Introduction: The topic of this thesis is the Prevention of Osteoporosis in Malabsorption Syndrome. The thesis is divided into two parts; theoretical and practical. The theoretical work in the first part deals with osteoporosis and osteoporosis risk factors with a focus on nutritional factors. Osteoporosis is a systemic metabolic disease of the skeleton characterised by decreased bone mass and changes in the quality of bone tissue. The etiology of osteoporosis is multifactorial. Malabsorption syndrome causes the small intestine, which is essential for absorbing nutrients, to malfunction. In the second part of the theoretical work, attention is paid to malabsorption syndrome and diseases that lead to its development. Objective: The objective of this work is to draw a comparison between the intake of calcium and other important nutrients in relation to bone metabolism for people with lactose intolerance, and compare this with recommended values and a control group of people without lactose intolerance. Methods: Dietary habits were evaluated using a questionnaire method and a detailed analysis of a four-day diet. The Nutriservis Professional programme was used to evaluate diets (determine energy values, amount of essential nutrients, fibre, calcium, plus other minerals and vitamins). Bone mineral...

In this research, beta-lactoglobulin was chemically modified by attaching different levels of stearic acid to the protein. The effect of this modification on hydrophobic!ty, emulsifying and foam properties, digestibility and allergenicity of the protein was investigated. It was found that the effect of fatty acid attachment or lipophilization depended on the amount of fatty acids attached to the protein. Incorporation of the hydrophobic ligands led to increased hydrophobic interactions, resulting in a decreasing solubility with extent of incorporation. Furthermore, the surface hydrophobicity measurements showed that the two fluorescence probes 8-anilinonaphthalene-l-sulfonate (ANS) and cis-parinaric acid (CPA) used for the surface hydrophobicity measurements were not equivalent This may support the. observation by earlier workers that ANS measures aromatic hydrophobicity and CPA aliphatic hydrophobicity. The studies on surface functional properties i.e. emulsifying and foaming properties, indicated that there was some improvement in these functional properties at low and medium levels of incorporation which decreased as the extent of fatty acid attachment further increased. The improvement, of these functional properties could be attributed to improved amphiphilicity of the proteins at these levels of incorporation. This research also showed that both high solubility and high ANS surface hydrophobicity is needed for the best emulsifying properties. In vitro digestibility studies showed a decrease in digestibility of the modified proteins with increased lipophilization. From the passive cutaneous anaphylaxis experiments, it was found that the level of fatty acid attachment to the protein had a significant effect on its ability to elicit IgE antibodies. Increased ability to elicit IgE antibodies was observed at a low level of fatty acid. When a medium level of fatty acid was attached the ability to elicit antibodies was reduced and almost completely destroyed when a higher level of fatty acid was incorporated. The above observations could be explained by the fact that the low level incorporation of fatty acid led to changes in the protein structure which exposed more allergenic sites. The almost complete destruction of the allergenicity could be attributed to denaturation of the protein which reduced or destroyed available allergenic sites. The antigenicity or binding of the modified proteins to the IgG antibodies raised against the native protein was studied by both direct and competitive enzyme linked immunosorbent assay. It was found that at low and medium levels of incorporation, the proteins demonstrated increased binding ability compared to the native protein. This was attributed to the increased exposure of antigenic sites on the protein with fatty acid incorporation. However, the protein with high level of incorporated fatty acid showed decreased binding ability. / Land and Food Systems, Faculty of / Graduate

Many consumers are unable to enjoy the benefits of milk, due to lactose-intolerance. Lactose-free milk is available, but at about 2 times the cost of regular milk or greater, it may be difficult for consumers to afford. The high cost of lactose-free milk is in part due to the added cost of the lactose hydrolysis process. Hydrolysis at refrigerated temperatures, possibly in the bulk tank or package, could increase the flexibility of the process, and potentially reduce the cost. A rapid β-galactosidase assay was used to determine the relative activity of commercially available lactase samples at different temperatures. Four enzymes exhibited low-temperature activity and were added to refrigerated raw and pasteurized milk at various concentrations and allowed to react for various lengths of time. The degree of lactose hydrolysis by each of the enzymes as a function of time and enzyme concentration was determined by HPLC. The two most active enzymes, as determined by the β-galactosidase assay, hydrolyzed over 98% of the lactose in 24 hours at 2°C using the supplier recommended dosage. The other two enzymes hydrolyzed over 95% of the lactose in 24 hours at two times the supplier recommended dosage at 2°C. Results were consistent in all milk types tested. The results show that it is feasible to hydrolyze lactose during refrigerated storage of milk using currently available enzymes.

