Showing papers by "Arthur C. Ouwehand published in 2002"

Probiotics: an overview of beneficial effects

Abstract: Food products fermented by lactic acid bacteria have long been used for their proposed health promoting properties. In recent years, selected probiotic strains have been thoroughly investigated for specific health effects. Properties like relief of lactose intolerance symptoms and shortening of rotavirus diarrhoea are now widely accepted for selected probiotics. Some areas, such as the treatment and prevention of atopy hold great promise. However, many proposed health effects still need additional investigation. In particular the potential benefits for the healthy consumer, the main market for probiotic products, requires more attention. Also, the potential use of probiotics outside the gastrointestinal tract deserves to be explored further. Results from well conducted clinical studies will expand and increase the acceptance of probiotics for the treatment and prevention of selected diseases.

The role of the intestinal microflora for the development of the immune system in early childhood.

Abstract: The intestinal tract performs many different functions; in addition to absorption and digestion it is also the body's largest organ of host defence. Part of the intestinal mucosal barrier function is formed by a common mucosal immune system which provides communication between the different mucosal surfaces of the body. The intestine also contains a microbial ecosystem with a large body of microbes, 1-11/2 kg in an adult. The microbes and their activity have a major impact on the development and functioning of the intestinal immune system and vice versa. This mutual influence also affects the host beyond the intestine. The intestinal colonisation with a balanced microflora is of main importance for the correct development of the immune system. The importance of the intestinal microflora is most clearly seen in germfree animals, but also diseases like atopy are associated with disturbances in the intestinal microflora. This often manifests itself in a low number of bifidobacteria. The use of probiotics or prebiotics to correct this imbalance and modulate the immune activity has received increasing scientific documentation. The precise mechanisms behind these immune modulatory activities are not well understood and require further investigation.

Effect of probiotics on constipation, fecal azoreductase activity and fecal mucin content in the elderly.

Abstract: Background: Constipation is a common problem in elderly subjects, probiotics have been suggested to improve intestinal motility and reduce fecal enzyme activity. Methods: Elderly subjects (n = 28) were enrolled in an open parallel study. The subjects were divided into 3 groups: 1 control group receiving juice; 1 group receiving juice supplemented with Lactobacillus reuteri, and 1 group receiving juice supplemented with Lactobacillus rhamnosus and Propionibacterium freudenreichii. During the first 3 weeks all subjects consumed unsupplemented juice. In the subsequent 4 weeks, the subjects received their designated juice. During the last 3 weeks, all subjects again received unsupplemented juice. From the subjects, defecation frequency, laxative use, fecal pH, mucin content and azoreductase activity were assessed during the last week of each period. Results: The subjects receiving the L. rhamnosus/P. freudenreichii-supplemented juice exhibited a 24% increase in defecation frequency. However, no reduction in laxative use was observed. The fecal azoreductase activity was also significantly reduced in this group. No changes in fecal pH or mucin excretion were observed. Conclusion: Some relief from constipation may be observed with the combination of L. rhamnosus/P. freudenreichii. This probiotic combination also reduced fecal enzyme activity. The tested probiotics did not affect the mucosal barrier.

Cytokine Production by the Murine Macrophage Cell Line J774.1 after Exposure to Lactobacilli

Abstract: Eleven strains of lactobacilli were tested for their ability to induce the murine macrophage-like cell line J774.1 to secrete cytokines. Some of the bacteria tested induce the production of interleukin(IL) 6, IL-12, and tumor necrosis factor a (TNF-alpha) by J774.1 cells. Seven strains also induced the production of IL-10. However, no IL-1beta was produced. Lactobacillus acidophilus TMC 0356 significantly induced the production of more IL-6, IL-10, IL-12, and TNF-alpha than the other bacteria tested (p < 0.0001; ANOVA). These results suggest that lactobacilli can activate macrophages to secrete both inflammatory and anti-inflammatory cytokines. Selected strains might be used to bring about pro or antiinflammatory immune reactions.

Adhesion of lactic acid bacteria to Caco-2 cells and their effect on cytokine secretion

Abstract: Cytokines secreted by human enterocytes play a critical role in mucosal and systemic immunity. Intestinal microorganisms can influence this secretion. In the present study, 30 strains of lactic acid bacteria were characterized for their adhesion to Caco-2 cells and their potential to stimulate proinflammatory cytokine secretion by this cell line. The bacteria adhered in a strain-dependent manner to Caco-2 cells. Contact with lactobacilli did not result in the production of IL-6 or IL-8. A slight IL-6 and IL-8 production by a Caco-2 cell was detected after exposure to 8 of the tested Bifidobacterium strains. No correlation was found between adhesion and cytokine induction among the bacteria tested. This indicates that lactic acid bacteria, even those with strong adhesive properties, are not very likely to trigger an inflammatory response in human enterocytes.

