Lactobacillus strain GG supplementation decreases colonic hydrolytic and reductive enzyme activities in healthy female adults

Probiotics intervention in colorectal cancer: From traditional approaches to novel strategies

ABSTRACT

The intestine harbors a large population of microorganisms that interact with epithelial cells to maintain host healthy physiological status. These intestinal microbiota engage in the fermentation of non-digestible nutrients and produce beneficial metabolites to regulate host homeostasis, metabolism, and immune response. The disruption of microbiota, known as dysbiosis, has been implicated in many intestinal diseases, including colorectal cancer (CRC). As the third most common cancer and the second leading cause of cancer-related death worldwide, CRC poses a significant health burden. There is an urgent need for novel interventions to reduce CRC incidence and improve clinical outcomes. Modulating the intestinal microbiota has emerged as a promising approach for CRC prevention and treatment. Current research efforts in CRC probiotics primarily focus on reducing the incidence of CRC, alleviating treatment-related side effects, and potentiating the efficacy of anticancer therapy, which is the key to successful translation to clinical practice. This paper aims to review the traditional probiotics and new interventions, such as next-generation probiotics and postbiotics, in the context of CRC. The underlying mechanisms of probiotic anti-cancer effects are also discussed, including the restoration of microbial composition, reinforcement of gut barrier integrity, induction of cancer cell apoptosis, inactivation of carcinogens, and modulation of host immune response. This paper further evaluates the novel strategy of probiotics as an adjuvant therapy in boosting the efficacy of chemotherapy and immunotherapy. Despite all the promising findings presented in studies, the evaluation of potential risks, optimization of delivery methods, and consideration of intra-patient variability of gut microbial baseline must be thoroughly interpreted before bench-to-bedside translation.

Kimchi improves irritable bowel syndrome: results of a randomized, double-blind placebo-controlled study

Background

Irritable bowel syndrome (IBS) can be caused by abnormal bowel movements, altered brain-gut axis, gut microbiota change, and low levels of inflammation or immune activation. The intake of food containing much fiber and lactic acid bacteria (LABs) can alleviate IBS.

Objective

This study was undertaken to confirm the alleviative effect of kimchi on symptoms of IBS.

Design

Three types of kimchi (standard kimchi, SK; dead nano-sized Lactobacillus plantarum nF1 (nLp) added to standard kimchi, nLpSK; or functional kimchi, FK) were given to 30 individuals in each of three groups, that is, the SK group (n = 30), the nLpSK group (n = 30), or the FK group (n = 30) at 210 g a day for 12 weeks. Food intake records, serum levels of inflammatory factors, fecal levels of harmful enzymes, and microbiome changes were investigated over the 12-week study period.

Results

After intervention, dietary fiber intake was increased in all groups. Typical IBS symptoms (abdominal pain or inconvenience, desperation, incomplete evacuation, and bloating), defecation time, and stool type were also improved. In serum, all groups showed reductions in tumor necrosis factor (TNF)-α (P < 0.001) levels. In addition, serum IL-4 (P < 0.001), IL-10 (P < 0.001), and IL-12 (P < 0.01) were significantly reduced in the nLpSK and FK groups, and serum monocyte chemotactic protein (MCP)-1 (P < 0.05) was significantly reduced in the nLpSK group. Furthermore, activities of fecal β-glucosidase and β-glucuronidase were significantly decreased in all three groups, and these reductions were greatest in the nLpSK group. Gut microbiome analysis showed that kimchi consumption increased Firmicutes populations at the expense of Bacteroidetes and Tenericutes populations. In addition, the Bifidobacterium adolescentis population increased significantly in the FK group (P = 0.026).

Conclusion

Kimchi intake helps alleviate IBS by increasing dietary fiber intake and reducing serum inflammatory cytokine levels and harmful fecal enzyme activities. Notably, nLp improved the immune system, and several functional ingredients in FK promoted the growth of Bifidobacterium adolescentis in gut.

The Role of Probiotics in Cancer Prevention

Simple Summary

Cancer is considered one of the leading causes of human mortality in the world and is the subject of much research. The risk of developing cancer depends on genetic factors, as well as the body’s immune status. The intestinal microbiome plays very important role in maintaining homeostasis in the human body. Probiotics have gained increasing medical significance due to the beneficial effect on the human body associated with the prevention and support of the treatment of many chronic diseases, including cancer in the absence of side effects. The aim of this review was to summarize the knowledge about the effect of probiotic microorganisms in the prevention of cancer. There is a lot of evidence that the use of probiotics can play an important role in cancer prevention and support anti-cancer therapies.

Abstract

The gut microbiome can play important role in maintaining homeostasis in the human body. An imbalance in the gut microbiome can lead to pro-inflammatory immune responses and the initiation of disease processes, including cancer. The research results prove some strains of probiotics by modulating intestinal microbiota and immune response can be used for cancer prevention or/and as adjuvant treatment during anticancer chemotherapy. This review presents the latest advances in research into the effectiveness of probiotics in the prevention and treatment support of cancer. The described issues concern to the anticancer activity of probiotic microorganisms and their metabolites. In addition, we described the potential mechanisms of probiotic chemoprevention and the advisability of using probiotics.

Microbial Metabolites as Molecular Mediators of Host-Microbe Symbiosis in Colorectal Cancer

The symbiosis between the gut microbiota and the host has been identified as an integral part of normal human physiology and physiological development. Research in germ-free or gnotobiotic animals has demonstrated the importance of this symbiosis in immune, vascular, hepatic, respiratory and metabolic systems. Disruption of the microbiota can also contribute to disease, and the microbiota has been implicated in numerous intestinal and extra-intestinal pathologies including colorectal cancer. Interactions between host and microbiota can occur either directly or indirectly, via microbial-derived metabolites. In this chapter, we focus on two major products of microbial metabolism, short-chain fatty acids and bile acids, and their role in colorectal cancer. Short-chain fatty acids are the products of microbial fermentation of complex carbohydrates and confer protection against cancer risk, while bile acids are compounds which are endogenous to the host, but undergo microbial modification in the large intestine leading to alterations in their bioactivity. Lastly, we discuss the ability of microbial modulation to mediate cancer risk and the potential to harness this ability as a prophylactic or therapeutic treatment in colorectal cancer.

