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Effective in vivo hydrolysis of milk lactose by beta-galactosidases in the presence of solid foods.

The feasibility of enzyme replacement therapy with exogenous, food-grade, microbial enzymes at mealtime to effect intragastrointestinal hydrolysis of the lactose from 360 ml of cow's milk consumed with a solid food meal (breakfast cereals) was investigated in adult Guatemalan lactose-malabsorbers using a hydrogen breath-analysis procedure to quantify the completeness of postprandial carbohydrate absorption. Adding 2 g of a commercial preparation of beta-galactosidase from Kluyveromyces lactis at mealtime to milk taken with a refined cereal (cornflakes) and an unrefined cereal (bran) reduced the production of excess breath H2 attributable to lactose maldigestion to a level not significantly different from that achieved with lactose-prehydrolyzed milk. Sucrase, as expected, had no effect on H2 production. A beta-galactosidase from Aspergillus niger was less effective that the K. lactis enzyme for in vivo hydrolysis. Thus, exogenous betagalactosidases can eliminate lactose malabsorption in lactase-deficient individuals even in the presence of solid foods, allowing lactose intolerant persons to consume milk and dairy products without gastrointestinal discomfort.

Adult↗

Effects of diets containing dried whey on the lactase activity of the small intestinal mucosa and the contents of the small intestine and cecum of the pig.

Two studies were conducted to establish the effects of dietary lactose supplied from dried whey on the lactase activity in the contents of the small intestine and cecum as well as the mucosa of the small intestine. In the first study, feeding 0, 10, 25, or 40% dried whey for 120 days did not alter the mucosal lactase specific activity (mumoles galactose released/mg protein) in the duodenum, upper jejunum, or lower ileum. In the second study, total lactase activity in the small intestine was estimated from the total activity found in 10-cm segments of each meter of small intestine. Feeding a diet containing 40% whey continuously from weaning at 5 weeks of age or from 12 weeks of age did not alter the total lactase activity of pigs killed at 21 weeks of age. Dietary lactose tended to increase the lactase activity in the contents of the cecum and small intestine, but the increases were not always statistically significant. In the second study, Chester White pigs had approximately threefold greater mucosal lactase activities than that of Hampshires. These two breeds may be suitable models for detailed studies into the relationships between lactase deficiency and lactose intolerance.

Animals↗

Risk of inadequate bone mineralization in diseases involving long-term suppression of dairy products.

BACKGROUND: Eighty percent of peak bone mass should be achieved from birth through adolescence. An adequate calcium intake is essential, and it is advisable that 60% of the recommended calcium allowance be dairy calcium. This study was conducted to examine bone mineral content (BMC) in patients with diseases that usually involve long-term suppression of dairy products. METHODS: Thirty patients, aged 2 to 14 years (mean, 7 years), 10 with late-onset, genetically induced lactose intolerance, 7 with cow's milk protein allergy, 3 with short-bowel syndrome, and 10 with hypercholesterolemia were involved in the study. They were receiving various dietary regimens for periods longer than 2 years: 14 patients received special formulas for children (lactose-free cow's milk formula, highly hydrolyzed cow's milk protein formula, soy protein isolate formula), 4 patients received liquid soy beverages, 6 patients received skim milk (1% fat), and 6 patients had exclusion of dairy products. Bone mineral density (BMD) was assessed by dual-energy x-ray absorptiometry. RESULTS: Nine patients had osteoporosis, 6 had osteopenia, and 15 had results within normal ranges. Overall, the group had a standard deviation score of -1.3 (osteopenia). The statistical correlation between the BMD value and the percentage intake of recommended daily allowance (RDA) of dairy (or substitute) calcium (in milligrams per day) was highly significant (P < 0.0001, r = 0.89). CONCLUSIONS: All patients with diseases involving total or partial withdrawal from milk products for a prolonged period are a group at potential risk of defective bone mineralization and should be monitored through BMD assessment.

Adolescent↗

Carbohydrate intolerance after acute gastroenteritis--a disappearing problem in Polish children.

The prevalence of carbohydrate intolerance in Polish children during an acute episode of gastroenteritis was determined. One hundred and seven consecutive children, less than 3 years old, with acute diarrhoea were enrolled into the study. Carbohydrate intolerance (diagnostic criteria: >0.5% reducing substances and stool pH less than 5.5) was diagnosed in 14/107 (13.08%) children: lactose intolerance was present in 12 (11.2%) patients; glucose polymer intolerance in 1 (0.93%) and monosaccharide intolerance in 1 (0.93%). The most important predisposing factor was rotavirus. In all cases the carbohydrate intolerance was transient, resolving within 5 days. Carbohydrate intolerance is also an infrequent problem in Polish children. Restriction of lactose-containing foods (use of lactose-free or low lactose formulas) for the majority of children with gastroenteritis does not seem to be justified.

