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Gastrointestinal dysfunction and disaccharide intolerance in children infected with human immunodeficiency virus.

Because gastrointestinal dysfunction is a major problem in children with human immunodeficiency virus (HIV) infection, we utilized breath hydrogen measurements to determine the relationship between disaccharide malabsorption and gastrointestinal dysfunction in HIV-infected children. We found a strong association between lactose intolerance and persistent diarrheal disease in this population (p less than 0.007, Mann-Whitney U test). We also found evidence of sucrose malabsorption and persistent diarrheal disease in three of the children. Extensive microbiologic evaluations failed to reveal an etiologic agent related to the occurrence of gastrointestinal symptoms. Our findings indicate that disaccharide intolerance is a common occurrence in HIV-infected children with persistent diarrheal disease. Careful attention to dietary intake may be required to ameliorate clinical symptoms and to maintain adequate nutrition.

Breath Tests↗

Human small-intestinal -galactosidases. Separation and characterization of three forms of an acid -galactosidase.

1. An acid beta-galactosidase, optimum pH4.0-4.5, in the human small-intestinal mucosa was separated and characterized. 2. Autolysis of mucosal homogenates at acid pH inactivated the lactase and hetero beta-galactosidase; the total activity of the acid beta-galactosidase was only slightly depleted, but a greater proportion of the enzyme was solubilized by this treatment. 3. Separation on a Sephadex G-200 column revealed that the acid beta-galactosidase could occur in at least three different forms, probably representing monomer, dimer and octamer or polymer of the enzyme. 4. The properties of the different forms of the acid beta-galactosidase were studied with regard to pH optimum, K(m), rate of hydrolysis of different substrates, and sensitivity to p-chloromercuribenzoate and tris as inhibitors. All these properties were the same for the different forms of the enzyme. 5. The acid beta-galactosidase hydrolyses lactose as well as hetero beta-galactosides and contributes to the lactase activity of intestinal biopsies also when measured at pH 6. This enzyme may therefore be responsible for a considerable part of the residual lactase activity found in lactose-intolerant patients.

Autolysis↗

Dietary manipulation of postprandial colonic lactose fermentation: I. Effect of solid foods in a meal.

The effect of adding solid foods--cornflakes, banana and hard-boiled egg--to a meal with 360 ml of intact milk containing 18 g of lactose was investigated in 13 lactose-malabsorbers and 10 lactose-absorbers chosen from 36 Guatemalan adults screened for their capacity to digest and absorb completely the lactose in this volume of milk. A six-hour hydrogen breath test was used as the index of carbohydrate absorption. Minimal breath H2 was excreted by lactose-absorbers with either the intact milk alone, the intact milk with solid foods, or lactose-prehydrolyzed milk with solids. In lactose-malabsorbers, however, the 6-h excretion of H2 with intact milk plus solid food was intermediary between milk alone and prehydrolyzed milk with solids. A relative net reduction of 47% in lactose malabsorption was produced by adding food, and the peak-rise in breath H2 was delayed by 2 hours. A physiological consequence of taking solid foods along with milk is a slower rate of colonic fermentation, and this may be the basis for reducing gastro-intestinal symptoms in lactose-intolerant malabsorbers.

Adult↗

Cholestyramine and medium-chain triglyceride in prolonged management of patients subjected to ileal resection or bypass.

The pathophysiology of cholerrheic enteropathy is described and a series of patients reviewed. Of 11 patients with chronic disabling diarrhea and steatorrhea after ileal resection or bypass, two had recurrent ileitis, three had lactose intolerance and six of those operated on five years or more previously had vitamin B(12) deficiency. Cholestyramine was given alone or with medium-chain triglyceride (MCT) or Portagen (MCT and lactose). The maximal response occurred when cholestyramine was given with Portagen - significantly reduced stool frequency and weight in all patients and stool fat in five. Restudy of five patients four to 11 months later showed the same pattern of response: cholestyramine with 70% MCT abolished symptoms in four patients (ileectomy) and 100% MCT alone greatly improved the condition of the fifth (extensive small bowel resection).

Adolescent↗

Effect of dietary lactose on the absorption of protein, fat and calcium in the postweaning rat.

