Increasing Expiratory Hydrogen in Lactose Intolerance Is Associated with Additional Food Intolerance/Malabsorption.

Single and/or combined food intolerance/malabsorption may cause nonspecific, functional gastrointestinal (GI) complaints. In lactose-intolerant patients we evaluated the influence of additional food intolerance/malabsorption with hydrogen (H2) breath tests. In a retrospective analysis of charts from 279 lactose-intolerant patients, we found 128 patients with only lactose intolerance (LIT). Then, we identified 106 LIT patients with additional histamine intolerance (HIT). Additionally, 45 LIT and HIT patients also had fructose malabsorption (FM). A hydrogen (H2) breath test was performed to evaluate LIT and FM. A serum diamine oxidase value of <10 U/mL and a response to a histamine-reduced diet was used to identify HIT. Using pairwise comparison with the Kruskal-Wallis test to associate the area under the curve (AUC) of LIT patients and, LIT with HIT, to LIT with HIT and FM it was found, that the exhaled hydrogen values were significantly higher in patients with two-fold and triple combined food intolerance/malabsorption (p < 0.004 and p < 0.001, respectively). Within the pool of 170 LIT patients with >20 ppm increase of expiratory H2 from baseline, there were 74 LIT-only patients, 60 LIT with HIT patients, and 36 LIT patients with additional HIT and FM. With the Kruskal-Wallis test AUCs demonstrated a significant difference between all three groups (p = 0.024). In patients with LIT, the presence of additional food intolerance/malabsorption, significantly increases expiratory H2 values. We demonstrate evidence, which may suggest HIT to embody an own GI disorder as food intolerance/malabsorption.

Methane breath tests and blood sugar tests in children with suspected carbohydrate malabsorption.

Carbohydrate malabsorption and subsequent gastrointestinal symptoms are a common clinical problem in pediatrics. Hydrogen (H2) and methane (CH4) breath tests are a cheap and non-invasive procedure for diagnosing fructose and lactose malabsorption (FM/LM) but test accuracy and reliability as well as the impact of non-hydrogen producers (NHP) is unclear. CH4 breath tests (MBT), blood sugar tests (BST) and clinical symptoms were compared with H2 breath tests (HBT) for FM/LM. 187/82 tests were performed in children (2 to 18 years) with unclear chronic/recurrent abdominal pain and suspected FM/LM. In FM and LM, we found a significant correlation between HBT and MBT/BST. In LM, MBT differentiated most of the patients correctly and BST might be used as an exclusion test. However, additional MBT and BST had no diagnostic advantage in FM. NHP still remain a group of patients, which cannot be identified using the recommended CH4 cut-off values in FM or LM. Reported symptoms during breath tests are not a reliable method to diagnose FM/LM. Overall a combined test approach might help in diagnosing children with suspected carbohydrate malabsorption.

Genetic predictors of celiac disease, lactose intolerance, and vitamin D function and presence of peptide morphins in urine of children with neurodevelopmental disorders.

Gastrointestinal disturbances, nutritional deficiencies, and food intolerances are frequently observed in children with neurodevelopmental disorders (NDD). To reveal possible association of celiac disease risk variants (HLA-DQ), lactose intolerance associated variant (LCT-13910C>T) as well as variant associated with vitamin D function (VDR FokI) with NDD, polymerase chain reaction-based methodology was used. Additionally, intestinal peptide permeability was estimated in NDD patients and healthy children by measuring the level of peptides in urine using high-performance liquid chromatography. Levels of opioid peptides, casomorphin 8, and gluten exorphin C were significantly elevated in urine samples of NDD patients (P = 0.004 and P = 0.005, respectively), but no association of genetic risk variants for celiac disease and lactose intolerance with NDD was found. Our results indicate that increased intestinal peptide permeability observed in analyzed NDD patients is not associated with genetic predictors of celiac disease or lactose intolerance. We have also found that FF genotype of VDR FokI and lower serum levels of vitamin D (25-OH) showed association with childhood autism (CHA), a subgroup of NDD. We hypothesize that vitamin D might be important for the development of CHA.

Effects of Whole Milk Supplementation on Gut Microbiota and Cardiometabolic Biomarkers in Subjects with and without Lactose Malabsorption.

