Use of probiotics in humans: an analysis of the literature

Probiotic mediated NF-κB regulation for prospective management of type 2 diabetes

Diabetes and other lifestyle disorders have been recognized as the leading cause of morbidity and mortality globally. Nuclear factor kappa B (NF-κB) is a major factor involved in the early pathobiology of diabetes and studies reveal that hyperglycemic conditions in body leads to NF-κB mediated activation of several cytokines, chemokines and inflammatory molecules. NF-κB family comprises of certain DNA-binding protein factors that elicit the transcription of pro-inflammatory molecules. Various studies have identified NF-κB as a promising target for diabetic management. Probiotics have been proposed as bio-therapeutic agents for treatment of inflammatory disorders and many other chronic clinical stages. The precise mechanisms by which probiotics acts is yet to be fully understood, however research findings have indicated their role in NF-κB modulation. The current review highlights NF-κB as a bio-therapeutic target for probable management of type 2 diabetes through probiotic intervention.

Lactobacillus acidophilus alleviates type 2 diabetes by regulating hepatic glucose, lipid metabolism and gut microbiota in mice

Diabetes, an endocrine and metabolic disorder, has become the third most non-infectious chronic disease that threatens human health. Type 2 diabetes (T2D) accounts for more than 90% of diabetic patients, mainly caused by environmental factors. Lactic acid bacteria (LAB) exhibit several health benefits to the host including regulating glucose and lipid metabolism and improving oxidative stress and inflammatory response. However, the anti-diabetic mechanism of probiotics has not been elucidated clearly. In this study, the anti-diabetic effects of Lactobacillus acidophilus KLDS1.1003 and KLDS1.0901 on T2D mice were assessed. Oral administration of L. acidophilus KLDS1.1003 and KLDS1.0901 for 6 weeks significantly improved the epithelial barrier function, which in turn lowered inflammation cytokines, including IL-8, TNF-α and IL-1β in liver and colon tissue, and prevented liver and colon tissue injuries to some extent. Additionally, L. acidophilus treatment regulated the expression genes that are related to glucose and lipid metabolism. The two tested strains down-regulated the expression of glycogen synthase kinase 3β (GSK-3β), fatty acid synthase (FAS) and sterol regulatory element-binding transcription factor 1c (SREBP-1c), and up-regulated the expression of protein kinase B (Akt). However, L. acidophilus KLDS1.0901 is better for improving T2D than L. acidophilus KLDS1.1003. Further research showed that L. acidophilus KLDS1.0901 supplementation could reshape gut microbiota, increasing short chain fatty acid-producing bacteria (Blautia, Roseburia and Anaerotruncus) and the level of SCFAs and decreasing the relative abundance of Gram-negative bacteria such as Desulfovibrio, Alistipes and Bacteroides. Notably, L. acidophilus KLDS1.0901 treatment restored the structure of gut microbiota similar to the control group. These findings suggested that L. acidophilus KLDS1.0901 might be used as a new type of antidiabetic drug candidate.

Optimise the microbial flora with milk and yoghurt to prevent disease

Pathogenic bacteria, which are temporary or permanent members of our microbial flora, cause or contribute to a wide range of human disease at all ages. Conditions include Alzheimer's disease, atherosclerosis, diabetes mellitus, obesity, cancer, autoimmunity and psychosis, amongst others. The mechanism of damage is inflammation which can be chronic or acute. An optimal microbial flora includes a wide range of pathogenic bacteria in low dose. This allows specific immunity to be developed and maintained with minimal inflammatory damage. Human milk has evolved to deliver an optimal microbial flora to the infant. Cow's milk has the potential, following appropriate fortification, to maintain an optimal human microbial flora throughout life. Yoghurt is a fermented milk product in which bacteria normally present in milk convert sugars to lactic acid. The acid suppresses the growth of pathogens in the oral cavity, oropharynx and oesophagus. Thus yoghurt can restore an optimal flora in these regions in the short term. Since bacteria are transported between epithelial surfaces, yoghurt will also optimise the flora elsewhere. The judicious use of milk and yogurt could prevent a high proportion of human disease.

