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Kefir improves lactose digestion and tolerance in adults with lactose maldigestion.

OBJECTIVE: Kefir is a fermented milk beverage that contains different cultures than yogurt. The objective of this study was to determine whether kefir improves lactose digestion and tolerance in adults with lactose maldigestion. DESIGN: Randomized block design. SUBJECTS: Fifteen healthy, free-living adults with lactose maldigestion. MAIN OUTCOME MEASURES: Breath hydrogen excretion and lactose intolerance symptoms were monitored hourly for 8 hours after each test meal. INTERVENTION: Subjects were fed test meals consisting of 20 g lactose portions of milk (2% reduced fat), plain and raspberry flavored kefir, and plain and raspberry flavored yogurt, each following an overnight (12 hour) fast. STATISTICAL ANALYSIS: Mixed model ANOVA was performed on raw or transformed data, followed by Tukey HSD post hoc tests (when appropriate). Significance was defined as P<.05. RESULTS: The breath hydrogen area under the curve (AUC) for milk (224+/-39 ppm x h) was significantly greater than for the plain yogurt (76+/-14 ppm x h, P<.001), the plain kefir (87+/-37 ppm x h, P<.001), and the flavored yogurt (76+/-14 ppm x h, P=.005). The flavored kefir had an intermediate response (156+/-26 ppm x h). The yogurts and kefirs all similarly reduced the perceived severity of flatulence by 54% to 71% relative to milk. Abdominal pain and diarrhea symptoms were negligible among the five treatments. APPLICATIONS/CONCLUSION: Because kefir improved lactose digestion and tolerance in this study, its use may be another potential strategy for overcoming lactose intolerance. Further studies of other types of kefir for improving lactose digestion are warranted.

Adult↗

Milk is a useful test meal for measurement of small bowel transit time.

To improve and standardize the measurement of small bowel transit time, milk was employed for the test meal instead of the conventional lactulose meal. Although 92% of the subjects were lactase deficient, only 2% were milk intolerant and 13% were lactose intolerant. Small bowel transit time with milk (milk breath hydrogen test) was 113 +/- 9 min (mean +/- SE, n = 20); the normal range calculated from the mean +/- 2 SD was 31-195 min. The coefficient of variation in the milk hydrogen breath test was 13 +/- 4% (n = 6), whereas in the lactulose hydrogen breath test, it was 39 +/- 16% (n = 10). The frequency of non-hydrogen producers, the occurrence of discomfort, and the reproducibility were better, though not significantly so, in the milk hydrogen breath test than in the lactulose. Since lactase activity in the intestine is variable in lactase-deficient subjects, small bowel transit times for milk may change from subject to subject. However, individual reproducibility of the milk hydrogen breath test is good. It could be useful for pharmacological experiments using paired comparison, for screening tests, or for the follow up of diseases in which small bowel transit time is affected.

Aged↗

Temperature of a test solution influences abdominal symptoms in lactose tolerance tests.

In lactose maldigesters, retarding gastric emptying (food/pharmaceuticals) improves tolerance to lactose. The role of temperature of test solution on the indicators of lactose intolerance was studied. After an overnight fast, 10 lactose maldigesters ingested, in three sessions, 50 g lactose in a randomized cross-over trial. The solutions were at temperatures of 20-21 degrees C (room temperature), 2-3 degrees C (cold) and 55-58 degrees C (hot). Gastrointestinal symptoms and indicators measuring lactose absorption were recorded. Abdominal pain was noticeably increased by the modification of temperature. The cold solution reduced flatulence and abdominal bloating, whereas the hot solution increased bloating and borborygmi. Breath hydrogen excretion tended to be augmented and retarded after cold solution. The temperature of the solution used in a lactose tolerance test affects the gastrointestinal symptoms, but has only minor effects on the other indicators of lactose maldigestion. The constant tendencies observed suggest that a room temperature solution is to be recommended for testing lactose digestion.

Abdomen↗

Lactose absorption and malabsorption in healthy Italian children: do the quantity of malabsorbed sugar and the small bowel transit time play roles in symptom production?

