Hydrogen breath test for the diagnosis of lactose intolerance,is the routine sugar load the best one?

AIM: To evaluate the prevalence of lactose intolerance (LI) following a load of 12.5 g in patients diagnosed as high-grade malabsorbers using the hydrogen breath test (HBT)-25.METHODS: Ninety patients showing high-grade malabsorption at HBT-25 were submitted to a second HBT with a lactose load of 12.5 g.Peak hydrogen production,area under the curve of hydrogen excretion and occurrence of symptoms were recorded.RESULTS: Only 16 patients (17.77%) with positive HBT-25 proved positive at HBT-12.5.Hydrogen production was lower as compared to HBT-25 (peak value 21.55 parts per million (ppm) ± 29.54 SD vs 99.43 ppm ± 40.01 SD; P < 0.001).Symptoms were present in only 13 patients.The absence of symptoms during the high-dose test has a high negative predictive value (0.84) for a negative low-dose test.The presence of symptoms during the first test was not useful for predicting a positive low-dose test (positive predictive value 0.06-0.31).CONCLUSION: Most patients with a positive HBT-25 normally absorb a lower dose of lactose and a strict lactose restriction on the basis of a "standard" HBT is,in most instances,unnecessary.Thus,the 25 g lactose tolerance test should probably be substituted by the 12.5 g test in the diagnosis of LI,and in providing dietary guidelines to patients with suspected lactose malabsorption/intolerance.

Glucose substrate in the hydrogen breath test for gut microbiota determination:A recommended noninvasive test

Intestinal dysbiosis and small intestinal bacterial overgrowth(SIBO)are common in patients with liver cirrhosis.Existing studies have not explored the association between gut dysbiosis and SIBO.We propose some suggestions for the authors’experimental methods and concepts,and we hope these suggestions can be adopted.The hydrogen breath test is worthy of recommendation due to its high accuracy and convenient operation.We suggest changing the substrate of the hydrogen breath test from lactulose to glucose to improve the accuracy of each parameter.SIBO is a small subset of gut dysbiosis,and we propose clarifying the concept of both.SIBO may be caused by liver cirrhosis or one of the pathogeneses of gastrointestinal diseases.Therefore,interference from other gastrointestinal diseases should be excluded from this study.

Relation between Gastrointestinal Adverse Effects in Gaucher Disease Patients and Intestinal Disaccharidases Activity Evaluated by Methane Hydrogen Breath Test

The aim of this paper is to study the disaccharidase profile in GD （Gaucher disease） patients treated or not with miglustat and compare it with a healthy control group. Miglustat is an iminosugar used as substrate inhibitor in the therapy of some lysosomal disorders, its main side effects resembling carbohydrate maldigestion symptoms and cause more than 50% of medication discontinuation among GD patients. In-vitro studies have revealed that miglustat can act as an inhibitor of some digestive enzymes. An exploratory non-interventional study was designed to compare the disaccharidase profile assessed by MHBT （methane hydrogen breath test） and to analyze the correlation with the reported gastrointestinal symptoms in GD patients （40） and healthy subjects （20）. MHBT was performed following the ingestion of lactose, sucrose and maltose on different days. Each participant completed two detailed surveys about dietary habits, medications and gastrointestinal symptoms previous and during the test. Twenty-one GD were receiving miglustat, 10 （47.6%） of them reported gastrointestinal side effects, and 7/10 （70%） recorded a positive MHBT （lactose 5, maltose 2, and sucrose 1）. In 6/19 （31.6%） patients that never been exposed to miglustat and 7/20 （35%） controls a positive MHBT were detected. The comparison of the malabsorption phenotype between GD patients exposed and not exposed to miglustat （p = 0.028） and control group （p 〈 0.04） showed high statistical significance for the group of patients treated with miglustat. These results suggest that miglustat therapy induces persistent changes in digestive enzyme activity in GD patients.

