Gastric emptying of lactose and milk in subjects with lactose malabsorption

Six lactose absorbers (LA) and 5 lactose malabsorbers (LM) had tests of gastric emptying with 750-ml meals of glucose in water, lactose in water, plain milk, and chocolate milk. The glucose and lactose meals emptied in a similar fashion in LA and LM subjects with a significant decrease in gastric emptying as the osmolarity of the meals was doubled. If the data are normalized by dividing lactose emptying by the emptying of glucose meals of twice the osmolality in each individual, the lactose malabsorbers empty significantly more lactose. Both LA and LM subjects emptied comparable amounts of milk meals having similar osmolarity. Chocolate milk, which had a higher osmolality than plain milk, emptied more slowly than plain milk in both groups, and this difference was significant in the LM group.     

Lactose malabsorption in Thai infants and children: effect of prolonged milk feeding.

More than one-third of Thai infants were lactose malabsorbers soon after birth and the percentage of lactose malabsorption increased with age. Beyond 4 years of age, all Thai children studied were lactose malabsorbers. Continued milk supplementation over the study period did not affect the ability to digest lactose in the amount given in the load test. Since the milk-supplemented group of children tended to have better weight gain and few undesirable gastrointestinal symptoms, it seems milk feedings can be used to advantage even among populations with a record of high lactose intolerance.     

Lactose malabsorption in adult patients at the Hospital das Clínicas de Ribeir?o Preto

A standard oral lactose tolerance test (LTT) was performed in 32 white and 18 non-white hospitalized Brazilian adults. A flat LTT was found in 22 (68,75%) white and in 17 (97,45%) non-white patients indicating a 78% overall rate of lactose malabsorption, Both lactose absorbers and malabsorbers showed a modal milk ingestion of less than a 1 glass/day. Symptoms related to milk consumption or lactose administration were more common among lactose malabsorbers. Estimations of disaccharidase activity in intestinal mucosa specimens obtained by peroral biopsy in 28 patients confirmed a high prevalence of lactose deficiency, and disclosed only one false result, in the patient with a flat LTT and high intestinal lactase levels.     

Lactase deficiency: a common genetic trait of the American Indian

Intestinal lactase activity was assessed indirectly in 156 American Indians by measuring breath hydrogen after an oral lactose load. Lactase deficiency was present in 66% of subjects and correlated highly with the percentage of Indian blood. Lactase deficiency was present by the age of 5 years and was unrelated to sex. Most lactase-deficient subjects (81%), but only a minority (23%) of lactase-sufficient subjects, developed symptoms after the oral lactose load, and among lactase-deficient subjects, symptoms occurred more frequently in adults than in children (P = 0.05). Indeed, by history, 53% of lactase-deficient adults, but only 10% of lactase-deficient children under 18 years of age, were aware of milk intolerance. Despite these differences, milk consumption was only slightly less (19 g) in the lactase-deficient subjects than in those with normal lactase activity (25 g) (P less than 0.05). The results indicate that lactase deficiency is a common autosomal genetic trait in the American Indian that becomes manifest in early childhood. Tolerance to dietary lactose appears to decline in the American Indian as he reaches adulthood, but in this population the decline in tolerance had only minor influence on lactose intake.     

Lactose malabsorption in adult patients with Crohn's disease

In order to evaluate, in adult patients with Crohn's disease (CD), the prevalence of lactose malabsorption and intolerance, and the percentage who can tolerate a physiologic amount of milk in their diet, we tested 37 patients with CD (19 with intestinal resection, and 18 without) and 67 healthy controls (C) with the H2-breath test after they had ingested increasing loads of lactose as 10% solution (12.5 g, 25 g, and 50 g). Patients with malabsorption after the 12.5-g dose were tested further with 250 ml of milk. In the total group of patients and in the subgroup of those with resection, the prevalence of malabsorption was higher than in controls at all lactose loads; in patients who had not undergone resection, no significant difference was observed with the 12.5-g dose. Eleven of 18 patients who were malabsorbers with the 12.5-g dose had malabsorption also with 250 ml milk; however, only three of them (8% of the total group) experienced symptoms of intolerance. We conclude that, in adult patients with CD, 1) the prevalence of lactose malabsorption is increased, 2) in patients who have undergone intestinal resection, malabsorption occurs at a lower dose of the sugar than in patients who did not, and 3) since only 8% of patients experienced symptoms of intolerance after the ingestion of milk 250 ml, this amount can be empirically inserted in the daily diet of an adult with CD.     

