority of the measured sites (femoral head, femoral neck, lumbar spine, radius, and Ward's triangle) was significantly higher in absorbers. There was no significant overall difference in BMD in g/cm 2 between absorbers and non-absorbers, but a significantly higher BMD using g/cm 2 was observed in absorbers in the total hip site., Conclusions: Postmenopausal women with PLD had lower Z-scores at most anatomic sites compared to healthy controls.

Studies on fermentable oligo-, di-, and monosaccharides as well as polyols (FODMAPs) intake in older adults are lacking. This study investigated the relationship between gastrointestinal (GI) symptoms and FODMAPs in aged care residents. The Gastrointestinal Symptom Rating Score questionnaire modified for patients with IBS (GSRS-IBS) was used to identify participants with IBS-like symptoms. Dietary intake was assessed for a subgroup of participants with highest total GSRS-IBS score (symptomatic cases) and age, sex, and level of care matched participants with low total GSRS-IBS score (asymptomatic controls). Seventy-four participants with a mean (SD) age of 86 (6.6) years completed the GSRS-IBS questionnaire and dietary data were collected using food diaries from a subsample of 27 symptomatic and 27 asymptomatic participants. The study found many older adults with functional gut symptoms. There were no differences between the groups for FODMAP intake and no significant relationship was found between FODMAP intake and total GSRS-IBS score. Lactose from milk and milk-based desserts was the biggest FODMAP contributor (16 g/day) and a significant relationship between total FODMAP intake and diarrhoea was found. A larger study sample in future studies is required to better capture symptomatic cases and manipulation of dietary FODMAPs may assist with the management of IBS in the elderly., Competing Interests: The authors declare no conflict of interest. The Department of Gastroenterology, Monash University has published an App on the Monash University Low FODMAP Diet, the proceeds of which partly go to the Department, but not to the individuals. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

Background: Lactase persistence is an autosomal dominant trait commonly distributed in Europe as well as some parts of east Africa and the Arabian Peninsula. Using real-time PCR to detect the -13910C > T variant common in the European population is a reliable analysis although other variants in the probe-binding site may cause errors in analysis. The aim of this study was to determine the prevalence of the variants in a Danish cohort examined for lactose intolerance as well as to improve the real-time PCR analysis for detection of the different variants., Methods: We genotyped 3395 routine samples using real-time PCR for the -13910C > T-variant. All consecutive samples identified as -13910CC were sequenced using Sanger Sequencing. Using the SDS software we examined various quality value settings to improve on the genetic analysis., Results: Using real-time PCR resulted in 100% successful genotyping of the -13910C > T variant. By using a quality value of 99% and sequencing the undetermined samples we improved the ability of the assay to identify variants other than -13910C > T. This resulted in a reduction of the diagnostic error rate by a factor of 2.4 while increasing the expenses only 3%., Conclusions: We conclude that using a quality value of 99% in the SDS software significantly improves the diagnostic efficiency of the real-time PCR assay for detecting variants associated to lactase persistence.

Objectives: Consumption of milk has been declining sharply in recent decades, particularly in developed countries. One of the reasons for this decline is the diagnosis or perception of lactose intolerance. The aim of this study was to investigate average consumption of milk and dairy products in the Campania region of Italy, one of the main producers of dairy products in the country., Methods: Individuals aged 18 to 75 y and living in Campania were invited to answer an online questionnaire regarding their average consumption of milk and dairy products. The questionnaire was posted on the public access hospital site, as well as on several Facebook pages of friends and hospital personnel., Results: The study found that 22.2% (260 of 1173) of responders from Campania do not drink milk, and 18.1% (213 of 1173) drink lactose-free milk, mainly because of gastrointestinal symptoms. The vast majority of the sample population chose to avoid consuming milk without undergoing the breath test for lactose intolerance or consulting a doctor. Women and underweight people drink more lactose-free milk than milk containing lactose. The population sample does not avoid dairy products; rather, they seem to be consumed quite frequently., Conclusion: The data support the need for mandatory implementation of a nutritional campaign to increase understanding regarding, for example, unnecessary avoidance of milk and excessive consumption of cheese., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The proportion of people suffering or reporting to have a hypersensitivity caused by cow's milk consumption is increasing, and even health professionals often face difficulties into elaborating properly with a milk reaction due to misdiagnosis. The scope of this review is to present literature data that lead into putting the border line between cow's milk allergy and cow's milk intolerance, mainly focusing on how the different pathophysiology leads to their different dietary diagnosis and management.

We surveyed 910 athletes to assess behaviours towards self-selected food/ingredient avoidance to minimize gastrointestinal distress. Fifty-five percent eliminated at least 1 high fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) food/category, with up to 82.6% reporting symptom improvement. In athletes indicating that high FODMAP foods trigger gastrointestinal symptoms, lactose (86.5%) was most frequently eliminated, followed by galactooligosaccharides (23.9%), fructose (23.0%), fructans (6.2%), and polyols (5.4%). Athletes avoid predominantly lactose and to a lesser extent other high FODMAP foods to reduce gastrointestinal distress.

This study was designed to see the prevalence of lactose intolerance and symptom correlation following oral lactose challenge in healthy volunteers in the north east part of Bangladesh. Symptoms of abdominal pain, nausea, borborygmi, flatulence, diarrhea and others were noted for 24 hours and blood glucose was estimated at 0 hour and 30 minutes after 50 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., lactose intolerance. Sensitivity and specificity of different symptoms were then found out. A total of 171 volunteers (male 123, female 48) with a mean age 34.08 years participated in this study. Lactose intolerance was found among 82.5% (n=141, M=100, F=41) subjects. Symptoms mostly experience by the lactose malabsorbers were diarrhea 93(66.0%), borborygmi 80(56.7%), abdominal pain 31(22.0%) and flatulence 32(22.7%). LM prevalence was found to increase with increasing number of symptoms up to 3 symptoms. A week positive correlation (r=0.205, P=0.007) was found between the number of symptoms and proportion of subjects having positive lactose tolerance test. Lactose intolerance among healthy adults of North East part of our country is as common as in other Asian countries including China and Malaysia. But LM is higher than that of Europeans and south Indians. Diarrhea and borborygmi were mostly associated with LM.