Age Factors↗

Distribution of physiological adult lactase phenotypes, lactose absorber and malabsorber, in Germany.

A total of 1805 apparently healthy, adult and adolescent Germans (1572 males and 233 females with a mean age of 20.3 years) were examined for lactose absorption capacity employing a field version of the breath hydrogen (H2) test. The diagnostic parameter, maximal change of breath hydrogen concentration 120 or 150 min after a load of 50 g lactose, showed a bimodal distribution, separating lactose absorbers (n = 1537, 85.2%) and lactose malabsorbers (n = 268, 14.8%). The distribution of the adult lactase phenotypes was independent of age, sex, and educational status. The incidence of gastrointestinal symptoms after lactose administration demonstrated the incongruity of lactose malabsorption and lactose intolerance. In addition to grouping by residence, the probands were classified according to the birthplaces of their grandparents in order to reconstruct the distribution pattern of the lactase phenotypes prior to World War I, a period of relative population stability. Considerable differences in the frequency of lactose malabsorption were found in regions corresponding to traditional ethnic groups within the German population: northwest Germany 6-9%, west and south 13-14%, southwest 23%, east (including formerly German territories east of rivers Oder and Neisse) 22%. These differences are discussed with reference to population history. The present fairly even distribution of the lactase phenotypes in West Germany is the result of internal migrations at the end of World War II.

Adolescent↗

Lactose absorption by postweaning rats from yogurt, quarg, and quarg whey.

Lactose-intolerant postweaning rats were fed experimental diets including yogurt, quargs prepared from yogurt culture and buttermilk culture, and two types of whey obtained from quarg processing. After feeding each diet for a period of 7 d, absence of blood glucose elevation and occurrence of diarrhea were used as indicators of lactose malabsorption. Blood glucose assays and absence of diarrhea indicated that yogurt and quargs prepared from yogurt and buttermilk culture were well tolerated by the rats. Wheys containing the same levels of viable organisms and lactose as the quargs caused severe symptoms of diarrhea and poor lactose absorption as indicated by no changes in blood glucose levels. Plate counts and enzyme assays of gastrointestinal contents confirmed presence of viable culture organisms and beta-galactosidase activity after feeding the two types of quarg. The availability of viable organisms, the exogenous lactase activity, and especially the slow gastric emptying may all have contributed to more efficient hydrolysis and digestion of lactose from quargs and yogurt than from the wheys.

Animals↗

Some new and important clues to the causes of colic.

Colic, or persistent unexplained crying in infants, is commonly encountered by health professionals. While not harmful to the child, it can place a great deal of stress on the parents and family. The cause of colic has not been definitively identified. Transient lactose intolerance, as a result of inadequate production of the enzyme lactase, is one possibility. Studies have shown a reduced crying time when formula or breast milk is incubated with lactase. Colief Infant Drops consist of lactase in a glycerol and water solution which, when added to formula or breast milk, converts lactose to simple sugars and makes the feed more easily digestible.

Animals↗

Protein patterns of brush-border fragments in congenital lactose malabsorption and in specific hypolactasia of the adult.

Brush-border membrane proteins of the small-bowel mucosa were separated on polyacrylamide gels from intestinal biopsy specimens obtained from four children with congenital lactose malabsorption and from two adults with specific hypolactasia. In three patients with the congenital type of lactase deficiency the protein band corresponding to brush-border lactase was reduced in intensity, but was never completely absent. No difference in gel patterns was detected when this pattern in congenital deficiency was compared to that obtained from the two patients with adult-type selective hypolactasia. In one patient with congenital lactose malabsorption the protein band corresponding to lactase activity was not detectable. The findings suggest that the mechanisms leading to low lactase activity in the congenital and adult forms of lactose intolerance are similar.

Adult↗

A new method for chemical analysis of faeces.

By using a centriflo membrane cone filter it has become possible to obtain an ultrafiltrate from a 24-h stool specimen. In this faecal fluid several clinical chemical parameters were analysed, such as pH, osmolality, creatinine, sodium, potassium, calcium, magnesium, chloride, bicarbonate, phosphate and lactate. Reference intervals for these substances were obtained in healthy individuals. The data of this control group were compared to those of patients with diarrhoea due to active inflammatory bowel disease, irritable bowel syndrome, lactose intolerance and persons with an ileostomy.

Adolescent↗

[Relationship between primary lactose malabsorption and consumption of dairy products].