Association between acute pancreatitis and small intestinal bacterial overgrowth assessed by hydrogen breath test

AIM To elucidate the effects of small intestinal bacterial overgrowth(SIBO) on the severity and complications of acute pancreatitis(AP).METHODS In total,208 patients with AP as defined by the revised Atlanta classification were admitted to Xuanwu Hospital of capital Medical University from 2013 to 2016. All patients were admitted within 72 h of AP onset. The hydrogen breath test was performed 7 d after AP onset to detect hydrogen production and evaluate the development of SIBO. The incidence of SIBO was analyzed in patients with AP of three different severity grades. The association between SIBO and complications of AP was also assessed.RESULTS Of the 27 patients with severe AP(SAP),seven(25.92%) developed SIBO. Of the 86 patients with moderately severe AP(MSAP),22(25.58%) developed SIBO. Of the 95 patients with mild AP(MAP),eight(8.42%) developed SIBO. There were significant differences in the rates of SIBO among patients with AP of different severities. Additionally,more severe APwas associated with higher rates of SIBO positivity(P < 0.05). SIBO in patients with AP mainly occurred within 72 h of the onset of AP. The incidence of organ failure was significantly higher in patients with SIBO than in those without(P < 0.05).CONCLUSION SIBO occurs more frequently in patients with MSAP or SAP than in those with MAP,usually ≤ 72 h after AP onset. Additionally,SIBO is associated with organ failure.

Four-sample lactose hydrogen breath test for diagnosis of lactose malabsorption in irritable bowel syndrome patients with diarrhea

AIM: To validate 4-sample lactose hydrogen breath testing(4SLHBT) compared to standard 13-sample LHBT in the clinical setting.METHODS: Irritable bowel syndrome patients with diarrhea(IBS-D) and healthy volunteers(HVs) were enrolled and received a 10 g, 20 g, or 40 g doselactose hydrogen breath test(LHBT) in a randomized, double-blinded, controlled trial. The lactase gene promoter region was sequenced. Breath samples and symptoms were acquired at baseline and every 15 min for 3 h(13 measurements). The detection rates of lactose malabsorption(LM) and lactose intolerance(LI) for a 4SLHBT that acquired four measurements at 0, 90, 120, and 180 min from the same data set were compared with the results of standard LHBT.RESULTS: Sixty IBS-D patients and 60 HVs were studied. The genotype in all participants was C/C-13910. LM and LI detection rates increased with lactose dose from 10 g, 20 g to 40 g in both groups(P < 0.001). 4SLHBT showed excellent diagnostic concordance with standard LHBT(97%-100%, Kappa 0.815-0.942) with high sensitivity(90%-100%) and specificity(100%) at all three lactose doses in both groups.CONCLUSION: Reducing the number of measurements from 13 to 4 samples did not significantly impact on the accuracy of LHBT in health and IBS-D. 4SLHBT is a valid test for assessment of LM and LI in clinical practice.

Early peak of hydrogen during lactose breath test predicts intestinal motility

Lactose breath test (LBT) is considered the gold standard for the diagnosis of lactose malabsorption. The test is considered positive for a peak of hydrogen (H2) ≥ 20 parts per million (ppm) above the baseline. Some patients (pts) showed a rapid peak between 30 and 90 minutes after lactose ingestion. The aim of this study was to evaluate the predictive value of an early peak during a LBT and an accelerated oro-cecal transit time (OCTT). We retrospectively analyzed all pts who referred to our Gastroenterology unit for Irritable Bowel Syndrome, from January to September 2012, who performed LBT, glucose and lactulose breath test. We consider a positive LBT for a peak of H2 > 20 ppm, a positive GHBT for a peak >12 ppm and we considered a normal OCCT a peak of H2 ≥ 10 ppm between 75 ± 105 min after lactulose load. The correlation between LBT and OCTT was evaluated by Pearson score. 93 pts (65 F/28 M mean age 47 ± 6 years) with a positive LBT, without small intestinal bacterial overgrowth were analyzed: 46 pts (32 F/14 M;mean age 48 ± 6 years) with an early peak (2 (≥20 ppm) were enrolled as case, and 47 pts matched for sex and age with a peak of H2 after 90 min were enrolled as controls. 72% (33/46) of the group with an early peak showed an accelerated, 17% (8/46) a normal and 11% (5/46) a delayed OCTT. Meanwhile, in control group 40.4% (19/47) showed a normal, 57.5% (27/47) a delayed and just 1 pts an accelerated OCTT. The specificity and sensibility of LBT for an accelerated OCTT were 97.9% and 71.7% respectively. The positive predictive value of LBT for an accelerated OCTT is 97.1%;the negative predictive value is 78%. There is a significant correlation between LBT and OCTT (p The presence of an early peak of H2 between 30 and 90 min after the ingestion of 25 gr of lactose could predict the presence of an accelerated OCTT in 97% of pts. If confirmed by further study, in this subset of pts, lactulose breath test for evaluating OCTT could be avoided.

