Self-reported Lactose Intolerance Research Articles

Lactose Intolerance and Health Disparities Among African Americans and Hispanic Americans: An Updated Consensus Statement

AbstractDairy foods contribute nine essential nutrients to the diet including calcium. potassium and vitamin D; nutrients identified by the 2010 Dietary Guidelines for Americans as being "of public health concern" within the U.S. population. Milk and milk product intake is associated with better diet quality and has been associated with a reduced risk of chronic diseases or conditions including hypertension, cardiovascular disease, metabolic syndrome, Type 2 Diabetes and osteoporosis. Some research also indicates dairy food intake may be linked to reduced body fat. when accompanied by energy-restriction. On average, both African Americans and Hispanic Americans consume less than the recommended levels of dairy foods, and perceived or actual lactose intolerance can be a primary reason for limiting or avoiding dairy intake. True lactose intolerance prevalence is not known because healthcare providers do not routinely measure for it, and no standardized assessment method exists. Avoiding dairy may lead to shortfalls of essential nutrients and increased susceptibility to chronic disease. This updated Consensus Statement aims to provide the most current information about lactose intolerance and health, with specific relevance to the African American and Hispanic American communities. Topics covered include diagnostic considerations, actual and recommended dairy food intake and levels of consumption of key dairy nutrients among African Americans and Hispanic Americans; prevalence of self-reported lactose intolerance among various racial/ethnic groups; the association between dairy food intake, lactose intolerance and chronic disease; and research-based management recommendations for those with lactose intolerance. Publication IndicesPubmed.

Prevalence and Presentation of Lactose Intolerance and Effects on Dairy Product Intake in Healthy Subjects and Patients With Irritable Bowel Syndrome

The effects of lactase deficiency on digestive symptoms and diet in patients with irritable bowel syndrome (IBS) have not been well defined. We assessed lactose absorption and tolerance and the intake of dairy products in healthy volunteers (controls) and patients with diarrhea-predominant IBS (D-IBS). Sixty patients diagnosed with D-IBS at the Sir Run Run Shaw Hospital, Hangzhou, China and 60 controls were given hydrogen breath tests to detect malabsorption and intolerance after administration of 10, 20, and 40 g lactose in random order 7-14 days apart; participants and researchers were blinded to the dose. We assessed associations between the results and self-reported lactose intolerance (LI). Malabsorption of 40 g lactose was observed in 93% of controls and 92% of patients with D-IBS. Fewer controls than patients with D-IBS were intolerant to 10 g lactose (3% vs 18%; odds ratio [OR], 6.51; 95% confidence interval [CI], 1.38-30.8; P = .008), 20 g lactose (22% vs 47%; OR, 3.16; 95% CI, 1.43-7.02; P = .004), and 40 g lactose (68% vs 85%; OR, 2.63; 95% CI, 1.08-6.42; P = .03). H(2) excretion was associated with symptom score (P = .001). Patients with D-IBS self-reported LI more frequently than controls (63% vs 22%; OR, 6.25; 95% CI, 2.78-14.0; P < .001) and ate fewer dairy products (P = .040). However, self-reported LI did not correlate with results from hydrogen breath tests. The risk of LI is related to the dose of lactose ingested and intestinal gas production and is increased in patients with D-IBS. Self-reported LI, but not objective results from hydrogen breath tests, was associated with avoidance of dairy products.

Sa1397 The Prevalence, Clinical Relevance and Impact on Diet of Lactose Intolerance in a Population With Lactase Deficiency: A Randomized, Double-Blind, Dose Response Study in Healthy Subjects and Patients With Diarrhea Predominant Irritable Bowel Syndrome

