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At least 19 recordsLinked to original sources
PubMed1996

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↗
PubMed2000

Temperature of a test solution influences abdominal symptoms in lactose tolerance tests.

In lactose maldigesters, retarding gastric emptying (food/pharmaceuticals) improves tolerance to lactose. The role of temperature of test solution on the indicators of lactose intolerance was studied. After an overnight fast, 10 lactose maldigesters ingested, in three sessions, 50 g lactose in a randomized cross-over trial. The solutions were at temperatures of 20-21 degrees C (room temperature), 2-3 degrees C (cold) and 55-58 degrees C (hot). Gastrointestinal symptoms and indicators measuring lactose absorption were recorded. Abdominal pain was noticeably increased by the modification of temperature. The cold solution reduced flatulence and abdominal bloating, whereas the hot solution increased bloating and borborygmi. Breath hydrogen excretion tended to be augmented and retarded after cold solution. The temperature of the solution used in a lactose tolerance test affects the gastrointestinal symptoms, but has only minor effects on the other indicators of lactose maldigestion. The constant tendencies observed suggest that a room temperature solution is to be recommended for testing lactose digestion.

Abdomen↗
PubMed1978

Blood glucose rise after lactose tolerance testing in infants.

Lactose tolerance tests are used clinically to screen children and infants. It is assumed that absorption of a lactose challenge in infants would occur in a predictable pattern prior to weaning. Twenty-one infants from 3 to 12 months of age were studied. The maximum blood glucose rise over fasting levels ranged from 11.0 to 62.0 mg/100 ml; the mean was 32.6 mg/100 ml. Six infants had a maximum rise of less than 20 mg/100 ml. Eleven infants (52%) had a maximum rise of greater than 30 mg/100 ml. Signs of intolerance were not noted in any subject. Weight and length were normally disturbed. Results indicate the variance in glucose rise existing within a population of infants growing normally and consuming milk. Gastric emptying, digestion, and absorption may influence the blood glucose rise after a lactose test. Established glucose levels used as an index to lactose absorption in older children and adults may not accurately reflect lactase activity in infants.

Blood Glucose↗
PubMed1997

The relationship between lactose tolerance test results and symptoms of lactose intolerance.

OBJECTIVE: A standard for the assessment of lactose malabsorption does not exist. As measured by lactose tolerance tests, insufficient increase in blood glucose or increased breath hydrogen (H2) excretion after lactose ingestion is regarded as pathological. In this study, we have tried to elucidate the relationship between lactose tolerance test results and symptoms after a lactose challenge. This relationship might be an indicator for the validity of the test. METHODS: In a prospective study, 309 consecutive patients with suspected lactose malabsorption underwent a lactose tolerance test. After consumption of 50 g of lactose, blood glucose and breath H2 concentrations were measured. During the test (240 min), the severity of bloating, flatulence, abdominal distention, and diarrhea were semiquantitatively scored as 0, 1, or 2. The individual sum of these four scores was calculated and denoted as the total symptom score (TSS). All subjects were classified according to their TSS to compare symptoms with peak breath-H2 concentration and change in blood glucose concentration, respectively. RESULTS: The glucose and breath H2 response were pathological in 51.1 and 39.5% of cases, respectively. A stepwise increase in TSS of 1 point was associated with a significant increase (p < 0.05) in mean peak H2 concentration. However, a significantly lower glucose increment compared with patients with a TSS of 0 was found only in patients with a TSS of 2 or 4. The mean symptom score differed significantly between the positive and negative breath tests (p < 0.001), but did not differ between the positive and negative glucose response results. CONCLUSIONS: This study shows that GI symptoms after a lactose challenge are strongly associated with the amount of H2 excretion. The relationship between the increase in glucose concentration and symptoms after a lactose load is less evident. Thus, the H2 breath test seems to be superior to the measurement of blood glucose increment as a diagnostic tool in lactose malabsorption, although the true predictive value of this test only can be determined after a period of dietary treatment.

Adult↗
PubMed1975

Rapid and portable methods of lactose tolerance test administration.

Abbreviated, portable methods of lactose tolerance test administration were investigated. Results obtained with the Ames Reflectance Meter/Dextrostix system for blood glucose determination during lactose tolerance testing were compared with those obtained from a standard method, the AutoAnalyzer. Subjects who had maximum blood glucose rises below 20 mg/100 ml were considered to have a flat lactose tolerance curve and were designated lactose nondigesters. Results of the two methods were very similar for determination of maximum rise in blood sugar over fasting level, for obtaining values of individual blood sugar determinations, and for diagnosis of lactose nondigesters. The effect of omission of the final blood sample on tolerance test results was examined. It was found that maximum rises in blood glucose occurred before the final sample in 31 of 35 cases on the AutoAnalyzer and in 26 of 27 cases on the Reflectance Meter. In no case did omission of the final sample change the results of the lactose tolerance test.