Using breath hydrogen analysis after an oral lactose load (2 g/kg; maximum 50 g), we investigated the prevalence of lactose malabsorption in 61 healthy Italian children aged 6-13 years. We also examined the relationship between symptoms and small bowel transit time and the degree of sugar malabsorption. Three of 61 subjects produced no H2 after both lactose and lactulose load and thus were eliminated at the outset. Lactose malabsorption was defined as excretion of greater than 20 ppm H2. Lactose intolerance was classified as mild (colicky pain, flatulence, abdominal distension, borborygmi) or severe (diarrhea). The frequency of lactose malabsorption in the children aged 6-8 years (group I) was 25%; in the children aged 8-11 years (group II), it was 35%, and in the children aged 11-13 years (group III) 56%. The differences in frequency between the first and the third groups were significant (p = 0.05). Three of 20 (15%) in group I, two of 20 (10%) in group II, and three of 18 (17%) in group III were classified not only as lactose malabsorbing, but also as lactose intolerant, with symptoms during and after the test. We found no difference in the small bowel transit times or in the quantities of malabsorbed lactose in symptomatic and asymptomatic malabsorbing subjects. Other factors that may play a role in symptom production are discussed.

Adolescent↗

[Lactose in human nutrition].

The disaccharide lactose is naturally present as a component of foods in milk and dairy products. In the gastrointestinal tract, lactose is hydrolysed by the enzyme beta-galactosidase (lactase) into glucose and galactose. These components are absorbed. In most people lactase activity decreases at the age of approximately 2 years of age. After this lactose intake can cause symptoms of bloating, flatulence, abdominal pain and diarrhoea due to the lactose reaching the large intestine. This phenomenon is called lactose intolerance. It is generally recommended that these people abandon the consumption of milk and dairy products. However, most lactose-intolerant people are able to digest small amounts of milk (approximately 200 ml). They can also consume cheese without (hard and semi-hard cheese) or only low lactose content (only present in 10% of soft cheese). These products are a very important source of calcium.

Adolescent↗

[Importance of nutritional status in digestion capacity and lactose tolerance].

The aim of this study is to determine the capacity of undernourished patients to digest and tolerate the lactose in milk administered by tube-feeding. It was a controlled double-blind crossover trial in 25 hospitalized patients who required enteral feeding due to medical reasons. They were divided in two groups differing by nutritional status: 10 patients in Group 1 were malnourished with a mean weight for height of 69% (+/-15% SD) of their ideal one; Group 2 had 15 well nourished patients (mean weight for height of 103 +/- 15%). Each patient received two dietary treatments: intact milk and hydrolyzed milk (> 90% of lactose hydrolyzed). Lactose digestion was measured by the hydrogen breath test. Hydrogen excretion with intact milk was 505 +/- 117 ppm in Group 1 versus 58 +/- 15 ppm in the control group. With hydrolyzed milk, these values were 53 +/- 27 and 14 +/- 23, respectively. The scoring of symptoms after drinking intact milk was 4.3 +/- 0.7 in Group 1 vs 1.5 +/- 0.3 in Group 2, and they were lower with hydrolyzed milk (0.5 +/- 0.2 vs 0.3 +/- 0.2 respectively). The undernourished group had a higher incidence of both lactose maldigestion (p < 0.0001) and lactose intolerance (p < 0.001) than the control group. Our results strongly suggest that undernourishment is accompanied always or almost always by lactose intolerance.

Adult↗

Molecular and cellular aspects and regulation of intestinal lactase-phlorizin hydrolase.