Introduction Lactose Intolerance (LI) is a common clinical syndrome; however there is a lack of high quality evidence about its epidemiology, diagnosis and clinical relevance in health and patients with functional gastrointestinal disease. Additionally the impact of LI on intake of dairy produce is uncertain because previous studies have often tested tolerance only at very high doses and/or failed to assess both self perceived and objective lactose tolerance. Aim To assess the prevalence of LI in a population with lactose malabsorption and the effect of LI on intake of dairy products in healthy volunteers (HVs) and patients with diarrhoea predominant irritable bowel syndrome (D-IBS). Methods A Chinese population known to have a high prevalence of lactase deficiency was studied. 60 D-IBS patients and 60 HVs underwent hydrogen breath test (HBT) at 10 g, 20 g, 40 g lactose on three test days in a randomised, double-blind three way cross-over study. Lactose Malabsorption (LM; H2 rise >20 ppm) and intolerance (LI ≥2 point rise on validated symptom score) were assessed at each dose. Genetic sequencing of the lactase gene promoter region was also performed. The impact of LI (both self-reported and from HBT) on lactose intake was assessed by dietary questionnaire. Results LM was prevalent in HVs and D-IBS patients (93% vs 92% at 40 g lactose, p=0.73). LI prevalence was lower in HVs than D-IBS patients at 10 g (3% vs 18%, OR 6.51 (CI 1.38 to 30.8), p=0.008), 20 g (22% vs 47%, OR 3.16 (CI 1.43 to 7.02), p=0.004) and 40 g (68% vs 85%, OR 2.63 (CI 1.08 to 6.42), p=0.03). The genotype in all participants was C/C-13 910 and no other SNP was identified on gene sequencing of the lactase gene regulatory sequence. Most participants (83/120 (69%)) included milk and dairy products in their diet; however D-IBS patients reported less frequent intake of dairy products than HVs and a smaller amount of lactose in the diet (D-IBS: 9.0 g (4.5–17.3) vs HVs: 19.5 g (6.0–36.4); p=0.040). D-IBS patients also self-reported LI more frequently than HVs (63% vs 22%, OR 6.25 (CI 2.78 to 14.0), p Conclusion The likelihood of LI is increased in patients with D-IBS, especially at low lactose doses. Self reported lactose intolerance, but not objective LI on HBT, was associated with avoidance of dairy products. Competing interests M Fox Grant/Research Support from: Nestle International, J Yang: None declared, Y Deng: None declared, Y Cong: None declared, M Fried: None declared, N Dai: None declared.

The Prevalence of Self-reported Lactose Intolerance and the Consumption of Dairy Foods Among African American Adults Are Less Than Expected

ObjectiveTo determine the self-reported incidence of lactose intolerance and its influence on dairy choices among African American adults. Design, Setting, and ParticipantsAn online survey closely matched to the 2000 US Census was administered to a nationally representative sample of African Americans (2016 adults) and a comparison sample of the general population (1084 adults). Statistical analyses performed included pair-wise f tests for proportion conducted on percent responses at the 95% confidence level. ResultsAfrican Americans were more likely to eat fewer dairy foods, experience physical discomfort after consumption, and believe they were lactose intolerant. While 49% of African Americans had ever experienced "some type of physical discomfort" after eating dairy foods, 24% believed they were lactose intolerant. Within this group, 85% of African Americans would be willing to consume more dairy products if they could avoid lactose intolerance symptoms. Conclusions and ImplicationsDairy food, calcium, and vitamin D intake in African Americans and the general population are below US recommendations. Deficiencies of these nutrients are associated with chronic diseases that disproportionately affect African Americans. In the United States, dairy foods are the primary source of calcium and vitamin D, and lactose intolerance can be a significant barrier to dairy food intake. However, self-described lactose intolerance is less than commonly reported in African American populations. Low dairy intake may reflect concerns about lactose intolerance, other factors such as learned food habits and cultural preferences. Nutrition recommendations for African Americans and the general population should focus on the health benefits of dairy foods, provide culturally sensitive dietary options, and strategies to increase tolerance.

