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PubMed1977

Lactose malabsorption among the Pima indians of Arizona.

Lactose loading tests and other means were used to determine the pattern of primary "adult" lactose malabsorption (LM) and milk use among 171 subjects, including 122 children and 49 adults, almost all of them Pima Indians of Arizona. LM develops at quite young ages in full-blooded Pima children: already in the 3- to 4-year age group, 40% had LM. Of 62 full-blooded Indians (greater than or equal to 4 years of age), 59 (95%) had LM. Of 41 Indians (greater than or equal to 4 years) who were of mixed Indian-northern European ancestry, however, only 25 (61%) had LM, and, among them, prevalence of LM correlated with degree of northern European admixture. Whereas only 21% of Pima lactose absorbers reported symptoms after the loading test, 72% of malabsorbers did so, with older malabsorbers more likely to experience symptoms. In their everyday lives, only 23% of malabsorbers recognized symptoms brought on by milk consumption, but the percentage of malabsorbers making such an association increased with age. Nevertheless the Pima, adults as well as children, continue to drink reasonable quantities of milk. Family pedigrees are consistent with the hypothesis that adult lactose absorption is inherited as an autosomal dominant trait. Over-all results of this study, moreover, support the geographic hypothesis advanced to explain ethnic or racial differences in prevalence of LM, rather than the induction hypothesis.

Adolescent↗
PubMed1996

The clinical relevance of lactose malabsorption in irritable bowel syndrome.

OBJECTIVE: The prevalence of lactose malabsorption (LM) in the Caucasian population of northern Europe is estimated to be low. Irritable bowel syndrome (IBS) is a very common diagnosis, and its symptoms are nearly identical to those of LM. Therefore we investigated the prevalence of LM among IBS patients in comparison with healthy volunteers. DESIGN: A double-blind clinical trial compared with healthy controls. SETTING: One out-patient gastroenterology clinic in the Netherlands. PATIENTS: 70 Caucasian IBS patients and 35 healthy volunteers (staff members). METHODS: All 105 underwent hydrogen (H2) breath and blood glucose tests, after an oral intake of 50 grams of lactose. The IBS patients were treated with a lactose-restricted diet for 6 weeks. They completed a lactose intake score before, and a symptom score scored by six separate criteria, before, during and after treatment. RESULTS: In 17 out of 70 (24.3%) IBS patients LM was detected, in comparison with 2 out of 35 (5.7%) controls (P < 0.009). There was no difference in the pre-entry mean lactose intake and symptom score between the LM positive and negative IBS patients. The mean symptom score of the LM positive group showed a marked decrease after 6 weeks of dietary therapy (P < 0.001). CONCLUSION: A substantial number of IBS patients showed a clinically unrecognized lactose malabsorption, which could not be discriminated by symptoms and dietary history, and which can be treated with a lactose-restricted diet. Therefore LM has to be excluded before the diagnosis IBS is made.

Adolescent↗
PubMedDate not supplied

[Current problems of lactase deficiency].

The tests with lactose loading followed by the assay of blood sugar were conducted in 500 normal subjects, aged from 18 to 89 years, and 262 patients with gastro-intestinal diseases, aged from 25 to 55 years. When lactose malabsorption was detected, aspiration biopsy of the small intestine mucosa was performed followed by the study of the structure and the level of a number of disaccharidases (lactase, maltase, saccharase). Lactose malabsorption was detected in 72 (14.4%) out of 500 normal subjects (10.6%--aged 18-59, and 20%--aged 60-89 years), among them there were 12.5% of Russians, 13% of Byelorussians and 5.8% of Ukrainians (aged 25-55 years). The secondary lactose malabsorption was recorded in 44% of patients with ulcerative colitis, in 33% of patients with chronic enterocolitis, in 11.5% of patients with gastric ulcer, in 8% of those with duodenal ulcer, in 23.5% of patients with chronic gastritis attended by lowered secretory function, and in 8% of those with enhanced secretory function.

Adolescent↗
PubMed2004

Lactose malabsorption in a population with irritable bowel syndrome: prevalence and symptoms. A case-control study.