As a primary factor in human evolution, natural selection is an important component of genetic research. Studies of lactase persistence suggest that positive selection has played a powerful role in the adaptation to a lifelong consumption of fresh milk. Using multiple research studies of lactase persistence and suspected corresponding single nucleotide genetic polymorphisms, this study combines data sources to determine whether evidence exists for natural selection of a specific cytosine-to-thymine genetic mutation located 13,910 base pairs (T-13910) upstream from the lactase gene. This polymorphism has potential to be a causal element for lactase persistence, and data suggest that natural selection has played a role in the rising frequency and distribution of this allele, if only in some regions. European and neighboring regions appear to have the highest frequencies with little or no frequency in Asia, Africa and Indonesia; however the presence of lactase persistence in those areas suggests convergent evolution may be occurring on a phenotypic level. To examine this possibility several other identified polymorphisms in the same region as the T-13910 will be included in this study

At the last time, we can see increased interest of lactose-free dairy products. The aim of the thesis was to evaluate offer of such products at selected retail chains in the South Bohemian region, then to conclude a sensory assessment of selected products and to verify of public awareness about lactose intolerance with a questionnaire survey. The widest offer of lactose-free dairy products has been found in Globus and Tesco, in the opposite the lowest offer has been found in Billa. Location of these products within the store was most the transparent in Globus (compared other stores). Three samples of white lactose free yoghurts and two samples of milk (with lactose and lactose-free) were evaluated by a sensory assessment. The sample of yoghurt from the company Madeta, line Nature was rated the best. On the contrary sample of yoghurt from the company Tatranská mliekáreň, line Nature´s Promise was rated the worst. The preference between two milk samples among the evaluators was balanced, despite large to moderate differences of intensity were described between them. Most respondents (79 %) knew what the term lactose intolerance means, but substantial part (22 %) of respondents badly indicated this the issue as allergy to milk casein. Because of high number of lactose-intolerant people in population this issue is still very actual, and it needs to be addressed.

From a public health perspective pain from low back and/or pelvis was studied in relation to pregnancy. Two interventions, water gymnastics or Friskis and Svettis ́ gymnastics for pregnant women, were evaluated regarding effects on symptoms and need for sick leave due to low back or pelvic pain. In an intervention study with 390 randomised women, 266 participated in physical activity during 60 minutes once a week during just about half their pregnancies. No one was sick-listed due to low back pain in the water gymnastic group compared to 6 women in the land-based exercise group (p=0.03). Some doubts may be raised regarding recommendations to pregnant women with a history of low back pain to participate in gymnastics. On the contrary, water gymnastics seems to be beneficial regarding low back pain. Methods to prevent pelvic pain in relation to pregnancy are not known. Furthermore, a possible relation between longstanding pelvic pain after pregnancy was investigated. Such a relation has never been described before. Fifteen subjects, women with defined posterior pelvic pain during and after pregnancy and as many controls without anamnesis of such pain were tested for lactose intolerance, using the BH2-test. A correlation was found, p=0.05 but results need to be confirmed in larger studies. The possible link towards explaining such a relation