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.     

Methodology of the H2 breath test. II. Importance of the test duration in the diagnosis of carbohydrate malabsorption

We analyzed the results of 352 consecutive four-hour lactose hydrogen breath tests with the aim of verifying whether the results after two hours have the same accuracy as those after four hours in the diagnosis of malabsorption of 20g of lactose. Our results show that in 208 subjects who proved to be lactose malabsorbers the mean changes in breath H2 concentration were higher at three and a half hours than at any other time. Moreover, although the majority of the subjects (63%) reached the cut-off value (more than 20 parts per million with respect to the baseline value) in the first two hours of the test, in 76 of our 208 lactose malabsorbers (37%) a hydrogen increase higher than the cut-off value is only detectable after the second hour of the test. Therefore, unlike those who believe that two samples of expired air at 0 time and after two hours are sufficient, we think that for greater diagnostic accuracy the lactose H2 breath test must be prolonged for at least 4 hours.     

Carbohydrate Malabsorption Syndromes and Early Signs of Mental Depression in Females

Fructose and lactose malabsorption are characterized by impaired duodenal fructose transport or by the deficiency of mucosal lactase, respectively. As a consequence, the nonabsorbed saccharides reach the colon, where they are broken down by bacteria to short fatty acids, CO₂, and H₂. Bloating, cramps, osmotic diarrhea, and other symptoms of irritable bowel syndrome are the consequence and can be seen in about 50% of carbohydrate malabsorbers. We have previously shown that fructose as well as lactose malabsorption were associated with signs of mental depression. It was therefore of interest to investigate possible interactions between fructose and lactose malabsorption and their influence on the development of signs of depression. In all, 111 otherwise healthy volunteers (81 females and 30 males) with gastrointestinal complaints were analyzed by measuring breath H₂ concentrations after an oral dose of 50 g lactose and of 50 g fructose one week apart. They were classified as normals, isolated fructose malabsorbers, isolated lactose malabsorbers, and combined fructose/lactose malabsorbers. All patients filled out a Becks depression inventory–questionnaire. Twenty-five individuals (22.5%) were neither fructose nor lactose malabsorbers (group 1), 69 (62.2%) were only fructose malabsorbers (group 2), 4 (3.6%) were only lactose malabsorbers (group 3), and 13 (11.7%) presented with fructose and lactose malabsorption together (group 4). Isolated fructose malabsorption and combined fructose/lactose malabsorption was significantly associated with a higher Becks depression score. Further analysis of the data show that this association was strong in females (P < 0.01), but there was no such association between carbohydrate malabsorption and early signs of depression in males. In conclusion, the data confirm that fructose malabsorption may play a role in the development of mental depression in females and additional lactose malabsorption seems to further increase the risk for development of mental depression.     

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.     

Relationship between methane production and breath hydrogen excretion in lactose-malabsorbing individuals

Recent studies have shown reduced breath hydrogen (H₂) excretion in methane (CH₄)-producing healthy individuals following ingestion of lactulose. This questions the reliability of the breath hydrogen test (BHT) in CH₄ excretors, but the relationship between CH₄ and H₂ excretion in other clinical applications of the BHT is not known. We reviewed BHT results in two groups of subjects: (1) 385 children tested for lactose malabsorption in a hospital setting, and (2) 109 lactose-malabsorbing patients tested with a home kit. The percentage of lactose malabsorbers in group 1 (51%) was the same regardless of CH₄-producing status (P=0.97). The BHT data from group 2 showed a positive correlation (r=0.6, P<0.000001) between the magnitude of the rise in CH₄ and H₂ concentrations, and the H₂ excretion curves were significantly higher in the CH₄-producing individuals. We conclude that attention to CH₄-producing status is not necessary in the interpretation of the lactose BHT.     

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.     

Lactose Malabsorption Is Associated with Early Signs of Mental Depression in Females (A Preliminary Report)

Lactose malabsorption is characterized by adeficiency of mucosal lactase. As a consequence, lactosereaches the colon where it is broken down by bacteria toshort-chain fatty acids, CO₂, andH₂. Bloating, cramps, osmotic diarrhea, and other symptoms ofirritable bowel syndrome are the consequence and can beseen in about 50% of lactose malabsorbers. Having madethe observation that females with lactose malabsorption not only showed signs of irritable bowelsyndrome but also signs of premenstrual syndrome andmental depression, it was of interest to establishwhether a statistical correlation existed betweenlactose malabsorption and mental depression. Thirtyfemale volunteers were analyzed by measuring breathH₂ concentrations after an oral dose of 50 glactose and were classified as normals or lactosemalabsorbers according to their breath H₂concentrations. All patients filled out a Beck'sdepression inventory questionnaire. Of the 30 femalevolunteers, six were lactose intolerant (20%) and 24were normal lactose absorbers (80%). Subjects with lactosemalabsorption showed a significantly higher score in theBeck's depression inventory than normal lactoseabsorbers did. The data thus suggest that lactosemalabsorption may play a role in the development of mentaldepression. In lactose malabsorption high intestinallactose concentrations may interfere with L-tryptophanmetabolism and 5-hydroxytryptamine (serotonin)availability. Lactose malabsorption should be considered inpatients with signs of mental depression.     