Progress in Diagnosis and Treatment of Small Intestinal Bacterial Overgrowth

Small intestinal bacterial overgrowth has been found to be associated with a variety of gastrointestinal disorders such as irritable bowel syndrome, inflammatory bowel disease, and, in recent years, diabetes mellitus and systemic sclerosis, among other extraintestinal diseases. Several novel diagnostic tools for small intestinal bacterial overgrowth have emerged in recent years, and several therapeutic approaches have been proposed. Therefore, it has become necessary to find an effective, safe, and simple diagnostic method and a safe treatment modality. This article provides a review of current diagnostic and therapeutic approaches to small intestinal bacterial overgrowth.

Breath hydrogen determination in patients following partial gastrectomy

AIM The study was aimed at the unknown mechanisms of gastrointestinal symptoms and accompanied malnutrition in patients following partial gastrectomy. METHODS Thirty six patients who had their gastric resection at least five years ago and forty one normal controls were included in the study. Nutritional status as indicated by anthropometry measurements, glucose hydrogen breath test G HBT) before and after antibiotic treatment and mouth cecum transit time (MCTT) with lactose hydrogen breath test (L HBT) were simultaneously determined. The Student's t test was used for statistical analysis of all the data of the study. RESULTS Anthropometry measurements showed that decreased values (at least 10% lower than the ideal values) of body weight (BW), triceps skinfold thickness (TSF) and mid arm circumference (MC) were observed in 63 2%, 94 7% and 73 3% of the patients studied respectively. A positive result of 50g G HHBT was seen in 10 out of 26 patients (38 5%) who undertook the test. Six of the 9 patients with negative 50g G HBT were positive following a 80g G HBT. Hydrogen excretion in six patients with positive 50g or 80g G BHT were significantly decreased after antibiotic treatment. Further studies of 25 L BHT showed a significant difference of MCTTs either between the post gastrectomy patients with or without chronic diarrhea, or between patient and control groups, i.e., an average MCTT of 58 8, 85 7 and 105 9 minutes in each group. CONCLUSION Malnutrition was common in patients a few years after their gastrectomies. About forty percent of positive G HBT, and effective antibiotic treatment and reduced MCTT determination were observed in these patients. The results suggested that bacterial overgrowth and increased small bowel transit may play a role in the development of gastrointestinal symptoms and related malnutrition in patients following gastrectomy.

Irritable bowel syndrome and small intestinal bacterial overgrowth:Meaningful association or unnecessary hype

Irritable bowel syndrome (IBS) is a common condition characterized by abdominal pain or discomfort, bloating, and altered stool form and passage. Small intestinal bacterial overgrowth (SIBO) is a condition in which there is overgrowth of bacteria in small bowel in excess of 105 colony forming units per milliliter on culture of the upper gut aspirate. Frequency of SIBO varied from 4%-78% among patients with IBS and from 1%-40% among controls. Higher frequency in some studies might be due to fallacious criteria [post-lactulose breath-hydrogen rise 20 PPM above basal within 90 min (early-peak)]. Glucose hydrogen breath test (GHBT) has a low sensitivity to diagnose SIBO. Hence, studies based on GHBT might have under-estimated frequency of SIBO. Therefore, it is important to analyze these studies carefully to evaluate whether the reported association between IBS and SIBO is over or under-projected. This review evaluates studies on association between SIBO and IBS, discordance between different studies, their strength and weakness including methodological issues and evidence on therapeutic manipulation of gut flora on symptoms of IBS.