Influence of Acute Multispecies and Multistrain Probiotic Supplementation on Cardiovascular Function and Reactivity to Psychological Stress in Young Adults: A Double-Blind, Randomized, Placebo-Controlled Trial

OBJECTIVE

The potential influence of probiotic supplementation on cardiovascular health and stress responsivity remains largely unexplored. Some evidence suggests the possibility that probiotics may influence blood pressure. A separate body of research suggests that exaggerated cardiovascular reactions to acute psychological stress in the laboratory predict cardiovascular morbidity and mortality. The current investigation explored the effect of acute probiotic use on (1) resting cardiovascular measures in healthy young adults and (2) cardiovascular and psychological reactions to an acute psychological stressor in the laboratory.

METHOD

Participants (N = 105, M [SD] age = 20.17 [1.26], 84.8% white) completed a 2-week, double-blind, and placebo-controlled trial of a multispecies and multistrain probiotic. Exclusion criteria included previous probiotic use, diagnosed gastrointestinal disorder, and/or current antibiotic use. At visits 1 and 2, participants completed the Paced Auditory Serial Addition Test, a widely used psychological stress task. Participants were randomly assigned to a probiotic blend or matched placebo.

RESULTS

Compared with placebo, 2-week probiotic supplementation did not affect resting measures of cardiovascular function, cardiovascular responses during or recovery from stress, or psychological reactions to acute psychological stress.

CONCLUSIONS

Contrary to expectations, short-term use of a probiotic supplement in healthy participants did not influence measures of cardiovascular function or responsivity to psychological stress. Future research is needed to determine species- and strain-specific effects of probiotics in healthy participants with various degrees of stress responsiveness, as well as in diseased populations.

Probiotics for prevention of radiation-induced diarrhea: A meta-analysis of randomized controlled trials

Background

Radiotherapy is commonly used for abdominal or pelvic cancer, and patients receiving radiotherapy have a high risk developing to an acute radiation-induced diarrhea. Several previous studies have discussed the effect of probiotics on prevention of radiation-induced diarrhea, but the results are still inconsistent.

Objective

We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the efficacy of probiotic supplementation for prevention the radiation-induced diarrhea.

Methods

Relevant RCTs studies assessing the effect of probiotic supplementation on clinical outcomes compared with placebo were searched in PubMed, EMBASE, and the Cochrane Library databases (up to March 30 2016). Heterogeneity was assessed with I² and H², and publication bias was evaluated using sensitive analysis.

Results

Six trials, a total of 917 participants (490 participants received prophylactic probiotics and 427 participants received placebo), were included in this meta-analysis. Compared with placebo, probiotics were associated with a lower incidence of radiation-induced diarrhea (RR: 0.55; 95% CI: 0.34–0.88; P = 0.01; I²: 87%; 95% CI: 75%-94%; H²: 2.8; 95% CI: 2.0–4.0). However, there is no significant difference in the anti-diarrheal medication use (RR: 0.68; 95% CI: 0.40–1.14; P = 0.14) or bristol scale on stool form (RR: 0.64; 95% CI: 0.35–1.17; P = 0.14).

Conclusion

Probiotics may be beneficial to prevent radiation-induced diarrhea in patients who suffered from abdominal or pelvic cancers during radiotherapy period.

Gut microbiota, probiotics and diabetes

Diabetes is a condition of multifactorial origin, involving several molecular mechanisms related to the intestinal microbiota for its development. In type 2 diabetes, receptor activation and recognition by microorganisms from the intestinal lumen may trigger inflammatory responses, inducing the phosphorylation of serine residues in insulin receptor substrate-1, reducing insulin sensitivity. In type 1 diabetes, the lowered expression of adhesion proteins within the intestinal epithelium favours a greater immune response that may result in destruction of pancreatic β cells by CD8+ T-lymphocytes, and increased expression of interleukin-17, related to autoimmunity. Research in animal models and humans has hypothesized whether the administration of probiotics may improve the prognosis of diabetes through modulation of gut microbiota. We have shown in this review that a large body of evidence suggests probiotics reduce the inflammatory response and oxidative stress, as well as increase the expression of adhesion proteins within the intestinal epithelium, reducing intestinal permeability. Such effects increase insulin sensitivity and reduce autoimmune response. However, further investigations are required to clarify whether the administration of probiotics can be efficiently used for the prevention and management of diabetes.