Hydrogen breath test quantification and clinical correlation of lactose malabsorption in adult irritable bowel syndrome and ulcerative colitis

Lactose malabsorption was studied, by hydrogen breath test, in 72 adults suffering from irritable bowel syndrome, in 20 ulcerative colitis patients, and in 69 healthy subjects. The minimum dose of lactose required to cause a positive breath test was determined, and the symptoms caused and the resulting hydrogen eliminated quantified. A high incidence of lactose malabsorption was shown at standard doses (up to 50 g) in both the healthy subjects (70%) and the patients (86% and 85%, respectively). In the irritable bowel syndrome and the ulcerative colitis groups, symptoms occurred with a smaller quantity of breath hydrogen, presumably in association with a greater individual sensitivity of the colon to distension. The threshold lactose dose was notably lower in the diseased subjects who registered as evidence a prevalence of malabsorption at a 20-g lactose load. The pathogenetic role of lactose malabsorption in the irritable bowel syndrome is emphasized, as is the importance of the personal lactose tolerance.     

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.     

Enzyme replacement for lactose malabsorption using a beta-D-galactosidase

We evaluated 10 healthy symptomatic lactose malabsorbers for effect of an oral beta-D-galactosidase derived from Aspergillus oryzae (Lactrase, Kremers Urban Company, Milwaukee, WI, U.S.A.) on symptom and breath hydrogen response to challenge with 50 g lactose. Basally and at 30-min intervals for 8 h after lactose challenge, end-alveolar breath samples were collected and analyzed for hydrogen using gas chromatography. Symptoms were scored at 30 min and hourly for 8 h, rating bloating, cramps, nausea, pain, diarrhea, and flatulence. Four challenges were performed on 4 separate days with at least 3 days between challenges. The first two challenges served as baselines. Just before ingestion of 50 g powdered lactose dissolved in 200 ml water, beta-D-galactosidase capsules were given orally as a 250-mg dose for the third challenge and a 500-mg dose for challenge 4. Hydrogen excretion, quantified by using a trapezoidal method for computing area under the discontinuous curve of breath hydrogen concentration, was decreased in subjects receiving beta-D-galactosidase (base-line I, 346.0 ppm/h; baseline II, 367.2 ppm/h; 250-mg galactosidase 208.2 ppm/h; 500-mg galactosidase, 178.0 ppm/h; p less than or equal to 0.05). Other analyzed parameters of H2 excretion were also decreased. Analysis of symptom response scores showed a dose-related decrease for bloating and flatus (p less than or equal to 0.05) and no statistical difference in the other assessed symptoms. We conclude that beta-D-galactosidase from Aspergillus oryzae, when given just before ingestion of lactose by lactose malabsorbers, can produce a dose-dependent reduction (statistically significant for the 500-mg dose) in breath hydrogen excretion, bloating, and flatus.     

Epidemiology of small bowel bacterial overgrowth and rice carbohydrate malabsorption in Burmese (Myanmar) village children.

Breath hydrogen tests were performed after a rice meal (3 g of cooked rice/kg of body weight, equivalent to 1 g of carbohydrate/kg of body weight) on 256 village children (age range 1-59 months) who were known hydrogen (H2) producers. Anthropometric measurements were made every three months and growth rates were calculated. A breath H2 excretion pattern that suggested small bowel bacterial overgrowth (SBBO), which was recognized as a transient maximum level of 10 ppm or more at 20-, 40-, or 60-min breath samples following the rice meal, was present in 53 (20.7%) children, and was more frequent in children 36-47 and 48-59 months old. This breath H2 excretion pattern was detected in 48 (33.3%) of 144 children who were rice malabsorbers (greater than 10 ppm H2 above baseline values in one of the breath samples taken between 90 and 240 min), and in only five (4.5%) of 112 rice absorbers. Children who had SBBO had a high relative risk (10.7) of being rice malabsorbers. Rice malabsorbers have a high relative risk (59.7) of having faltered growth, accompanied by a large etiologic fraction (94%). This same risk (6.68) and an etiologic fraction of 62% exist in children with untreated SBBO. These findings emphasize the need for interventions aimed at reducing the prevalence of SBBO or similar conditions as detected by the breath H2 excretion pattern to prevent rice malabsorption and growth faltering.     