Whether or not abdominal symptoms occur in subjects with small intestinal lactose malabsorption might depend on differences in colonic fermentation. To evaluate this hypothesis, we collected fecal samples from subjects with lactose malabsorption with abdominal complaints (LM-IT, n = 11) and without abdominal complaints (LM-T, n = 8) and subjects with normal lactose digestion (NLD, n = 15). Lactose malabsorption was diagnosed using a (13)C-lactose breath test. Colonic fermentation was characterized in fecal samples at baseline and after incubation with lactose for 3 h, 6 h and 24 h through a metabolomics approach using gas chromatography-mass spectrometry (GC-MS). Fecal water cytotoxicity was analyzed using a colorimetric assay. Fecal water cytotoxicity was not different between the three groups (Kruskall-Wallis p = 0.164). Cluster analysis of the metabolite patterns revealed separate clusters for NLD, LM-T and LM-IT samples at baseline and after 24 h incubation with lactose. Levels of 5-methyl-2-furancarboxaldehyde were significantly higher in LM-IT and LM-T compared to NLD whereas those of an unidentified aldehyde were significantly higher in LM-IT compared to LM-T and NLD. Incubation with lactose increased short chain fatty acid (SCFA) concentrations more in LM-IT and LM-T compared to NLD. In conclusion, fermentation patterns were clearly different in NLD, LM-IT and LM-T, but not related to differences in fecal water cytotoxicity.

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

True lactose intolerance (symptoms stemming from lactose malabsorption) is less common than is widely perceived, and should be viewed as just one potential cause of cows' milk intolerance. There is increasing evidence that A1 beta-casein, a protein produced by a major proportion of European-origin cattle but not purebred Asian or African cattle, is also associated with cows' milk intolerance. In humans, digestion of bovine A1 beta-casein, but not the alternative A2 beta-casein, releases beta-casomorphin-7, which activates μ-opioid receptors expressed throughout the gastrointestinal tract and body. Studies in rodents show that milk containing A1 beta-casein significantly increases gastrointestinal transit time, production of dipeptidyl peptidase-4 and the inflammatory marker myeloperoxidase compared with milk containing A2 beta-casein. Co-administration of the opioid receptor antagonist naloxone blocks the myeloperoxidase and gastrointestinal motility effects, indicating opioid signaling pathway involvement. In humans, a double-blind, randomized cross-over study showed that participants consuming A1 beta-casein type cows' milk experienced statistically significantly higher Bristol stool values compared with those receiving A2 beta-casein milk. Additionally, a statistically significant positive association between abdominal pain and stool consistency was observed when participants consumed the A1 but not the A2 diet. Further studies of the role of A1 beta-casein in milk intolerance are needed.

Background and Aim: It has been reported that small intestinal bacterial overgrowth (SIBO) may lead to false positive diagnoses of lactose malabsorption (LM) in irritable bowel syndrome patients. The aim of this study was to determine the influence of SIBO on lactose hydrogen breath test (HBT) results in these patients., Methods: Diarrhea-predominant irritable bowel syndrome patients with abnormal lactose HBTs ingested a test meal containing (99m) Tc and lactose. The location of the test meal and the breath levels of hydrogen were recorded simultaneously by scintigraphic scanning and lactose HBT, respectively. The increase in hydrogen concentration was not considered to be caused by SIBO if ≥ 10% of (99m) Tc accumulated in the cecal region at the time or before of abnormal lactose HBT., Results: LM was present in 84% (31/37) of irritable bowel syndrome patients. Twenty of these patients agreed to measurement of oro-cecal transit time. Only three patients (15%) with abnormal lactose HBT might have had SIBO. The median oro-cecal transit time between LM and lactose intolerance patients were 75 min and 45 min, respectively (Z=2.545, P=0.011)., Conclusions: Most of irritable bowel syndrome patients with an abnormal lactose HBT had LM. SIBO had little impact on the interpretation of lactose HBTs. The patients with lactose intolerance had faster small intestinal transit than LM patients., (© 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.)

Fibromyalgia syndrome is characterized by chronic generalized pain accompanied by a broad symptomatologic spectrum. Besides chronic fatigue, sleep disturbances, headaches and cognitive dysfunction that are extensively described in the literature, a considerable proportion of patients with fibromyalgia experience gastrointestinal symptoms that are commonly overlooked in the studies that are not specifically dedicated to evaluate these manifestations. Nevertheless, various attempts were undertaken to explore the gastrointestinal dimension of fibromyalgia. Several studies have demonstrated an elevated comorbidity of irritable bowel syndrome (IBS) among patients with fibromyalgia. Other studies have investigated the frequency of presentation of gastrointestinal symptoms in fibromyalgia in a nonspecific approach describing several gastrointestinal complaints frequently reported by these patients such as abdominal pain, dyspepsia and bowel changes, among others. Several underlying mechanisms that require further investigation could serve as potential explanatory hypotheses for the appearance of such manifestations. These include sensitivity to dietary constituents such as gluten, lactose or FODMAPs or alterations in the brain-gut axis as a result of small intestinal bacterial overgrowth or subclinical enteric infections such as giardiasis. The gastrointestinal component of fibromyalgia constitutes a relevant element of the multidisciplinary pathophysiologic mechanisms underlying fibromyalgia that need to be unveiled, as this would contribute to the adequate designation of relevant treatment alternatives corresponding to these manifestations.