BACKGROUND: Symptoms after intake of milk are common in persons with irritable bowel syndrome (IBS). The aims of this study were to compare the prevalence of lactose malabsorption (LM) and symptoms related to intake of milk and lactose in subjects with IBS with that of healthy volunteers, and to search for symptoms that are characteristic of LM. METHODS: A case-control study in a Norwegian population was initiated. Subjects with IBS were asked for symptoms related to intake of milk and lactose, tested for LM, and compared with a group of healthy volunteers. RESULTS: The study comprised a total of 187 persons (82 with IBS and 105 volunteers), females/males: 138/49, mean age 47 years. In subjects with IBS and in healthy volunteers, LM was present in 3/74 (4.1%) and 4/105 (3.8%), respectively (ns), milk-related symptoms in 32/79 (40%) and 13/105 (12%), respectively (P < 0.001) and symptoms after intake of lactose in 28/74 (38%) and 21/104 (20%), respectively (P=0.01). Borborygmi starting within 5 h after intake of lactose and lasting for more than 2 h indicated LM (OR 61 (95% CI: 8-475), P < 0.001). CONCLUSIONS: IBS and LM are unrelated disorders in a Norwegian population. Milk-related symptoms and symptoms after intake of lactose are unreliable predictors for LM. Precise symptom-based criteria might enhance the diagnostic accuracy for LM.

Adult↗
PubMed2006

Low lactase activity in a small-bowel biopsy specimen: should dietary lactose intake be restricted in children with small intestinal mucosal damage?

OBJECTIVE: Small intestinal mucosal damage can result in decreased lactase activity (LA). When LA is low in a small-bowel biopsy (SBB) specimen, a reduction of dietary lactose intake is usually advised. This is often done by reducing dietary dairy products, which also reduces the intake of calcium, protein and vitamins. Since intestinal damage can have a patchy character and LA varies along the horizontal axis of the small intestine, the relevance of SBB measurement for intestinal LA could be questioned. We compared LA in the SBB with the in vivo capacity to digest lactose using the Lactose Digestion Index (LDI). MATERIAL AND METHODS: LA was measured in 18 children aged 0.8-10.9 years (mean 3.9, SD 2.4) undergoing SBB for various indications. In all children the LDI was determined using the (13)C-lactose/(2)H-glucose test. RESULTS: In 9/18 biopsy specimens LA was low (<10 U/g protein). LDI was normal in 14/18 patients. In 8 out of 9 patients with normal lactase activity, LDI was also normal, while in 6 out of 9 patients LDI was normal despite low LA in the biopsy. In patients with normal LDI, histology was normal in 6/14, in 4/14 mild histological changes (Marsh II) were seen and in 4 patients histological damage was severe (grade III). CONCLUSIONS: In children with small-bowel mucosal damage, lactose digestive capacity can remain high despite low LA and histological changes in an SBB. Extrapolation of LA in SBB specimens to overall lactose digestive capacity may not be reliable. The advice concerning the restriction of intake of dairy products cannot be based on the data of the SBB only.

Biopsy↗
PubMed1994

Intestinal permeability.

Damage to the mucosal barrier may be assessed, non-invasively by use of sugar probes, which permeate through the transcellular or paracellular (tight junction) routes. A standardised test, with analysis of a five hour urine collection has proved useful in studying the sequelae of non-steroid anti-inflammatory drug (NSAID) administration, untreated coeliac disease, and enteric infections. Choice of probe molecule is crucial and lactulose/l-rhamnose seem to be satisfactory, in contrast with polyethylene glycol. Significant correlations have been seen between permeability and plasma IgA concentrates in nephropathy, and between permeability and the passage of neutrophil chemotactic agents. The increased permeability associated with NSAID treatment may relate to the adverse effects of NSAIDs on enterocyte mitochondrial morphology and metabolism. These two factors may predispose the mucosa to permeation of bacterial chemoattractant molecules that elaborate a local inflammatory response. A similar mechanism may operate in patients with untreated Crohn's disease, who show abnormally high permeability. Remission induced by treatment with elemental diets coincides with a reduction in permeability. The period to relapse correlated with the inability of patients to maintain low permeability to sugar probes. These results suggest a mechanism for the benefits of elemental enteral nutrients in the treatment of Crohn's disease.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1992

Galactitol is not a cause of senile cataract.