Colonic flora, probiotics, obesity and diabetes

Obesity results from alterations in the body's regulation of energy intake, expenditure, and storage. Animal and human data demonstrate that phylogenic changes occur in the microbiota composition in obese individuals. Furthermore, evidence from animal models suggest that the alterations of the gut microbiota with obesity results in increased energy extraction and lipid deposition, altered release of entero-hormones, increased intestinal permeability and metabolic endotoxemia. Treatment with pre- and probiotics may reverse many of metabolic effects linked with the altered microbiota in obese patients. The gut microbiota is, therefore, a potential nutritional and pharmacological target for the management of obesity and obesity-related disorders.

Probiotics as therapy in gastroenterology: a study of physician opinions and recommendations

GOALS

The objective of this study was to determine how gastroenterologists perceive and use probiotic-based therapies in practice.

BACKGROUND

In the United States, there has been a recent increase in research investigating the therapeutic capacities of probiotics in human disease and an accompanying increase in product availability and marketing. How medical care providers have interpreted the available literature and incorporated it into their practice has not been earlier assessed.

STUDY

A 16-question survey (see Survey, Supplemental Digital Content 1, http://links.lww.com/JCG/A14) was distributed to practicing gastroenterologists and physicians with a specific interest in GI disorders within a large metropolitan area.

RESULTS

All physicians responded that they believed probiotics to be safe for most patients and 98% responded that probiotics have a role in treating gastrointestinal illnesses or symptoms. Currently 93% of physicians have patients taking probiotics most often for irritable bowel syndrome. Commonly used probiotics included yogurt-based products, Bifidobacterium infantis 35624 (Align), and VSL#3. Most surveyed physicians recommended probiotics for irritable bowel syndrome, antibiotic, and Clostridium difficile-associated diarrhea because they believed that the literature supports their usage for these conditions. However, physician practice patterns did not consistently correlate with published, expert-panel-generated recommendations for evidence-based probiotic use.

CONCLUSIONS

This study suggests most gastrointestinal disease specialists recognize a role for and have used probiotics as part of their therapeutic armamentarium; however, the effective implementation of this practice will benefit from additional supporting studies and the eventual development of clinical practice guidelines supported by the major gastroenterology societies.

The effect of probiotics on host metabolism: the microbiota and fermentation

When probiotics are ingested, they become part of the intestinal microflora. Their most important documented effects seem to be 3-fold in supporting or stimulating the immune process and being helpful in treating or affecting the process of infection; affecting luminal pathophysiology that has been shown in many animal experiments; and their role on fermentation of nutrients. Although there is understanding of the role of the microflora on the fermentation process, the effective clinical role is not yet completely understood or shown. The fermentation process consists of the action of bacterial enzymes from the microflora or probiotic organisms on nutrients. The carbohydrate nutrients are the main source of nutrients for the bacterial flora. Although protein and fats may be metabolized by the fermentation process, they are less well understood. Soluble fiber is the main food for probiotic and microbiota organisms. In addition, prebiotic substances are very effective in being metabolized by the organisms. Strains of both Lactobacillus and Bifidobacterium species are effective as lactic acid producing organisms. Their main product is short-chain fatty acids. Butyric, acetic, and propionic are readily produced and either absorbed into the portal circulation or excreted in the stool. Butyrate is the main fuel for colonocytes, whereas acetic and propionic acid are an integral part of cholesterol synthesis. The affect on lipid metabolism by various probiotic organisms and probiotics is discussed. There are some preliminary studies on the importance of the microbiota and the potential importance of probiotic organisms added to this microbiota in lipid metabolism. However, the obvious importance and details of probiotic influence need to be evaluated in future studies.

Positive interactions with the microbiota: probiotics

Rigorous research in the field of probiotics is a fairly new phenomenon although first reports about beneficial effects of specific gut bacteria on human health originated already a century ago. A prerequisite for such a scrutiny has been a definition of criteria for probiotics. Recently, novel molecular technologies have characterized both potential targets of probiotic action, like gut microbiota and established and candidate probiotic strains in more detail. We thus propose here revised criteria for selection ofprobiotics. In addition to several promising clinical studies e.g., in the prevention and treatment of atopic eczema, certain probiotics have been found to maintain intestinal equilibrium by enhancing the gut mucosal barrier via manipulation of expression of several their own and the host's genes. Introduction of genetic engineering has provided advanced tools to amend probiotics' properties in the fight against different inflammatory conditions.