The aim of this study was to compare the impact of whole milk supplementation on gut microbiota and cardiometabolic biomarkers between lactose malabsorbers (LM) and absorbers (LA). We performed a pair-wise intervention study of 31 LM and 31 LA, 1:1 matched by age, sex, body mass index, and daily dairy intake. Subjects were required to add 250 mL/day whole milk for four weeks in their routine diet. At the beginning and the end of the intervention period, we collected data on gut microbiota and cardiometabolic biomarkers. Whole milk supplementation significantly increased Actinobacteria (P < 0.01), Bifidobacterium (P < 0.01), Anaerostipe (P < 0.01), and Blautia (P = 0.04), and decreased Megamonas (P = 0.04) in LM, but not LA. Microbial richness and diversity were not affected. The fecal levels of short-chain fatty acids (SCFAs) remained stable throughout the study. Body fat mass (P < 0.01) and body fat percentage (P < 0.01) reduced in both groups, but the changes did not differ between groups. No significant differences in other cardiometabolic markers were found between LM and LA. When compared with LA, whole milk supplementation could alter the intestinal microbiota composition in LM, without significant changes in fecal SCFAs and cardiometabolic biomarkers.

Association between increased plasma levels of homocysteine and depression observed in individuals with primary lactose malabsorption.

BACKGROUND: Current literature proposes associations between homocysteine (HCY), folic acid (FA), vitamin B12 metabolism and depression. However, the exact underlying biological mechanisms remain unclear. This study aimed at evaluating a possible link between primary adult-type lactose malabsorption (PALM), HCY, FA and vitamin B12 metabolism and depressive disorder. METHODS: Plasma levels of HCY, FA and vitamin B12 were determined in 78 patients with PALM and 160 individuals with lactase persistence sub-grouped by the presence or absence of major depression. RESULTS: In 78 patients with PALM, the subgroup of 22 individuals with major depression showed significantly higher median (interquartile range) HCY (10.10 [8.46-12.03] vs. 8.9 [7.54-9.86] µmol/L, p = 0.029) and lower plasma FA levels (5.7 [4.68-9.14] vs. 6.95 [5.24-10.56] µmol/L, p = 0.272) compared to the subgroup of 56 individuals without depression, respectively. No such associations could be observed for those 160 individuals without PALM (i.e., lactase persistence) Plasma HCY levels were positively correlated with depressive symptoms (p = 0.052), and showed negative correlations with FA (p = < 0.001) and vitamin B12 (p = 0.029), respectively. CONCLUSION: Depressed individuals with PALM were found with significantly higher HCY and lower FA levels compared to non-depressed individuals with PALM, however, this association was absent in the subgroup of lactase persistent individuals. These findings suggest an association between increased HCY levels, lactose malabsorption and depression.

Assessment of tryptophan metabolism and signs of depression in individuals with carbohydrate malabsorption.

This prospective cross-sectional study aimed to investigate the potential association between primary-adult lactose malabsorption, fructose malabsorption, tryptophan (TRP) metabolism and the presence of depressive signs. Overall 251 patients, who were referred for lactase gene C/T-13910 polymorphism genotyping and fructose hydrogen/methane breath testing, were included. All participants filled out the Beck Depression Inventory (BDI II). Serum concentrations of tryptophan (TRP), kynurenine (KYN), kynuric acid (KYNA), and TRP competing amino acids (leucine, isoleucine, valine, phenylalanine, tyrosine) were measured by high-pressure liquid-chromatography. Logistic regression analysis was performed with lactose malabsorption, fructose malabsorption and all potential biomarkers of TRP metabolism to assess the effect on signs of depression, defined as a BDI II score > 13. Primary-adult lactose malabsorption and fructose malabsorption was detected in 65 (25.90%) and 65 (25.90%) patients, respectively. Fructose malabsorption was significantly associated with BDI II score, whereas no such relationship was found for lactose malabsorption. Serum levels of TRP and TRP metabolites were no predictors of depression. The authors suggest to conduct further prospective longitudinal studies in order to get further insight of associations between carbohydrate malabsorption, biomarkers and mood disorders.

A relationship between vitamin D, parathyroid hormone, calcium levels and lactose intolerance in type 2 diabetic patients and healthy subjects.