Carbohydrates are hydrolyzed in the intestinal lumen by specific enzymes to monosaccharides before transport across the brush border membrane of epithelial cells into the cell interior. The enzymes implicated in the digestion of carbohydrates in the intestinal lumen are membrane-bound glycoproteins that are expressed at the apical domain of the enterocytes. Absent or reduced activity of one of these enzymes is the cause of disaccharide intolerance and malabsorption, the symptoms of which are abdominal pain, cramps or distention, flatulence, nausea and osmotic diarrhea. Lactose intolerance is the most common intestinal disorder that is associated with an absence or drastically reduced levels of an intestinal enzyme, in this case lactase-phlorizin hydrolase (LPH). The pattern of reduction of activity has been termed late onset of lactase deficiency or adult type hypolactasia. It was thought that the regulation of LPH was post-translational and was associated with altered structural features of the enzyme. Recent studies, however, suggest that the major mechanism of regulation of LPH is transcriptional. Other forms of lactose intolerance include the rare congenital lactase deficiency and secondary forms, such as those caused by mucosal injury, due to infectious gastroenteritis, celiac disease, parasitic infection, drug-induced enteritis and Crohn's disease. This review will shed light on important strucural and biosynthetic aspects of LPH, the role played by particular regions of the LPH protein in its transport, polarized sorting, and function, as well as on the gene expession and regulation of the activity of the enzyme.

Animals↗

Effect of predominant methanogenic flora on the outcome of lactose breath test in irritable bowel syndrome patients.

BACKGROUND: The relationship between hydrogen and methane production is a possible confounding factor in the interpretation of H(2) breath tests (HBT), but is usually disregarded for the interpretation of HBT and, in most instances, only H(2) excretion is measured. The present study was designed to evaluate the effect of predominant fasting methane CH(4) or H(2) production on the outcome of lactose HBT, in a large, homogeneous series of adult patients with irritable bowel syndrome (IBS). PATIENTS AND METHODS: A lactose HBT was performed in 237 IBS patients with predominant fasting methane production (CH(4)>H(2)), recording the outcome of the test, amount of gas excreted and occurrence of clinical symptoms. Data were compared to those of 237 age- and sex-matched IBS patients with low fasting CH(4) excretion. RESULTS: The test was positive in 124 predominant CH(4) producers (52.3%) (PMP), as compared to 201 (84.8%) low methane producers (LMP) (P<0.0001). Peak hydrogen concentration and area under the curve of H(2) were significantly (P<0.001) lower, and the occurrence of symptoms during the test less frequent, in PMP vs LMP patients. During the test, CH(4) excretion doubled in 57/113 (50.4%) patients with negative HBT, and in 49/124 (39.5%) with positive HBT. CONCLUSIONS: Patients with predominant fasting methane production excrete less H(2) than LMP, after an oral load of lactose. The lower prevalence of severe lactose intolerance in PMP, as well as lower incidence of symptoms during the test, is, indeed, related to lower and slower H(2) excretion. The assumption that H(2) excretion is an effective means of quantifying the amount of malabsorbed carbohydrates is questionable in PMP. Methane-producing patients likely have a higher 'false negative' rate as compared to LMP after an oral load of lactose. Nonetheless, as symptoms are related to the amount of gas produced in the colon, HBT identifies patients with 'lactose intolerance', irrespective of the presence of lactose malabsorption, and helps in predicting the effect of lactose-restricted diet.

Adolescent↗

Developmental changes of lactose malabsorption in normal Chinese children: a study using breath hydrogen test with a physiological dose of lactose.

The malabsorption of a physiological dose of lactose (0.5 g/kg body weight) was studied in 726 healthy Chinese children, ranging in age from 3 to 18 years, using the breath hydrogen test. The prevalence of lactose malabsorption was found to increase with age; it occurred in less than 15% of preschool-age children and in approximately 45% of younger school-age and 60% of older school-age children. Approximately 70% of adolescents measured showed malabsorption. The critical period of change was from 6 to 7 years of age, with the lactose malabsorption rate rising abruptly from 12 to 43%. The incidence of lactose intolerance in teenagers and adolescents was 27 and 33%, respectively. The great majority of them had only dull abdominal pain. No case of lactose intolerance was seen in children less than 9 years of age. These results indicated that preschool Chinese children can absorb a physiological dose of lactose (equivalent to the average amount of milk consumed daily) without any adverse effects. In contrast, one half of school-age children and two thirds of adolescents were malabsorbers.

Administration, Oral↗

Lactose malabsorption and tolerance of lactose-hydrolyzed milk. A double-blind controlled crossover study.