Effect of Predominant Methanogenic Flora on Outcome of Lactose Hydrogen Breath Test in Controls and Irritable Bowel Syndrome Patients of North India

The relationship between methanogenic flora and hydrogen (H₂) production is considered to be a possible confounding factor in the interpretation of hydrogen breath tests (H₂BT). Therefore, the present study was conducted prospectively and included 154 IBS patients (fulfilling Rome II criteria) and 286 age-and-sex-matched apparently healthy controls. Each subject underwent H₂BT after overnight fasting using 25 g lactose. Methane and H₂ were measured using an SC Microlyser from Quintron, USA, at baseline and every 30 min for a total of 4 h. Subjects with fasting methane concentration <10 ppm were labeled as low methane producers (LMP) and >10 ppm as predominant methane producers (PMP). A rise >20 ppm over base line in hydrogen concentration was taken as +ve hydrogen breath test. IBS and control groups included 66.78% and 67.53% males, respectively. Mean age in the two groups were 48.52 ± 30.54 years (range 15–68 years) and 45.67 ± 30.54 years (range 15–78 years), respectively. Hydrogen breath test was +ve in 77/154 (50%) IBS patients and in 142/286 (49.65%) in controls (P > 0.05). It was also observed that the hydrogen breath test was −ve due to PMP in 5/77 (6.49%) of IBS patients and in 29/154 (20.14%) in controls. PMP affected lactose hydrogen breath tests in 6.49–20.14% subjects. This effect is more apparent in apparently healthy subjects as compared to patients with IBS.     

Lactose malabsorption and intolerance and peak bone mass

BACKGROUND & AIMS: Lactose malabsorption per se is not associated with alterations of bone mineral density (BMD) or calcium intake, but when intolerance symptoms are present a lower calcium intake and reduction of BMD values are evident. The purpose of this study was to evaluate whether lactose intolerance interferes with the achievement of an adequate peak bone mass in young adults. METHODS: Of 103 enrolled healthy subjects, 55 proved to be lactose malabsorbers with H(2) breath test after lactose administration, and 29 of them experienced intolerance symptoms (diarrhea, abdominal pain, bloating, flatulence). Lumbar and femoral BMD by dual-energy X-ray absorptiometry was measured, and calcium intake and biochemical indices of bone and mineral metabolism were evaluated. RESULTS: Lumbar and femoral BMD, calcium intake, and mineral metabolism did not differ between malabsorbers and absorbers, although among malabsorbers, intolerant subjects showed significant alterations of all these parameters in comparison with tolerant subjects. A strict correlation was evident between BMD values and both severity of symptoms and calcium intake and between calcium intake and severity of symptoms. CONCLUSIONS: Lactose intolerance prevents the achievement of an adequate peak bone mass and may, therefore, predispose to severe osteoporosis.     

Application of the Glucose Hydrogen Breath Test for the Detection of Bacterial Overgrowth in Patients with Cystic Fibrosis––A Reliable Method?

Patients with cystic fibrosis (CF) have recently been deemed highly susceptible for bacterial intestinal overgrowth (BIO). We aimed to define the prevalence of BIO in children with CF by applying the H₂-glucose breath test. Forty children with CF and ten healthy children received 1 g/kg D-glucose orally. Breath samples for H₂ content (ppm) were collected for 3 h. BIO was suspected if the breath hydrogen content increased by more than 20 ppm or if baseline concentrations topped 20 ppm. In 27 of 40 CF children (68%), breath hydrogen content exceeded 20 ppm. Whereas the breath hydrogen exhalation persisted above 20 ppm in almost all these children throughout the sampling period, none of the remaining children increased above this threshold. The high rate of CF children with elevated fasting hydrogen breath concentrations indicates that this phenomenon is less a sign of BIO rather than a consequence of global malabsorption and intestinal dysmotility.     

Interval sampling of breath hydrogen (H2) as an index of lactose malabsorption in lactase-deficient subjects

Interval sampling of breath hydrogen content was used in lactose malabsorbers: (1) to compare hydrogen responses following increasing oral doses of lactose in milk and aqueous solutions; (2) to determine the reproducibility of interval breath sampling, and (3) to compare carbohydrate malabsorption following ingestion of either regular milk or milk containingLactobacillus acidophilus. Significant differences in breath hydrogen responses due to increasing amounts of lactose in milk and aqueous solutions were observed. The individual breath hydrogen responses were reproducible using the same lactose dose on different days. There was no significant difference in breath hydrogen responses or symptoms following administration of either regular milk or milk containingLactobacillus acidophilus. Breath hydrogen sampling at intervals, as performed in these studies, provides a sensitive and reproducible index of lactose malabsorption.Supported by the Oklahoma Agricultural Experiment Station, Stillwater, Oklahoma, and the Veterans Administration.     

Lactose malabsorption and intolerance in the elderly.