Antimicrobial activity of enterocins from Enterococcus faecalis SL-5 against Propionibacterium acnes, the causative agent in acne vulgaris, and its therapeutic effect

A lactic acid bacterial strain was isolated from human fecal specimen and identified as Enterococcus faecalis SL-5. The isolated strain showed antimicrobial activity against Gram-positive pathogens assayed, especially the highest activity against Propionibacterium acnes. The antimicrobial substance was purified and verified as a bacteriocin (named ESL5) of E. faecalis SL-5 by activity-staining using P. acnes as an indicator. N-terminal sequence of ESL5 was determined (MGAIAKLVAK) and sequence analysis revealed that it is almost identical to the some of enterocins including L50A/B of E. faecium L50 and MR10A/B of E. faecalis MRR 10-3. From the sequencing data of L50A/B structural genes, the nucleotide sequence showed 100% identity with that of the MR10A/B structural genes, implying that ESL5 is an equivalent of enterocin MR10. Meanwhile, we also tested the therapeutic effect of anti-P. acnes activity in patients with mild to moderate acne because of its pathogenic role to acne vulgaris. For this purpose, a concentrated powder of CBT SL-5 was prepared using cell-free culture supernatant (CFCS) of E. faecalis SL-5 and included in a lotion for application in the patients. The study showed that CBT SL-5 lotion significantly reduced the inflammatory lesions like pustules compared to the placebo lotion. Therefore our results indicate that the anti-P. acnes activity produced by E. faecalis SL-5 has potential role to the treatment of acne as an alternative to topical antibiotics.

Probiotics and prebiotics in dietetics practice

Probiotics and prebiotics share a unique role in human nutrition, largely centering on manipulation of populations or activities of the bacteria that colonize our bodies. Benefits of regular consumption of probiotics or prebiotics include enhanced immune function, improved colonic integrity, decreased incidence and duration of intestinal infections, down-regulated allergic response, and improved digestion and elimination. Research has shown that probiotics and prebiotics may be useful in achieving these and other positive effects, provided that proper strain, product selection, and dosing guidelines of commercial products are followed. There is a need to consolidate the basic and applied research on probiotics and prebiotics into useful tools for food and nutrition professionals. Information on probiotic species, applications for specific strains, dosages and forms, safety, and shelf life is not sufficiently summarized to allow practical and consistent recommendations to be made by most food and nutrition professionals. In addition, prebiotic fibers-although providing nutraceutical and nutritional value-are a group of diverse carbohydrate ingredients that are poorly understood in regard to their origin, fermentation profiles, and dosages required for health effects. The science and practice-based guidelines presented here will enhance clinician and client understanding of probiotics and prebiotics, with the aim of improving appropriate recommendation and informed use of these emerging dietary ingredients and the products containing them.

Gut microbiota and its possible relationship with obesity

Obesity results from alterations in the body's regulation of energy intake, expenditure, and storage. Recent evidence, primarily from investigations in animal models, suggests that the gut microbiota affects nutrient acquisition and energy regulation. Its composition has also been shown to differ in lean vs obese animals and humans. In this article, we review the published evidence supporting the potential role of the gut microbiota in the development of obesity and explore the role that modifying the gut microbiota may play in its future treatment. Evidence suggests that the metabolic activities of the gut microbiota facilitate the extraction of calories from ingested dietary substances and help to store these calories in host adipose tissue for later use. Furthermore, the gut bacterial flora of obese mice and humans include fewer Bacteroidetes and correspondingly more Firmicutes than that of their lean counterparts, suggesting that differences in caloric extraction of ingested food substances may be due to the composition of the gut microbiota. Bacterial lipopolysaccharide derived from the intestinal microbiota may act as a triggering factor linking inflammation to high-fat diet-induced metabolic syndrome. Interactions among microorganisms in the gut appear to have an important role in host energy homeostasis, with hydrogen-oxidizing methanogens enhancing the metabolism of fermentative bacteria. Existing evidence warrants further investigation of the microbial ecology of the human gut and points to modification of the gut microbiota as one means to treat people who are over-weight or obese.