To assess the effect of dietary lactose on the intestinal absorption of protein, fat and calcium in lactose intolerance due to low levels of intestinal lactase, balance studies were carried out on postweaning rats (initial weight 164 g) for a period of 10 days. The experimental diets contained either 10% or 30% lactose, while in the control diets the lactose was replaced with equivalent amounts of sucrose. The excretions of fecal and urinary nitrogen, calcium and fat are expressed as precent of intake over the 10-day period. The fecal excretion of nitrogen and fat was significantly higher in the lactose groups (P less than 0.05). The fecal calcium excretion, however, was lower in the lactose groups, the difference being significantly only in the case of the 30% lactose diet (P less than 0.001). There was no difference in urinary nitrogen excretion between the lactose and sucrose groups, but urinary calcium excretion was significantly higher in the rats fed the 30% lactose diet (P less than 0.01). These findings suggest that dietary lactose may reduce the absorption of protein and fat, but not of calcium, in individuals with low levels of intestinal lactase activity.

Animal Nutritional Physiological Phenomena↗

Influence of loperamide on lactose handling and oral-caecal transit time.

BACKGROUND: The influence of pharmacologically prolonged oral caecal transit time on lactose handling is examined in the wake of finding improved lactose handling during naturally occurring prolonged oral-caecal transit time. METHODS: Sixteen normal male volunteers with lactose maldigestion were pretreated with 8 and 12 mg loperamide on different days and lactose handling was compared by measuring areas under the curve during lactose breath H2 testing (3 h). The oral-caecal transit time was similarly measured using lactulose and exhaled breath H2. Symptom scores were recorded and, in three subjects, blood sugar was simultaneously measured. RESULTS: The mean +/-S.E.M. baseline oral-caecal transit time was 56.9 +/- 5.9 min. Loperamide significantly prolonged oral-caecal transit time (90.3 +/- 11.1 and 82.1 +/- 13.9 min for 12 and 8 mg loperamide, respectively; P < 0.05). The lactose breath H2 area under the curve with 12 mg loperamide was significantly less than at baseline (7685 +/- 985.6 vs. 10243.1 +/- 1607, respectively; P < 0.05). Significantly fewer symptoms were recorded with both doses of loperamide during the 3 h test but with 12 mg loperamide only on follow-up. There was no significant rise in blood sugar at any time in the three subjects studied. CONCLUSIONS: Loperamide-induced graded prolongation of oral-caecal transit time is associated with significantly improved lactose handling as measured by a reduction of the area under the curve. Symptoms of lactose intolerance may also be improved with loperamide. Prolongation of oral-caecal transit time with loperamide may be useful as adjunctive or primary therapy of carbohydrate intolerance in patients with rapid transit.

Administration, Oral↗

Eating disorders in inflammatory bowel disease.

Before or after their diagnosis, each of three patients with inflammatory bowel disease had an established eating disorder. Two had bulimia and one was presumed to have had anorexia/bulimia. In addition to the usual modes of weight control, such as vomiting and fasting, two of the patients, all of whom were lactose intolerant, used milk ingestion as a purgative.

Adolescent↗

Effect of cow's milk on the gastrointestinal tract: a persistent dilemma for the pediatrician.

The confusing area of cow's milk intolerance is explored in an attempt to define the various mechanisms whereby milk affects gastrointestinal function, resulting in clinical symptoms (diarrhea, vomiting, gastrointestinal bleeding, etc.). The adverse reaction of infants to cow's milk ingestion may relate to lactose intolerance (enzymatic), a direct toxic reaction to the mucosal surface resulting in epithelial damage, or it may be immunologically mediated. Factors such as increased intestinal permeability to milk proteins during the newborn period may also contribute to susceptibility of young infants to milk sensitivity. The relative roles of systemic (milk agglutinins) and local immunity (SIgA antibodies) in milk intolerance are discussed and differential immunologic responses (IgE versus IgA/IgM) considered in the pathogenesis. It was concluded that new techniques such as organ culture of intestinal biopsy specimens are needed to establish the diagnosis of hypersensitivity and to begin to provide ways of adequately treating the condition.

Agglutinins↗

Lactose causes heart arrhythmia in the water flea Daphnia pulex.

The cladoceran Daphnia pulex is well established as a model for ecotoxicology. Here, we show that D. pulex is also useful for investigating the effects of toxins on the heart in situ and the toxic effects in lactose intolerance. The mean heart rate at 10 degrees C was 195.9+/-27.0 beats/min (n=276, range 89.2-249.2, >80% 170-230 beats/min). D. pulex heart responded to caffeine, isoproteronol, adrenaline, propranolol and carbachol in the bathing medium. Lactose (50-200 mM) inhibited the heart rate by 30-100% (K(1/2)=60 mM) and generated severe arrhythmia within 60 min. These effects were fully reversible by 3-4 h. Sucrose (100-200 mM) also inhibited the heart rate, but glucose (100-200 mM) and galactose (100-200 mM) had no effect, suggesting that the inhibition by lactose or sucrose was not simply an osmotic effect. The potent antibiotic ampicillin did not prevent the lactose inhibition, and two diols known to be generated by bacteria under anaerobic conditions were also without effect. The lack of effect of l-ribose (2 mM), a potent inhibitor of beta-galactosidase, supported the hypothesis that lactose and other disaccharides may affect directly ion channels in the heart. The results show that D. pulex is a novel model system for studying effects of agonists and toxins on cell signalling and ion channels in situ.