BACKGROUND: Type 2 diabetes mellitus is chronic metabolic disorder. Common gastrointestinal symptoms in type 2 diabetic patients are flatulence, constipation and/or diarrhea. Reason for these may be lactose intolerance leading to change in vitamin D, Calcium and parathyroid hormone which further regulate bone mineralization. AIM: To measure lactose intolerance, vitamin D, calcium and parathyroid hormone in type 2 diabetic patients. MATERIAL AND METHODS: 150 type 2 diabetic patients attending Endocrinology Clinic in PGI, Chandigarh and 150 age and sex matched healthy controls were enrolled. Lactose intolerance was measured using non-invasive lactose breath test. 25-hydroxyvitamin D (total) and Parathyroid hormone were measured in plasma using immunoassay. Serum calcium was measured using auto analyzer. T score was recorded from DXA scan for bone mineral density measurement. RESULTS: Lactose intolerance was observed significantly higher (p<0.001) diabetic patients (59.3%) as compared to controls (42%). Levels of plasma 25-OH vitamin D (total), parathyroid hormone and serum calcium were significantly lower in patients as compared to controls. Furthermore, levels of plasma 25-OH vitamin D (total), parathyroid hormone and serum calcium were more decreased in lactose intolerant diabetic patients than lactose tolerant patients. Sixty seven percent (67%) of diabetic patients suffered from osteoporosis and 20% of controls. Eighty percent (80%) diabetic patients and 16% controls with osteoporosis suffered from lactose intolerance. CONCLUSION: From this study we can conclude that measurement of lactose intolerance using non-invasive lactose breath test is suggested for type 2 diabetic patients along with timely measurement of 25-OH vitamin D (total), calcium and parathyroid hormone levels.

Effects of milk containing only A2 beta casein versus milk containing both A1 and A2 beta casein proteins on gastrointestinal physiology, symptoms of discomfort, and cognitive behavior of people with self-reported intolerance to traditional cows' milk.

BACKGROUND: Cows' milk generally contains two types of ß-casein, A1 and A2 types. Digestion of A1 type can yield the peptide ß-casomorphin-7, which is implicated in adverse gastrointestinal effects of milk consumption, some of which resemble those in lactose intolerance. This study aimed to compare the effects of milk containing A1 ß-casein with those of milk containing only A2 ß-casein on inflammation, symptoms of post-dairy digestive discomfort (PD3), and cognitive processing in subjects with self-reported lactose intolerance. METHODS: Forty-five Han Chinese subjects participated in this double-blind, randomized, 2 × 2 crossover trial and consumed milk containing both ß-casein types or milk containing only A2 ß-casein. Each treatment period was 14 days with a 14-day washout period at baseline and between treatment periods. Outcomes included PD3, gastrointestinal function (measured by smart pill), Subtle Cognitive Impairment Test (SCIT), serum/fecal laboratory biomarkers, and adverse events. RESULTS: Compared with milk containing only A2 ß-casein, the consumption of milk containing both ß-casein types was associated with significantly greater PD3 symptoms; higher concentrations of inflammation-related biomarkers and ß-casomorphin-7; longer gastrointestinal transit times and lower levels of short-chain fatty acids; and increased response time and error rate on the SCIT. Consumption of milk containing both ß-casein types was associated with worsening of PD3 symptoms relative to baseline in lactose tolerant and lactose intolerant subjects. Consumption of milk containing only A2 ß-casein did not aggravate PD3 symptoms relative to baseline (i.e., after washout of dairy products) in lactose tolerant and intolerant subjects. CONCLUSIONS: Consumption of milk containing A1 ß-casein was associated with increased gastrointestinal inflammation, worsening of PD3 symptoms, delayed transit, and decreased cognitive processing speed and accuracy. Because elimination of A1 ß-casein attenuated these effects, some symptoms of lactose intolerance may stem from inflammation it triggers, and can be avoided by consuming milk containing only the A2 type of beta casein. TRIAL REGISTRATION: ClinicalTrials.gov/NCT02406469.

Assessment of vitamin D status and serum CrossLaps levels in adults with primary lactose malabsorption.