The concept of lactose intolerance has become embedded in Western medicine and developing economy medicine. It is based on evidence that intestinal lactase activity persists into later childhood and throughout life in only a minority of the world's population, notably northern European-derived populations. These people have the T single nucleotide polymorphism (SNP) of the rs49882359 allele (C/T), also known as C/T-13910, the MCM6 gene which positively influences the lactase LCT gene. Other lactase persistent (LP) populations are found in Africa and the Middle East with different genetic variants. These SNPs represent co-evolution with dairying since the agricultural revolution and nutrient-dependent ecological adaptation. That said, gastrointestinal symptoms considered due to small intestinal lactose malabsorption are poorly correlated with lactase non-persistence (LNP), the situation for most people. With LNP, colonic microbiome lactase enables lactose fermentation to occur so that none is found in faeces. Whether the short chain fatty acids (SCFAs) and gases (hydrogen, carbon dioxide and methane) produced cause symptoms is dose-dependent. Up to 25 g of lactose at any one time can usually be consumed by a LNP person, but its food and meal pattern context, the microbiomic characteristics, age and other factors may alter tolerance. Thus, the notion that lactose intolerance is a disorder or disease of LNP people is misplaced and has been one of cultural perspective. What actually matters is whether a particular dairy product as normally consumed give rise to symptoms. It is, therefore, proposed that lactose tolerance tests be replaced with dairy food tolerance tests.

Emerging evidence suggests an association between food sensitivity and gut microbiota in children with nephrotic syndrome. Diminished proteinuria resulted from eliminating cow's milk and the use of an oligoantigenic diet which excluded gluten, especially in patients with immune-related conditions, i.e., celiac disease and nephrotic syndrome. The mechanisms underlying the association of diet, gut microbiota, and dysregulation of the immune system are unknown. Gut microbiota is influenced by a number of factors including diet composition and other environmental epigenetic exposures. The imbalance in gut microbiota may be ameliorated by gluten-free and dairy-free diets. Gluten-free diet increased the number of unhealthy bacteria while reducing bacterial-induced cytokine production of IL-10. Thus, gluten-free diet may influence the composition and immune function of gut microbiota and should be considered a possible environmental factor associated with immune-related disease, including nephrotic syndrome. Furthermore, the imbalance of gut microbiota may be related to the development of cow's milk protein allergy. Investigations are needed to fill the gaps in our knowledge concerning the associations between the gut microbiome, environmental exposures, epigenetics, racial influences, and the propensity for immune dysregulation with its inherent risk to the developing individual.

Thus, we have discovered that the children of the first half-year of life have different degrees of severity of transient lactase insufficiency basing on the results of hydrogen respiratory test. It was set that the starting dose of enzyme lactase must depend on the degree of severity of displays of transient lactase insufficiency, taking into account the indexes of hydrogen respiratory test.

"Lactose intolerance (LI)" is considered a common problem in Asians, and in many parts of the world. Its prevalence and age of manifestation varies between by Asian country, for possible genetic or cultural reasons. Studies in Indonesian children 3-15 years old (y) are available within the past two decades, using a pure lactose tolerance test. The prevalences of lactose malabsorption (LM) in pre-elementary (3-5 y), elementary (6-11 y), and junior high (12-14 y) school-children were 21.3%, 57.8%, and 73%, respectively. An increasing trend for LM prevalence was seen within the pre-elementary group, from 9.1% at 3 y to 28.6% at 5 y. The most frequent symptoms of LI in junior high school (JHS) group were abdominal pain (64.1%), abdominal distention (22.6%), nausea (15.1%), flatulence (5.7%), and diarrhea (1.9%), mostly within one hour of lactose ingestion. In children with regular and irregular milk drinking, LM occurred in 81.2% and 69.6%; LI was found in 56.2% and 52.1%, respectively. Most JHS children with dairy-associated recurrent abdominal pain (RAP) symptoms proved to be malabsorbers. Dairy products most related to RAP were milk and yogurt. LI was found in 81% of RAP children with abdominal pain most frequently, followed by nausea, bloating, diarrhea, borborygmi, and flatulence. Symp-tom onset occurred 30 minutes after lactose ingestion, especially nausea, bloating, and abdominal pain. In RAP children LI symptoms mostly found in breath hydrogen concentration>20 ppm. More LI symptoms were found in lactose malabsorbers, but symptoms were mild and generally disappeared in 7 hours, and in most by 15 hours.

Objective: To determine attitudes, beliefs, and barriers related to adequate milk consumption in low-income women ages ≥ 60 years., Methods: Nine focus groups were conducted with a convenience sample of 59 women at congregate meal sites in a metropolitan area. Grounded in Social Cognitive Theory, focus group questions were used to explore personal, behavioral, and environmental factors associated with milk consumption., Results: Key response themes indicated a positive attitude for the taste of milk (except for low-fat), a primary belief that milk was important for bones and health, and a primary barrier of gastrointestinal side effects., Conclusions and Implications: Knowledge regarding the benefits of milk and the dislike of its taste were not the primary reason for the lack of consumption. Instead, gastrointestinal side effects seemed to be the major barrier to adequate consumption. Future nutrition campaigns should test strategies for lactose intolerance management when communicating with low-income older women., (Copyright © 2014 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.)

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

Background: Lactose intolerance (LI) is a common medical problem with limited treatment options. The primary symptoms are abdominal pain, diarrhea, bloating, flatulence, and cramping. Limiting dairy foods to reduce symptoms contributes to low calcium intake and the risk for chronic disease. Adaptation of the colon bacteria to effectively metabolize lactose is a novel and potentially useful approach to improve lactose digestion and tolerance. RP-G28 is novel galacto-oligosaccharide (GOS) being investigated to improve lactose digestion and the symptoms of lactose intolerance in affected patients., Methods: A randomized, double-blind, parallel group, placebo-controlled study was conducted at 2 sites in the United States. RP-G28 or placebo was administered to 85 patients with LI for 35 days. Post-treatment, subjects reintroduced dairy into their daily diets and were followed for 30 additional days to evaluate lactose digestion as measured by hydrogen production and symptom improvements via a patient-reported symptom assessment instrument., Results: Lactose digestion and symptoms of LI trended toward improvement on RP-G28 at the end of treatment and 30 days post-treatment. A reduction in abdominal pain was also demonstrated in the study results. Fifty percent of RP-G28 subjects with abdominal pain at baseline reported no abdominal pain at the end of treatment and 30 days post treatment (p = 0.0190). RP-G28 subjects were also six times more likely to claim lactose tolerance post-treatment once dairy foods had been re-introduced into their diets (p = 0.0389)., Conclusions: Efficacy trends and favorable safety/tolerability findings suggest that RP-G28 appears to be a potentially useful approach for improving lactose digestion and LI symptoms. The concurrent reduction in abdominal pain and improved overall tolerance could be a meaningful benefit to lactose intolerant individuals.