Intestinal crosstalk: a new paradigm for understanding the gut as the "motor" of critical illness

For more than 20 years, the gut has been hypothesized to be the "motor" of multiple organ dysfunction syndrome. As critical care research has evolved, there have been multiple mechanisms by which the gastrointestinal tract has been proposed to drive systemic inflammation. Many of these disparate mechanisms have proved to be important in the origin and propagation of critical illness. However, this has led to an unusual situation where investigators describing the gut as a "motor" revving the systemic inflammatory response syndrome are frequently describing wholly different processes to support their claim (i.e., increased apoptosis, altered tight junctions, translocation, cytokine production, crosstalk with commensal bacteria, etc). The purpose of this review is to present a unifying theory as to how the gut drives critical illness. Although the gastrointestinal tract is frequently described simply as "the gut," it is actually made up of (1) an epithelium; (2) a diverse and robust immune arm, which contains most of the immune cells in the body; and (3) the commensal bacteria, which contain more cells than are present in the entire host organism. We propose that the intestinal epithelium, the intestinal immune system, and the intestine's endogenous bacteria all play vital roles driving multiple organ dysfunction syndrome, and the complex crosstalk between these three interrelated portions of the gastrointestinal tract is what cumulatively makes the gut a "motor" of critical illness.

Prebiotics, probiotics, and dietary fiber in gastrointestinal disease

Microecology of the gastrointestinal tract is the physiologic basis for the effect of dietary fiber, prebiotics and probiotics on the host. The ecology consists of the gastrointestinal tract, primarily the intestines, the foods that are fed into the tract, and the flora living within. Within this ecology, normal flora and probiotics, ferment dietary fiber and prebiotics to produce short chain fatty acids and substances that are absorbed and effect the host at the intestinal level and systemically. In this review, we will discuss the effects of prebiotics, probiotics and dietary fiber in gastrointestinal disorders and diseases.

Emerging drugs for irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common chronic gastrointestinal disorders, yet its pathophysiology is incompletely understood and pharmacological treatments remain unsatisfactory. Current therapeutic choices include a range of drugs aimed at normalising bowel habits, reducing pain or treating comorbid psychological symptoms. However, this individual symptom-targeted approach remains unsatisfactory in terms of global symptom relief and patient satisfaction. In the last decade, further characterisation of IBS pathophysiology has provided new and exciting targets at different levels of the brain-gut axis for the development of several candidate drugs. Advances in clinical trial design will help to evaluate these compounds in different IBS patient populations.

A hypothesis: is diverticulitis a type of inflammatory bowel disease?

It is accepted by epidemiologists that diverticula formation in the colon is related to a deficiency in dietary fiber intake, but the cause of acute diverticulitis remains unknown. A hypothesis is presented that acknowledges from the literature that fiber deficiency is also related to an altered intestinal microecology with a change in the bacterial flora. It is hypothesized that the change in the flora with a decrease in their influence on the immune process permits a low-grade chronic inflammation in the mucosa, which is the first step in developing an acute infection of diverticula or diverticulitis. There is some evidence that the low-grade chronic inflammation is present in subjects with diverticula, which is the forerunner of acute diverticulitis. This hypothesis is strengthened by early reports that anti-inflammatory mucosal agents such as mesalamine and immune process regulators such as probiotics may improve diverticulitis.

Probiotics and their use in diverticulitis

Probiotics are live microorganisms that when ingested affect the intestinal microbial flora and benefit the health of the host. Probiotics have been shown to have a positive effect on various gastrointestinal and other conditions; however, the beneficial effect of probiotics on treating diverticulitis and diverticular disease has not yet been clearly demonstrated. In this paper, the theoretical framework for using probiotics to prevent or treat diverticular disease is reviewed, and two preliminary studies on the use of probiotics for maintenance of remission of uncomplicated diverticular disease are briefly summarized.

Recommendations for probiotic use

Probiotics are live microbial organisms that are administrated as supplements or in foods to benefit the host. It is the recommendation that they may be helpful in the prevention and treatment of acute diarrhea in adults and children, the prevention of antibiotic-associated diarrhea in adults and children, and the maintenance of remission and prevention of pouchitis. Although early results indicate that probiotics may also be useful in immunologic modulation to prevent atopy, treatment of radiation intestinal disease, vaginosis, ulcerative colitis, and the irritable bowel syndrome, the studies available are not sufficient to say they are definitely helpful. Even fewer data are available to recommend probiotics for the treatment of H pylori and Crohn disease and for the prevention of cardiovascular risk factors or other degenerative diseases. Clearly, larger and better-designed studies of probiotics are necessary, including comparative and dose-ranging trials.