BACKGROUND/OBJECTIVES: Primary adult-type lactose malabsorption (PALM) is a widespread inherited autosomal recessive condition, which is considered to be associated with osteoporosis. This prospective study aimed at assessing the 25-hydroxy-vitamin D (25(OH)D) status and serum CrossLaps levels in individuals with PALM and normal controls. SUBJECTS/METHODS: All participants (n=210) underwent genotyping for the LCT C/T-13910 polymorphism, 25(OH)D and CrossLaps measurements and clinical examinations. In addition, the anthropometric data (that is, height, weight and body mass index) were determined. RESULTS: Fifty-five individuals with PALM (that is, LCT C/C-13910 homozygotes) showed lower 25(OH)D (mean: 24.95±10.04 vs 28.59±9.56 ng/ml, P=0.018) and higher CrossLaps serum levels (mean: 0.46±0.31 vs 0.43±0.49 ng/ml, P=0.251) compared with 155 normal controls (that is, LCT C/T-13910 hetero- or T/T-13910 homozygotes). Anthropometric data were similar between PALM probands and controls. CONCLUSIONS: Individuals with PALM were found to have lower 25(OH)D and higher CrossLaps serum levels compared with normal controls. In order to preserve life-long bone health, routine 25(OH)D and CrossLaps serum measurements should be performed in individuals with PALM.

Inhibition of the glycaemic response by onion: a comparison between lactose-tolerant and lactose-intolerant adults.

This pilot study compared inhibition of the glycaemic response to glucose by a dietary source of quercetin glucosides (onion) in lactose-tolerant adults (n=12) and lactose-intolerant adults (n=12). We hypothesised that lactose-intolerant people (who do not express lactase) will retain intact quercetin glucosides that can inhibit glucose uptake via the glucose transporter SGLT1, whereas lactose-tolerant people (who do express lactase) will hydrolyse quercetin glucosides to free quercetin that does not inhibit glucose uptake. In a glucose tolerance test, reduction in peak glucose levels by an onion meal was higher in lactose-intolerant people than in lactose-tolerant people (44.2 versus 19.3%, P=0.04). Incremental area under the blood glucose curve was reduced more in lactose-intolerant people, but was not statistically significant (54.5 versus 42.1%, P=0.42). A diet containing quercetin glucosides may be of greater benefit for glycaemic control in lactose-intolerant people than in lactose-tolerant people.

Clinical evaluation, biochemistry and genetic polymorphism analysis for the diagnosis of lactose intolerance in a population from northeastern Brazil.

OBJECTIVE: This work aimed to evaluate and correlate symptoms, biochemical blood test results and single nucleotide polymorphisms for lactose intolerance diagnosis. METHOD: A cross-sectional study was conducted in Fortaleza, Ceará, Brazil, with a total of 119 patients, 54 of whom were lactose intolerant. Clinical evaluation and biochemical blood tests were conducted after lactose ingestion and blood samples were collected for genotyping evaluation. In particular, the single nucleotide polymorphisms C>T-13910 and G>A-22018 were analyzed by restriction fragment length polymorphism/polymerase chain reaction and validated by DNA sequencing. RESULTS: Lactose-intolerant patients presented with more symptoms of flatulence (81.4%), bloating (68.5%), borborygmus (59.3%) and diarrhea (46.3%) compared with non-lactose-intolerant patients (p<0.05). We observed a significant association between the presence of the alleles T-13910 and A-22018 and the lactose-tolerant phenotype (p<0.05). After evaluation of the biochemical blood test results for lactose, we found that the most effective cutoff for glucose levels obtained for lactose malabsorbers was <15 mg/dL, presenting an area under the receiver operating characteristic curve greater than 80.3%, with satisfactory values for sensitivity and specificity. CONCLUSIONS: These data corroborate the association of these single nucleotide polymorphisms (C>T-13910 and G>A-22018) with lactose tolerance in this population and suggest clinical management for patients with lactose intolerance that considers single nucleotide polymorphism detection and a change in the biochemical blood test cutoff from <25 mg/dL to <15 mg/dL.

Clinical evaluation, biochemistry and genetic polymorphism analysis for the diagnosis of lactose intolerance in a population from northeastern Brazil