Background: The health consequences of lactose intolerance (LI) are unclear., Aims: To investigate the effects of LI on stature and vitamin D status., Hypotheses: LI subjects will have similar heights and vitamin D status as controls., Subjects and Methods: Prepubertal children of ages 3-12 years with LI (n=38, age 8.61 ± 3.08y, male/female 19/19) were compared to healthy, age- and gender-matched controls (n=49, age 7.95±2.64, male/female 28/21)., Inclusion Criteria: prepubertal status (boys: testicular volume <3cc; girls: Tanner 1 breasts), diagnosis of LI by hydrogen breath test, and no history of calcium or vitamin D supplementation. Vitamin D deficiency was defined as 25-hydroxyvitamin D [25(OH)D] <50 nmol/L. Gender-adjusted midparental target height (MPTH) z-score was calculated using NCHS data for 18 year-old adults. Data were expressed as mean ± SD., Results: There was no significant difference in 25(OH)D between the LI and non-LI subjects (60.1±21.1, vs. 65.4 ± 26.1 nmol/L, p = 0.29). Upon stratification into normal weight (BMI <85(th) percentile) vs. overweight/obese (BMI ≥85(th) percentile), the normal weight controls had significantly higher 25(OH)D level than both the normal weight LI children (78.3 ± 32.6 vs. 62.9 ± 23.2, p = 0.025), and the overweight/obese LI children (78.3±32.6 vs. 55.3±16.5, p = 0.004). Secondly, there was no overall difference in height z-score between the LI children and controls. The normal weight LI patients had similar height as normal controls (-0.46 ± 0.89 vs. -0.71 ± 1.67, p = 0.53), while the overweight/obese LI group was taller than the normal weight controls (0.36 ± 1.41 vs. -0.71 ± 1.67, p = 0.049), and of similar height as the overweight/obese controls (0.36 ± 1.41 vs. 0.87 ± 1.45, p = 0.28). MPTH z-score was similar between the groups., Conclusion: Short stature and vitamin D deficiency are not features of LI in prepubertal children.

Objectives: Bloating and distention are often attributed to dietary factors by patients with irritable bowel syndrome (IBS). This study examined the effects of gas production and visceral hypersensitivity on digestive symptoms after lactose ingestion in a population with lactase deficiency., Methods: IBS patients (n=277) and healthy controls (HCs, n=64) underwent a 20-g lactose hydrogen breath test (LHBT) with evaluation of hydrogen gas production and lactose intolerance (LI) symptoms. Abdominal distention (199 IBS, 40 HCs) was measured during LHBT. Rectal sensitivity (74 IBS, 64 HCs) was assessed by barostat studies., Results: Hydrogen production and distention were similar in IBS patients and HCs during LHBT; however, LI was more frequent in IBS (53.8 vs. 28.1%, P<0.001), especially bloating (39.0% vs. 14.1%, P<0.001) and borborygmi (39.0 vs. 21.9%, P=0.010). Only 59.0% of patients with bloating had distention. No correlation was observed between girth increment and bloating (P=0.585). IBS patients had lower rectal sensory thresholds (P=0.001). Multivariate analysis indicated that hydrogen production increased bloating (odds ratio (OR) 2.19, 95% confidence interval (CI) 1.09-4.39, P=0.028) and borborygmi (OR 12.37, 95% CI 3.34-45.83, P<0.001) but not distention (P=0.673). Visceral hypersensitivity was associated with bloating (OR 6.61, 95% CI 1.75-25.00, P=0.005) and total symptom score (OR 3.78, 95% CI 1.30-10.99, P=0.014)., Conclusions: Gas production and visceral hypersensitivity both contribute to digestive symptoms, especially bloating and borborygmi, in IBS patients after lactose ingestion. Objective abdominal distention is not correlated with subjective bloating.

Approximately 70% of the world's population is lactase deficient. This article reviews the evolutionary history of lactase deficiency, recent recommendations to establish screening, and clinical practice guidelines for increased diagnosis of this important, yet often misunderstood condition of malabsorption.

Background: symptoms attributed to the lactose intolerance are an important public health issue because of their prevalence and social relevance. Also because they may cause undue rejection of dairy products consume with potential health consequences. Transit time is a putative factor implied in the severity of symptoms associated with lactose., Objectives: to elucidate the relation between orocecal transit time (OCTT) and lactose intolerance symptoms., Methods: observational study in patients referred to a lactose hydrogen breath test who showed an increase in breath H2 excretion higher than 25 ppm. OCTT was measured with the breath test and symptoms of lactose tolerance with a validated scale. Symptoms were measured twice: before receiving the lactose, inquiring about self perceived symptoms when patients consumed dairy products at home ("home symptoms"), and again after completing the lactose breath test ("test symptoms")., Results: 161 patients were included. There was no correlation between OCTT and home symptoms (r = -0.1). When OCTT was faster than 60 minutes, intensity of "test symptoms" was similar to "home symptoms". However, in patients with normal or slow OCTT, the "home symptoms" were more intense than the "test symptoms" (p < 0.05). At home, symptoms were independent of OCTT but with the lactose test load the symptoms were proportionately more intense with faster OCTT., Conclusions: in lactose maldigesters, selfreported symptoms of lactose intolerance are more pronounced at home than after a high lactose challenge. Intolerance symptoms that patients attributed to lactose consume at home are due to factors other than fast OCTT.