Stimulation of the Secretion of Pro‐Inflammatory Cytokines by Bifidobacterium Strains

Abstract: To characterize the ability of bifidobacteria to affect the production of macrophage-derived cytokines, a murine macrophage-like cell line, J774.1, was cultured in the presence of 27 strains of heat-inactivated bifidobacteria. Bifidobacterium adolescentis and B. longum, known as adult-type bifidobacteria, induced significantly more pro-inflammatory cytokine secretion, IL-12 and TNF-alpha, by J774.1 cells, than did the infant-type bifidobacteria, B. bifidum, B. breve, and B. infantis (P<0.01). In contrast, B. adolescentis did not stimulate the production of anti-inflammatory IL-10 from J774.1 cells as the other tested bacteria did. The results suggest that the adult-type bifidobacteria, especially B. adolescentis, may be more potent to amplify but less able to down-regulate the inflammatory response.

Resected human colonic tissue: new model for characterizing adhesion of lactic acid bacteria.

Abstract: Adhesion to the intestinal mucosa is one of the main selection criteria for probiotic strains. The adhesion of commonly used probiotic strains to human intestinal tissue pieces and mucus was assessed. The strains tested adhered to the intestinal tissue at low levels and adhered to the intestinal mucus at higher levels.

Inventory of microorganisms with a documented history of use in food

Abstract: In order to classify traditionally used microorganisms (starter cultures) as safe food ingredients, The IDF in collaboration with EFFCA (European Food and Fed Cultures Association) has compiled an inventory of microorganisms with a documented history of use in food. The inventory is supplied with explanatory text dealing with taxonomic changes that have taken place over time. The use of the microorganisms is documented by sales information and through literature references. The inventory is by no means exhaustive, and is based on the knowledge of the participating experts, not that of the whole food or dairy industry. This inventory is intended for information only, not as a complete inventory of microorganisms for use in food, or to exclude any other existing products unknown to the participating experts. The list mentions major applications for the included culture or strain. This information is taken from the literature and it does not imply that the strain or culture could not be applied in the production of other foodstuffs.

In vitro adhesion of propionic acid bacteria to human intestinal mucus

Abstract: Propionic acid bacteria (PAB) have widely been used as starter cultures. Their potential as probiotics has, however, received little attention. Adhesion to the intestinal mucosa is considered one of the main selection criteria for probiotic micro-organisms. Therefore, in the current study the adhesion of PAB to human intestinal mucus was investigated in an in vitro model. The tested PAB ex- hibited a low to moderate level of adhesion (0.4 to 4.5% of the applied bacteria). Because adhesion to mucus and bovine serum albumin were similar, it is likely that the adhesion to mucus is the result of non-specific interactions. The adhesion to mucus could be significantly enhanced by prior adhesion of existing probiotic strains. The PAB did not affect the adhesion of these probiotics. Adhesion of the moderately adhering strains was found to be close to maximum within 30 s showing that the adhesion happens almost instantaneously, while the adhesion of the low binding strains increased unti l1ho f incubation. These results together with earlier observations on the properties of PAB indicate that selected PAB have good prerequisites for probiotic use. Propionibacterium / adhesion / intestinal mucus / probiotic

Lactobacillus paracasei subsp. paracasei F19: Survival, Ecology and Safety in the Human Intestinal Tract—A Survey of Feeding Studies within the PROBDEMO Project

Abstract: Lactobacillus paracasei F19 is an emerging probiotic strain that shows considerable promise for use in functional foods for intestinal health. In a multicentre European research project, human feeding trials provided an insight into the ability of this strain to survive gastric transit and transiently colonize the human intestinal tract. Analysis of the faecal microbiota in healthy human volunteers showed that a proportion of the subjects carried a strain indistinguishable from L. paracasei F19 naturally within their intestines. When consumed in different foods, L. paracasei F19 survived gastric transit in healthy infants, adults, and elderly subjects. The bacterium transiently colonized both the colonic lumen and mucosa. Molecular analysis of faecal and colonic biopsy samples from children fed the probiotic showed that L. paracasei F19 did not perturb the population dynamics of other major populations of bacteria in the intestinal microbiota. This strain was well tolerated by young children, healthy adults, adults with milk-hypersensitivity and elderly subjects infected with Helicobacter pylori . Keywords: F19, Lactobacillus , microbiota, paracasei, probiotic, survival.

Food microorganisms: Health benefits, safety evaluation and strains with documented history of use in foods

Abstract: This scientific summary reviews the latest research related to health benefits and safety evaluation of lactic acid bacteria (LAB) and introduces an inventory of food microorganism species with a history of safe use in foods. The inventory has been produced in collaboration between the International Dairy Federation (IDF) and European Food and Feed Cultures Association (EFFCA). It is not to be regarded as being complete since many locally used dairy or food starter strains with a long history of safe use have not yet been included. The literature on recent research on the use of various LAB in clinical and nutritional treatment of severely compromised individuals has mainly disclosed a positive influence on the treatment and prevention of various diseases. Reports on adverse effects and even infections caused by LAB have appeared occasionally, but mostly in cases where the LAB appear accidentally and rarely in cases where LAB has been administered intentionally. Increasing evidence is accumulating that certain LAB are able to interact with the gastrointestinal tract and its mucosal immune system. No adverse effects of using LAB have been reported in the great number of controlled human trials, which is a strong indication that laboratory (dairy) strains of probiotic LAB are safe - even when administered to severely immune compromised individuals.