BACKGROUND: Lactase activity declines with age in rats, but it is not clear whether this model is also shared by humans. Few studies have evaluated lactose intolerance and malabsorption in the elderly and no definite conclusions can be drawn. The aim of our study was therefore to verify the impact of age on lactose intolerance and malabsorption. METHODS: Eighty-four healthy subjects took part in the study. Thirty-three were <65 years, 17 were between 65 and 74 years and 34 were >74 years. All the subjects underwent a preliminary evaluation of intestinal gas production capacity and oro-cecal transit time by H2/CH4 breath test after lactulose. After a 3-day period, an H2/CH4 breath test after lactose was performed. The occurrence of intolerance symptoms during the test and in the 24 h after the test was recorded. RESULTS: Breath H2 and CH4 excretion parameters at fasting and after lactulose did not differ between the three groups. Cumulative breath H2 excretion after lactose was higher in subjects >74 years than in subjects <65 years and in subjects aged 65-74 years, while no difference was found between the latter two groups. In subjects >74 years, the prevalence of lactose malabsorption was higher than in the other two groups, while no significant difference was observed between subjects <65 years and subjects aged 65-74 years. Within the malabsorber subjects, the prevalence of lactose intolerance was higher in subjects <65 years than in those aged 65-74 years and in those aged >74 years. No significant difference was found between the latter two groups. No difference was found between the three groups in terms of daily calcium intake and a significant negative correlation between symptom score and daily calcium intake was only found in the group of subjects aged <65 years. CONCLUSIONS: As age increases, the prevalence of lactose malabsorption shows an increase while the prevalence of intolerance symptoms among malabsorbers shows a decrease. Accordingly, daily calcium intake was similar among the adults and elderly studied.     

Breath testing to evaluate lactose intolerance in irritable bowel syndrome correlates with lactulose testing and may not reflect true lactose malabsorption

OBJECTIVES: An increased prevalence of lactose intolerance is seen in irritable bowel syndrome (IBS). Recently, we demonstrated a high prevalence of abnormal lactulose breath test results in IBS suggesting bacterial overgrowth. Because symptoms of lactose intolerance result from bacterial fermentation, the purpose of this study was to determine whether an abnormal lactose breath test is reflective of malabsorption or early presentation to bacteria. METHODS: Subjects with diarrhea-predominant IBS were enrolled. On day 1, subjects underwent a lactulose breath test after an overnight fast. Within 1 wk, subjects returned after fasting for a lactose breath test with simultaneous blood glucose measurements every 15 min to complete a lactose tolerance test (LTT). Symptoms were evaluated 3 h after lactose administration. RESULTS: Twenty subjects completed the study. One subject inadvertently received dextrose through the intravenous and was excluded. Of the remaining 19 subjects, three (16%) had an abnormal LTT suggesting malabsorption. In all, 10 subjects (53%) had an abnormal lactose breath test, 14 (74%) had an abnormal lactulose breath test, and 11 (58%) had symptoms after lactose administration. The agreement with symptoms was moderate (kappa = 0.47) and fair (kappa = 0.24) when compared to the lactose breath test and LTT, respectively. There was a fair correlation between lactose breath test and LTT (kappa = 0.29). However, lactose breath test hydrogen levels >166 ppm were universally predictive of abnormal LTT. Finally, a significant correlation was seen between the hydrogen production on lactose and lactulose breath test (r = 0.56, p = 0.01). CONCLUSIONS: Lactose breath testing in IBS subjects does not seem to reflect malabsorption; it may be an indicator of abnormal lactulose breath test, suggesting bacterial overgrowth.     

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.     

Impaired absorptive capacity for carbohydrate in the aging human

Breath hydrogen (H₂) analysis was utilized to determine whether intestinal absorption of carbohydrate might decline with age. Twenty-one healthy subjects (aged 65–89 years, mean age 79.1) and 19 control subjects (aged 20–64 years, mean age 35.6) were fed a meal containing 100 g carbohydrate after an overnight fast. Breath H₂ concentrations were analyzed in samples collected intermittently by the end-expiratory technique. A rise in breath H₂ concentration of 20 ppm over baseline was considered evidence of intestinal carbohydrate malabsorption: 7 of 21 aged and 0 of 19 control subjects excreted excess H₂ (P<0.02). Further testing of subjects with meals containing 25–200 g carbohydrate demonstrated a progressive reduction in absorptive capacity with advancing age, while young controls absorbed up to 200 g carbohydrate in a meal. In the group of older subjects carbohydrate malabsorption was not accompanied by clinical determinants of undernutrition. Subtle carbohydrate malabsorption should be considered when evaluating weight loss in old age and in fashioning nutritional programs for the elderly.Presented in part at the Annual Meeting of the American Federation for Clinical Research, Washington, DC, May 1979.This work was supported in part by a grant from the Overseas Shipholding Corp.     

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.