Intestinal bacterial overgrowth in the early stage of severe acute pancreatitis is associated with acute respiratory distress syndrome

BACKGROUND In the early stage of acute pancreatitis(AP),a large number of cytokines induced by local pancreatic inflammation seriously damage the intestinal barrier function,and intestinal bacteria and endotoxins enter the blood,causing inflammatory storm,resulting in multiple organ failure,infectious complications,and other disorders,eventually leading to death.Intestinal failure occurs early in the course of AP,accelerating its development.As an alternative method to detect small intestinal bacterial overgrowth,the hydrogen breath test is safe,noninvasive,and convenient,reflecting the number of intestinal bacteria in AP indirectly.This study aimed to investigate the changes in intestinal bacteria measured using the hydrogen breath test in the early stage of AP to clarify the relationship between intestinal bacteria and acute lung injury(ALI)/acute respiratory distress syndrome(ARDS).Early clinical intervention and maintenance of intestinal barrier function would be highly beneficial in controlling the development of severe acute pancreatitis(SAP).AIM To analyze the relationship between intestinal bacteria change and ALI/ARDS in the early stage of SAP.METHODS A total of 149 patients with AP admitted to the intensive care unit of the Digestive Department,Xuanwu Hospital,Capital Medical University from 2016 to 2019 were finally enrolled,following compliance with the inclusion and exclusion criteria.The results of the hydrogen breath test within 1 wk of admission were collected,and the hydrogen production rates at admission,72 h,and 96 h were calculated.The higher the hydrogen production rates the more bacteria in the small intestine.First,according to the improved Marshall scoring system in the 2012 Atlanta Consensus on New Standards for Classification of Acute Pancreatitis,66 patients with a PaO2/FiO2 score≤1 were included in the mild AP(MAP)group,18 patients with a PaO2/FiO2 score≥2 and duration<48 h were included in the moderately SAP(MSAP)group,and 65 patients with a PaO2/FiO2 score≥2 and duration>48 h were included in the SAP group,to analyze the correlation between intestinal bacterial overgrowth and organ failure in AP.Second,ALI(PaO2/FiO2=2)and ARDS(PaO2/FiO2>2)were defined according to the simplified diagnostic criteria proposed by the 1994 European Union Conference.The MSAP group was divided into two groups according to the PaO2/FiO2 score:15 patients with PaO2/FiO2 score=2 were included in group A,and three patients with score>2 were included in group B.Similarly,the SAP group was divided into two groups:28 patients with score=2 were included in group C,and 37 patients with score>2 were included in group D,to analyze the correlation between intestinal bacterial overgrowth and ALI/ARDS in AP.RESULTS A total of 149 patients were included:66 patients in the MAP group,of whom 53 patients were male(80.3%)and 13 patients were female(19.7%);18 patients in the MSAP group,of whom 13 patients were male(72.2%)and 5 patients were female(27.8%);65 patients in the SAP group,of whom 48 patients were male(73.8%)and 17 patients were female(26.2%).There was no significant difference in interleukin-6 and procalcitonin among the MAP,MSAP,and SAP groups(P=0.445 and P=0.399,respectively).There was no significant difference in the growth of intestinal bacteria among the MAP,MSAP,and SAP groups(P=0.649).There was no significant difference in the growth of small intestinal bacteria between group A and group B(P=0.353).There was a significant difference in the growth of small intestinal bacteria between group C and group D(P=0.038).CONCLUSION Intestinal bacterial overgrowth in the early stage of SAP is correlated with ARDS.

Levothyroxine therapy and impaired clearance are the strongest contributors to small intestinal bacterial overgrowth: Results of a retrospective cohort study