Eleven lactose-intolerant patients were investigated in a double-blind crossover controlled study. In random sequence they received 500 ml of either ordinary cow milk (lactose content, 25 g) or the same amount of low-lactose milk (85% of the lactose hydrolyzed), which had been processed by Lactozym 3000 L for 24 h at 4 degrees C. A significantly increased blood glucose rise from fasting levels was demonstrated in the low-lactose tests. Similarly, a significant reduction of liquid stool frequency, abdominal colics, distention, borborrhygmia, and flatulence was demonstrated. It was concluded that further studies, including long-term treatment of lactose-intolerant children, are indicated.

Adult↗

Acute gastroenteritis in infants under 6 months old.

Sixty two babies under the age of 6 months who were admitted with gastroenteritis completed a study of gradual refeeding compared with abrupt refeeding after a period of rehydration. There was no difference in the incidence of recurrence of diarrhoea due to lactose intolerance, effect on weight, or duration of hospital stay. Twenty six babies (42%) had recurrence of diarrhoea after refeeding, all of whom settled with the introduction of a lactose free soya based formula. Well nourished babies under 6 months of age with mild to moderately severe gastroenteritis can be fed immediately with full strength milk feeds after rehydration. The introduction of a lactose free soya based preparation may provide an alternative to repeated attempts at regrading with cows' milk feeds in those patients with lactose intolerance.

Acute Disease↗

[Experience with hydrogen (H2) breath test].

The authors applied regularly the hydrogen (H2) breath test during the medical investigations in patients with gastrointestinal symptoms. On the basis of the repeated examinations the hydrogen (H2) breath test is a sensitive, well repeatable method. After analysing of 108 examinations the authors have observed in 51.8% lactose intolerance, in 17.8% small intestinal bacterial overgrowth syndrome, in 46.4% motility disorders. The proportion of "low hydrogen producers" was 14.3%. Only 1/5 of patients with new diagnosed lactose intolerance had knowledge about the intolerance, and 10% was asymptomatic. In case of small intestinal bacterial overgrowth syndrome the repeated hydrogen (H2) test may indicate the effectivity of applied antibiotic therapy. The mean orocaecal transit time was 99 minutes and the normal range was 66-132 minutes, counted on the basis of mean +/- 2 SD. The authors suggest that the results support the important role of hydrogen (H2) breath test in the modern gastroenterological diagnostics.

Breath Tests↗

[Disorders of lactase hydrolysis in patients with ulcerous colitis and irritable colon].

In 28 patients the existence of deficiency in lactase activity was examined indirectly with lactose tolerance test (LTT). Patients were divided in three groups. The first group consisted of 12 patients with confirmed diagnosis of "Irritable-colon syndrome". The second was composed of 6 patients suffering from ulcerative colitis. The third examined group was control group made of healthy persons without any gastrointestinal or metabolic disorders. To exclude the possible of monosaccharide malabsorption, all patients underwent glucose-tolerance test (GTT). Milk tolerance questionnaire was performed in all examined patients. All clinical signs were observed for 12 hours after performing LTT. Following the statistical analysis it was found that there was greater frequency of lactose intolerance in two first groups (I and II), comparing with the results obtained in the control group. Low raise of glucose level (less than 1.11 mmol/l) in the majority of patients was connected with characteristic lactose-intolerance clinical signs and symptoms.

Adult↗

[Lactose tolerance in children with chronic gastroduodenal zone diseases].

We determined the dependence of the frequency of lactose intolerance, particular features of the clinical presentation and laboratory showings on lactase deficiency on the basis of a complex clinical, anamnestic and laboratory study of 149 children with chronic gastroduodenal pathologies. It was established that the prevalence of lactose intolerance in children with superficial gastroduodenitis amounts to 58.8%, in children with erosive gastroduodenitis--66.7% and in children with stomach ulcers--83.3%. During the oral lactose load and a subsequent laboratory study we revealed an impairment of the hydrolytic function of small intestines accompanied by an increase of fecal excretion of carbohydrates (lactose and monosaccharides) as well as a considerable enhancement of bacterial fermentation. The detection of fecal excretion of the total glycoprotein hexoses characterizes a disorder of the morphofunctional state of the gastrointestinal tract in children with intestinal enzymopathies.