Adult↗
PubMed1999

Ibuprofen augments gastrointestinal symptoms in lactose maldigesters during a lactose tolerance test.

BACKGROUND: Clinical symptoms during lactose tolerance test mimic those seen after therapeutic administration of prostaglandins, and resemble inflammatory processes. AIM: To investigate the possibility that lactose-induced gastrointestinal symptoms are associated with prostaglandins and/or nitric oxide. METHODS: After an overnight fast, nine maldigesters ingested lactose or sucrose with or without an inhibitor of prostaglandin synthesis (ibuprofen), in a randomised double-blind crossover trial. Gastrointestinal symptoms, concentrations of PGE2-M in blood and urine, and urinary 6-keto PGF1alpha (as indicators of prostaglandin synthesis), and urinary nitrate and nitrite as well as cyclic GMP excretions (as indicators of nitric oxide formation), were measured. RESULTS: Ibuprofen increased the first 3-h symptom scores (flatulence + borborygmi + abdominal bloating + pain) caused by lactose (P=0.008) but not sucrose. The concentrations of PGE2-M in the plasma and in the urine were unaffected. Lactose increased the urinary excretion of 6-keto PGF1alpha by about 30% (P=0.17), which was inhibited by ibuprofen (P=0.02). The production of nitric oxide was unaffected by lactose or ibuprofen. CONCLUSION: The inhibition of prostaglandin synthesis intensified gastrointestinal symptoms in lactose maldigesters, suggesting a negligible role for prostanoids in lactose-induced symptoms.

Adult↗
PubMed1977

Reinvestigation of lactose intolerant children: lack of correlation between continuing lactose intolerance and small intestinal morphology, disaccharidase activity, and lactose tolerance tests.

Thirty children on a lactose-free diet aged from 2-38 months who had previously been diagnosed as having secondary lactose intolerance were reinvestigated on 32 occasions by an oral lactose tolerance test, small intestinal biopsy, and measurement of disaccharidase activity in order to detect the presence of continuing lactose intolerance before reintroduction of milk. No correlation was found between continuing lactose intolerance, as diagnosed by the development of watery stools containing excess reducing substances after an oral load of lactose, and maximum blood glucose rise during a lactose tolerance test, lactase levels, and small intestinal morphology.

Child, Preschool↗
PubMed2001

The effect of a lactose-restricted diet in patients with a positive lactose tolerance test, earlier diagnosed as irritable bowel syndrome: a 5-year follow-up study.

DESIGN AND METHODS: Prospectively, the effect of a lactose-restricted diet was evaluated among irritable bowel syndrome patients with lactose malabsorption. Lactose malabsorption was defined by a positive hydrogen breath test and a positive blood-glucose test. An analysis of symptoms was completed before, during, 6 weeks after and 5 years after starting the diet. In addition, the number of visits made by the patients to the outpatient clinic was scored during 6 years. RESULTS: In 17 out of 70 irritable bowel syndrome patients (24.3%), lactose malabsorption was detected. There was no difference in the symptom score between patients with a positive lactose tolerance test and patients with a negative lactose tolerance test. After 6 weeks of the lactose-restricted diet, symptoms were markedly improved in lactose malabsorption-positive patients (P < 0.001). After 5 years, one patient was lost for follow-up, and 14 out of the remaining 16 lactose malabsorption patients (87.5%) still had no complaints during the lactose-restricted diet. Two patients chose not to follow the diet continuously and accepted the discomfort caused by lactose intake. Only two out of 16 patients (12.5%) no longer experienced any benefit from lactose restriction. In the 5 years before their diagnosis of lactose malabsorption, these 16 patients visited the outpatient clinic a total of 192 times (mean 2.4 visits per year per person; range 1-7 visits). In the 5 years after diagnosis, they visited the outpatient clinic a total of 45 times (mean 0.6 visits per year per person; range 0-6 visits; P < 0.0001). CONCLUSIONS: In a large majority of irritable bowel syndrome patients with lactose malabsorption, which was previously clinically unrecognized, a lactose-restricted diet improved symptoms markedly both in the short term and the long term. Furthermore, visits by all patients to the outpatient clinic were reduced by 75%. We conclude that diet therapy is extremely cost- and time-saving. Therefore, it is strongly recommended that lactose malabsorption, which is easily treatable, is excluded before diagnosing irritable bowel syndrome.