OBJECTIVE: This work aimed to evaluate and correlate symptoms, biochemical blood test results and single nucleotide polymorphisms for lactose intolerance diagnosis. METHOD: A cross-sectional study was conducted in Fortaleza, Ceará, Brazil, with a total of 119 patients, 54 of whom were lactose intolerant. Clinical evaluation and biochemical blood tests were conducted after lactose ingestion and blood samples were collected for genotyping evaluation. In particular, the single nucleotide polymorphisms C>T-13910 and G>A-22018 were analyzed by restriction fragment length polymorphism/polymerase chain reaction and validated by DNA sequencing. RESULTS: Lactose-intolerant patients presented with more symptoms of flatulence (81.4%), bloating (68.5%), borborygmus (59.3%) and diarrhea (46.3%) compared with non-lactose-intolerant patients (p<0.05). We observed a significant association between the presence of the alleles T-13910 and A-22018 and the lactose-tolerant phenotype (p<0.05). After evaluation of the biochemical blood test results for lactose, we found that the most effective cutoff for glucose levels obtained for lactose malabsorbers was <15 mg/dL, presenting an area under the receiver operating characteristic curve greater than 80.3%, with satisfactory values for sensitivity and specificity. CONCLUSIONS: These data corroborate the association of these single nucleotide polymorphisms (C>T-13910 and G>A-22018) with lactose tolerance in this population and suggest clinical management for patients with lactose intolerance that considers single nucleotide polymorphism detection and a change in the biochemical blood test cutoff from <25 mg/dL to <15 mg/dL.

Correlation Between Capillary and Venous Blood Glucose in the Lactose Tolerance Test.

BACKGROUND: The lactose tolerance test is a classic method for the study of lactose malabsorption. However, the methodology used has not been standardized, and this leads to differences in results. AIM: The aim of this report was to analyze whether capillary blood glucose measurement is in agreement with venous blood glucose when performing lactose tolerance test. METHODS: This is a prospective study of consecutive patients with suspected lactose malabsorption who had lactose tolerance test performed in venous and capillary blood simultaneously, using a load of 50 g lactose. Agreement was measured using the concordance correlation coefficient of Lin (95 % CI) and Bland-Altman plots. The degree of agreement was measured using the Kappa index. A value of p < 0.05 was considered statistically significant. RESULTS: Eighty-four patients (68 % women) were included. The concordance correlation coefficient showed very poor agreement between the two techniques: 0.68 (0.58-0.77), 0.72 (0.62-0.8), and 0.77 (0.69-0.83) for baseline, 30, and 60 min, respectively. The Bland-Altman plots showed that capillary blood glucose measurements result in higher levels than venous blood glucose measurements, with mean differences of 0.39, 0.77, and 1.1 mmol/L at baseline, 30, and 60 min, respectively. The degree of agreement was low, with a Kappa index of 0.59 (p < 0.001). CONCLUSIONS: The test measured in venous blood is not in agreement with the measurement obtained from capillary blood. It is likely that the diagnostic accuracy attributed without distinction to lactose tolerance test in different studies for lactose malabsorption is incorrect, making it necessary to specify the analysis method.

Vitamin D Status and Adiposity in Pediatric Malabsorption Syndromes.

BACKGROUND: The combined effects of nutrient malabsorption and adiposity on vitamin D status are unclear in pediatric malabsorption syndromes. AIM: To determine the relationship between adiposity and serum 25-hydroxyvitamin D (25(OH)D) in malabsorption disorders. METHODS: Prepubertal children of ages 3-12 with either lactose intolerance (LI) (n = 38, age 8.61 ± 3.08, male/female 19/19), or celiac disease (CD) (n = 24) were compared to healthy controls (n = 49, age 7.95 ± 2.64, male/female 28/21). A separate cohort of combined prepubertal and pubertal subjects with inflammatory bowel disease (IBD) (n = 59, age 16.4 ± 2.2, male/female 31/27) were also compared to healthy controls (n = 116, male/female 49/67, age 14.6 ± 4.4). Vitamin D deficiency was defined as 25(OH)D of <50 nmol/l, overweight as body mass index (BMI) of ≥ 85th but <95th percentile, and obesity as BMI ≥ 95th percentile. RESULTS: Among the controls, 25(OH)D was significantly higher in the normal-weight prepubertal controls vs. the overweight/obese controls (p = 0.001), and similarly so for the combined cohort of prepubertal and pubertal controls (p = 0.031). In contrast, there was no significant difference in 25(OH)D concentration between the normal-weight vs. overweight/obese patients with LI (p = 0.335), CD (p = 0.387), and IBD (p = 0.883). CONCLUSION: There is no association between adiposity and serum 25(OH)D in pediatric malabsorption syndromes.

Decrease in TSH levels after lactose restriction in Hashimoto's thyroiditis patients with lactose intolerance.