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.     

Exaggerated pancreatic polypeptide secretion in Pima Indians: can an increased parasympathetic drive to the pancreas contribute to hyperinsulinemia, obesity, and diabetes in humans?

Vagally-mediated hyperinsulinemia is a common abnormality in various rodent models of genetic and hypothalamic obesity that have a high propensity for type 2 diabetes. We hypothesized that Pima Indians, a population with a high prevalence of hyperinsulinemia, obesity, and type 2 diabetes also have an increased parasympathetic drive to the pancreas. To test this, we measured plasma concentrations of insulin and pancreatic polypeptide (PP), a surrogate marker of pancreatic vagal tone, in lean and obese Pima Indian and Caucasian children (n = 43, 26P/17C, 7 +/- 1 y) and adults (n = 92, 61P/31C, 31 +/- 5 y). Pima Indian children had approximately 2-fold higher fasting insulin and 57% higher fasting PP concentrations than age- and sex-matched Caucasian children (P < .05). Although there was no difference in fasting PP concentration between Pima Indian and Caucasian adults, in response to a mixed meal, Pima Indians had a 51% higher early (30 minutes) PP concentration and 2-fold higher early insulin concentration than Caucasians (P < .05). PP concentrations at 60 minutes and 120 minutes after the meal were also markedly higher in both lean and obese Pima Indians compared with lean and obese Caucasians. These results suggest that Pima Indians may have an increased parasympathetic drive to the pancreas, which could lead to a primary hypersecretion of insulin and contribute to their high propensity for obesity and diabetes, as is the case in various rodent models of obesity.     

Lactose malabsorption in Greek adults: correlation of small bowel transit time with the severity of lactose intolerance.

Using breath hydrogen analysis after 139 mmol (50 g) oral lactose load, we investigated the prevalence of lactose malabsorption in 200 Greek adults and examined the relationship between symptoms and small bowel transit time. One hundred and fifty subjects had increased breath hydrogen concentrations (greater than 20 ppm) after the lactose load. In these individuals peak breath hydrogen concentration was inversely related to small bowel transit time (r = 0.63, 6 = 6.854, p less than 0.001) and the severity of symptoms decreased with increasing small bowel transit time. Lactose malabsorbers with diarrhoea during the lactose tolerance test had a small bowel transit time of 51 +/- 22 minutes (x +/- SD; n = 90) which was significantly shorter than the small bowel transit time of patients with colicky pain, flatulence, and abdominal distension (74 +/- 30, n = 53; p less than 0.001) and both groups had significantly shorter small bowel transit time than that of asymptomatic malabsorbers (115 +/- 21 n:7; p less than 0.001). When the oral lactose load was reduced to 33 mmol (12 g), the small bowel transit time increased five-fold and the overall incidence of diarrhoea and/or symptoms decreased dramatically. These results indicate that the prevalence of lactase deficiency in Greece may be as high as 75% and suggest that symptom production in lactose malabsorbers is brought about by the rapid passage down the small intestine of the malabsorbed lactose.     

Influence of intestinal parasitism on lactose absorption in well-nourished African children.

Hydrogen breath tests were performed in Gabon (Central Africa) after a loading dose of lactose in 67 well-nourished African children (50 with intestinal parasites and 17 unparasitized) and in 18 unparasitized young adults. All had normal nutritional status, and none had diarrhea or digestive symptoms. Parasites that were found included Ascaris lumbricoides in 76% of the parasitized children, Trichuris trichiura in 58%, Giardia in 24%, Entamoeba histolytica in 20%, Schistosoma intercalatum in 16%, and Necator Americanus in 14%. A similar proportion of parasitized (64%) or unparasitized (62.8%) subjects were lactose malabsorbers. Giardia infection was associated with a higher, but not significantly different, proportion of lactose intolerance (10 of 12, 83.3%). The presence of infection with A. lumbricoides or T. trichiura did not increase the percentage of lactose malabsorption. These data indicate that a decrease of lactase activity in well-nourished African children is not related to the presence or the importance of Ascaris or other intestinal parasites if the nutritional status is normal.     

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?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?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.     

Lactose malabsorption and rate of bone loss in older women.