AIM To identify a set of contributors, and weight and rank them on a pathophysiological basis.METHODS Patients who have undergone a lactulose or glucose hydrogen breath test to rule out small intestinal bacterial overgrowth(SIBO) for various clinical symptoms, including diarrhoea, weight loss, abdominal pain, cramping or bloating, were seen as eligible for inclusion in a retrospective single-centre study. Clinical data such as co-morbidities, medication, laboratory parameters and other possible risk factors have been identified from the electronic data system. Cases lacking or with substantially incomplete clinical data were excluded from the analysis. Suspected contributors were summarised under four different pathophysiological pathways(impaired gastric acid barrier, impaired intestinal clearance, immunosuppression and miscellaneous factors including thyroid gland variables) and investigated using the χ2 test, Student's t-test and logistic regression models.RESULTS A total of 1809 patients who had undergone hydrogen breath testing were analysed. Impairment of the gastric acid barrier(gastrectomy, odds ratio: OR = 3.5, PPI therapy OR = 1.4), impairment of intestinal clearance(any resecting gastric surgery OR = 2.6, any colonicresection OR = 1.9, stenosis OR = 3.4, gastroparesis OR = 3.4, neuropathy 2.2), immunological factors(any drug-induced immunosuppression OR = 1.8), altered thyroid gland metabolism(hypothyroidism OR = 2.6, levothyroxine therapy OR = 3.0) and diabetes mellitus(OR = 1.9) were associated significantly to SIBO. Any abdominal surgery, ileocecal resection, vagotomy or Ig A-deficiency did not have any influence, and a history of appendectomy decreased the risk of SIBO. Multivariate analysis revealed gastric surgery, stenoses, medical immunosuppression and levothyroxine to be the strongest predictors. Levothyroxine therapy was the strongest contributor in a simplified model(OR = 3.0).CONCLUSION The most important contributors for the development of SIBO in ascending order are immunosuppression, impairment of intestinal clearance and levothyroxine use, but they do not sufficiently explain its emergence.

Probiotic effects on intestinal fermentation patterns in patients with irritable bowel syndrome

AIM： To determine whether Lactobacillus casei strain Shirota （Yakult） can alter small intestinal bacterial overgrowth （SIBO）, as tested by the lactulose breath test, and whether this is associated with changes in symptoms in irritable bowel syndrome （IBS）. METHODS： 18 patients with IBS （Rome Ⅱ criteria）, who showed an early rise in breath hydrogen with lactulose （ERBHAL）, consumed 65 mL of Yakult daily for 6 wk. Lactulose breath test was repeated at the end of the treatment period. Symptoms were recorded daily using a 10 cm visual analogue scale. RESULTS： 14 patients completed the study, 9 （64%） had reversal of ERBHAL, with the median time of first rise in breath hydrogen increasing from 45 to 75 min （P = 0.03）. There was no significant improvement in the symptom score with probiotic therapy, except for wind （P = 0.04）. Patients commencing with at least moderate symptoms and who no longer had ERBHAL at the end of treatment, showed improvement in the overall symptoms scores [median final score 5.3 （IQR 3.9-5.9）, 55% reduction; n = 6] to a greater extent than those who had had persisting ERBHAL [final score 6.9 （5.0-7.0）, 12% reduction; n = 5; P = 0.18]. CONCLUSION： Yakult is effective in altering fermentation patterns in the small bowel, consistent with reducing SIBO. The loss of ERBHAL was associated with reduced symptoms. The true interpretation of these findings awaits a randornised, controlled trial.

Small intestinal bacterial overgrowth syndrome

Human intestinal microbiota create a complex polymi-crobial ecology. This is characterised by its high population density, wide diversity and complexity of interaction. Any dysbalance of this complex intestinal microbiome, both qualitative and quantitative, might have serious health consequence for a macro-organism, including small intestinal bacterial overgrowth syndrome (SIBO).SIBO is defined as an increase in the number and/or alteration in the type of bacteria in the upper gastro-intestinal tract. There are several endogenous defence mechanisms for preventing bacterial overgrowth: gastric acid secretion, intestinal motility, intact ileo-caecal valve, immunoglobulins within intestinal secretion and bacte-riostatic properties of pancreatic and biliary secretion. Aetiology of SIBO is usually complex, associated with disorders of protective antibacterial mechanisms (e.g. achlorhydria, pancreatic exocrine insuff iciency, immuno-deficiency syndromes), anatomical abnormalities (e.g. small intestinal obstruction, diverticula, f istulae, surgical blind loop, previous ileo-caecal resections) and/or motility disorders (e.g. scleroderma, autonomic neuropathy in diabetes mellitus, post-radiation enteropathy, small intestinal pseudo-obstruction). In some patients more than one factor may be involved. Symptoms related to SIBO are bloating, diarrhoea, malabsorption, weight loss and malnutrition. The gold standard for diagnosing SIBO is still microbial investigation of jejunal aspirates. Noninvasive hydrogen and methane breath tests are most commonly used for the diagnosis of SIBO using glucose or lactulose. Therapy for SIBO must be com-plex, addressing all causes, symptoms and complica-tions, and fully individualised. It should include treatment of the underlying disease, nutritional support and cyclical gastro-intestinal selective antibiotics. Prognosis is usually serious, determined mostly by the underlying disease that led to SIBO.