Carbohydrate malabsorption such as in lactose intolerance or enteric infection causes symptoms that include abdominal pain. Because this digestive disorder increases intracolonic osmolarity and acidity by accumulation of undigested carbohydrates and fermented products, we tested whether these two factors (hypertonicity and acidity) would modulate colorectal afferents in association with colorectal nociception and hypersensitivity. In mouse colorectum-pelvic nerve preparations in vitro, afferent activities were monitored after application of acidic hypertonic saline (AHS; pH 6.0, 800 mosM). In other experiments, AHS was instilled intracolonically to mice and behavioral responses to colorectal distension (CRD) measured. Application of AHS in vitro excited 80% of serosal and 42% of mechanically-insensitive colorectal afferents (MIAs), sensitizing a proportion of MIAs to become mechanically sensitive and reversibly inhibiting stretch-sensitive afferents. Acute intracolonic AHS significantly increased expression of the neuronal activation marker pERK in colon sensory neurons and augmented noxious CRD-induced behavioral responses. After three consecutive daily intracolonic AHS treatments, mice were hypersensitive to CRD 4-15 days after the first treatment. In complementary single fiber recordings in vitro, the proportion of serosal class afferents increased at day 4; the proportion of MIAs decreased, and muscular class stretch-sensitive afferents were sensitized at days 11-15 in mice receiving AHS. These results indicate that luminal hypertonicity and acidity, two outcomes of carbohydrate malabsorption, can induce colorectal hypersensitivity to distension by altering the excitability and relative proportions of colorectal afferents, suggesting the potential involvement of these factors in the development of abdominal pain.

Background: The role of small intestinal bacterial overgrowth (SIBO) in functional digestive disorders in the pediatric population is a matter of controversy, since methods currently used to establish this diagnosis are difficult to interpret. The aim of this work was to analyze the characteristics of the lactulose H(2) breath test (LHBT) in children with functional gastrointestinal symptoms according to more recent criteria., Methods: Seventy-two patients and 17 controls were enrolled. A questionnaire was administered regarding digestive symptoms (abdominal pain, bloating, vomiting, and bowel-movement disorders). A lactose hydrogen breath test was performed to rule out lactose malabsorption and a LHBT was used to measure the time elapsed between lactulose oral ingestion and an increment of H(2) concentration of 20 ppm over basal., Results: There were no differences of age and gender between patients and controls. Mean time to 20-ppm change was shorter in patients (56.3 ± 3 min) compared to healthy children (74.7 ± 5 min), p\0.05. In 39% of patients, rise of H(2) occurred during the first 40 min after lactulose ingestion, and in almost all controls, an increment was observed between 50 and 90 min (p\0.05). Symptoms were unrelated to time to 20-ppm change., Conclusions: An abnormal LHBT was found in children with functional symptoms of the digestive tract, but the exact mechanism involved, accelerated intestinal transit or SIBO, needs to be confirmed by an additional method.

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

Discussions and debates have recently emerged on the potential positive and negative effects of cow's milk in the paediatric community, also under the pressure of public opinion. The negative effects of cow's-milk consumption seem to be limited to iron status up to 9 to 12 months; then no negative effects are observed, provided that cow's milk, up to a maximum daily intake of 500 mL, is adequately complemented with iron-enriched foods. Lactose intolerance can be easily managed and up to 250 mL/day of milk can be consumed. Allergy to cow's-milk proteins is usually transient. Atopic children may independently be at risk for poor growth, and the contribution of dairy nutrients to their diet should be considered. The connection of cow's milk to autistic spectrum disorders is lacking, and even a cause-effect relation with type 1 diabetes mellitus has not been established because many factors may concur. Although it is true that cow's milk stimulates insulin-like growth factor-1 and may affect linear growth, association with chronic degenerative, noncommunicable diseases has not been established. Finally, fat-reduced milk, if needed, should be considered after 24 to 36 months. Cow's milk represents a major source of high nutritional quality protein as well as of calcium. Moreover, it has growth-promoting effects independent of specific compounds. Its protein and fat composition, together with the micronutrient content, is suggestive of a functional food, whose positive effects are emphasised by regular consumption, particularly under conditions of diets poor in some limiting nutrients, although in industrialised countries cow's milk's optimal daily intake should be around 500 mL, adequately complemented with other relevant nutrients.

Irritable bowel syndrome is one of several highly prevalent functional gastrointestinal disorders (FGID) displaying symptoms of gastrointestinal dysmotility and visceral hypersensitivity. Substantial overlap of symptoms and comorbidities occur not only between irritable bowel syndrome and other FGID but also with gastrointestinal disorders that are not related to motility (eg, celiac disease and lactose intolerance) and to somatic conditions (eg, fibromyalgia and chronic fatigue syndrome). Pathogenic mechanisms common among FGIDs may include alternations in intestinal and colonic microflora. Evidence is also emerging of an interplay between gut immune cells/activity and alternations in motility, secretion, and sensation. The role of cytokine activity and inflammation is important in this regard. As recommended by Rome III, diagnostic testing should be guided by the patient's age, primary symptom characteristics, and other clinical and laboratory features. The high prevalence of coexisting conditions suggests the need to routinely assess patients for related disorders. Treatment should be based on an individualized evaluation, explanation, and reassurance.

Malabsorption of carbohydrates such as fructose, lactose or sorbitol can often be detected among patients suffering from so-called non specific abdominal complaints. Sometimes the differential diagnosis may be difficult. So far successful treatment consists of dietary interventions only. Nevertheless, many questions are remaining still unanswered., (Copyright © 2011 Arab Journal of Gastroenterology. Published by Elsevier Ltd. All rights reserved.)