OBJECTIVES: to study the prevalence of lactose malabsorption with increasing age and to determine whether lactose malabsorbers consume less dietary calcium, have lower bone mineral density or display faster bone loss than lactose absorbers. DESIGN: 80 healthy Caucasian women aged 40-79 years (20 per decade) were studied for 1 year. METHODS: breath hydrogen exhalation was measured for 3 after a 50 g oral lactose challenge. Bone density was assessed in the radius, femoral neck, lumbar spine and total body by dual energy x-ray absorptiometry and dietary calcium intake was estimated by 4-day diet records and food-frequency questionnaires. RESULTS: lactose malabsorption rose with age (15% in those aged 40-59 years versus 50% in those aged 60-79; P < 0.01). Malabsorbers aged 70-79 years consumed significantly less calcium than lactose absorbers of this age (P < 0.05). Baseline total body calcium values were lower in lactose malabsorbers (n=26) than in lactose absorbers (n=54) but age-adjustment eliminated this difference. Bone change (% per year) was correlated with dietary calcium intake at the femoral neck and trochanter (P < 0.05) but was not statistically greater in malabsorbers than in absorbers. CONCLUSIONS: the ability to absorb lactose declines in the 7th decade. This may contribute to decreased dietary intakes of milk products and calcium in elderly women. However, lactose malabsorption without reduction in calcium intake has little effect on bone mineral density or the rate of bone loss.     

Comparative tolerance of elderly from differing ethnic backgrounds to lactose-containing and lactose-free dairy drinks: a double-blind study.

Milk intolerance was investigated in 87 healthy elderly individuals with a mean age of 77 years who were given 240 ml of a chocolate dairy drink twice in one week with a light lunch. No significant differences in symptomatic responses distinguished the subjects consuming a lactose-free (LF) drink from those consuming a drink containing 4.5% lactose (LC) under double-blind study conditions. Breath hydrogen analysis during lactose tolerance testing identified 23 malabsorbers, none of whom responded exclusively to the LC drink, although five were symptomatic on both days, and two had symptoms only on the day the LF drink was served. A similar percentage of absorbers (72%) and malabsorbers (70%) were asymptomatic on both days. Factors other than lactose malabsorption appeared to be responsible for the symptoms of intolerance reported, and most may have been psychosomatic in origin.     

Lactase deficiency and lactose intolerance-related symptoms in adult healthy subjects from western France]

The prevalence of lactase deficiency (LD) and lactose intolerance is not well known in France. Using breath hydrogen and methane analysis after 50 g oral lactose load, we investigated the prevalences of LD, lactose intolerance, and methane producer status in 102 healthy adults born in western France, and we examined the relationships between these parameters and the daily milk consumption. In 10 subjects with LD and lactose intolerance, we studied the reproducibility of the lactose hydrogen breath test results for the diagnosis of LD and lactose intolerance and estimated the quantity of lactose malabsorbed in comparison with the lactulose hydrogen breath test. The prevalence of LD was 23.4 percent and symptoms of lactose intolerance were observed in 50 percent of the 24 subjects with LD. The daily milk consumption was not significantly different in the 24 subjects with LD and in the 78 subjects without LD (281 +/- 197 vs 303 +/- 217 ml/24 h). The prevalence of methane producer status was 42.1 percent. The symptomatic group of lactose malabsorbers (n = 12) was characterized by a shorter lactose mouth to caecum transit time (39 +/- 20 vs 88 +/- 48 min; P less than 0.05), and more marked hydrogen production (6.1 +/- 2.3 vs 3.4 +/- 2.4 10(3) ppm.min; P less than 0.04). In the 10 subjects with LD and lactose intolerance, the hydrogen breath test was reproducible for diagnosis of LD and lactose intolerance, and for hydrogen production. The quantity of lactose malabsorbed was 60 percent. In France, symptoms of lactose intolerance are not severe and do not affect the daily consumption of milk and dairy products.     