This study was designed to determine the influence of lactose malabsorption on the consumption of dairy products. We studied 157 children and 43 adults. The Breath-hydrogen test was used to define their level of lactose digestion. The prevalence of lactose maldigesters was 12%. We found a large relationship between the consumption of milk and milk products and age. Malabsorbers consumed more fermented dairy products (ripened cheese and yogurt) than did absorbers (p < 0.05). Subjects with normal lactose absorption consumed more milk, butter, cream cheese and global lactose than the maldigesters (p < 0.05). Lactose intolerance, familiar consumption and geographic origins had little influence on an individual's consumption habits.

Adolescent↗

[Analysis of lactase activities of small intestine mucous membrane by double labeled stable isotope technique in subjects with lactase deficiency].

OBJECTIVE: Low lactase activity in small intestine mucosa is the main reason for the occurrence of lactose malabsorption (LM) and lactose intolerance (LI). It would be the basis for the research on LM and LI to find an accurate method to analyze the activity of lactase. METHODS: In this study, 43 volunteers were selected and divided into LM and LI group according to the results of H2 breath test and symptoms record. Twenty-five grams of 13C-lactose and 0.5 g 2H-glucose in 250ml solution were consumed by all the volunteers. The concentration of total plasma glucose, 13C- glucose and 2H-glucose were measured, the ratio of [13C-glucose]/[2H-glucose] and lactose digestion index (LDI)were calculated which could reflect the lactase activities in the mucous membrane of small intestine. RESULTS: It was found that there was no significant difference in the concentration of total glucose and 13C-glucose, while the LDI in LM group (0.47 +/- 0.15) was significantly higher than LI group (0.34 +/- 0.14). There was no significant relationship between LDI and 6h cumulative breath H2 amount (r = 0.12, P = 0.46). The 13 C-lactose/2 H-glucose challenged test showed there was still residual lactase activity in small intestine. CONCLUSION: It was concluded that 13C-lactose/2H-glucosetest can accurately and sensitively determine the lactase activity on small intestinal mucous membrane and digestible lactose amount.

Adult↗

Galactose consumption induces conditioned flavor avoidance in rats.

Recent findings revealed that intragastric infusions of galactose conditioned a flavor avoidance in adult rats. To determine whether the galactose-conditioned avoidance was due to the infusion procedure, we investigated the flavor conditioning effect of orally consumed galactose. Food-restricted rats drank a flavored galactose solution, a flavored fructose solution and a flavored saccharin solution in separate one-bottle training sessions; grape, cherry and orange flavors were used. Because fructose is sweeter than galactose, saccharin was added to the galactose solution to increase its palatability. Pre- and posttraining preferences for the galactose and fructose solutions were evaluated in two-bottle choice tests. Also, preferences for the sugar-paired flavors were evaluated in two-bottle tests with the flavors presented in saccharin. In Experiment 1, rats were trained with flavored 80 g/L fructose, 80 g/L galactose + 2 g/L saccharin, and 2 g/L saccharin solutions (20 mL/d). Their preference for the flavored galactose solution changed (P < 0.01) from 76% (pretraining) to 19% (posttraining). The rats also avoided (P < 0.05) the flavor paired with the galactose solution in choice tests with the fructose-paired flavor and the saccharin-paired flavor. Similar pre- to posttraining preference reversals were obtained in Experiments 2 and 3, which used 20 g/L galactose and fructose solutions, and 20 g/L galactose and fructose solutions mixed with 20 g/L glucose, respectively. These findings, together with the intragastric infusion data, demonstrate that galactose has aversive postingestive consequences in adult rats even at low concentrations (20 g/L). Unlike lactose intolerance, which is due to intestinal malabsorption, this galactose-induced flavor avoidance is presumably due to the slow and incomplete postabsorptive metabolism of galactose.

Animals↗

Case of congenital short small intestine: survival with use of long-term parenteral feeding.

Isolated congenital short small intestine is a rare anomaly. Of six (one male, five females) previously reported cases, four died in infancy from intractable diarrhea. We report the case of 7-year-old boy with this syndrome in whom a 2-year period of parenteral feeding at home allowed normal weight gain, growth, and development while intestinal adaptation occurred. Parenteral feeding was discontinued at age 2 1/3 years, and for the past 5 years his weight has remained between the tenth and 25th percentiles and his stature between the 25th and 50th percentiles. His development has been normal and he functions at or above grade level at school. Coefficient of fat absorption has increased from 54% to 81%. Vitamin B12 absorption has improved but has not normalized. He remains lactose intolerant. We believe his survival, growth, and development would have been compromised if he had not received a prolonged period of parenteral feeding.