Comparison of Lactase Variant MCM6-13910C&gt;T Testing and Self-Report of Dairy Sensitivity in Patients with Irritable Bowel Syndrome: 2010 ACG/AstraZeneca Fellow Award

Purpose: Agreement between medically documented lactase deficiency and self-reported lactose intolerance is poor. Patients with irritable bowel syndrome (IBS) may present with similar symptoms and up to 60% report sensitivity to dairy products. The single nucleotide polymorphism (SNP), -13910C>T (rs4988235), on the MCM6 gene (upstream from the LCT lactase gene) has been reported to be 100% associated with adult lactase non-persistence in European Caucasians. The level of agreement between this genetic variant and self-report of sensitivity to dairy products in IBS patients is not yet known. Aim: Evaluate the agreement of MCM6 -13910C>T genotype with patient self-report of dairy sensitivity (DS). Methods: In a case-control study (DK76797), 645 subjects with IBS and 323 controls had been recruited from a large tertiary-care center and asked to complete a self-report Bowel Disease Questionnaire (BDQ) that included the gastrointestinal symptoms of the Rome criteria for IBS, as well as self-report of DS. Blood samples were obtained, DNA extracted, and genotype performed using an Illumina GoldenGate panel. Lactase non-persistence (LNP) was indicated by genotype CC, and lactase persistence (LP) by either TT or TC genotypes. Review of medical records identified those cases who had a previous lactose hydrogen-methane breath test (LHMBT). Agreement of genotype with self report of DS and LHMBT results were calculated with kappa (κ) statistic (95% CI). Results: Median age of the sample was 50 years (range 18-70) with 433 (78%) females. 539 (98%) were Caucasian. 262 (46%) of cases v. 32 (10%) of controls reported DS (p<0.05). 81 (14%) of cases and 48 (15%) of controls had the LNP genotype (N.S.) with minor allele frequencies of 34 and 35% in each groups. Agreement between genotype and DS was 80% in controls and 55% in cases, with the number of cases reporting DS but being LP (n=218) far exceeding those with LNP (n=44). The κ values (95% CI) for cases and controls were 0.05 (-0.01-0.11) and 0.09 (-0.04-0.22), respectively. 20 subjects had a previous LHMBT with excellent agreement between genotype and LHMBT with a κ-statistic of 0.83 [0.50-1.0]. Conclusion: Patients with IBS frequently report DS. However, self-report of DS is a poor indicator of true underlying LNP genotype. Supported by NIH DK76797.

Lactose malabsorption and intolerance: a systematic review on the diagnostic value of gastrointestinal symptoms and self-reported milk intolerance

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

National Institutes of Health Consensus Development Conference: Lactose Intolerance and Health

National Institutes of Health (NIH) consensus and stateof-the-science statements are prepared by independent panels of health professionals and public representatives on the basis of 1) the results of a systematic literature review prepared under contract with the Agency for Healthcare Research and Quality; 2) presentations by investigators working in areas relevant to the conference questions during a 2-day public session; 3) questions and statements from conference attendees during open discussion periods that are part of the public session; and 4) closed deliberations by the panel during the remainder of the second day and morning of the third. This statement is an independent report of the panel and is not a policy statement of the National Institutes of Health or the U.S. government. The following statement is an abridged version of the panel’s report, which is available in full at http: //consensus.nih.gov/2010/lactosestatement.htm. Lactose intolerance is the syndrome of diarrhea, abdominal pain, flatulence, or bloating occurring after lactose ingestion. These symptoms, which are produced by malabsorption of lactose, a sugar found in milk and other dairy products, often cause afflicted individuals to avoid dairy products in their diets. Lactose malabsorption is caused by a decreased ability to digest lactose that is due to a deficiency in the levels of the enzyme lactase. Lactase breaks lactose down into 2 simpler sugars, glucose and galactose, which are readily absorbed into the bloodstream. This enzyme is produced by expression of the lactase‐phlorizin hydrolase gene in the cells lining the small intestine. All infants produce lactase and successfully digest lactose provided by human milk or by infant formulas. However, sometime after weaning, a genetically programmed decrease in lactase (lactase nonpersistence) occurs in most children worldwide. The symptoms of lactose intolerance result from bacterial fermentation of undigested lactose in the colon. Lactose malabsorption can be diagnosed by having individuals ingest a standard dose of lactose after fasting and measuring breath hydrogen; elevated breath hydrogen levels are caused by bacterial fermentation of undigested lactose in the colon. Other diagnostic tools include measuring lactase activity in an intestinal biopsy sample or genetic testing for the common polymorphism that is linked to lactase nonpersistence. The demonstration of lactose malabsorption does not necessarily indicate that an individual will have symptoms. Many variables determine whether a person who malabsorbs lactose develops symptoms, including the dose of lactose ingested, the residual intestinal lactase activity, the ingestion of food along with lactose, the ability of the colonic flora to ferment lactose, and individual sensitivity to the products of lactose fermentation.