Effects of age on lactose malabsorption in Oklahoma Native Americans as determined by breath H2 analysis

Breath H₂ excretion was used to determine lactose malabsorption in 30 healthy females and 30 healthy males between the ages of 3 and 64 yr who were at least 7/8 Native American. The test meal consisted of 5 ml reconstituted nonfat dry milk (0.25 g lactose) per kg of body weight. On the basis of breath H₂ tests in 15 control subjects with normal oral lactose tolerance tests, a response factor of 20 ppm was selected as the upper limit for lactose absorbers. Of the 60 subjects in the study group, 36 (60%) were classified as lactose malabsorbers since they had a response factor of 20 ppm or greater of breath H₂. Only 3 of 20 children (15%) who were under the age of 12 yr were nondigesters of the small lactose dose used in this study. Approximately 82 percent (82.5%) of subjects who were 13 yr and older were lactose malabsorbers. Adolescence appears to be the period in which malabsorption of lactose becomes evident in Native North Americans.Supported by the Nutrition Foundation, Inc., New York, New York; Biomedical Sciences Support Grant (USPH) 5-S05-RR7077 to The Research Foundation, Oklahoma State University.     

Vertebral ankylosing hyperostosis (Forestier's disease) and HLA antigens in Pima Indians

Vertebral ankylosing hyperostosis is a common skeletal disorder among Pima Indians. Prevalence rates of approximately 50% have been reported in Pima Indian males aged 44 or older. The HLA-B27 antigen is also found more commonly in Pima Indians than in Caucasians (18% versus 6%). Because of the increased prevalence of both vertebral ankylosing hyperostosis and HLA-B27 in Pima Indians, a possible association between the two was thought to exist. Therefore, histocompatibility testing was done on 44 adult male Pima Indians age 55 or older with classic vertebral ankylosing hyperostosis and 33 age-matched controls. No significant association between any histocompatibility antigen phenotype or haplotype and vertebral ankylosing hyperostosis was found. This disease, therefore, connot be classified with the HLA-B27 associated spondylarthropathies.     

Development, Validation, and Applicability of a Symptoms Questionnaire for Lactose Malabsorption Screening

Lactase deficiency has a high prevalence worldwide. Thus, a valid symptom scale would be a useful tool for identifying patients with lactose malabsorption. Objective To develop, validate, and apply a symptoms questionnaire on lactose malabsorption to identify lactose malabsorbers diagnosed with the gold-standard hydrogen breath test. Methods In the first part of the study, 292 patients completed a questionnaire at the end of a 50-g lactose breath test. The questionnaire included five items (diarrhea, abdominal cramping, vomiting, audible bowel sounds, and flatulence or gas) scored on a 10-cm visual analogue scale. In the second part of the study, 171 patients completed the questionnaire twice: first, according to their opinion when consuming dairy products at home and second, after a 50-g lactose breath test. Patients were grouped as absorbers or malabsorbers according to the result of the breath test. Results Diarrhea, abdominal cramping, and flatulence were scored significantly higher in malabsorbers than in absorbers. Total score of the symptomatic questionnaire was significantly higher in malabsorbers (17.5 versus 3.0, P < 0.01). According to receiver operator characteristics (ROC) analysis, the most discriminant cut-off of the total score to identify lactose malabsorption was 6.5 (sensitivity 0.75, specificity 0.67). In 58 malabsorbers the effect size of the questionnaire to determine sensitivity to change was 1.32. In the second part of the study, scoring of the home questionnaire was higher than after the lactose-breath test. The lactose malabsorbers rate was higher according to the home questionnaire than after the lactose breath test (72% versus 52%). The home questionnaire had excellent sensitivity (0.82) but low specificity (0.35). Conclusion We developed and validated a five-item symptoms questionnaire for lactose malabsorption. This is a valid test that permits patients with a total score lower than 7 to be excluded from future studies.     

Resting metabolic rate and body composition of Pima Indian and Caucasian children.

Since a low metabolic rate (for a given body size and body composition) is a risk factor for body weight gain and obesity is prevalent among Pima Indians, we have tested whether Pima Indian children have a low resting metabolic rate (RMR) as compared to Caucasian children. Body composition (bioelectrical resistance) and RMR were measured in 43 Pima Indian children (22 male/21 female, mean +/- s.d. 9.9 +/- 1.1 years) and 42 Caucasian children (21 male/21 female, 9.7 +/- 1.2 years). Pima children were taller (143 +/- 9 vs. 137 +/- 8 cm, P less than 0.001), heavier (48.6 +/- 15.8 vs. 32.9 +/- 7.8 kg, P less than 0.001) and fatter (39 +/- 10 vs. 24 +/- 7% fat, P less than 0.001) than Caucasians. Absolute values of RMR were higher in Pimas than in Caucasians (6234 +/- 1201 vs. 5171 +/- 715 kJ/day, P less than 0.001), but similar when adjusted for differences in body size, body composition and sex. Contrary to our hypothesis, we did not find a decreased RMR in Pima children when compared to Caucasian children. Therefore, the high prevalence of obesity in Pima children at age 10 suggests that excess energy intake and/or low levels of physical activity might be the major aetiological factor. However, this study does not exclude the possibility that a low metabolic rate might be a predisposing factor at an earlier age.     