goes through the fact that lactose intolerance and “irritable bowel syndrome”, IBS, often overlap and lactose intolerance test is recommended to be included in investigation of IBS. Can low back/pelvic pain in relation to pregnancy sometimes be correlated to lactose intolerance? / Med utgångspunkt från ett folkhälsoperspektiv studerades smärta från ländrygg och eller bäcken hos gravida kvinnor. Två interventioner, vattengymnastik respektive Friskis och Svettis ́ Vänta-barn-gympa, utvärderades avseende symtom på smärta från ländrygg och bäcken samt sjukskrivning härför i samband med graviditet. I en interventionsstudie med 390 randomiserade kvinnor deltog 266 kvinnor i fysisk aktivitet under en timma per vecka under drygt halva graviditeten. Ingen var sjukskriven för ländryggsmärta i vattengymnastikgruppen jämfört med 6 kvinnor i gymnastikgruppen (p=0.03). Viss försiktighet föreslås när det gäller att rekommendera vanlig gymnastik till kvinnor med anamnes på ryggsmärta under graviditet medan vattengymnastik förefaller ha god effekt för just ländryggsmärta. Någon metod för att förebygga bäckensmärta finns inte beskriven. Vidare studeras ett eventuellt samband mellan laktosintolerans och kvarstående bäckensmärta, något som inte tidigare undersökts. När det gäller sambandet graviditet – laktosintolerans gjordes en pilotstudie med 15 deltagare och lika många kontroller. Ett visst samband kunde konstateras, p=0.05, men resultaten måste verifieras i större studier. Den tänkbara förklaringsmekanismen bakom sambandet med laktosintolerans går via ”irritable bowel syndrome”, IBS. Symtom från IBS och från laktosintolerans överlappar varandra och det rekommenderas att laktosbelastning skall ingå i utredning av oklara buksmärtor. Kan även bäckensmärtor i samband med graviditet i vissa fall ha samband med laktosintolernas?

L’ingénierie des compléments alimentaires solides offre plusieurs avantages dans la formulation industrielle des produits alimentaires, en termes de production, stockage, et manipulation. Pour ces raisons, l’objectif de cette thèse était d’élaborer des ‘cargos’ bio-réactifs, permettant l’encapsulation d’une enzyme exogène capable de réaliser la réaction d’hydrolyse des molécules de lactose. Aujourd’hui il est établi que les symptômes caractéristiques de l’intolérance au lactose sont associés à une carence en lactase dans le gros intestine. Ainsi, fournir au corps humain de la lactase est l’application ciblée par ce travail, par la conception de matériaux siliciques comme support d’encapsulation. En général, les types de cargos développés doivent surmonter les conditions gastriques pour libérer l’enzyme dans le gros intestine. La silice poreuse amorphe est un matériau inorganique non-toxique qui assure une bonne protection dans des conditions acides et permet une libération contrôlée au pH légèrement basique du colon. L’utilisation de silice amorphe poreuse permet à coût réduit d’obtenir une structure intrinsèque contrôlée (forme, taille particulaire, diamètre du pore) et une chimie de surface modifiable. En accord avec les objectifs principaux, quatre stratégies d’encapsulation bio-adaptées ont été étudiées comme de potentiels voies pour la production de compléments alimentaires solides d’intérêt pour le traitement de l’intolérance au lactose : (i) immobilisation de l’enzyme par adsorption dans des matériaux siliciques meso-macroporeux pré-synthétises, (ii) immobilisation de l’enzyme sur des particules de silice faiblement poreuses recouvertes par des liposomes, (iii) encapsulation de l’enzyme dans des nanoparticules de lipides solides (SLNs), (iv) encapsulation de l’enzyme dans une matrice de biopolymère recouvert d’une coque de silice mésoporeuse / The engineering of solid dietary supplements provides several advantages in the industrial formulation of food products, in terms of its production, storage and handling. Thereby, the goal of this doctoral work is