Microbial bile salt hydrolases mediate the efficacy of faecal microbiota transplant in the treatment of recurrent Clostridioides difficile infection

OBJECTIVE

Faecal microbiota transplant (FMT) effectively treats recurrent Clostridioides difficile infection (rCDI), but its mechanisms of action remain poorly defined. Certain bile acids affect C. difficile germination or vegetative growth. We hypothesised that loss of gut microbiota-derived bile salt hydrolases (BSHs) predisposes to CDI by perturbing gut bile metabolism, and that BSH restitution is a key mediator of FMT's efficacy in treating the condition.

DESIGN

Using stool collected from patients and donors pre-FMT/post-FMT for rCDI, we performed 16S rRNA gene sequencing, ultra performance liquid chromatography mass spectrometry (UPLC-MS) bile acid profiling, BSH activity measurement, and qPCR of bsh/baiCD genes involved in bile metabolism. Human data were validated in C. difficile batch cultures and a C57BL/6 mouse model of rCDI.

RESULTS

From metataxonomics, pre-FMT stool demonstrated a reduced proportion of BSH-producing bacterial species compared with donors/post-FMT. Pre-FMT stool was enriched in taurocholic acid (TCA, a potent C. difficile germinant); TCA levels negatively correlated with key bacterial genera containing BSH-producing organisms. Post-FMT samples demonstrated recovered BSH activity and bsh/baiCD gene copy number compared with pretreatment (p<0.05). In batch cultures, supernatant from engineered bsh-expressing E. coli and naturally BSH-producing organisms (Bacteroides ovatus, Collinsella aerofaciens, Bacteroides vulgatus and Blautia obeum) reduced TCA-mediated C. difficile germination relative to culture supernatant of wild-type (BSH-negative) E. coli. C. difficile total viable counts were ~70% reduced in an rCDI mouse model after administration of E. coli expressing highly active BSH relative to mice administered BSH-negative E. coli (p<0.05).

CONCLUSION

Restoration of gut BSH functionality contributes to the efficacy of FMT in treating rCDI.

Potential effect of probiotics in the treatment of breast cancer

Breast cancer is one of the most important causes of cancerrelated morbidity and mortality in the world. Probiotics, as functional food, have the potential to act against breast cancer, as evidenced by cell-based and animal model experiments. Probiotic may be useful in prevention or treatment of breast cancer by modulating the gastrointestinal bacteria and the systemic immune system. However, large-scale clinical trials and intensive research are mandatory to confirm the in vitro and in vivo results and exploring the probiotics-related metabolic, immune, and molecular mechanisms in breast cancer. This current review summarizes the available data related to probiotics and their potential role in the treatment of breast cancer.

Physicochemical Properties and Intestinal Health Promoting Water-Insoluble Fiber Enriched Fraction Prepared from Blanched Vegetable Soybean Pod Hulls

Different methods can be used to change the fiber compositions of food, and they consequently affect the physicochemical properties and physiological activities. The present study compared the effects of a blanching treatment on the physicochemical properties of water-insoluble fiber enriched fraction (WIFF) from three varieties of vegetable soybean pod hulls (tea vegetable soybean pod hull, TVSPH; black vegetable soybean pod hull, BVSPH; 305 vegetable soybean pod hulls, 305VSPH) and evaluated their effects on intestinal health in hamsters. Blanching may increase the soluble dietary fiber (SDF) content of WIFF in the 305VSPH variety by solubilizing cell wall components and releasing water-soluble sugars. Thus, the WIFF in the 305VSPH variety after blanching may be composed of cellulose and pectic substances. The WIFF of the blanched 305VSPH (B-305VSPH) variety exhibited the highest physicochemical properties, such as a water-retention capacity (11.7 g/g), oil-holding capacity (9.34 g/g), swelling property (10.8 mL/g), solubility (12.2%), and cation-exchange capacity (221 meq/kg), of the three varieties examined. The supplementation of B-305VSPH WIFF in the diet resulted in significantly (p < 0.05) lower cecal and fecal ammonia; activities of fecal β-d-glucosidase, β-d-glucuronidase, mucinase, and urease; as well as higher cecal total short-chain fatty acids relative to other diets. In addition, microbial analysis suggested that fecal bifidobacteria growth was enhanced by the consumption of B-305VSPH WIFF. Therefore, B-305VSPH WIFF may be applicable as a potential functional ingredient in the food industry for the improvement of intestinal health.

Functional microbiomics: Evaluation of gut microbiota-bile acid metabolism interactions in health and disease

There is an ever-increasing recognition that bile acids are not purely simple surfactant molecules that aid in lipid digestion, but are a family of molecules contributing to a diverse range of key systemic functions in the host. It is now also understood that the specific composition of the bile acid milieu within the host is related to the expression and activity of bacterially-derived enzymes within the gastrointestinal tract, as such creating a direct link between the physiology of the host and the gut microbiota. Coupled to the knowledge that perturbation of the structure and/or function of the gut microbiota may contribute to the pathogenesis of a range of diseases, there is a high level of interest in the potential for manipulation of the gut microbiota-host bile acid axis as a novel approach to therapeutics. Much of the growing understanding of the biology of this area reflects the recent development and refinement of a range of novel techniques; this study applies a number of those techniques to the analysis of human samples, aiming to illustrate their strengths, drawbacks and biological significance at all stages. Specifically, we used microbial profiling (using 16S rRNA gene sequencing), bile acid profiling (using liquid chromatography-mass spectrometry), bsh and baiCD qPCR, and a BSH enzyme activity assay to demonstrate differences in the gut microbiota and bile metabolism in stool samples from healthy and antibiotic-exposed individuals.