Ampicillin↗

Lactase degradation by human enteric bacteria.

Twelve non-pathogenic bacteria and two yeast strains isolated from the duodenal aspirate or mucosa of five children with diarrhoea were tested for their ability to degrade non-human lactase in vitro. Both yeast strains and eleven of the bacterial strains significantly reduced lactase activity. A similar action on human lactase could be a cause of lactose intolerance.

Bacteria↗

Calcium absorption from milk in lactase-deficient subjects.

Intestinal calcium absorption from milk containing lactose (+) and from another containing glucose (-) was studied in eight patients with normal lactase (NL) and seven lactase-deficient (LD) subjects to determine if lactase deficiency is implicated in Ca absorption. The results were compared with data obtained from Ca ingestion in a water solution. Ca absorption was measured by a double-isotope technique and the kinetic indices were obtained by a deconvolution method. With (-), Ca absorption was identical in NL and LD subjects and slightly higher than with water solution (15%, NS). With (+), Ca absorption in NL subjects was identical with that from water solution; in LD subjects it increased (23%, p less than 0.02). These data indicate that: Ca is absorbed equally well from milk as from water solution; (+) favors Ca absorption in LD subjects, which suggests that milk ingestion might be encouraged in LD subjects to avoid Ca deficiency; and (-) should be a valuable alternative for lactose-intolerant patients.

Animals↗

Assessment of the influence of hydrogen nonexcretion on the usefulness of the hydrogen breath test and lactose tolerance test.

The recognition of hydrogen nonexcretion in up to 20% of tested subjects and the large ethnic differences in the prevalence of lactose malabsorption make it necessary to reassess the diagnostic usefulness of the lactose tolerance test and the hydrogen breath test. Both tests were performed in 83 consecutive patients with suspected lactose malabsorption who ingested 50 g lactose. On a separate day a hydrogen breath test was performed after 25 g lactulose. The prevalence of hydrogen nonexcretion was 18%. The diagnostic usefulness of hydrogen breath test was influenced both by the individual threshold for hydrogen excretion and the amount of malabsorbed lactose. In addition to baseline values, breath samples for hydrogen measurements have to be taken at 30, 60, 90, 180, and 240 minutes after ingestion of lactose. For the lactose tolerance test only one measurement of serum glucose at 30 minutes is needed in addition to the baseline measurement. The combination of both tests excludes the influence of hydrogen nonexcretion, but even if a combined diagnostic approach utilizing the lactose hydrogen breath test and lactose tolerance test is used, 6% of patients presenting with symptoms suggestive of lactose intolerance cannot be classified.

Adolescent↗

Dairy sensitivity, lactose malabsorption, and elimination diets in inflammatory bowel disease.

The ability of inflammatory bowel disease (IBD) patients to tolerate dairy products and the guidance they receive from physicians and nutritionists on this subject are important considerations in the management of their IBD. Although most affected persons are able to consume a glass of milk daily without discomfort, additional consideration must be given to specific factors that can be relevant to certain individuals. The declaration by patients that they are "dairy sensitive" may be related to lactose intolerance or malabsorption, the long-chain triacylglycerol content of milk, allergy to milk proteins, as well as psychologic factors and the misconception that dairy products can be detrimental to their health. The prevalence of lactose malabsorption is significantly greater in patients with Crohn disease involving the small bowel than it is in patients with Crohn disease involving the colon or ulcerative colitis. In the latter colonic conditions the prevalence of lactose malabsorption is mainly determined by ethnic risk, which is based on genetic factors. In addition, lactose malabsorption in Crohn disease of the small bowel may be determined by factors other than lactase enzyme activity, such as bacterial overgrowth and/or small bowel transit time. Physicians differ widely in the advice they give their patients: some dogmatically advise avoidance of dairy products when the diagnosis is made whereas others discount the possible role of dairy in the management of IBD. IBD patients avoid dairy products more than they would need to based on the prevalence of lactose malabsorption and/or milk intolerance, probably partly because of incorrect patient perceptions and arbitrary advice from physicians and authors of popular diet books. Adequate scientific and clinical information is now available to permit recommendations about the intake of dairy products for each IBD patient.

Humans↗

Lactose digestion in pregnant African-Americans.