to design bio-responsive carriers for the encapsulation of an exogenous enzyme able to catalyze the hydrolysis of lactose towards simple sugar molecules. In fact, there is a consensus that the onset of symptoms characteristic of lactose intolerance are associated with lactase deficiency in the small intestine. Providing the organism with exogenous lactase is the underlying application targeted by this work through the design of silicabased materials for encapsulation. The different types of bio-carriers developed had to overcome the simulated gastric conditions in order to release active enzyme molecules in the small intestine. Amorphous porous silica is a very good and non-toxic component affording protection versus acidic conditions, while providing controlled release. This inorganic material approved by the US Food and Drug Administration (FDA) has a relatively low cost, and presents a controlled structure (shape, size, pore diameter), as well as tunable surface chemistry. In agreement with the main objectives, four bio-adapted encapsulation strategies were investigated as potential routes to produce solid dietary supplements for lactose intolerance treatment: (i) physical entrapment of the enzyme in pre-synthesized meso-macroporous silica materials, (ii) physical entrapment of the enzyme in low porosity silica particles coated by liposomes, (iii) encapsulation of the enzyme into thermosensitive solid lipid nanoparticles (SLNs) (iv) encapsulation of the enzyme into a biopolymer matrix coated in a mesoporous silica shell

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In recent years, there has been an increasing demand for foods with some functional property, being the dairy products the largest range of functional products manufactured on the market today. Nevertheless, a large part of the world population is restricted to the consumption of dairy by having a deficiency or absence in the production of lactase in the gut. Thus, this study aimed to develop a probiotic Minas fresh cheese with low-lactose content and evaluate their physico-chemical, sensorial and technological characteristics as well as the viability of probiotic bacteria during storage. Six cheese formulations (T1 to T6) were prepared with milk treated with lactase enzyme (β-galactosidase) at concentrations of 0,3, 0,6 and 0,9 g / L in reaction times of 12 and 24 hours, all of which added by 1% of probiotic culture (Lactobacillus acidophilus e Bifidobacterium sp.). Two other formulations, T7 and T8, were both developed without the addition of lactose and only T7 containing probiotic. The lactose was reduced more than 70% for all treatments added lactase, reaching 93,23% in the treatment with larger amount of enzyme. The physico-chemical evaluation showed that all the cheeses were developed in accordance with current legislation regarding the parameters of moisture and fat. It was observed that the acidity values were significantly lower (ρ <0,05) for cheese with less lactose content and for chesse without probiotic culture to the values found for the other treatments. Although the counts of Lactobacillus acidophilus were below the established minimum, the counts of Bifidobacterium sp. always remained above 106 CFU g-1, regardless of the amount of enzyme lactase added. In the analysis of instrumental texture, there were no significant differences (ρ> 0.05) among treatments for the parameters of firmness, cohesiveness and gumminess. In the sensory analysis, panelists found the taste more sweet and less acid in the sample with higher hydrolysis of lactose, and found no difference in texture compared to controls. Based on the results obtained, it can be said that the enzyme lactase effectively reduced the lactose content in the developed cheeses, and did not change the physico-chemical, sensorial and technological neither the probiotic viability, being a positive option for the dairy market, especially