Adolescent↗
PubMedDate not supplied

[Analysis of a lactose tolerance test].

OBJECTIVE: The present study analyzes the Lactose Tolerance Test in order to propose a reduction in the length of it. DESIGN: Cross-sectional, descriptive study. METHODS: Glycemia curves of patients considered tolerant and intolerant were compared. Results were analyzed for 56 patients. A cost minimization analysis was performed. RESULTS: Six patients had a normal curve of tolerance and the other 50 had flat curves. Both groups had similar basal levels of glycemia 93.3 and 90.3 (p=0.1). Glycemia levels measured at 30 minutes were 122 and 86.0 (p= 0.003) and at 60 minutes 108.3 and 87.5 (p=0.02), both groups being statistically different. Values at 120 minutes were not statically different between both groups (p=0.4) and not different from basal levels. CONCLUSIONS: Diagnosis of lactose intolerance could be made using a shorter test, without considering the 120-minute figure. A 25% reduction in user s cost could be attained using the modified method as compared with the standard test.

Adult↗
PubMed1985

Oral lactose tolerance test in foals: technique and normal values.

Oral lactose tolerance tests were evaluated in 25 healthy foals (principals) assigned to 4 groups of approximately 1 week, 4 weeks, 8 weeks, and 12 weeks of age. Lactose monohydrate (1 g/kg of body weight [in a 20% water solution]) was administered via nasogastric tube after a 4-hour fast. Plasma glucose concentrations were monitored before dosing (0 minutes) and sequentially for 300 minutes. Six control foals were given a volume of water equivalent to the volume of lactose monohydrate administered to principal foals. After oral lactose loading, mean plasma glucose concentrations of all principal foals increased from 99.76 mg/dl at 0 minutes to 176.80 mg/dl by 90 minutes. Peak increases in plasma glucose concentrations were attained by 8% of the foals (2 foals) at 30 minutes, 76% (19 foals) at 60 minutes, and 16% (4 foals) at 90 minutes. The mean plasma glucose concentration increase of principal foals, regardless of age or time of peaking, was 77.04 mg/dl. There was no significant (P greater than 0.05) difference in fasting plasma glucose concentrations (0 minutes) among the 4 groups of principal foals or between principal and control foals; however, there was a significant (P less than 0.05) difference in peak glucose concentrations between 1-week-old and 12-week-old principal foals, with the older foals having the higher concentrations. Mean plasma glucose concentrations of control foals decreased from 79.67 mg/dl at 0 minutes to 55.17 mg/dl by 180 minutes. The mean peak decrease in plasma glucose concentrations of control foals, regardless of time of peaking, was 24.50 mg/dl.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1978

Improved accuracy of lactose tolerance test in children, using expired H2 measurement.

Expired hydrogen and blood glucose were measured during an oral lactose tolerance test in 163 children aged between 9 months and 14 years. Lactose malabsorption, defined as an abnormal increase in expired H2 during a lactose tolerance test, was found in 54 children. Of these, 30 were found to be lactose intolerant as the increased expired H2 was accompanied by clinical symptoms. The other 109 children, in whom there was no rise in expired H2, were assumed to have normal lactose absorption. In children with lactose intolerance the increase in expired H2 tended to occur earlier after lactose ingestion than in children with malabsorption. The mean value of the rise in blood glucose was 2.4 mmol/100 ml) in the lactose-tolerant children and 1.0 mmol/1 (18 mg/100 ml) in the lactose-intolerant ones. Although this difference is significant (p less than 0.001), the rise in blood glucose, in predicting the correct diagnosis, was wrong in 13% of cases in the lactose-tolerant group, and wrong in 37% in the lactose-intolerant group (95% confidence limits 9-19% and 22-53% respectively). It is concluded that a rise in blood glucose, whether or not of more that 1.2 mmol/1 (22mg/100 ml) is of little help in differentiating lactose tolerance from intolerance.

Adolescent↗
PubMed1979

Reduced rate of breath hydrogen excretion with lactose tolerance tests in young children using whole milk.

On 14 occasions, 1.75 g/kg of body weight of lactose was given in whole milk to preschool children who had significant malabsorption with aqueous lactose solution. The volume of hydrogen excreted in the breath was less after the milk meal. Moreover, the hydrogen response to the nonabsorbable disaccharide, lactulose, was greater with aqueous, solution than with a liquid meal but their difference disappeared when metoclopramide was given with the lactulose: meal. The slower hydrogen production is attributed to slower intestinal delivery of lactose in meals; this phenomenon may account for clinical lactose tolerance often seen in children with demonstrated lactose malabsorption.

Animals↗