Background: Lactose intolerance is a common complication of diarrhoea in infants with malnutrition and a cause of treatment failure. A combination of nutritional injury and infectious insults in severe protein energy malnutrition reduces the capacity of the intestinal mucosa to produce lactase enzyme necessary for the digestion of lactose. The standard management of severe malnutrition involves nutritional rehabilitation with lactose-based high energy formula milk. However, some of these children may be lactose intolerant, possibly contributing to the high rate of unfavorable treatment outcomes. This study was therefore designed to establish the prevalence of lactose intolerance and associated factors in this population., Methods: A descriptive cross sectional study involving 196 severely malnourished children with diarrhoea aged 3-60 months was done in Mwanamugimu Nutrition Unit (MNU), Mulago hospital between October 2006 and February 2007., Results: During the study period, 196 severely malnourished children with diarrhoea were recruited, 50 (25.5%) of whom had evidence of lactose intolerance (stool reducing substance >or= 1 + [0.5%] and stool pH < 5.5) and it occurred more commonly in children with kwashiorkor 27/75 (36.0%) than marasmic-kwashiorkor 6/25 (24.0%) and marasmus 17/96 (17.7%). Oedematous malnutrition (p = 0.032), perianal skin erosion (p = 0.044), high mean stool frequency (p = < 0.001) and having >or=2 diarrhoea episodes in the previous 3 months (p = 0.007) were the independent predictors of lactose intolerance. Other factors that were significantly associated with lactose intolerance on bi-variate analysis included: young age of 3-12 months; lack of up to-date immunization; persistent diarrhoea; vomiting; dehydration, and abdominal distension. Exclusive breastfeeding for less than 4 months and worsening of diarrhoea on initiation of therapeutic milk were the other factors., Conclusions: The prevalence of lactose intolerance in this study setting of 25.5% is relatively high. Routine screening by stool pH and reducing substances should be performed especially in the severely malnourished children with diarrhoea presenting with oedematous malnutrition, perianal skin erosion, higher mean stool frequency and having had >or=2 diarrhoea episodes in the previous 3 months. Use of lactose-free diets such as yoghurt should be considered for children found to have evidence of lactose intolerance and whose response on standard therapeutic milk formula is poor.

The objective of this study was to determine the efficacy of live and killed probiotics to decrease the presence of hydrogen using the breath hydrogen test (BHT). This pretest-posttest control group design single blinded randomized study was performed in 5 government elementary schools in Tuminting subdistrict, Manado, Indonesia from March to May 2008. The study for inclusion as subjects consisted of healthy 10-12 year old children with heights and weights within normal limits using the Centers for Disease Control (CDC) criteria whose BHT was 220 parts per million (ppm), indicating lactose malabsorption. One hundred thirty children were screened, 86 met criteria, 43 children were randomized into two groups. Thirty-nine children who were given live probiotic and 40 children who were given killed probiotic completed the study. There was a significant difference when comparing the BHT results before and 120 minutes after giving probiotic for the children taking both the live and the killed probiotic (p < 0.001). When the children taking the live and killed probiotics were compared, there was no difference in the BHT at 120 minutes of probiotic (p = 0.453) by t-test. The administration of live or killed probiotic for 2 weeks can decrease the results of a BHT in children with lactose malabsorption. No adverse reactions attributable to treatment were noted.

Food, dietary fibre and espresso coffee interfere with the absorption of levothyroxine. Malabsorptive disorders reported to affect the absorption of levothyroxine include coeliac disease, inflammatory bowel disease, lactose intolerance as well as Helicobacter pylori (H. pylori) infection and atrophic gastritis. Many commonly used drugs, such as bile acid sequestrants, ferrous sulphate, sucralfate, calcium carbonate, aluminium-containing antacids, phosphate binders, raloxifene and proton-pump inhibitors, have also been shown to interfere with the absorption of levothyroxine.

Background: The role of carbohydrate maldigestion or malabsorption remains unclear in patients with irritable bowel syndrome (IBS). The purpose of this study was to examine the impact of identifying lactose maldigestion (LM) and fructose malabsorption (FM) on patients with and without IBS., Methods: Patients who received lactose and fructose challenge testing formed the study group. Carbohydrate challenge testing was performed with 50 g lactose and 25 g fructose. Breath samples were collected and analyzed for hydrogen, methane, and CO2 (for correction) using a MicroLyzer Model SC (QuinTron Instrument Company, Milwaukee, WI). Questionnaires were used to assess Rome III IBS criteria, compliance with carbohydrate dietary modifications, and changes in symptoms., Results: One hundred and twenty-one of the 181 (67%) study subjects were able to be contacted 8 months to 4 years after carbohydrate testing. LM (21) and FM (2) were seen in 33% of the 66 IBS subjects. LM (12) and FM (9) were seen in 33% of the 55 subjects without IBS. Seventy-seven percent of IBS and 72% of those without IBS reported compliance with dietary advice. Of the subjects who reported compliance, 47% of IBS and 77% of those without IBS reported that, after identifying LM or FM, their symptoms resolved or improved., Conclusions: Carbohydrate maldigestion has a similar incidence in patients with and without IBS and both populations have similar compliance with therapeutic diets. However, patients without IBS are more likely to have improvement in symptoms when dietary changes are instituted when compared to IBS patients.

This review summarizes what is known about the effect of diet on irritable bowel syndrome (IBS) symptoms emphasizing data from randomized, controlled clinical trials. Studies suggest that IBS symptoms in one quarter of patients may be caused or exacerbated by one or more dietary components. Recent studies indicate that a diet restricted in fermentable, poorly absorbed carbohydrates, including fructose, fructans (present in wheat and onions), sorbitol, and other sugar alcohols is beneficial, but confirmatory studies are needed. Despite a long history of enthusiastic use, fiber is marginally beneficial. Insoluble fiber may worsen symptoms. Some patients with IBS, especially those with constipation, will improve with increased intake of soluble fiber. Prebiotic fibers have not been adequately tested. Daily use of peppermint oil is effective in relieving IBS symptoms. The usefulness of probiotics in the form of foods such as live-culture yogurt and buttermilk for IBS symptoms is not established. In clinical practice, it is very difficult to establish that a patient's symptoms result from an adverse reaction to food. A double blind placebo-controlled food challenge is the most reliable method, but it is not suitable for routine clinical use. A modified exclusion diet and stepwise reintroduction of foods or trials of eliminating classes of food may be useful.

Aim: To estimate the prevalence of the lactase non-persistent genotype (C/C-13910) in a northern Russian population in accordance with ethnicity, and to evaluate self-reported milk consumption depending on lactase activity., Methods: Blood samples for genotyping lactase activity, defining the C/T-13910 variant by polymerase chain reaction, and direct sequencing were taken from 231 medical students of Russian origin aged 17-26 years. We analyzed milk product consumption by questionnaire which was specially designed for the estimation of milk consumption and abdominal complaints., Results: We found that the prevalence of the C/C-13190 genotype in the northern Russian population was 35.6%. The other genotypes nearby C/T-13910 and associated with lactase activity were not present in the study population. The consumption of milk among people with the non-persistent genotype tended to be lower than among the lactose tolerant subjects, but was not statistically significant., Conclusion: An investigation of the lactase persistent genotype in a northern Russian population has not been performed before. The genotype did not affect the consumption of milk products in this population which could be explained by low consumption of milk products among the entire study population.