for being able to reduce lactose intolerance symptoms. / Nos últimos anos, houve um aumento na procura por alimentos com alguma propriedade funcional, sendo os derivados lácteos a maior gama de produtos funcionais industrializados atualmente disponíveis no mercado. Porém uma grande parte da população mundial está restringida ao consumo de lácteos por possuir uma deficiência ou ausência na produção de enzima lactase no intestino. Desta forma, o presente trabalho teve como objetivo desenvolver queijos Minas Frescal probióticos com baixo teor de lactose e avaliar suas características físico-químicas, sensoriais e tecnológicas bem como a viabilidade das bactérias probióticas durante o armazenamento. Seis formulações de queijo (T1 a T6) foram elaboradas com leite tratado com a enzima lactase (β-galactosidade) nas concentrações de 0,3, 0,6 e 0,9 g/L em tempos de reação de 12 e 24 horas, sendo todas adicionadas de 1% de cultura probiótica (Lactobacillus acidophilus e Bifidobacterium sp.). Outras duas formulações, T7 e T8, foram desenvolvidas ambas sem adição de lactase e somente T7 contendo probiótico. A lactose foi diminuída em mais de 70% em todos os queijos adicionados de enzima lactase, chegando a atingir 93,23% no tratamento com maior quantidade da enzima. A avaliação físico-química demonstrou que todos os queijos desenvolvidos estavam de acordo com a legislação vigente quanto aos parâmetros de umidade e gordura no extrato seco. Observou-se que os valores de acidez foram significativamente menores (ρ<0,05) para o queijo com menor teor de lactose e para o queijo sem adição de probiótico que os valores encontrados para os demais tratamentos. Apesar das contagens de Lactobacillus acidophilus ficarem abaixo do mínimo estabelecido, as contagens de Bifidobacterium sp. mantiveram-se sempre acima de 106 UFC.g-1, independente da quantidade de enzima lactase adicionada. Na análise do perfil de textura instrumental, não foram detectadas diferenças significativas (ρ>0,05) entre os tratamentos quanto aos parâmetros de firmeza, coesividade e gomosidade. Quanto à análise sensorial, os provadores detectaram o menor gosto ácido e maior gosto doce na amostra com maior hidrólise de lactose, e não observaram diferença quanto à textura em relação aos controles. Com base nos resultados obtidos, pode se concluir que a enzima lactase reduziu de maneira eficaz o teor de lactose nos queijos desenvolvidos, não alterando as características físico-químicas, sensoriais e tecnológicas e nem a viabilidade probiótica, mostrando-se como uma opção positiva para o mercado de laticínios, especialmente por poder reduzir os sintomas da intolerância à lactose.

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2017-11-27T20:53:26Z No. of bitstreams: 1 edilenemqa-tese.pdf: 4986958 bytes, checksum: 98721b3ed915b46fe60ca445665ea3ca (MD5) / Made available in DSpace on 2017-11-27T20:53:26Z (GMT). No. of bitstreams: 1 edilenemqa-tese.pdf: 4986958 bytes, checksum: 98721b3ed915b46fe60ca445665ea3ca (MD5) Previous issue date: 2016-09-26 / Metabolic syndrome (MS) is a complex disorder with a strong genetic basis and multifactorial etiology. Insulin resistance (IR) causes MS and it can be triggered by intestinal inflammation like the use of lactose in patients intolerant of this carbohydrate. It was found that variants in the lactase gene are associated with lactase non persistence LNP and MS in a population sample of Salvador/Bahia; and whether these variants are modifying the response to diet-therapeutic intervention in patients with this syndrome; also compared the biochemical test of lactose tolerance (LTT) with genetic diagnosis; and tested the association of mutations in the lactase gene with cofactors SM (TGL, HDL-C, blood pressure, glucose levels, waist circumference), with anthropometric variables (Arm Circumference, Body Mass Index, Hip Circumference, hip-waist ratio,lean massand fat mass percentages) and