Prevalence of Self-reported Lactose Intolerance in a Multiethnic Sample of Adults

In Brief According to the National Institute of Diabetes and Digestive and Kidney Diseases, between 30 and 50 million Americans have the potential for lactose-intolerance symptoms. However, lactose-intolerance prevalence rates in practical life settings may be lower than originally suggested. The goal of this study was to determine the prevalence of self-reported lactose intolerance among a national sample of European American (EA), African American (AA), and Hispanic American (HA) adults. A nationally representative sample of randomly generated telephone numbers was purchased from a commercial sample provider. A nationally representative sample of randomly selected telephone numbers were called from the Survey Research Unit's Computer-Assisted Telephone Interviewing facility at the University of Alabama at Birmingham. Interviews were completed by a total of 1,084 respondents between the ages of 19 and 70 years with 486 EAs, 355 AAs, and 243 HAs. The response rate was 24.2%, and the cooperation rate was 34.2%. The age-adjusted lactose-intolerance prevalence estimates were 7.72%, 19.50%, and 10.05% for EAs, AAs, and HAs, respectively. For all respondents in the sample, the crude and age-adjusted self-reported lactose-intolerance prevalence rates were 13.38% and 12.04%, respectively. These results indicate that the prevalence of perceived lactose intolerance is significantly lower than what has been previously estimated. Health professionals need to be aware of the misrepresentation of currently estimated lactose-intolerance rates and should continue to encourage individuals with lactose intolerance to consume dairy foods first to help meet key nutrient recommendations with proper guidance and education Some counseling tips about lactose problems

Prevalence of Self-reported Lactose Intolerance in a Multiethnic Sample of Adults

Nutrition Today: September 2009 - Volume 44 - Issue 5 - p 228-229 doi: 10.1097/NT.0b013e3181be7043

M1792 Self-Reported Milk Intolerance and Symptomatic Lactose Malabsorption: Differential Diagnosis or Manifestation of the Irritable Bowel Syndrome?

M1792 Self-Reported Milk Intolerance and Symptomatic Lactose Malabsorption: Differential Diagnosis or Manifestation of the Irritable Bowel Syndrome?

Lactose intolerance in patients with irritable bowel syndrome from northern India: A case–control study

Symptoms of irritable bowel syndrome (IBS) and lactose intolerance (LI) overlap. Data on the frequency of LI in patients with IBS from India are scanty. The aim of this study was to evaluate: (i) the frequency of LI in patients with IBS and its various subtypes as compared with healthy subjects (HS) from northern India; (ii) the relationship between self-reported milk intolerance and laboratory evidence of LI; and (iii) the role of small intestinal bacterial overgrowth in LI in patients with IBS. 124 patients with IBS (Rome II criteria) and 53 age- and gender-matched HS were studied for LI using the lactose hydrogen breath test (LHBT) and the lactose tolerance test (LTT). Symptoms following lactose ingestion (diarrhea, bloating or distension) during the test and history of milk intolerance were recorded. Sixty-nine of the patients with IBS also underwent a glucose hydrogen breath test (GHBT). Patients with IBS were classified into those with diarrhea (IBS-D; >3 loose stools/d), constipation predominant (IBS-C; <3 stools/week) and indeterminate (IBS-I; between >or=3/week and <or= 3/d). 89/124 (72%) and 32/53 (60%, P = ns) IBS patients and HS were positive by LHBT and 82/124 (66%) and 38/53 (71%, P = ns) by LTT. Lactose intolerance as diagnosed either by LHBT or LTT was comparable among IBS patients and HS (102/124, 82% vs 41/53, 77%; P = ns). Peak breath hydrogen values during LHBT were also comparable among patients with IBS and HS (64 +/- 40 p.p.m. vs 61 +/- 44 p.p.m.). Patients with IBS developed symptoms following lactose ingestion more frequently than HS (68/124 vs 18/53, P = 0.01). Glucose hydrogen breath test was positive in 9/69 (13%) patients with IBS and was comparable among patients with (8/57, 14%) and without LI (1/12, 8%). Thirty had IBS-D whereas 94 had other subtypes of IBS (IBS-C, n = 9 and IBS-I, n = 85). The frequency of LI in IBS-D was similar to that of other subtypes (26/30, 86% vs 76/94, 80%; P = ns). The positive and negative predictive value of self-reported milk intolerance in detecting LI was 81% and 23%, respectively. The frequency of LI is high and comparable among IBS patients and HS from northern India. Patients with IBS more often reported symptoms following lactose ingestion despite levels of breath hydrogen being similar to HS. The frequency of LI in patients with IBS-D was comparable to that in patients with other types of IBS. Self-reported milk intolerance has poor sensitivity in detecting LI.