Child Development↗

Protein-losing enteropathy and malabsorption in acute measles enteritis.

Gastrointestinal protein loss and xylose and lactose absorption were both abnormal in underweight children with acute measles and diarrhoea. The protein loss was equivalent to a mean absolute albumin loss of 1.68 plus or minus 0.21 g/day, while the mean one-hour blood xylose level was 0.93 plus or minus 0.38 mmol/l (14.0 plus or minus 5.7 mg/100 ml) in the acute stage and 1.71 plus or minus 0.43 mmol/l (25.6 plus or minus 6.5 mg/100 ml) after recovery (P less than 0.01). Lactose intolerance was found in four children out of 17 tested. Thus faecal protein loss and malabsorption may contribute significantly to the development of malnutrition after measles.

Acute Disease↗

Adaptation of lactose maldigesters to continued milk intakes.

Twenty-five lactose-maldigesting and lactose-intolerant African Americans, ranging in age from 13 to 39 y, were given gradually increasing amounts of lactose in milk over a period of time until the maximum lactose dose tolerated was determined. Seventeen (77%) of the 22 subjects who completed the study tolerated > or = 12 g lactose and 5 (23%) tolerated < 12 g. Breath-hydrogen tests done on each subject with the maximum dose of lactose tolerated showed that only four (18%) had a breath-hydrogen concentration < 5 ppm above fasting concentration. This study suggests that the majority of African-American young adults who claim intolerance to moderate amounts of milk can ultimately adapt and tolerate > or = 12 g lactose in milk (the equivalent of 8 oz of full-lactose milk) with minimal or no discomfort if milk is ingested in gradually increasing amounts. The mechanism of adaptation is assumed to be an increased tolerance to colonic lactose-fermentation products.

Adaptation, Physiological↗

Human small-intestinal beta-galactosidases. Separation and characterization of one lactase and one hetero beta-galactosidase.

1. Two beta-galactosidases from human small-intestinal mucosa were separated by gel-filtration chromatography and the properties of the two enzymes were studied. Lactose and four hetero beta-galactosides were used as substrates. 2. One of the enzymes was particle-bound and could be partially solubilized with papain. Of the substrates hydrolysed by this enzyme, lactose was hydrolysed most rapidly. This enzyme is thus essentially a disaccharidase and is named lactase. It is presumably identical with the ;lactase 1' described earlier. 3. The other enzyme was mainly soluble and hydrolysed all artificial substrates used, whereas no lactase activity could be detected. This enzyme has therefore been designated hetero beta-galactosidase. 4. p-Chloromercuribenzoate (0.1mm) inhibited the hetero beta-galactosidase completely but did not influence the activity of the lactase. Tris was a competitive inhibitor of both enzymes. 5. The residual lactase activity in the mucosa of lactose-intolerant patients may be exerted by a small amount of remaining lactase as such, or possibly by a third enzyme with a more acid pH optimum.

Chloromercuribenzoates↗

Intestinal retinol esterification and serum retinol in children with cystic fibrosis.

Children with cystic fibrosis (CF) often have a poor vitamin A status. We found in the present work a reduced level of serum retinol in older children with this disease. As retinol enters intestinal lymph as retinyl esters, the enzyme acyl-CoA:retinol acyltransferase (ARAT) may be of importance for retinol absorption. We have assayed ARAT activity in duodenal mucosal homogenate from children with CF. There was a large variation within the group. However, mean ARAT activity was not significantly decreased, as compared with controls. Thus, the lack of pancreatic enzymes probably is the main reason for reduced vitamin A absorption in CF. In celiac disease and in lactose intolerance--both mucosal disorders--a significant reduction of mean ARAT activity was found.

Acyltransferases↗

Enzymatic maturation of the gastrointestinal tract and its relevance to food allergy and intolerance in infancy.

The biologic clock that determines the temporal sequence of maturation of digestive and absorptive processes in the gastrointestinal tract is genetically predetermined, but may be modified by dietary, hormonal, or other factors. In general it may be said that the gastrointestinal tract of full-term neonates is capable of digesting and absorbing a nutritionally adequate quantity of dietary protein but capacity is limited. Very low birth weight preterm infants, who are surviving the early neonatal period in increasing numbers, have immaturity of a wide range of digestive and membrane-associated absorptive processes; in addition macromolecular absorption may be increased. Whether a limited capacity to digest food protein results in increased or altered antigenic stimulation of these immature infants remains speculative with present knowledge. Immaturity of intestinal lactase may lead to problems of lactose intolerance, but there is recent evidence that lactase activity may be inducible by milk feeding.

Absorption↗