other factors associated with MS: insulin, total cholesterol, LDL-C, VLDL-C, C-reactive protein, HOMA-IR, renal function (creatinine, urea, uric acid, microalbuminuria) and vitamin D. There were two studies: a case-control with 257 cases (MS) and 210 controls and other clinical trial study, which was conducted with three types of diet in patients with metabolic syndrome: diet 1 - No lactose; Diet 2 - Lactose and energy restriction; Diet 3 - Only energy restriction. In all groups were also evaluated for nine SNPs in the lactase (LCT) gene. The genotyping of SNPs was carried out by TaqMan assays. Data were analyzed using SPSS, 20.0, and the Hardy-Weinberg Equilibriumhaplotype frequencies were calculated using Arlequin, 2000 program. The results showed that all diets improve several MSaspects after two months of intervention, especially in the diet 1, that also decreased inflammation, insulin resistance and dyslipidemia (LDL-C). In addition,it was the diet that most took out patients of the MS: 2.72 times more likely to get out of MS than diet 3. LNP was high in both cases and controls. There was compatibility between clinical diagnosis for LNP by Lactose Tolerance Test and two of the studied SNPs, they were rs4988253 and rs182549, those that have proved functional studies. Thus, it is suggested the analysis of LCT gene polymorphisms before the nutritional therapeutics for patients with MS, as well as to take out the lactose in their diet. / A S?ndrome Metab?lica (SM) ? uma desordem complexa, de forte base gen?tica e de etiologia multifatorial. Dentre as suas causas, encontra-se a Resist?ncia ? Insulina (RI) que pode ser desencadeada pela inflama??o intestinal, pelo uso de lactose em pacientes intolerantes a este carboidrato. Verificou-se quais variantes no gene da lactase est?o associados ? IL e SM em amostra da popula??o de Salvador/Bahia; e tamb?m se estas variantes s?o modificadoras da resposta ? interven??o dietoter?pica em portadores desta s?ndrome; comparou-se tamb?m o teste bioqu?mico de toler?ncia ? lactose (TTL) com o diagn?stico gen?tico; e testou-se a associa??o das muta??es no gene da lactase com os cofatores da SM (TGL, HDL-c, press?o arterial, glicemia, circunfer?ncia da cintura), com vari?veis antropom?tricas (circunfer?ncia do bra?o, ?ndice de massa corporal, circunfer?ncia do quadril, raz?o cintura quadril, percentual de massa magra e massa gorda) e com outros fatores associados ? SM: insulina, colesterol total, LDL-C, VLDL, Prote?na C reativa, HOMA-IR, fun??o renal (creatinina, ur?ia, ?cido ?rico, microalbumin?ria) e vitamina D. Foram realizados dois estudos: um caso-controle com 257 casos (SM) e 210 controles e outro estudo de tipo ensaio cl?nico, que foi realizado com tr?s tipos de dieta com os pacientes com SM: dieta 1 ? sem lactose; dieta 2 ? sem lactose e com restri??o energ?tica; Dieta 3 ? apenas restri??o energ?tica. Em ambos os grupos tamb?m foram avaliados 9 SNPs no gene da lactase. A genotipagem dos SNPs foi realizada pela tecnologia de ensaios TaqMan. Os dados foram analisados pelo programa SPSS ver 20.0 e a adequa??o das frequ?ncias genot?picas ao Equilibrio de Hardy-Weinberg e c?lculo da frequ?ncia dos hapl?tipos formados pelos polimorfismos foram obtidos atrav?s do programa Arlequin ver 2000. Os resultados mostraram que todas as dietas melhoram o quadro da SM ap?s dois meses de interven??o, com destaque para a dieta 1, que tamb?m diminuiu a inflama??o, resist?ncia ? insulina e a dislipidemia (LDL-C). Al?m disso foi a dieta que mais tirou paciente da SM: apresentou 2,72 vezes mais chances de sair da SM que a dieta 3. A intoler?ncia ? lactose foi alta tanto em casos como em controles. Houve compatibilidade do TTL com os SNPsrs4988253 e rs182549, os ?nicos que possuem estudos funcionais. Assim, sugere-se an?lise de polimorfismos do gene da lactase antes da prescri??o nutricional para pacientes com SM, bem como, a retirada da lactose da dieta.