p-Cresyl Sulfate

If chronic kidney disease (CKD) is associated with an impairment of kidney function, several uremic solutes are retained. Some of these exert toxic effects, which are called uremic toxins. p-Cresyl sulfate (pCS) is a prototype protein-bound uremic toxin to which many biological and biochemical (toxic) effects have been attributed. In addition, increased levels of pCS have been associated with worsening outcomes in CKD patients. pCS finds its origin in the intestine where gut bacteria metabolize aromatic amino acids, such as tyrosine and phenylalanine, leading to phenolic end products, of which pCS is one of the components. In this review we summarize the biological effects of pCS and its metabolic origin in the intestine. It appears that, according to in vitro studies, the intestinal bacteria generating phenolic compounds mainly belong to the families Bacteroidaceae, Bifidobacteriaceae, Clostridiaceae, Enterobacteriaceae, Enterococcaceae, Eubacteriaceae, Fusobacteriaceae, Lachnospiraceae, Lactobacillaceae, Porphyromonadaceae, Staphylococcaceae, Ruminococcaceae, and Veillonellaceae. Since pCS remains difficult to remove by dialysis, the gut microbiota could be a future target to decrease pCS levels and its toxicity, even at earlier stages of CKD, aiming at slowing down the progression of the disease and decreasing the cardiovascular burden.

SYNbiotics Easing Renal failure by improving Gut microbiologY (SYNERGY): a protocol of placebo-controlled randomised cross-over trial

BACKGROUND

Emerging evidence suggests modulating the microbiota in the large bowel of patients with chronic kidney disease (CKD) through pre- and/probiotic supplementation may inhibit the development of key nephrovascular toxins. To date, quality intervention trials investigating this novel treatment in CKD are lacking. The aim of SYNERGY is to assess the effectiveness of synbiotics (co-administration of pre- and probiotics) as a potential treatment targeting the synthesis of uremic toxins, specifically, indoxyl sulphate (IS) and p-cresyl sulphate (PCS).

METHODS/DESIGN

Thirty-seven patients with moderate to severe CKD (Stage IV and V, pre-dialysis) will be recruited to a double-blind, placebo-controlled, randomised cross-over trial. Patients will be provided with synbiotic therapy or placebo for 6 weeks, with a 4 week washout before cross-over. The primary outcome is serum IS, total and free (unbound) concentrations, measured using ultra-performance liquid chromatography. Secondary outcomes include serum PCS, total and free (unbound) concentrations; cardiovascular risk, measured by serum lipopolysaccharides, serum trimethylamine-N-oxide (TMAO) and inflammation and oxidative stress markers; kidney damage, measured by 24 hour proteinuria and albuminuria, estimated glomerular filtration rate and renal tubule damage (urinary kidney injury molecule-1); patients' self assessed quality of life; and gastrointestinal symptoms. In addition, the effects on the community structure of the stool microbiota will be explored in a subset of patients to validate the mechanistic rationale underpinning the synbiotic therapy.

DISCUSSION

IS and PCS are two novel uremic toxins implicated in both cardiovascular disease (CVD) and progression of CKD. Preliminary studies indicate that synbiotic therapy maybe a promising strategy when considering a targeted, tolerable and cost-efficient therapy for lowering serum IS and PCS concentrations. This trial will provide high quality 'proof-of-concept' data to elucidate both the efficacy of synbiotic therapy for lowering the toxins and whether reductions in serum IS and PCS translate into clinical benefits. Considering the potential of pre- and probiotics to not only shift toxin levels, but to also impede CVD and CKD progression, SYNERGY will provide vital insight into the effectiveness of this innocuous nutritional therapy.

TRIAL REGISTRATION

Universal Trial Number: U1111-1142-4363. Australian New Zealand Clinical Trials Registry Number: ACTRN12613000493741, date registered: 2nd May 2013.

Three measurable and modifiable enteric microbial biotransformations relevant to cancer prevention and treatment

Interdisciplinary scientific evaluation of the human microbiota has identified three enteric microbial biotransformations of particular relevance for human health and well-being, especially cancer. Two biotransformations are counterproductive; one is productive. First, selective bacteria can reverse beneficial hepatic hydroxylation to produce toxic secondary bile acids, especially deoxycholic acid. Second, numerous bacterial species can reverse hepatic detoxification-in a sense, retoxify hormones and xeonobiotics-by deglucuronidation. Third, numerous enteric bacteria can effect a very positive biotransformation through the production of butyrate, a small chain fatty acid with anti-cancer activity. Each biotransformation is addressed in sequence for its relevance in representative gastrointestinal and extra-intestinal cancers. This is not a complete review of their connection with every type of cancer. The intent is to introduce the reader to clinically relevant microbial biochemistry plus the emerging evidence that links these to both carcinogenesis and treatment. Included is the evidence base to guide counseling for potentially helpful dietary adjustments.

Water-insoluble fiber-rich fraction from pineapple peel improves intestinal function in hamsters: evidence from cecal and fecal indicators

Pineapple peel, a byproduct of agricultural processing, contains high levels of water-insoluble fiber-rich fraction (WIFF) (~42%, wt/wt). Our previous work has demonstrated that cellulose, hemicellulose (xylan and xyloglucan), and pectic substances are the major polysaccharides of pineapple-peel WIFF. Based on its chemical composition and unique characteristics, we hypothesized that daily consumption of WIFF would improve intestinal function in hamsters. Male Golden Syrian hamsters were fed a diet supplemented with either 5% cellulose or various amounts of WIFF (2.5%, 5%, or 10%). Activities of fecal bacterial enzymes, short-chain fatty acid concentrations, and microbial number in the cecal content, and also biochemical indicators in the cecal and feces of hamsters, were evaluated in all groups. The supplementation of WIFF in a diet at a level of 2.5% significantly (P < .05) decreased the daily fecal ammonia output; shortened the gastrointestinal transit time; reduced the activities of β-D-glucosidase, β-D-glucuronidase, mucinase, and urease in feces; and also enhanced the total amounts of short-chain fatty acid in the cecal content and the growth of gut microflora such as Lactobacillus spp and Bifidobacterium spp. These results indicate that WIFF could improve cecal ecosystem function of hamsters by reducing the toxic compounds excreted by intestinal microflora. Therefore, pineapple-peel WIFF could be a promising candidate for a functional ingredient beneficial to human intestinal function and health.