We aimed to evaluate the prevalence of lactose intolerance (LI) in patients with Hashimoto's thyroiditis(HT) and the effects of lactose restriction on thyroid function in these patients. Eighty-three HT patients taking L-thyroxine (LT4) were enrolled, and lactose tolerance tests were performed on all patients. Lactose intolerance was diagnosed in 75.9 % of the patients with HT. Thirty-eight patients with LI were started on a lactose-restricted diet for 8 weeks. Thirty-eight patients with LI (30 euthyroid and 8 with subclinical hypothyroidism), and 12 patients without LI were included in the final analysis. The level of TSH significantly decreased in the euthyroid and subclinical hypothyroid patients with LI [from 2.06 ± 1.02 to 1.51 ±1.1 IU/mL and from 5.45 ± 0.74 to 2.25 ± 1.88 IU/mL,respectively (both P<0.05)]. However, the level of TSH in patients without LI did not change significantly over the 8 weeks (P>0.05). Lactose intolerance occurs at a high frequency in HT patients. Lactose restriction leads to decreased levels of TSH, and LI should be considered in hypothyroid patients who require increasing LT4 doses,have irregular TSH levels and are resistant to LT4 treatment.

Reliable analysis of the single nucleotide polymorphism of lactase persistence LPH(-13910) C/T from saliva derived DNA: validation of a standardized saliva collection system.

BACKGROUND: The purpose of this study was to investigate the applicability of the Greiner Saliva Collection System (SCS) to obtain human genomic DNA for the analysis of single nucleotide polymorphisms (SNP) in the clinical routine laboratory. METHODS: Saliva and EDTA-blood were collected pair-wise from 112 participants. DNA was prepared by two automated procedures (MagNA Pure LC or MagNa Pure compact) and analyzed by UV-spectrophotometry and real-time PCR. RESULTS: Mean saliva derived DNA concentration was 52.7 ng/µL ± 36.4 (1000 µL, MagNA Pure LC) and 9.2 ng/µL ± 5.6 (200 µL, MagNA Pure compact) with A260/A280 ratios of 1.9 ± 0.1 and 2.1 ± 0.3 for MagNA Pure LC and MagNA Pure compact, respectively. SNP analysis for caucasian adult type lactase persistence showed a 100% success rate from saliva derived DNA and as reference from blood derived DNA. Matching genotypes were obtained in each sample pair. CONCLUSIONS: Saliva obtained with the standardized SCS yielded sufficient amounts of DNA in high purity and was found to represent a suitable and reliable source of human DNA for SNP analysis in the clinical routine laboratory.

Associations between lactase persistence and the metabolic syndrome in a cross-sectional study in the Canary Islands.

BACKGROUND: The single nucleotide polymorphism (SNP) LCT -13910 C>T, associated with genetically determined phenotypes of lactase persistence (LP) or non-persistence (LNP), was studied in relation to the metabolic syndrome (MS). AIM OF THE STUDY: The aim was to determine if milk intake and MS are associated. We applied Mendelian randomization (MR). The SNP, LCT -13910 C>T, with the genotypes LP (TT/CT) and LNP (CC), was taken as a proxy for milk consumption. METHODS: A representative sample of adults belonging to the Canary Islands Nutrition Survey (ENCA) in Spain aged 18-75 years (n = 551) was genotyped for the LCT -13910 C>T polymorphism. We used the International Diabetes Federation (IDF) criteria to define MS. RESULTS: 60% of the population was LP and 40% LNP. One hundred seven LP subjects (35.0%) and 53 LNP subjects (25.6%) showed MS (chi (2) = 5.04, p = 0.025). LP subjects showed a significantly higher odds ratio (OR) for MS than LNP subjects computed for the whole population: both the crude OR (1.56; 95% CI 1.06-2.31) and adjusted OR for sex, age, daily energy intake, physical activity and educational level (1.57; 95% CI 1.02-2.43). Adjusted OR for women with LP was 1.93; 95% CI 1.06-3.52. CONCLUSIONS: The T allele of the SNP might constitute a nutrigenetic factor increasing the susceptibility of LP subjects, especially women, to develop MS in the Canary Islands.

A comparison of diagnostic tests for lactose malabsorption--which one is the best?