小肠细菌过度生长的概念变迁及其诊断进展

小肠细菌过度生长(SIBO)是指各种原因所致小肠内细菌数量过度增长或菌群种类发生较大改变的现象,该概念于20世纪70年代首次被提出,主要用于描述胃肠手术后患者出现腹痛、腹泻及营养不良的病理、生理机制。随着认识的深入,越来越多的证据表明SIBO与炎症性肠病、肠易激综合征、乳糜泻、脂肪性肝病等消化系统疾病,甚至与糖尿病、肥胖等代谢性疾病有着密切的关系。然而,目前对诊断SIBO的“金标准”及方法尚存在一些争议。该文就SIBO的概念变迁及诊断进行综述。

儿童小肠细菌过度生长与幽门螺杆菌感染的相关性分析

目的:探讨儿童小肠细菌过度生长(SIBO)与幽门螺杆菌(Hp)感染之间的相关性。方法:选取2020年6月—2022年3月徐州医科大学附属医院儿科住院的78例腹痛伴腹胀患儿,通过碳13呼气试验和快速尿素酶法试验,均为阳性者为Hp阳性组(44例),均为阴性者为Hp阴性组(34例)。通过甲烷氢呼气试验检测两组SIBO的情况。结果:Hp阳性组中有33例(75.00%)为SIBO阳性,Hp阴性组中有7例(20.59%)为SIBO阳性,两组SIBO阳性率比较,差异有统计学意义(χ^(2)=22.728,P<0.05),并且SIOB与Hp呈正相关关系(r=0.475,P<0.05)。结论:SIBO是一种需要高度重视的肠道疾病,儿童SIBO与Hp感染密切相关,故在临床中应该及时发现和治疗Hp感染,并综合考虑各种因素,以制订个性化的治疗方案,提高治疗效果。

甲烷氢呼气试验在非酒精性脂肪性肝病患者中的应用

目的:分析非酒精性脂肪性肝病(NAFLD)患者甲烷氢呼气试验结果,探讨其与小肠细菌过度生长(SIBO)的关系。方法:选取2019年6月至2021年6月通过超声诊断明确的NAFLD患者94例(NAFLD组),健康体检者40例(对照组),所有受试者均接受身高、体重及肝功能、血脂等检测,完善以乳果糖为底物的甲烷氢呼气试验,检测SIBO情况,并进行统计学分析。结果:NAFLD组患者与对照组人员比较,BMI、ALP、TG、LDL、ALT、GGT有统计学差异(P<0.05),TC、AST、TBil、ALB、PT在组间均无统计学差异(P>0.05)。NAFLD组SIBO阳性率为58.51%,且口盲传输时间(OCTT)延长,均高于对照组,差异有统计学意义(P<0.05)。结论:NAFLD患者SIBO阳性率高于健康体检者,且OCTT延长,存在肠动力异常,SIBO阳性患者的症状可能与OCTT及氢气浓度有关,针对SIBO及肠动力的调节可以为NAFLD的治疗提供依据。

功能性腹胀发病机制的研究

目的探讨功能性腹胀的发病机制。方法对符合罗马Ⅲ标准的64例功能性腹胀患者、33例便秘型肠易激综合征(IBS)伴中重度腹胀患者、33例功能性便秘伴中重度腹胀患者及20例正常对照者进行研究。应用X线腹部立位平片对肠道气体量进行评估;采用乳果糖呼氢的方法对肠道菌群改变进行评估;采用不透X线的标志物测定4h胃及48h结肠排空率;采用ELISA法测定空腹血清降钙素基因相关肽(CGRP)及P物质的水平对患者内脏敏感性状况进行评估;采用SAS及SDS量表对心理因素进行评分。结果①乳果糖呼氢阳性率、胃肠排空率、血清CGRP、血清P物质含量及SDS、SAS评分各组间比较差异均有统计学意义(P均<0.05),而肠道气体量各组间比较无统计学差异(P>0.05)。②功能性腹胀组与正常对照组比较,乳果糖呼氢阳性率、胃肠排空率、血清P物质含量及SDS和SAS评分差异有统计学意义(P均<0.05),而肠道气体量与血清CGRP含量相比较则无统计学差异(P均>0.05)。结论功能性腹胀的发病可能与患者肠道菌群异常、胃肠运动功能障碍、精神心理异常、内脏高敏感性有关,而与肠道气体产生量无关。