Molecularly-defined lactose malabsorption, milk consumption and anthropometric differences in adult males

Lactose malabsorption (LM) may be associated with reduced skeletal calcium content. Diagnosis to date has been based on indirect methods, with a high false-negative rate. Identification of the LCT polymorphism led to development of a PCR-based test. To evaluate the PCR-based test compared to a combination the hydrogen breath test and the lactose tolerance test, and investigate anthropometrical differences, changes in bone mineral density and oral calcium intake according to LCT polymorphism and milk-drinking habits. All participants (n = 278) underwent clinical examination, with measurement of height, weight and bone density (DXA), and were genotyped for LCT polymorphism (LCT CC or LCT TT: CC is associated with LM). A subgroup (n = 51) had a hydrogen breath test and a lactose tolerance test, in addition to genotyping. Detection of LM by LCT polymorphism was highly significant (p = 0.001). The correlation between LCT genotype and self-reported milk-intolerance or dislike of milk with was slight, but the correlation with functional tests was highly significant. Non-milk-drinkers were lighter (-5 kg) and significantly shorter (-4 cm) than milk-drinkers (p = 0.07 and 0.04, respectively). Total calcium consumption was lower among non-milk-drinkers by about 18% (p = 0.03). Genotyping is an economic, quick and convenient method for diagnosing lactose malabsorption, with results comparable to existing tests. Sufficient calcium consumption may be relevant to body growth, as milk-drinkers were taller. Negative calcium bone balance may be prevented when provision is made for adequate calcium intake.

Genetically defined adult-type hypolactasia and self-reported lactose intolerance as risk factors of osteoporosis in Finnish postmenopausal women

To study the relationships of molecularly defined lactose malabsorption (LM) and self-reported lactose intolerance (LI) to bone mineral density (BMD) and fractures among Finnish postmenopausal women. A cross-sectional study of two cohorts. Helsinki University Central Hospital. One cohort was population-based and comprised 453 women, aged 62-78 (mean 69) y. Another comprised 52 women, aged 69-85 (mean 75) y, with osteoporotic fractures and 59 control women, aged 69-83 (mean 74) y, without osteoporosis. A single nucleotide polymorphism of the lactase (LCT) gene at chromosome 2q21-22 was studied. It shows complete association with intestinal disaccharidase activity, with the genotype CC(-13 910) meaning adult-type hypolactasia (primary LM) and the genotypes CT(-13 910) and TT(-13 910) lactose absorption. BMD of the heel was measured by dual-energy X-ray absorptiometry (DXA). In the population-based cohort, 16.0% of women had self-reported LI but only 15.3% of them had the CC(-13 910) genotype. Calcium intake from dairy products (P = 0.10) and BMD, adjusted for age, weight, height, exercise, smoking, and estrogen use (P = 0.71) were similar for the genotypes. Women with self-reported LI had reduced calcium intake from dairy products (P < 0.0001) but they were more frequent users of calcium supplements than lactose-tolerants (P < 0.0001). Adjusted BMD was similar for lactose intolerant and tolerant women (P = 0.60). Of 104 women with previous fracture in the population-based cohort, 13.5% had the CC(-13 910) genotype, which did not differ from the prevalence of 19.3% among 347 women without fractures (P = 0.29). The frequency of the CC(-13 910) genotype (23.1%) for 52 women with established osteoporosis was similar as for 59 control women (15.3%) (P = 0.19). Molecularly defined LM and self-reported LI are not risk factors for osteoporosis, if calcium intake from diet and/or supplements remains sufficient. Our study confirms the poor correlation between self-reported LI and LM established by different techniques.