BACKGROUND: Perceived milk intolerance is a common complaint, and tests for lactose malabsorption (LM) are unreliable. This study assesses the agreement between diagnostic tests for LM and describes the diagnostic properties of the tests. METHODS: Patients above 18 years of age with suspected LM were included. After oral intake of 25 g lactose, a combined test with measurement of serum glucose (s-glucose) and hydrogen (H2) and methane (CH4) in expired air was performed and symptoms were recorded. In patients with discrepancies between the results, the combined test was repeated and a gene test for lactose non-persistence was added. The diagnosis of LM was based on an evaluation of all tests. The following tests were compared: Increase in H2, CH4, H2+CH4 and H2+CH4x2 in expired air, increase in s-glucose, and symptoms. The agreement was calculated and the diagnostic properties described. RESULTS: Sixty patients were included, seven (12%) had LM. The agreement (kappa-values) between the methods varied from 0.25 to 0.91. The best test was the lactose breath test with measurement of the increase in H2 + CH4x2 in expired air. With a cut-off level < 18 ppm, the area under the ROC-curve was 0.967 and sensitivity was 100%. This shows that measurement of CH4 in addition to H2 improves the diagnostic properties of the breath test. CONCLUSION: The agreement between commonly used methods for the diagnosis of LM was unsatisfactory. A lactose breath test with measurement of H2 + CH4x2 in expired air had the best diagnostic properties.

LCT 13910 C/T polymorphism, serum calcium, and bone mineral density in postmenopausal women.

SUMMARY: LCT 13910 CC genotype is associated with lactose intolerance, a condition often resulting in reduced milk intake. Women with the CC genotype were found to have decreased serum calcium and reduced bone mineral density. INTRODUCTION: The CC genotype of the 13910 C/T polymorphism of the LCT gene is linked to lactose intolerance and low calcium intake. METHODS: We studied 595 postmenopausal women, including 267 osteoporotic, 200 osteopenic, and 128 healthy subjects. Genotyping, osteodensitometry, and laboratory measurements were carried out. RESULTS: Frequency of aversion to milk consumption was 20% for CC genotype and 10% for TT + TC genotypes (p = 0.03). The albumin-adjusted serum calcium was 2.325 +/- 0.09 mmol/L for CC genotype and 2.360 +/- 0.16 mmol/L for TT + TC genotypes (p = 0.031). Bone mineral density (BMD; Z score) was lower in the CC than TT + TC genotypes, respectively, at the radius (0.105 +/- 1.42 vs 0.406 +/- 1.32; p = 0.038), at the total hip (-0.471 +/- 1.08 vs -0.170 +/- 1.09; p = 0.041), and at the Ward's triangle (-0.334 +/- 0.87 vs -0.123 +/- 0.82; p = 0.044). CONCLUSION: LCT 13910 C/T polymorphism is associated with decreased serum calcium level and lower BMD in postmenopausal women.

Lactose intolerance in prostate cancer patients: incidence and associated factors.

OBJECTIVE: Osteoporosis is common in prostate cancer (CaP) patients both before and after institution of androgen deprivation therapy and is associated with significant morbidity. Lactose intolerance (LI) can affect bone mass but has not been studied in this group of patients. The objective of this study was to compare the incidence of LI in CaP patients with that in the general population and to identify factors affecting lactose intolerance in CaP patients. MATERIAL AND METHODS: Fifty-five men with CaP planned for bilateral orchidectomy were enrolled in the study and their baseline characteristics including age, weight, height, body mass index (BMI), prostate-specific antigen, serum calcium profile, lactose tolerance status, physical activity, alcohol intake and smoking, bone mineral density and calcium intake were registered. The data on lactose tolerance in these patients were compared with those of 81 age-matched controls (data taken from the available database). RESULTS: The incidence of LI in CaP patients was significantly less than that in the control group (36.2% and 58.3%, respectively, p = 0.027). A significantly greater number of CaP patients in the lactose-tolerant group had a calcium intake of >1500 mg/day (p = 0.03) and that of milk >500 ml/day (p = 0.05) than those in the intolerant group. Age >70 years, BMI <25 kg/m2, height >163 cm, lower physical activity and co-abuse of alcohol and smoking significantly correlated with the presence of LI (p < or = 0.05). Patients with serum calcium <9 mg/dl had higher fasting breath H2 levels and a higher proportion had a BMI >25 kg/m2 and weight >65 kg. CONCLUSIONS: The incidence of LI in CaP patients is less than that in the general population despite a higher incidence of osteoporosis, indicating a complex etiology of CaP-related osteoporosis. Certain physical characteristics and personal habits are important in determining lactose-tolerant status.