健康成人可接受牛奶摄入量实验研究

目的找出严重乳糖不耐受者最低可接受牛奶摄入量,观察此摄入量在健康成人中的耐受情况。方法采用氢呼气试验从38名受试者中筛选出8名有水样状腹泻的乳糖不耐受者,分成低、高剂量组参加饮奶试验。两组症状评分之和大致相等,据文献报道及单因素优选法(黄金分割法)确定两组对象分别饮用25g和38.2g奶粉(分别含6.25g和9.55g乳糖)和水冲调成的200ml牛奶,分析受试者氢呼气浓度变化值、症状评分、粪便乳糖含量(醋酸铅法)。采用随机整群抽样方法选取健康的100名青年、80名中年、100名老年人,观察摄入25g奶粉后出现的耐受症状。结果两组受试者在饮奶试验中无一例腹泻发生,仅有不同程度的轻微症状;高剂量组(B组)对象饮奶后,其氢呼气浓度、症状评分、粪便乳糖均高于低剂量组(A组)。健康成人饮用25g奶粉冲调的牛奶后,80.3%的对象未产生任何乳糖不耐受症状。结论结果表明健康成人即使为乳糖不耐受者也能饮用适量牛奶,大多数健康成人摄入25g奶粉(含乳糖6.25g)后不会出现任何乳糖不耐受症状,建议20g奶粉(含乳糖5g,配成160ml牛奶)作为我国成年人的最低可接受牛奶摄入量。

应用氢呼气试验对乳糖酶缺乏症的研究

目的：探讨国人对乳糖耐受性。方法：采用不同剂量乳糖进行氢呼气试验。对１３６名健康汉族成人分为３组，Ａ，Ｂ，Ｃ组乳糖负荷量分别为２５ｇ，１２．５ｇ，６．２５ｇ。Ｄ组为从Ｃ组氢呼气试验阴性中再给予１２．５ｇ乳糖重复试验。结果：Ａ，Ｂ，Ｃ，Ｄ组乳糖吸收不良发生率分别为８５．０％，４８．９％，２．０％和４６．７％；乳糖不耐受率分别为５４．３％，３０．４％，２．０％和２０．０％。Ａ，Ｂ，Ｃ组乳糖吸收不良发生率及乳糖不耐受率均有极显著性差异（Ｐ＜０．００１）；Ｂ，Ｄ组间均无显著性差异（Ｐ＞０．０５）。结论：国人乳糖耐受量为６．２５ｇ，饮用牛奶每次以１２５ｍｌ为合理营养。

肝硬化小肠细菌过度生长情况分析

目的了解肝硬化患者不同CTP分级及出现不同并发症时与小肠细菌过度生长(SIBO)的关系。方法对68例肝硬化患者,均行葡萄糖氢呼气试验(GHBT)检测SIBO情况,按不同CTP分级、不同并发症分组统计,并设立健康对照组,对检测结果作对比分析。结果 (1)肝硬化患者SIBO与健康对照组比较差异有统计学意义(P<0.05);(2)CTP级A级、B级、C级患者SIBO阳性率及氢呼气浓度平均值呈渐进性增高,A级、B级与C级相比组间差异有统计学意义(P<0.05);(3)不同并发症患者SIBO阳性率及氢呼气浓度不一,其中无并发症患者与上消化道出血患者、肝性脑病患者、自发性腹膜炎患者及多种并发症患者相比差异均有统计学意义(P<0.05)。结论肝硬化患者往往合并有SIBO,其与CTP分级相关,而且与肝硬化出现的不同并发症密切相关。