Probiotics in dairy foods: a review

Purpose

– There is need for exhaustive studies to be undertaken to identify various probiotic strains and to understand the actual mechanism of action by which these probiotics exert their health benefits in order to exploit its fullest health benefits expressed by various kinds of the probiotic strains. The paper aims to discuss these issues.

Design/methodology/approach

– The health effects of the probiotics can be accessed by in vivo as well as the in vitro studies of live microorganisms and their biological active compounds on various disease-causing organisms and their harmful metabolites.

Findings

– The paper is a brief review of recent findings about the health benefits of probiotic strains of microorganisms. The health effects of fermented food items were known since the time immemorial, but the actual cause of this was a mystery. Recent discoveries led to the author's knowledge about the mechanism through which they exert these curative effects which is either by competitive inhibition of harmful microbes in gut or by production of biological active compounds against disease-causing organisms and their harmful metabolites.

Originality/value

– Probiotics are commonly consumed as part of fermented foods which are produced with active live cultures, so various new types of these probiotic cultures can be introduced which can act as food as well as curative agents for treating and preventing various types of diseases at nominal costs.

β-Glucuronidase and β-glucosidase activity and human fecal water genotoxicity in the presence of probiotic lactobacilli and the heterocyclic aromatic amine IQ in vitro

The aim of the study was to assess the genotoxicity of fecal water (FW) and the activity of fecal enzymes (β-glucuronidase and β-glucosidase) after incubation with 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ) and probiotic lactobacilli: Lb. casei 0900, Lb. casei 0908, and Lb. paracasei 0919. Our results show that the carcinogen IQ greatly increased FW genotoxicity (up to 16.92 ± 3.03 U/mg) and the activity of fecal enzymes (up to even 1.4 ± 0.16 U/mg) in 15 individuals (children, adults and elderly). After incubation with IQ, the activity of β-glucuronidase was reduced by Lactobacillus bacteria by 76.0% (Lb. paracasei 0908) in the FW of children, and by 82.0% (Lb. paracasei 0919) in the elderly; while that of β-glucosidase was reduced by 55.0% in children (Lb. casei 0908) and 90.0% (Lb. paracasei 0919) in elderly subjects. Lactobacilli decreased the genotoxicity of FW after incubation with IQ to the greatest extent in adults (by 64.5%). Probiotic lactobacilli, in the presence of IQ, efficiently inhibits activity of fecal enzymes to the level of control. Genotoxicity inhibition depends on the person's age, its individual microbiota and diet.

A potential role of probiotics in colorectal cancer prevention: review of possible mechanisms of action

A number of investigations, mainly using in vitro and animal models, have demonstrated a wide range of possible mechanisms, by which probiotics may play a role in colorectal cancer (CRC) prevention. In this context, the most well studied probiotics are certain strains from the genera of lactobacilli and bifidobacteria. The reported anti-CRC mechanisms of probiotics encompass intraluminal, systemic, and direct effects on intestinal mucosa. Intraluminal effects detailed in this review include competitive exclusion of pathogenic intestinal flora, alteration of intestinal microflora enzyme activity, reduction of carcinogenic secondary bile acids, binding of carcinogens and mutagens, and increasing short chain fatty acids production. Reduction of DNA damage and suppression of aberrant crypt foci formation have been well demonstrated as direct anti-CRC effects of probiotics on intestinal mucosa. Existing evidence clearly support a multifaceted immunomodulatory role of probiotics in CRC, particularly its ability to modulate intestinal inflammation, a well known risk factor for CRC. The effectiveness of probiotics in CRC prevention is dependent on the strain of the microorganism, while viability may not be a prerequisite for certain probiotic anticancer mechanisms, as indicated by several studies. Emerging data suggest synbiotic as a more effective approach than either prebiotics or probiotics alone. More in vivo especially human studies are warranted to further elucidate and confirm the potential role of probiotics (viable and non-viable), prebiotics and synbiotics in CRC chemoprevention.

Development of microencapsulation delivery system for long-term preservation of probiotics as biotherapeutics agent

The administration of probiotic bacteria for health benefit has rapidly expanded in recent years, with a global market worth $32.6 billion predicted by 2014. The oral administration of most of the probiotics results in the lack of ability to survive in a high proportion of the harsh conditions of acidity and bile concentration commonly encountered in the gastrointestinal tract of humans. Providing probiotic living cells with a physical barrier against adverse environmental conditions is therefore an approach currently receiving considerable interest. Probiotic encapsulation technology has the potential to protect microorganisms and to deliver them into the gut. However, there are still many challenges to overcome with respect to the microencapsulation process and the conditions prevailing in the gut. This review focuses mainly on the methodological approach of probiotic encapsulation including biomaterials selection and choice of appropriate technology in detailed manner.

