Probiotics our little Friends

PROBIOTICS: OUR LITTLE FRIENDS

Introduction

When ingested in a proper count, probiotics are the microorganisms that impart health benefits to the host [1]. Most commonly used strains are Bifidobacterium and Lactobacillus, which are the predominant group of the gut microflora [2]. The Probiotics have been around for more than a decade now and due to numerous researches done on them, the probiotics have gained a recognition because of their multiple health benefits. The general population as well the food market has become very interested in this type of microorganisms.

Often claims have been made by the food industries that their probiotic product is the best, but the selection of the microbes is a tedious job and depends upon the gastrointestinal mucosa, gastric acid, bile ability to stick to the intestinal lining and the competitive expulsion of the bacteria [3]. The mechanism behind the benefits provided by the probiotics are unknow but are most likely to be multi factorial.

Probiotics have been shown to supress Diarrhea [4], combat or minimize lactose intolerance [5], anti colorectal cancer [6], reduce bowel irritability [7], and the secretion of anti microbial substances and strengthening the gut epithelial and adherence to the mucosa and epithelium [8], etc.

The benefits provided by these probiotic products tends to be strain specific, that is why a maximum number of these strains should be consumed [9]. The selection and careful manufacturing of these strains and careful manufacturing of probiotics products allow these health benefits. The objective of this reading is to explore the various mechanisms of the action of the probiotics.

CONTENT: MODE OF ACTION

 Epithelial Barrier Modification

The epithelial is constantly in touch with the Lumina and the enteric flora. The intestinal barrier is the prime defence mechanism used to maintain the integrity of gut and protect the organisms. Defence of this barrier consists of the mucosa layer, anti microbial peptides and the production of IgA. Once this barrier is disrupted, bacteria and food antigens can reach the submucosa and cause inflation. Consumption of anti-pathogenic microbes contribute to this barrier enhancement, for This probiotics has been extensively studied in their involvement in maintaining this barrier.

Several studies have indicated that enhancing the expression of a gene involved in tight junction signaling, it is a possible mechanism to reinforce or to maintain the integrity of the gut [10]. Moreover, incubating the gut with Lactobacilli increases the secretion of various gene coding adherence junction proteins [11]. Recent data have suggested that probiotics may repair the barrier function after the damage has been done. Mucosal production may be increased by in vivo of probiotics, but further studies are required.

Competitive Expulsion of the Pathogenic Microorganisms

The term Competitive expulsion was first used in 1969 by Greenberg, to refer to a scenario where one species competes with another vigorously for survival inside the gut of the host [12]. This can take place via a lot of mechanisms Hostile microecology, Production and secretion of anti microbial substances, Selective metabolites and depletion of essential nutrients [13].

Probiotics act by antagonistic activity by preventing the interaction of surface protein and the mucins [14]. This happens via the various mechanisms of the probiotic and one such mechanism used by the probiotics is the modification of the environment making it less suitable for the competitor. Some LABs and Bifidobacterium share the carbohydrates binding sites with the Enteropathogens this makes them compete [15]. This entire mechanism is based on steric hindrance and this is how the pathogen is eliminated

Production of Antimicrobial Substance

One of the proposed theories as to how the probiotics work is the production of LMW compounds mainly the organic acids and the production of antimicrobial substances, bacteriocins.

Acetic acid, Lactic acid have a strong inhibitory action against the gram-negative bacteria and have been proven to be the most effective compound contributing to the suppressed activity of the pathogens [16]. They work by lowering the pH making the environment unfit for the survival and, they enter the cytoplasm and kill the pathogen from inside. Many LABs also produce bacteriocins which kill the pathogen by disintegrating the cell wall of the pathogen by pore formation [17].

Probiotics and its effects on Immune Response

It is well established that Probiotics can exert immunomodulatory effect, the probiotics have the unique ability to interact with the Epithelial and the Dendric Cells (DC).

{Dendric cells are the antigens presenting cells, their main function is to process antigen and provide it to T cells of the immune system}

The immune system consists of two mechanisms innate and adaptive. The adaptive immune system works by T and B lymphocytes and hence they are specific to the type of antigen. Taking in consideration the innate immune system, it responds to Pathogen associated molecular Pattern (PAPM), shared by a vast majority of pathogens [18]. The primary response is triggered by (PPR) Protein Recognition Receptors they in turn bind PAMP. The immune response is however, much more complex and has various steps and throughout these steps signals are forwarded when interaction with bacteria takes place [19]. The probiotics interact with the DC which boosts immunity (innate and adaptive). Probiotics also interact with the IECs (intestinal epithelial cells). Both IECs and DC interact with the gut flora/ probiotics via the PPR which in turn boost the immunity [19].

My Personal views to this would be that Probiotics sure are a superfood of the future and has tremendous health benefits, but most of the proven health benefits mechanisms of Probiotics are in Vitro. Thus, more in-depth studies are required.

Conclusion

This reading

gives the mechanism of action of probiotics but the quest for a better understanding of probiotics continues. This data that we had is a reservoir of information, a reservoir big like an ocean, an ocean with endless possibilities. The future findings and researches hold the key for the importance probiotics and its role in food industry.

References

           Miriam B, Diaz J, Quezada S, et all: probiotic mechanism of action, 2012

1-     WHO: health and nutritional properties of the probiotics in foods including powder milk with live acid bacteria. 2001 www.foa.org

2-     Guarner F, Malagelada Jr: Gut flora in health and disease, 2003.

3-     Collins JK, Thomton G, Sullivan Go: selection of probiotic strains foe human application, dairy, 1998

4-     Lye HS, Kuan CY, Ewe JA, et all: improvement of hypertension by probiotics,2009

5-     Pelletierx, Laure-Boussuge S, Donazzolo: Hydrogen excretion upon the consumption of dairy products in lactose intolerant male subjects; importance of live microbes,2001

6-     Rafter J, Bennette H, Caderni G, et all: Dietary symbiotics reduces the risk of cancer in colon cancer patients,2007

7-     Hoayyedi P, Ford AC, Talley NJ, et all: efficiency of the probiotic to cure the irritable bowel syndrome,2010

8-     Collad MC, et all:bio active foods in promoting health, Chennai, academic press,2010

9-     Williams NT: Probiotics AMJ :Health pharma system,2010