Adaptation, Physiological↗

Delta 10 ppm versus delta 20 ppm: a reappraisal of diagnostic criteria for breath hydrogen testing in children.

OBJECTIVE: To reevaluate the timing and level of rise in breath hydrogen (H2) excretion following oral lactose challenge in children with respect to the subsequent development of symptoms consistent with lactose intolerance. METHODS: Breath hydrogen test (BHT) data from 581 individuals < 19 yr of age (mean age 7.4 yr), all of whom had a fasting baseline breath H2 concentration of < 20 ppm, were reviewed. All subjects ingested 2 g/kg lactose (maximum 50 g) and had breath H2 analysis at 30-min intervals for 3 h. Symptoms of abdominal pain, bloating, gas, and diarrhea were monitored. RESULTS: Seventeen percent of subjects had no H2 detectable in their breath at any time, 41% had a rise < 10 ppm from baseline, 6% increased 10-19 ppm, and 36% had a rise > or = 20 ppm. Symptom development (gas, bloating, abdominal pain, diarrhea) was similar in the non-H2 excretors, the delta < 10 ppm, and the delta 10-19 ppm groups. Compared to the < 10 ppm or < 20 ppm groups, subjects with a rise of > or = 20 ppm were more likely to develop diarrhea (p < 0.0001), gas (p < 0.0001), bloating (p < 0.0001), and abdominal pain (p < 0.0001). Symptoms were more common in the > or = 20 ppm group than in the delta 10-19 ppm group (p < 0.02 for diarrhea, p < 0.0001 for gas, bloating, and abdominal pain). Fifty-three percent of subjects with a rise in breath H2 < 20 ppm reported symptoms during or after the BHT, and 9% of those with a rise > or = 20 ppm were asymptomatic. CONCLUSION: A rise of breath H2 concentration of > or = 20 ppm over baseline appears to correlate better with subsequent symptom development than does > or = 10 ppm. However, the frequently poor association between symptoms of lactose intolerance and breath H2 excretion suggest caution in the interpretation of the clinical significance of the BHT.

Abdominal Pain↗

Hydrogen breath test for diagnosis of lactose malabsorption: the importance of timing and the number of breath samples.

BACKGROUND: The hydrogen breath test (H(2)BT) is the most widely used procedure in the diagnostic workup of lactose malabsorption and lactose intolerance. AIM: To establish whether a simplified two- or three-sample test may reduce time, costs and staff resources without reducing the sensitivity of the procedure. PATIENTS AND METHODS: Data from 1,112 patients (292 men, 820 women) with a positive 4 h, nine-sample H(2)BT were retrospectively analyzed. Patients were stratified according to the degree of lactose malabsorption, the occurrence and type of symptoms. Loss of sensitivity in the procedure was evaluated taking into account two-sample tests (0 min and 120 min or 0 min and 210 min) or three-sample tests (0 min, 120 min and 180 min or 0 min, 120 min and 210 min). RESULTS: Using a two-sample test (0 min and 120 min or 0 min and 210 min) the false-negative rate was 33.4% and 22.7%, respectively. With a three-sample test (0 min, 120 min and 180 min or 0 min, 120 min or 210 min), lactose malabsorption was diagnosed in 91.2% (1,014 of 1,112) patients and in 96.1% (1,068 of 1,112) patients, respectively. Of 594 patients with abdominal symptoms, 158 (26.6%) and 73 (12.2%) would have false-negative results with 0 min and 120 min or 0 min and 210 min two-sample tests, respectively. The three-sample tests, 0 min, 120 min and 180 min or 0 min, 120 min and 210 min, have a false-negative rate of 5.9% and 2.1%, respectively. CONCLUSIONS: A three-sample H(2)BT is time- and cost-sparing without significant loss of sensitivity for the diagnosis both of lactose malabsorption and lactose intolerance.

Adult↗