Probiotics Lactobacillus rhamnosus GG, Lactobacillus acidophilus suppresses DMH-induced procarcinogenic fecal enzymes and preneoplastic aberrant crypt foci in early colon carcinogenesis in Sprague Dawley rats

Diet makes an important contribution to colorectal cancer (CRC) risk implying risks for CRC are potentially reducible. Therefore, the probiotics have been suggested as the prophylactic measure in colon cancer. In this study, different probiotics were used to compare their protective potential against 1,2 dimethylhydrazine dihydrochloride (DMH)-induced chemical colon carcinogenesis in Sprague Dawley rats. Animals belonging to different probiotic groups were fed orally with 1 × 10(9) lactobacilli daily for 1 week, and then a weekly injection of DMH was given intraperitoneally for 6 wks with daily administration of probiotic. Lactobacillus GG and L.acidophilus + DMH-treated animals had maximum percent reduction in ACF counts. A significant decrease (P < 0.05) in fecal nitroreductase activity was observed in L.casei + DMH and L.plantarum + DMH-treated rats whereas β-glucuronidase activity decreased in L.GG + DMH and L.acidophilus + DMH-treated rats. Animals treated with Bifidobacterium bifidum + DMH had significant decreased β-glucosidase activity. However, not much difference was observed in the colon morphology of animals belonging to various probiotic + DMH-treated rats compared with DMH-treated alone. The results indicated that probiotics, L.GG, and L.acidophilus can be used as the better prophylactic agents for experimental colon carcinogenesis.

Submerged fermentation of Lactobacillus rhamnosus YS9 for γ-aminobutyric acid (GABA) production

γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter in central nervous system, and its application in drugs and functional foods has attracted great attention. To enhance production of γ-aminobutyric acid, Lactobacillus rhamnosus YS9, a strain isolated from Chinese traditional fermented food pickled vegetable, was grown under submerged fermentation. Its cultivation conditions were investigated. When culture pH condition was adjusted to the optimal pH of glutamate decarboxylase activity, culture of Lb. rhamnosus YS9 in medium supplemented with 200 mM of monosodium glutamate and 200 μM of pyridoxal phosphate (PLP), produced 187 mM of GABA.

Metabolic activities of ginseng and its constituents, ginsenoside rb1 and rg1, by human intestinal microflora

To evaluate the difference in expressing pharmacological effects of ginseng by intestinal microflora between Koreans, metabolic activities of ginseng, ginsenoside Rb₁ and Rg₁ by 100 fecal specimens were measured. The β-glucosidase activity for p-nitrophenyl- β-D-glucopyranoside was 0 to 0.42 μmol/min/mg and its average activity (mean±SD) was 0.10±0.07 μmol/min/mg. The metabolic activities of ginsenosides Rb₁ and Rg₁ were 0.01 to 0.42 and 0.01 to 0.38 pmol/min/mg, respectively. Their average activities were 0.25±0.08 and 0.15±0.09 pmol/min/mg, respectively. The compound K-forming activities from ginsenoside Rb₁ and ginseng extract were 0 to 0.11 and 0 to 0.02 pmol/min/mg, respectively. Their average compound K-forming activities were 0.24±0.09 pmol/min/ mg and 2.14±3.66 fmol/min/mg, respectively. These activities all were not different between males and females, or between ages. Although compound K-forming activity from the aqueous extract of ginseng was low compared to that from ginenoside Rb₁, their profiles were similar to those of isolated compounds. Based on these findings, we believe that the intestinal bacterial metabolic activities of ginseng components are variable in individuals and may be used as selection markers for responders to ginseng.

Pre-, pro-, and synbiotics: do they have a role in reducing uremic toxins? A systematic review and meta-analysis

Objective. This paper assessed the effectiveness of pre-, pro-, and synbiotics on reducing two protein-bound uremic toxins, p-cresyl sulphate (PCS) and indoxyl sulphate (IS). Methods. English language studies reporting serum, urinary, or fecal PCS and/or IS (or their precursors) following pre-, pro-, or synbiotic interventions (>1 day) in human adults were included. Population estimates of differences in the outcomes between the pre- and the postintervention were estimated for subgroups of studies using four meta-analyses. Quality was determined using the GRADE approach. Results. 19 studies met the inclusion criteria, 14 in healthy adults and five in haemodialysis patients. Eight studies investigated prebiotics, six probiotics, one synbiotics, one both pre- and probiotics, and three studies trialled all three interventions. The quality of the studies ranged from moderate to very low. 12 studies were included in the meta-analyses with all four meta-analyses reporting statistically significant reductions in IS and PCS with pre- and probiotic therapy. Conclusion. There is a limited but supportive evidence for the effectiveness of pre- and probiotics on reducing PCS and IS in the chronic kidney disease population. Further studies are needed to provide more definitive findings before routine clinical use can be recommended.

The effects of probiotics on colon cancer development

While several effects beneficial to health have been attributed to the probiotic lactic acid bacteria, perhaps the most interesting and controversial remains that of anti-cancer activity. The vast majority of studies in this area deal with protective effects against colon cancer. There is no direct experimental evidence for cancer suppression in human subjects as a result of the consumption of probiotic cultures in fermented or unfermented dairy products. However, there is a wealth of indirect evidence, based largely on laboratory studies. Reports in the literature, regarding the anti-cancer effects of lactic acid bacteria, fall into the following categories: in vitro studies, animal studies, epidemiological studies and human dietary intervention studies. Examples of these reports will be given in the present review. The mechanisms by which probiotic bacteria may inhibit colon cancer are still poorly understood. However, several potential mechanisms are being discussed in the literature and these will also be addressed in the present review.

Intestinal health benefits of the water-soluble carbohydrate concentrate of wild grape ( Vitis thunbergii ) in hamsters

The dose-response relationship of the water-soluble carbohydrate concentrate (WSCC) from wild grape ( Vitis thunbergii Sieb. & Zucc.) on intestinal health was investigated in this study. WSCC contained carbohydrates up to 71.9 g/100 g, including arabinose-rich pectic polysaccharide, hemicelluloses, glucose, and fructose. The consumption of WSCC (0.5 and 1.5 g/100 g of diet) effectively (P < 0.05) shortened gastrointestinal transit time (-62.3 to -63.0%), decreased toxic cecal ammonia (-59.3 to -63.0%) and daily fecal ammonia output (-29.7 to -41.4%), decreased the activities of fecal β-glucuronidase (-78.6%), β-glucosidase (-80.5 to -87.5%), mucinase (-64.6 to -72.7%), and urease (-83.2 to -86.0%), increased fecal moisture content (116-129%), and also increased short-chain fatty acid levels in cecal contents (1.8-3.3-fold). These findings suggested that consumption of wild grape WSCC might diminish the exposure of intestinal mucosa to toxic ammonia and other detrimental compounds and, hence exert, favorable effects on improving gastrointestinal milieu.