Inventing probiotic functional foods for patients with allergic disease.

Abstract: Objective The primary objective of this review is to discuss the rationale for and applicability of probiotics as part of the nutritional approach to the prevention and management of allergic disease. Data Sources This review represents a synthesis of recent literature published in the fields of probiotics, nutrition, and allergic disease. Study Selection The expert opinions of the authors were used to select the relevant data for the review. Results The hygiene hypothesis suggests that allergic disease may arise from a lack of counterbalancing microbial exposure at an early age. Thus, the initial compositional development of gut microbiota is considered a key determinant in the development of both the immune responder phenotype and the normal gut barrier functions. A wide range of data documents the specific actions of selected probiotics. The regulatory role of probiotics in allergic disease has been demonstrated as improving the clinical course or preventing the development of atopic eczema in infants given a probiotic-supplemented diet. In addition, certain types of fatty acids and antioxidants have been proposed for protective effects against the development of allergy and to diminish the inflammatory response in allergic disease. Conclusions The increase in the prevalence of allergic disease during the past decades is likely to be explained by changes in the environment, including reduced microbial exposure and altered food consumption. Scientifically composed functional foods containing probiotics and other functional components offer a nutritional strategy for both the prevention and the management of allergic disease. Further research is needed to characterize the gut microbiota and to clarify the mechanisms of action that control specific physiologic processes not only in the evolution of allergic disease in at-risk populations but also in the management of allergic diseases.

Probiotics: on-going research on atopic individuals.

Abstract: The challenge for the modern health care system is to fight against the increasing prevalence of atopic disease. The introduction of scientifically composed probiotic functional foods for prophylactic or therapeutic purposes could be one solution. Probiotics are live microbial food supplements or components of bacteria which have beneficial effects on human health. Specific strains have been demonstrated to exert powerful anti-pathogenic, anti-inflammatory and anti-allergic effects. The hygiene hypothesis suggests that atopic disease may arise from a lack of counterbalancing microbial exposure at an early age. The initial compositional development of the gut microflora is considered a key determinant of the development of both the immune responder phenotype and normal gut barrier functions. The regulatory role of probiotics in human allergic disease was first emphasised in the demonstration of a suppressive effect on lymphocyte proliferation and interleukin-4 generation in vitro. Subsequently, a significant improvement in the clinical course of atopic eczema was reported in infants given a probiotic-supplemented diet. The potential of probiotics to reduce the risk of atopic disease has recently been demonstrated in a double-blind, placebo-controlled study: probiotics administered pre- and postnatally for 6 months to at-risk subjects reduced the prevalence of atopic eczema to half of that observed in infants receiving placebo. Ongoing research is directed towards the development of novel techniques to characterise the gut microflora. Future research will clarify the mechanisms to control specific physiological processes in the evolution of atopic disease in at-risk populations or in the management of allergic diseases.

Interactions between Lignans and Probiotics

Abstract: A diet rich in plant lignans has been suggested to have anti-cancer properties. Also selected probiotics are suggested to have anti-tumour activity. In the current study the interactions between the plant lignan 7-hydroxymata iresinol (HMR) and ? ve selected probiotic microorganisms was investigated. The results showed that presence of HMR affected the growth of Lactobacillus johnsonii La1. Compared with the control, the growth was slower during the exponentia l growth phase when L. johnsonii La1 was cultured in the presence of HMR. Differences in the growth of the other four microorganisms were not statistically significant. The in vitro adhesion of L. casei Shirota to intestinal mucus was found to be more than doubled after growth in the presence of HMR. No conversion of HMR was observed by any of the five tested strains. The data obtained from these experiment s suggest that plant lignans have some influence on probiotics. However , the mechanisms and the in vivo relevance of these interactions have yet to be resolved. The tested probiotics do not participate in the conversion of plant lignans to their biologically active form. Keywords: probiotics, lignans, mucus adhesion.

DOSIMETRY IN THE IRRADIATION OF THIN CULTURE LAYERS USING A 60Co RADIOTHERAPY UNIT AT 20 CM SSD

Abstract: In order to reach a dose rate of ca. 20 Gy/min with a typical 60Co radiotherapy unit, lactic acid bacteria (LAB) are irradiated at a 20 cm source-to-specimen distance (SSD). By choosing an SSD which is a fourth part of the conventional 80 cm, the dose rate in the specimen is increased by a factor of ca. 16. A Monte Carlo simulation of the CGR Alcyon II 60Co radiotherapy unit at 20 cm SSD is performed using a BEAM-EGS4 Monte Carlo code. As a result of calculations, relative dose distributions in a solid-water phantom are shown, together with measured thermoluminescence dosimetry (TLD) data. An additional scattering component due to the sideways scattering from the beam limiting device structures of the radiotherapy unit is seen in the beginning of the BEAM data.