Diagnosis, Symptoms, and Calcium Intakes of Individuals with Self-Reported Lactose Intolerance

Objective: To determine methods of diagnosis, symptoms, and calcium intake from food and supplements for individuals with self-reported lactose intolerance.Methods/Design: Cross-sectional survey using a mailed questionnaire.Subjects/Setting: A convenience sample of 189 adults with self-reported lactose intolerance living in the metropolitan area of Vancouver Canada responded to posters or advertisements, and 159 returned completed questionnaires.Measures of Outcome: Methods of diagnosis, symptoms experienced and their severity were self-reported. Estimated calcium intake from food and supplements was assessed using a food frequency questionnaire. Data were analyzed using descriptive statistics, chi-square, Pearson correlation analysis, t-tests and Analysis of Variance.Results: Participants were 47 ± 15 years of age; 72% female and 28% male; 67% Caucasian; and 54% had self-diagnosed their lactose intolerance. Of the 42% diagnosed by a physician, only 10% had been diagnosed by valid tests. Mean estimated food calcium intake was 591 ± 382 mg/d and did not differ between those who were self- or physician-diagnosed. Only 11.5% of participants met their age-appropriate Adequate Intake (AI) from food calcium sources alone. Calcium supplements were used by 65% and provided an average of 746 ± 703 mg calcium/day to those who used them; mean intakes of this group met the AI.Conclusions: Calcium intake from food sources alone is inadequate to meet the AI in individuals with self-reported lactose intolerance. Physicians managing lactose intolerance need current information on how the AI can be met through appropriate food choices and possible supplementation.

Self-reported milk intolerance in irritable bowel syndrome: what should we believe?

Background & aims: The real importance of lactose malabsorption in irritable bowel syndrome (IBS) is still controversial. The aim is to define the relationship between patient perception of milk tolerance/intolerance, lactose malabsorption and abdominal symptoms in IBS. Methods: A hydrogen breath test (HBT) after an oral load of lactose was carried out in 475 consecutive IBS patients, diagnosed according to the Rome criteria. Data were analyzed in 201 age- and sex-matched pairs of IBS patients, classified according to self-reported milk tolerance/intolerance. Hydrogen peak and excretion, predominant presenting symptom and the occurrence of symptoms during the test, were evaluated. Results: The prevalence of positive HBT and the occurrence of symptoms during the test was similar in milk “tolerant” (68.6%, 40.7% respectively) and “intolerant” patients (75.6%, 42.7% respectively), as well as peak (76.4 vs 75.2 ppm) and amount of H 2 excreted (57.8 vs. 53.2 ppm/h). The positive predictive value for self-reported milk intolerance was 0.75, and the negative predictive value in regular milk users was 0.31, reflecting the prevalence of lactose malabsorption in the general population more than the awareness of milk tolerance. Conclusions: In IBS patients, self-reported milk intolerance does not help in identifying lactose malabsorbers. The opposite does not rule out the occurrence of symptoms after a lactose load. Lactose is, indeed, responsible for symptoms in some IBS patients, however, these patients can only be identified by the occurrence of symptoms during the test, and not on the individual perception of milk intolerance.

Lactose malabsorption, irritable bowel syndrome and self-reported milk intolerance