A meta-analysis of probiotic efficacy for gastrointestinal diseases

Background

Meta-analyses on the effects of probiotics on specific gastrointestinal diseases have generally shown positive effects on disease prevention and treatment; however, the relative efficacy of probiotic use for treatment and prevention across different gastrointestinal diseases, with differing etiology and mechanisms of action, has not been addressed.

Methods/Principal Findings

We included randomized controlled trials in humans that used a specified probiotic in the treatment or prevention of Pouchitis, Infectious diarrhea, Irritable Bowel Syndrome, Helicobacter pylori, Clostridium difficile Disease, Antibiotic Associated Diarrhea, Traveler's Diarrhea, or Necrotizing Enterocolitis. Random effects models were used to evaluate efficacy as pooled relative risks across the eight diseases as well as across probiotic species, single vs. multiple species, patient ages, dosages, and length of treatment. Probiotics had a positive significant effect across all eight gastrointestinal diseases with a relative risk of 0.58 (95% (CI) 0.51–0.65). Six of the eight diseases: Pouchitis, Infectious diarrhea, Irritable Bowel Syndrome, Helicobacter pylori, Clostridium difficile Disease, and Antibiotic Associated Diarrhea, showed positive significant effects. Traveler's Diarrhea and Necrotizing Enterocolitis did not show significant effects of probiotcs. Of the 11 species and species mixtures, all showed positive significant effects except for Lactobacillus acidophilus, Lactobacillus plantarum, and Bifidobacterium infantis. Across all diseases and probiotic species, positive significant effects of probiotics were observed for all age groups, single vs. multiple species, and treatment lengths.

Conclusions/Significance

Probiotics are generally beneficial in treatment and prevention of gastrointestinal diseases. Efficacy was not observed for Traveler's Diarrhea or Necrotizing Enterocolitis or for the probiotic species L. acidophilus, L. plantarum, and B. infantis. When choosing to use probiotics in the treatment or prevention of gastrointestinal disease, the type of disease and probiotic species (strain) are the most important factors to take into consideration.

Functional analysis of colonic bacterial metabolism: relevant to health?

With the use of molecular techniques, numerous studies have evaluated the composition of the intestinal microbiota in health and disease. However, it is of major interest to supplement this with a functional analysis of the microbiota. In this review, the different approaches that have been used to characterize microbial metabolites, yielding information on the functional end products of microbial metabolism, have been summarized. To analyze colonic microbial metabolites, the most conventional way is by application of a hypothesis-driven targeted approach, through quantification of selected metabolites from carbohydrate (e.g., short-chain fatty acids) and protein fermentation (e.g., p-cresol, phenol, ammonia, or H(2)S), secondary bile acids, or colonic enzymes. The application of stable isotope-labeled substrates can provide an elegant solution to study these metabolic pathways in vivo. On the other hand, a top-down approach can be followed by applying metabolite fingerprinting techniques based on (1)H-NMR or mass spectrometric analysis. Quantification of known metabolites and characterization of metabolite patterns in urine, breath, plasma, and fecal samples can reveal new pathways and give insight into physiological regulatory processes of the colonic microbiota. In addition, specific metabolic profiles can function as a diagnostic tool for the identification of several gastrointestinal diseases, such as ulcerative colitis and Crohn's disease. Nevertheless, future research will have to evaluate the relevance of associations between metabolites and different disease states.

Relevance of protein fermentation to gut health

It is generally accepted that carbohydrate fermentation results in beneficial effects for the host because of the generation of short chain fatty acids, whereas protein fermentation is considered detrimental for the host's health. Protein fermentation mainly occurs in the distal colon, when carbohydrates get depleted and results in the production of potentially toxic metabolites such as ammonia, amines, phenols and sulfides. However, the effectivity of these metabolites has been established mainly in in vitro studies. In addition, some important bowel diseases such as colorectal cancer (CRC) and ulcerative colitis appear most often in the distal colon, which is the primary site of protein fermentation. Finally, epidemiological studies revealed that diets rich in meat are associated with the prevalence of CRC, as is the case in Western society. Importantly, meat intake not only increases fermentation of proteins but also induces increased intake of fat, heme and heterocyclic amines, which may also play a role in the development of CRC. Despite these indications, the relationship between gut health and protein fermentation has not been thoroughly investigated. In this review, the existing evidence about the potential toxicity of protein fermentation from in vitro animal and human studies will be summarized.

Effect of ingestion of soy yogurt on intestinal parameters of rats fed on a beef-based animal diet

The aim of this study was to investigate whether the ingestion of soy yogurt fermented with Enterococcus faecium CRL 183 would modify the intestinal count of enterococci, fecal pH and ammonia content in rats fed on a diet containing red meat. The rats were placed in 4 groups: for 60 days, group I was given a standard casein-based rodent feed and groups II-IV, the beef-based feed. From day 30, groups III-IV also received the following products: III) soy yogurt; IV) suspension of E. faecium CRL 183. At the start and on days 30 and 60, feces were collected for the determination of pH, ammonia content, count of enterococci and identification of their species. On day 60, rats were sacrificed and their colons also removed for count of enterococci and identification of their species. Rats that ingested soy yogurt showed no significant change (P<0.05) in fecal counts of Enterococcus spp., but, this rat group showed a higher count of E. faecium than rats that ingested suspension of E. faecium CRL 183. The ingestion of soy yogurt and E. faecium culture caused a significant rise (P < 0.05) in fecal pH and ammonia content. Our results suggest that consumption of soy yogurt fermented with E. faecium CRL 183 and L. helveticus subsp. jugurti could change the species of Enterococcus spp. present in the feces and colon of rats fed on a beef-based diet. However, the fermented soy product and the pure culture of E. faecium CRL 183 also induced undesirable effects such as the increase of fecal pH and ammonia content in the feces of rats fed on a beef-based diet.