OBJECTIVE: This paper reports on the status of lactose digestion during early and late pregnancy and at 8 weeks postpartum in an African-American population. The hypothesis is that lactose digestion and milk tolerance do not change throughout pregnancy and do not differ from those of non-pregnant African-American women. DESIGN AND SUBJECTS: This longitudinal study determined lactose digestion after ingesting 240 ml of 1% fat milk containing 12 g of lactose at: (1) early pregnancy, prior to 16 weeks (n=148); (2) late pregnancy, 30-35 weeks (n=77); and (3) 8 weeks postpartum (n=93). One hundred and one comparably matched non-pregnant African-American women served as controls. RESULTS: Prevalence of lactose digestion, as measured by breath hydrogen, was 80.2% in the control women, 66.2% in early pregnancy, 68.8% in late pregnancy and 75.3% postpartum. The prevalence of women reporting symptoms was approximately 20% regardless of lactose absorption status. However, the control women reported significantly more symptoms than did the pregnant women. CONCLUSIONS: This study indicates that there is no significant change in lactose digestion during pregnancy. The prevalence of lactose intolerance for the pregnant African-American women studied is similar to that for non-pregnant African-American women and similar to previous prevalence reports in adult African-Americans. There was no change in the tolerance of lactose noted during pregnancy in these women. There were, however, fewer symptoms reported by the lactose-maldigesting pregnant women.

Academic Medical Centers↗

The human rumen.

The cow is a ruminant, and cow's milk has evolved to promote bacterial growth in the upper small bowel; whereas human milk has evolved to discourage bacterial growth. Examination of the constituents of the two milks shows that their differences can be accounted for in terms of this difference in function. Children who are fed a calf's diet tend to develop a rumen. This may lead to chronic diarrhoea and malnutrition and may be a factor in diarrhoea ascribed to cow's-milk-protein allergy and lactose intolerance.

Animals↗

Carbohydrate intolerance and kidney stones in children in the Goldfields.

Renal stones have been reported as a common finding in Australian Aboriginal children. The stones are predominantly urate in composition. We report on five children with nephrolithiasis from the Goldfields region of Western Australia. All were diagnosed when under 5 years of age, the majority being under 3 years. All five children also had lactose intolerance, and we postulate that carbohydrate malabsorption, together with the ensuing chronic diarrhoea and intraluminal breakdown of sugars by enteric bacteria may result in a situation of chronic metabolic acidosis. Chronic metabolic acidosis can lead to protein catabolism, increased urate excretion and the formation of renal stones. Carbohydrate intolerance may be an aetiological factor in the development of renal stones and possibly chronic renal disease, particularly in Aboriginal Australians. Renal disease represents one of the most significant factors affecting the health of Australian Aboriginal people. The incidence of end stage renal failure in this population exceeds that of non-Aboriginals by a factor of 13:1, and this disproportionate figure is increasing. It is likely that chronic renal damage is multifactorial; however, it is probable that at least some aetiological factors have their onset during childhood.

Carbohydrates↗

[Lactose malabsorption in ulcerative colitis. A case-control study].

BACKGROUND: The role of lactose malabsorption in ulcerative colitis is controversial. The aim of this study was to compare the prevalence of lactose malabsorption in a group of ulcerative colitis patients and a control group and to modify lactose consumption in view of the results. METHODS: Lactose malabsorption was studied using the hydrogen breath test in 52 patients with ulcerative colitis and 34 controls after ingestion of 25 g of lactose. A questionnaire on ingestion of milk products was also administered. RESULTS: Of the 52 patients with ulcerative colitis, 13 (25%) presented lactose malabsorption compared with 11 of the 34 (32%) controls (p = 0.45). Twenty-four patients (46%) had been advised to completely eliminate lactose from their diets. Twenty-seven of the 39 patients without malabsorption had reduced or eliminated lactose consumption after being diagnosed with ulcerative colitis. CONCLUSIONS: No significant differences in the prevalence of lactose malabsorption was found between patients with ulcerative colitis and controls. We believe that systematic elimination of lactose from the diets of these patients is erroneous. In our environment, we recommend the hydrogen breath test only in patients with symptoms of lactose intolerance.

Adolescent↗

Should yoghurt cultures be considered probiotic?

Probiotics are live micro-organisms that when administered in adequate amounts confer a health benefit on the host. Consumption of yoghurt has been shown to induce measurable health benefits linked to the presence of live bacteria. A number of human studies have clearly demonstrated that yoghurt containing viable bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii sp. bulgaricus) improves lactose digestion and eliminates symptoms of lactose intolerance. Thus, these cultures clearly fulfil the current concept of probiotics.

Dietary Supplements↗