Lactose malabsorption and intolerance: What should be the best clinical management?

Lactose malabsorption (LM) is the incomplete hydrolysis of lactose due to lactase deficiency, which may occur as a primary disorder or secondary to other intestinal diseases. Primary adult-type hypolactasia is an autosomal recessive condition resulting from the physiological decline of lactase activity. Different methods have been used to diagnose LM. Lactose breath test represents the most reliable technique. A recent consensus conference has proposed the more physiological dosage of 25 g of lactose and a standardized procedure for breath testing. Recently a new genetic test, based on C/T13910 polymorphism, has been proposed for the diagnosis of adult-type hypolactasia, complementing the role of breath testing. LM represents a wellknown cause of abdominal symptoms although only some lactose malabsorbers are also intolerants. Diagnosing lactose intolerance is not straightforward. Many non-malabsorber subjects diagnose themselves as being lactose intolerant. Blind lactose challenge studies should be recommended to obtain objective results. Besides several studies indicate that subjects with lactose intolerance can ingest up to 15 g of lactose with no or minor symptoms. Therefore a therapeutic strategy consists of a lactose restricted diet avoiding the nutritional disadvantages of reduced calcium and vitamin intake. Various pharmacological options are also available. Unfortunately there is insufficient evidence that these therapies are effective. Further double-blind studies are needed to demonstrate treatment effectiveness in lactose intolerance.     

Assessment of lactose absorption by measurement of urinary galactose

Individuals with sufficient intestinal lactase hydrolyze ingested lactose to galactose and glucose and these monosaccharides are absorbed. Lactose is not digested completely when intestinal lactase activity is low and the disaccharide is malabsorbed. Breath hydrogen excretion after lactose ingestion is used commonly to diagnose lactose malabsorption. However, no direct tests are currently used to assess lactose absorption. We tested a new method of assessing lactose absorption in 26 healthy individuals. Each subject ingested 50 g of lactose. Participants were evaluated for lactose malabsorption using a standard 3-h breath hydrogen test. In addition, the urinary excretions of galactose, lactose, and creatinine were quantitated for 3-5 h after lactose ingestion. On the basis of breath hydrogen analysis after lactose ingestion, 12 individuals were lactose malabsorbers (defined as a rise in the breath hydrogen concentration of greater than 20 parts per million above the baseline value). The 14 subjects who did not malabsorb lactose by breath hydrogen testing (defined as a rise in the breath hydrogen concentration of less than or equal to 20 parts per million above the baseline value), had significantly more galactose in their urine 1, 2, and 3 h after lactose ingestion than lactose malabsorbers. The ratio of excreted lactose to excreted galactose was significantly decreased in lactose absorbers compared with lactose malabsorbers (p less than 0.001). Determination of the ratio of urinary galactose to urinary creatinine separated lactose absorbers from lactose malabsorbers completely (p less than 0.001). We conclude from this study that the determination of urinary galactose, urinary lactose/galactose ratio, and urinary galactose/creatinine ratio may be used to assess lactose digestion and absorption in healthy adults.     

Manifestation and occurrence of selective adult-type lactose malabsorption in Finnish teenagers

In 1969–1970, a simple random sample of 129 Finnish school-aged children was examined to study selective adult-type lactose malabsorption (SLM) in this age category. SLM was found in 8 children. All subjects were reexamined 5 years later. SLM was reconfirmed in these 8 persons and found in 3 additional subjects who had normal lactose absorption in the first examination. The prevalence of SLM was 9.3%, being 8.5% in the age category 12–15 years and 9.9% in that 16–20 years. Low rise of blood glucose in the lactose tolerance test of the first examination, very low milk consumption, milk intolerance, and history of gastrointestinal symptoms were found to be of low predictive value as indicators of SLM. It was also concluded that information about dietetic sources of lactose is important to persons with SLM, but categorical exclusion of lactose from the diet is not necessary, at least in the Finnish population.The study was supported by the Finnish Cultural Foundation and the Foundation for Pediatric Research in Finland.