A probiotic mixture including galactooligosaccharides decreases fecal β-glucosidase activity but does not affect serum enterolactone concentration in men during a two-week intervention

A high serum concentration of enterolactone, an enterolignan produced by colonic microbiota from precursors in cereals, vegetables, and fruits, is associated with reduced risk of acute coronary events. Probiotics and prebiotics modify colonic metabolism and may affect the serum enterolactone concentration. The effects of a probiotic mixture alone and with galactooligosaccharides (GOS) on serum enterolactone concentration and fecal metabolism were investigated in 18 healthy men. Participants received 3 interventions, each for 2 wk: 1) probiotics [Lactobacillus rhamnosus strains GG (LGG) and LC705, Propionibacterium freudenreichii ssp. shermanii JS, and Bifidobacterium breve Bb99, for a total amount of 2 × 10(10) CFU/d]; 2) probiotics and GOS 3.8 g/d; 3) probiotics, GOS, and rye bread (minimum 120 g/d). Serum enterolactone and fecal dry weight, enzyme activities, pH, SCFA, lactic acid bacteria, bifidobacteria, propionibacteria, and the strains LGG and LC705 were determined. The serum enterolactone concentration (nmol/L) tended to be decreased from baseline [mean (95% CI) 18.6 (10.8-26.4)] by probiotics alone [15.2 (7.8-22.7); P = 0.095], was not significantly affected by probiotics with GOS [21.5 (13.2-29.8)], and was increased by probiotics with GOS and rye bread [24.6 (15.4-33.7); P < 0.05]. Probiotics alone did not affect fecal β-glucosidase activity and bifidobacteria, but probiotics with GOS decreased β-glucosidase activity and increased bifidobacteria compared with baseline (P < 0.05) and with probiotics alone (P < 0.01). In conclusion, this probiotic mixture with or without GOS does not significantly affect serum enterolactone concentration. Because probiotics with GOS decreased fecal β-glucosidase activity but not serum enterolactone, the reduced fecal β-glucosidase, within the range of activities measured, does not seem to limit the formation of enterolactone.

The ability of green tea to positively modulate key markers of gastrointestinal function in rats

The beneficial effects of selenium-containing green tea (Se-GTE, 1.44 mg selenium/kg dry leaves) and China green tea (CH-GTE, 0.13 mg selenium/kg leaves) on the population size of lactobacilli and bifidobacteria and the activity of two microbial enzymes in the caeca of rats have been investigated. Oral gavage of rats with Se-GTE extract for 6 days resulted in a significant increase in caecal counts of lactobacilli and bifidobacteria (p < 0.05) while significantly reducing the caecal counts of bacteroides and clostridial bacteria. In contrast, gavaging the rats with CH-GTE extract for 6 days resulted in a slight but not significant increase in the numbers of caecal lactobacilli and bifidobacteria but decreased significantly the numbers of bacteroides (p < 0.05) and clostridia (p < 0.05). In addition, rats gavaged with CH-GTE and Se-GTE showed a 17.2% and 21.3% reduction in the activity of the bacterial enzyme β-glucuronidase, respectively, when compared with the rats gavaged with water only. β-glucuronidase is considered to be one of the enzymes that increases the risk for colorectal cancer. Moreover, gavaging rats with these teas resulted in 19% and 25.5% increments in the activity of β-glucosidase, respectively. In conclusion, Se-GTE showed both bifidogenic and lactogenic effects and the high level of selenium may be behind the superiority of this tea over CH-GTE.

Effect of probiotic Lactobacillus (Lacidofil® cap) for the prevention of antibiotic-associated diarrhea: a prospective, randomized, double-blind, multicenter study

Antibiotic-associated diarrhea (AAD) is a common complication of antibiotic use. There is growing interest in probiotics for the treatment of AAD and Clostridium difficile infection because of the wide availability of probiotics. The aim of this multicenter, randomized, placebo-controlled, double-blind trial was to assess the efficacy of probiotic Lactobacillus (Lacidofil® cap) for the prevention of AAD in adults. From September 2008 to November 2009, a total of 214 patients with respiratory tract infection who had begun receiving antibiotics were randomized to receive Lactobacillus (Lacidofil® cap) or placebo for 14 days. Patients recorded bowel frequency and stool consistency daily for 14 days. The primary outcome was the proportion of patients who developed AAD within 14 days of enrollment. AAD developed in 4 (3.9%) of 103 patients in the Lactobacillus group and in 8 (7.2%) of 111 patients in the placebo group (P=0.44). However, the Lactobacillus group showed lower change in bowel frequency and consistency (50/103, 48.5%) than the placebo group (35/111, 31.5%) (P=0.01). Although the Lacidofil® cap does not reduce the rate of occurrence of AAD in adult patients with respiratory tract infection who have taken antibiotics, the Lactobacillus group maintains their bowel habits to a greater extent than the placebo group.

The impact of pre- and/or probiotics on human colonic metabolism: does it affect human health?

Since many years, the role of the colonic microbiota in maintaining the host's overall health and well-being has been recognized. Dietary modulation of the microbiota composition and activity has been achieved by the use of pre-, pro- and synbiotics. In this review, we will summarize the available evidence on the modification of bacterial metabolism by dietary intervention with pre-, pro- and synbiotics. Enhanced production of SCFA as a marker of increased saccharolytic fermentation is well documented in animal and in vitro studies. Decreased production of potentially toxic protein fermentation metabolites, such as sulfides, phenolic and indolic compounds, has been less frequently demonstrated. Besides, pre-, pro- and synbiotics also affect other metabolic pathways such as the deconjugation of secondary bile acids, bacterial enzyme activities and mineral absorption. Data from human studies are less conclusive. The emergence of new analytical techniques such as metabolite profiling has revealed new pathways affected by dietary intervention. However, an important challenge for current and future research is to relate changes in bacterial metabolism to concrete health benefits. Potential targets and expected benefits have been identified: reduced risk for the metabolic syndrome and prevention of colorectal cancer.