Summary: LCT 13910 CC genotype is associated with lactose intolerance, a condition often resulting in reduced milk intake. Women with the CC genotype were found to have decreased serum calcium and reduced bone mineral density., Introduction: The CC genotype of the 13910 C/T polymorphism of the LCT gene is linked to lactose intolerance and low calcium intake., Methods: We studied 595 postmenopausal women, including 267 osteoporotic, 200 osteopenic, and 128 healthy subjects. Genotyping, osteodensitometry, and laboratory measurements were carried out., Results: Frequency of aversion to milk consumption was 20% for CC genotype and 10% for TT + TC genotypes (p = 0.03). The albumin-adjusted serum calcium was 2.325 +/- 0.09 mmol/L for CC genotype and 2.360 +/- 0.16 mmol/L for TT + TC genotypes (p = 0.031). Bone mineral density (BMD; Z score) was lower in the CC than TT + TC genotypes, respectively, at the radius (0.105 +/- 1.42 vs 0.406 +/- 1.32; p = 0.038), at the total hip (-0.471 +/- 1.08 vs -0.170 +/- 1.09; p = 0.041), and at the Ward's triangle (-0.334 +/- 0.87 vs -0.123 +/- 0.82; p = 0.044)., Conclusion: LCT 13910 C/T polymorphism is associated with decreased serum calcium level and lower BMD in postmenopausal women.

Summary: Low calcium intake hampers bone mineral acquisition in adolescent girls. This study explores dietary calcium sources and nutrients possibly associated with vertebral mass. Milk intake is not influenced by genetic variants of the lactase gene and is positively associated with serum IGF-1 and with lumbar vertebrae mineral content and density., Introduction: Low calcium intake hampers bone mineral acquisition during adolescence. We identified calcium sources and nutrients possibly associated with lumbar bone mineralization and calcium metabolism in adolescent girls and evaluated the possible influence of a genetic polymorphic trait associated with adult-type hypolactasia., Methods: Lumbar bone mineral content (BMC), bone mineral density (BMD), and area, circulating IGF-1, markers of bone metabolism, and -13910 LCT (lactase gene) polymorphism; and intakes of milk, dairy products, calcium, phosphorus, magnesium, proteins, and energy were evaluated in 192 healthy adolescent girls., Results: After menarche, BMC, BMD, serum IGF-1, and serum PTH were tightly associated with milk consumption, but not with other calcium sources. All four parameters were also associated with phosphorus, magnesium, protein, and energy from milk, but not from other sources. Girls with milk intakes below 55 mL/day have significantly lower BMD, BMC, and IGF-1 and higher PTH compared to girls consuming over 260 mL/day. Neither BMC, BMD, calcium intakes, nor milk consumption were associated with -13910 LCT polymorphism., Conclusions: Milk consumption, preferably to other calcium sources, is associated with lumbar BMC and BMD in postmenarcheal girls. Aside from being a major source of calcium, milk provides phosphates, magnesium, proteins, and as yet unidentified nutrients likely to favor bone health.

Lactose malabsorption is a very common condition characterized by intestinal lactase deficiency. Primary lactose malabsorption is an inherited deficit present in the majority of the world's population, while secondary bypolactasia can be the consequence of an intestinal disease. The presence of malabsorbed lactose in the colonic lumen may cause gastrointestinal symptoms. This condition is known as lactose intolerance. Lactase non-persistence is the ancestral state, whilst two single nucleotide polymorphisms in the lactase gene have been associated with lactase persistence. These are C/T 13910 and G/A 22018 substitutions. Lactase persistence, this Mendelian dominant trait, only became advantageous after the invention of agriculture, when milk from domesticated animals became available for adults to drink. Lactase persistence is then strongly correlated with the diary history of the population. Diagnosis is assessed clinically by elimination of dietary lactose or, better, by non-invasive tests including hydrogen breath test and genetic test. In patients with lactase non-persistence, treatment should be considered exclusively if intolerance symptoms are present. In the absence of guidelines, the common therapeutic approach tends to exclude milk and dairy products from the diet. However, this strategy may have serious nutritional disadvantages. Several studies have been carried out to find alternative approaches, such as exogenous beta-galactosidase, yogurt and probiotics for their bacterial lactase activity, strategies that can prolong contact time between enzyme and substrate delaying gastrointestinal transit time, and chronic lactose ingestion to enhance colonic adaptation.

Background: A lactose-free diet is commonly prescribed to subjects with hypolactasia. We tested the effectiveness of a single ingestion of tilactase (a beta-D-galactosidase from Aspergillus oryzae) in adults with hypolactasia, previously assessed by lactose H(2)-breath test., Materials and Methods: After measurement of orocecal transit time (OCTT, by lactulose H(2)-breath test) and lactose H(2)-breath testing plus placebo, a total of 134 subjects were positive to hypolactasia and underwent lactose H(2)-breath testing plus either low (6750 U) or standard (11,250 U) doses of tilactase. The appearance of gastrointestinal symptoms during the tests was monitored., Results: OCTT was longer in malabsorbers (subjects without bloating, abdominal pain and/or diarrhoea, n = 25) than in intolerants (bloating, abdominal pain and/or diarrhoea, n = 109, P < 0.02). Malabsorbers had longer time to H(2) peak (P < 0.03), lower H(2) peak levels (P < 0.002) and smaller integrated H(2) excretion levels (P < 0.005) than intolerants. After tilactase ingestion, integrated H(2) levels were decreased by 75% (low dose) and 87% (standard dose) in malabsorbers, and by 74% (low dose) and 88% (standard dose) in intolerants. In the latter group, total symptom score were decreased by 76% (low dose) and by 88% (standard dose) (P < 0.0001)., Conclusion: A single oral administration of tilactase is highly effective in decreasing symptoms and hydrogen excretion of hypolactasia assessed by lactose H(2)-breath test. If confirmed by long-term observations, ingestion of tilactase might be a better option than exclusion diets in intolerant subjects with hypolactasia.