Introdução: A má digestão de lactose detectada por testes respiratórios é bastante comum em pacientes com síndrome do intestino irritável (SII), e alguns pacientes com SII referem exacerbar seus sintomas após a ingestão de leite e produtos lácteos. A fim de uma melhor percepção sobre este tema, este trabalho investigou os efeitos da dieta isenta de lactose em pacientes com SII e teste respiratório de hidrogênio para avaliação da digestão de lactose normal ou anormal. Objetivo: Avaliar os efeitos de uma dieta isenta de lactose em pacientes de SII com ou sem teste positivo para má digestão de lactose (teste respiratório). Métodos: 80 pacientes atendidos no Ambulatório de Doenças Funcionais Intestinais do Serviço de Gastroenterologia Clínica do HCFMUSP foram recrutados para o estudo prospectivo. Os pacientes preencheram os critérios de Roma III para SII. Durante o ensaio do teste respiratório de hidrogênio todos os sintomas desencadeados pela ingestão de lactose foram anotados. Ambos os grupos de pacientes com e sem má digestão de lactose, foram submetidos a uma dieta isenta de lactose durante 4 semanas. A história prévia de intolerância ao leite e derivados também foi documentada. No final de cada semana, os pacientes foram solicitados a informar a respeito dos seus sintomas, e os resultados, foram devidamente marcados de acordo com a sua intensidade (Escore Global). Além disso, foi também obtida a Avaliação Global do Paciente no final do tratamento (AFG). Resultados: 33/80 (41,25%) pacientes com SII tiveram um teste respiratório anormal para a má digestão de lactose, e 47/80 dos pacientes (58,75%) com SII tiveram um teste respiratório normal (ns). Não houve diferença significativa na freqüência de queixas de intolerância prévia ao leite e derivados em ambos os grupos. No entanto, mais pacientes no grupo com má digestão de lactose referiram sintomas durante o teste respiratório com 25 g de lactose do que o grupo com digestão normal a lactose (p <0,001). Ambos os grupos igualmente melhoraram após uma dieta isenta de lactose, quando avaliados pelo escore geral e pelo AFG. Conclusões: Ambos os grupos de pacientes com SII, com e sem má digestão de lactose, melhoraram após 4 semanas de dieta isenta de lactose. Os nossos resultados sugerem que outros mecanismos, além da intolerância à lactose, devem ser levados em conta para explicar a melhora com uma dieta isenta de lactose em pacientes com SII / Introduction: Lactose intolerance detected by respiratory tests is rather common in patients with irritable bowel syndrome(IBS); also, some IBS patients refer their symptoms exacerbate after ingestion of milk and dairy products. In order to gain some insight into this topic we investigated the effects of a lactose-free diet in IBS patients with and without lactose intolerance diagnosed by means of the hydrogen respiratory test. Objective: To evaluate the effects of a lactose-free diet in IBS patients with and without lactose intolerance. Methodos: 80 patients who attended the outpatient clinic at the University of São Paulo School of Medicine Hospital, Brazil, were recruited for this prospective study. Patient met the Rome III criteria for IBS. During the hydrogen respiratory test all the symptoms triggered by lactose ingestion were taken down. Both groups of patients, with and without lactose intolerance, were submitted to a lactose-free diet for 4 weeks. Previous history of milk/dairy products intolerance was documented. At the end of each week, patients were asked to inform about their symptoms and the results were duly scored according to their intensity (Global Score). Also, the Patient Final Global Evaluation of the Treatment (PFGET) was obtained as well. Results: 33/80 (41.25%) IBS patients had an abnormal respiratory test for lactose intolerance; 47/80 (58.75%) IBS patients had a normal respiratory test (n.s.). There was no significant difference in the frequency of previous complaints after milk/dairy products ingestion in both groups. However, more patients in the lactose intolerant group referred symptoms during the respiratory test with 25 g of lactose than the lactose tolerant group (p<0,001). Both groups similarly improved after a lactose-free diet when evaluated by both the Global Score and the PFGET. Conclusions: Both groups of IBS patients, with and without lactose intolerance, improved after a 4-week lactose-free diet. Our results suggest that other mechanisms, in addition to lactose intolerance, should be taken into account to explain why IBS patients improve with a lactose-free diet