Cancer-preventing attributes of probiotics: an update

Cancer is a serious global public health problem. Cancer incidence and mortality have been steadily rising throughout the past century in most places of the world. There are several epidemiological evidences that support a protective role of probiotics against cancer. Lactic acid bacteria and their probioactive cellular substances exert many beneficial effects in the gastrointestinal tract, and also release various enzymes into the intestinal lumen and exert potential synergistic (LAB) effects on digestion and alleviate symptoms of intestinal malabsorption. Consumption of fermented dairy products with LAB may elicit anti-tumor effects. These effects are attributed to the inhibition of mutagenic activity, the decrease in several enzymes implicated in the generation of carcinogens, mutagens, or tumor-promoting agents, suppression of tumors, and epidemiology correlating dietary regimes and cancer. Specific cellular components in lactic acid bacteria seem to induce strong adjuvant effects including modulation of cell-mediated immune responses, activation of the reticulo-endothelial system, augmentation of cytokine pathways, and regulation of interleukins and tumor necrosis factors. Studies on the effect of probiotic consumption on cancer appear promising, since recent in vitro and in vivo studies have indicated that probiotic bacteria might reduce the risk, incidence and number of tumors of the colon, liver and bladder. The protective effect against cancer development may be ascribed to binding of mutagens by intestinal bacteria, may suppress the growth of bacteria that convert procarcinogens into carcinogens, thereby reducing the amount of carcinogens in the intestine, reduction of the enzymes beta-glucuronidase and beta-glucosidase and deconjugation of bile acids, or merely by enhancing the immune system of the host. There are isolated reports citing that administration of LAB results in increased activity of anti-oxidative enzymes or by modulating circulatory oxidative stress that protects cells against carcinogen-induced damage. These include glutathione-S-transferase, glutathione, glutathione reductase, glutathione peroxidase, superoxide dismutase and catalase. However, there is no direct experimental evidence for cancer suppression in human subjects as a result of the consumption of probiotic cultures in fermented or unfermented dairy products, but there is a wealth of indirect evidence based largely on laboratory studies.

Why are they having infant colic? A nested case-control study

We aimed to analyse infant (birth characteristics, feeding type, faecal enzyme activities) and environmental (maternal smoking, nutrition and psychological status, mother-child bonding, family structure, support for the mother, familial atopy) risk factors for infant colic and to follow infants with respect to physical growth, sleeping status up to 8 months of age in a nested case-control study. 660 mothers who delivered at Dr Zekai Tahir Burak Maternity Hospital, were enrolled within 3-72 h post delivery. Each infant with inconsolable persistent crying and four matched infants with no crying episodes were invited by phone to Hacettepe University Ihsan Doğramacı Children's Hospital at 30-45 days post partum. At 40-55 days, we examined the infants and gave mothers a questionnaire, including crying characteristics of the infants; 47 infants were diagnosed with colic and 142 as non-colic. When the infants were 7-8 months old, another interview was done. The colic group had higher proportions of less-educated (≤ 8 years) and smoking mothers, extended family and families with domestic violence than the non-colic group. The colic group of mothers had significantly higher rates of 'impaired bonding' in the Postpartum Bonding Questionnaire, higher scores on the Edinburgh Postnatal Depression Scale, higher scores for hostility subscales of the Brief Symptom Inventory and a more irregular sleep pattern than the non-colic group. No differences were revealed for faecal enzyme activities. At 7-8 months, the colic group was shorter than the non-colic group. Colic was associated with various perinatal factors (maternal education, smoking habits, cheese consumption, hostility scores and domestic violence) and having colic in infancy negatively affected the sleeping pattern and the height of the infant.

Constipation is relieved more by rye bread than wheat bread or laxatives without increased adverse gastrointestinal effects

Rye bread and lactobacilli modify the colonic environment and have the potential to relieve constipation and could be a safe and convenient alternative to laxatives. The effects of rye bread and cultured buttermilk with Lactobacillus rhamnosus GG (LGG) on bowel function and colon metabolism were investigated and compared with laxatives in 51 constipated adults. They were randomized to receive whole-grain rye bread (minimum 240 g/d), LGG (2 x 10(10) colony-forming units/d), whole-grain rye bread (minimum 240 g/d) + LGG (2 x 10(10) colony-forming units/d), white wheat bread (maximum 192 g/d), or laxatives (as usual for a participant) for 3 wk. Participants recorded their dietary habits, bowel function, and gastrointestinal symptoms. Fecal weight, pH, SCFA and bacterial enzyme activities, total intestinal transit time (TITT), and breath hydrogen were determined. Rye bread, compared with white wheat bread, shortened TITT by 23% (P = 0.040), increased weekly defecations by 1.4 (P = 0.014), softened feces [odds ratio (OR) 3.98; P = 0.037], eased defecation (OR 5.08; P = 0.018), increased fecal acetic acid and butyric acid contents by 24% (P = 0.044) and 63% (P <0.001), respectively, and reduced fecal beta-glucuronidase activity by 23% (P = 0.014). Compared with laxatives, rye bread reduced TITT by 41% (P = 0.006), fecal beta-glucuronidase activity by 38% (P = 0.033), and fecal pH by 0.31 units (P = 0.006). LGG did not relieve constipation or significantly affect colonic metabolism. Gastrointestinal adverse effects did not significantly differ among the study groups. In conclusion, rye bread relieves mild constipation and improves colonic metabolism compared with white wheat bread and commonly used laxatives without increasing gastrointestinal adverse effects.