Background: Despite the reported tolerance to a low dose of lactose, many lactose malabsorbers follow a rigorous lactose-free diet also avoiding lactose-containing drugs. Up to now, only a few case reports have described the onset of gastrointestinal symptoms in lactose malabsorbers following the ingestion of these drugs. It has been suggested that capsules/tablets contain no more than 400 mg of lactose., Aim: To evaluate breath H(2) excretion and intolerance symptoms after ingestion of a capsule containing 400 mg of lactose or placebo through a randomized, cross-over, double-blind, controlled study., Methods: Seventy-seven lactose maldigesters with intolerance underwent two H2 breath tests with both 400 mg of lactose and 400 mg of placebo. Gastrointestinal symptoms occurring in the 8 h following the ingestion of different substrates were evaluated by a visual-analogue scale., Results: Ingestion of 400 mg of lactose did not cause a significant difference in breath H2 excretion or in the severity of gastrointestinal symptoms compared to placebo., Conclusion: In patients with lactase deficiency, drugs containing 400 mg of lactose or less can be used safely.

Essential fatty acid (EFA) deficiency in mice induces fat malabsorption. We previously reported indications that the underlying mechanism is located at the level of the intestinal mucosa. We have investigated the effects of EFA deficiency on small intestinal morphology and function. Mice were fed an EFA-deficient or control diet for 8 wk. A 72-h fat balance, the EFA status, and small intestinal histology were determined. Carbohydrate absorptive and digestive capacities were assessed by stable isotope methodology after administration of [U-(13)C]glucose and [1-(13)C]lactose. The mRNA expression and enzyme activity of lactase, and concentrations of the EFA linoleic acid (LA) were measured in small intestinal mucosa. Mice fed the EFA-deficient diet were markedly EFA-deficient with a profound fat malabsorption. EFA deficiency did not affect the histology or proliferative capacity of the small intestine. Blood [13C6]glucose appearance and disappearance were similar in both groups, indicating unaffected monosaccharide absorption. In contrast, blood appearance of [13C]glucose, originating from [1-(13)C]lactose, was delayed in EFA-deficient mice. EFA deficiency profoundly reduced lactase activity (-58%, P<0.01) and mRNA expression (-55%, P<0.01) in mid-small intestine. Both lactase activity and its mRNA expression strongly correlated with mucosal LA concentrations (r=0.77 and 0.79, respectively, P<0.01). EFA deficiency in mice inhibits the capacity to digest lactose but does not affect small intestinal histology. These data underscore the observation that EFA deficiency functionally impairs the small intestine, which in part may be mediated by low LA levels in the enterocytes.

Background & Aims: The contribution of lactase to isoflavone bioavailability has not been clarified. We evaluated the association between lactase activity and the bioavailability of isoflavone glucosides in Japanese adults., Methods: Twenty-six Japanese adult participants completed a study that included tests of breath hydrogen after a lactose load, orocecal transit time, and isoflavone glucoside absorption. Lactose malabsorbers were defined as those with an increase in breath hydrogen level (DeltaH(2)) of more than 20 ppm after a load of lactose (20 g). Participants ingested 200 ml soymilk, and serum isoflavones were analyzed until 480 min., Results: Serum daidzein and genistein levels increased rapidly until 60 min, then slowly increased. The increases of serum isoflavones in the early phase, but not the later phase, were suppressed in lactose malabsorbers. DeltaH(2 max) after a load of lactose inversely correlated with serum daidzein levels at 30 min. The percentage of equol producers tended to be greater among lactose malabsorbers (P=0.067)., Conclusions: Lactase may be involved in absorption of isoflavone glucosides in the small intestine, but the bacterial deglycosylation in the large intestine compensates the reduction of isoflavone absorption. The beneficial effect of isoflavones may not be impaired by low lactase activity.

Dairy foods (DFs) contain complex ingredients that could affect different diseases. The control of lactose digestion phenotypically divides populations into those who can [lactase persistent (LP)] and those who cannot [lactase nonpersistent (LNP)] assimilate lactose. LNP subjects, however, can adapt to lactose intolerance through intestinal bacteria. The DF/LNP status interactions may function as disease risk modifiers. We evaluated the relationship between DF and LNP with colorectal, breast, prostate, ovarian, lung, and stomach cancer and inflammatory bowel diseases (IBD; Crohn's disease and ulcerative colitis). Yearly per capita DF consumption, LNP national prevalence, cancer mortality, and incidence of IBD were obtained from several sources. A negative binomial regression model was used to derive incremental risks. There were statistically significant (P

Lactose malabsorption is not always associated with intolerance symptoms. The factors responsible for symptom onset are not yet completely known. As differences in visceral sensitivity may play a role in the pathogenesis of functional symptoms, we evaluated whether an alteration of visceral sensitivity is present in subjects with lactose intolerance. Thirty subjects, recruited regardless of whether they were aware of their capacity to absorb lactose, underwent an evaluation of intestinal hydrogen production capacity by lactulose breath test, followed by an evaluation of lactose absorption by hydrogen breath test after lactose administration and subsequently an evaluation of recto-sigmoid sensitivity threshold during fasting and after lactulose administration, to ascertain whether fermentation modifies intestinal sensitivity. The role of differences in gastrointestinal transit was excluded by gastric emptying and mouth-to-caecum transit time by (13)C-octanoic and lactulose breath tests. Lactulose administration induced a significant reduction of discomfort threshold in subjects with lactose intolerance but not in malabsorbers without intolerance symptoms or in subjects with normal lactose absorption. Perception threshold showed no changes after lactulose administration. Severity of symptoms in intolerant subjects was significantly correlated with the reduction of discomfort thresholds. Visceral hypersensitivity should be considered in the induction of intolerance symptoms in subjects with lactose malabsorption.