It has been postulated that the accumulation of sugar alcohol, galactitol, from milk induces cataract in the eye lens through an osmotic mechanism. In this study the concentrations of galactitol and other sugar alcohols (sorbitol, mannitol and inositol) were measured by sensitive gas chromatography in the lenses of 15 patients operated on for senile idiopathic cataracts and in 14 clear lenses removed at autopsy. Large amounts of inositol (mean +/- SD, 4.1 +/- 3.1 vs 4.7 +/- 3.0 mumol/g lens wet weight) and small amounts of mannitol and sorbitol were detected in both study groups. Galactitol levels remained clearly below the detection limit (2 nmol/g) in all lenses. It seems unlikely that senile cataract is a result of the accumulation of galactitol in the eye lens.

Adult↗
PubMed1977

Individual sensitivity to lactose in lactose malabsorption.

The clinical significance of lactose malabsorption and the individual sensitivity to lactose were investigated in 20 patients with verified lactose malabsorption. Thirteen patients were relieved of all symptoms while seven improved only on a lactose-free dth lactose-free milk but following provocation with increasing amounts of lactose, the tendency to diarrhea and abdominal discomfort increased considerably. Three patients experienced discomfort after provocation with only 5 gl lactose. On provocation with increasing amounts of lactose the seven patients who had not recovered also developed increased abdominal discomfort but none of them developed increased tendency to diarrhea. It is concluded that, in addition to lactose malabsorption, these patients must suffer from ittitable colon with tendency to constipation.

Abdomen↗
PubMed1975

Studies on the etiology of milk intolerance in Japanese adults.

1. The incidence of milk intolerance is approximately 19% in Japanese adults when 200 ml of milk is given. However, a much greater incidence was assumed when considered under the criteria of Western standard. 2. The lactase activity was significantly greater in milk drinkers than non-drinkers. And, internationally, the active is higher in those nationalities whose milk consumption is greater. 3. Lactase is an adaptive enzyme and rather easily induced by lactose load feeding in animals. From the data of our own and of the literature, it was further confirmed that environmental factors play a more important role than genetic factors in the etio-pathogenesis of milk intolerance.

Adolescent↗
PubMed2005

Genetic evidence in support of a shared Eurasian-North African dairying origin.

The process by which pastoralism and agriculture spread from the Fertile Crescent over the past 10,000 years has been the subject of intense investigation by geneticists, linguists and archaeologists. However, no consensus has been reached as to whether this Neolithic transition is best characterized by a demic diffusion (with a significant genetic input from migrating farmers) or a cultural diffusion (without substantial migration of farmers). Milk consumption and thus lactose tolerance are assumed to have spread with pastoralism and we propose that by looking at the relevant mutations in and around the lactase gene in human populations, we can gain insight into the origin(s) and spread of dairying. We genotyped the putatively causal allele for lactose tolerance (-13910T) and constructed haplotypes from several polymorphisms in and around the lactase gene (LCT) in three North African Berber populations and compared our results with previously published data. We found that the frequency of the -13910T allele predicts the frequency of lactose tolerance in several Eurasian and North African Berber populations but not in most sub-Saharan African populations. Our analyses suggest that contemporary Berber populations possess the genetic signature of a past migration of pastoralists from the Middle East and that they share a dairying origin with Europeans and Asians, but not with sub-Saharan Africans.

Africa↗
PubMed2000

Lactose intolerance: diagnosis and management.

Lactose intolerance affects hundreds of millions of people worldwide. Although the presentation is frequently atypical, it should be part of the differential diagnosis when evaluating nonspecific gastrointestinal symptoms. We review the terminology, types of lactase deficiencies, diagnostic procedures, and management.

Ethnicity↗