Background. The relationship between lactose malabsorption, irritable bowel syndrome and development of intestinal symptoms is unclear, especially when the ingested dose of milk is small. Thus, the role of hydrogen breath testing in the diagnostic work-up of patients with nonspecific intestinal symptoms is still debated. Aims. To establish the relationship between lactose malabsorption, severe self-reported milk intolerance, irritable bowel syndrome and related symptoms. Methods. The prevalence of lactose malabsorption was prospectively assessed by means of a hydrogen breath test in 839 patients (503 with irritable bowel syndrome, based on the Rome criteria, regularly consuming milk, and 336 subjects who identified themself as milk intolerant, after an oral load of 25 g lactose). The test was considered “positive” when a hydrogen peak exceeding 20 ppm over baseline values was observed in two or more samples. Attempts were also made to establish whether the predominant presenting symptom (diarrhoea, constipation, alternating diarrhoea and constipation, pain and gaseousness) might be helpful in predicting the outcome of the breath test. Results. The prevalence of a positive breath test was comparable in the two groups (337 patients with irritable bowel syndrome (66.9%) vs 240 patients with milk intolerance (71.4%)). The same holds true for the first peak of hydrogen excretion, total hydrogen output and prevalence of symptoms during, and in the four hours after, the test. The predominant presenting symptom was not useful for predicting outcome of the test either in regular milk users or in milk intolerant subjects. Conclusions. The almost identical results of the lactose breath test of patients with irritable bowel syndrome and subjects with self-reported milk intolerance suggests that the two conditions overlap to such an extent that the clinical approach should be the same. A lactose breath test should always be included in the diagnostic work-up for irritable bowel syndrome, as fermentation of malabsorbed lactose is likely responsible for triggering symptoms. Conversely, lactase deficiency is probably irrelevant in most subjects not affected by irritable bowel syndrome, within a moderate milk consumption.

A randomized trial of Lactobacillus acidophilus BG2FO4 to treat lactose intolerance

Lactose intolerance is the most common disorder of intestinal carbohydrate digestion. Lactobacillus acidophilus BG2FO4 is a strain of lactobacilli with properties of marked intestinal adherence and high beta-galactosidase activity. This study was designed to determine whether oral feeding of Lactobacillus acidophilus BG2FO4 leads to a lactose-tolerant state. We studied 42 subjects with self-reported lactose intolerance and performed breath-hydrogen tests to determine whether they were lactose maldigesters. Subjects with established lactose maldigestion (n = 24) were invited to be randomly assigned to an omeprazole-treated (hypochlorhydric) group or a non-omeprazole-treated group, but 6 subjects chose not to participate. All randomly assigned subjects (n = 18) ingested Lactobacillus acidophilus BG2FO4 twice per day for 7 d and stool samples were collected. Breath-hydrogen tests were performed and symptom scores were recorded at baseline and after lactobacilli ingestion. Lactose maldigestion was established in 24 of 42 subjects (57%) with self-reported lactose intolerance. In 18 lactose-maldigesting subjects, overall hydrogen production and symptom scores after ingestion of Lactobacillus acidophilus BG2FO4 were not significantly different from baseline values. Live Lactobacillus acidophilus BG2FO4 was recovered in stool samples from 7 subjects. Lactose intolerance is overreported in subjects with gastrointestinal symptoms after lactose ingestion. Treatment of lactose-maldigesting subjects with and without hypochlorhydria with Lactobacillus acidophilus BG2FO4 for 7 d failed to change breath-hydrogen excretion significantly after lactose ingestion.

Does lactose intolerance predispose to low bone density? A population-based study of perimenopausal Finnish women.

The relationship of lactase malabsorption to osteoporosis is unclear. We examined the relationship of self-reported lactose intolerance (LI) to bone mineral density (BMD) in perimenopausal Finnish women. A random population sample of 2025 women aged 48-59, who underwent spinal and femoral BMD measurement with dual X-ray absorptiometry in Kuopio, Finland during 1989-1991 formed the study population. Out of these women, 162 women reported LI. The mean dairy calcium intake was 558 mg/day in women with LI and 828 mg/day in other women (p < 0.0001). The mean spinal BMDs were 1.097 and 1.129 g/cm2 (-2.8%) (p = 0.016) and the mean femoral BMDs were 0.906 and 0.932 g/cm2 (-2.8%) (p = 0.012) for the LI and other women, respectively. After adjusting for weight, age, years since menopause, and the history of hormone replacement therapy, these differences changed to -2.7% (p = 0.016) for the spinal and -2.4% (p = 0.012) for the femoral BMD, respectively. Dairy calcium intake was an independent determinant of femoral BMD. The addition of calcium intake variables into the multivariate model did not affect the spinal BMD difference, but weakened the femoral BMD difference to -1.9% (p = 0.075). Our results suggest that LI slightly reduces perimenopausal BMD, possibly through reduced calcium intake.