Gut Microbiome
Whenever we think of bacteria, fungi, protozoa all that comes to our mind is something that will harm us, make us sick and weak. But, that’s not true always because some specific bacteria in our body are very essential to carry out every bodily function concisely and optimally and they have a direct impact on the body’s major metabolic functions and modulate several activities and synchronize it well. These bacteria or microorganisms are called ‘Good Bacteria’. The Human body consists of two types of bacteria identified as Good and Bad. As the name suggests, bad ones are responsible for various disease conditions deteriorating the overall health of an individual. Good ones are those that support the organ system to carry out various functions ensuring that they are being carried out optimally and also keep a check on the proliferation of harmful pathogens, inhibit their growth, prevent them from colonizing and causing any discomfort to the host.
Our gut is a host of many such good bacteria, where they reside, grow and flourish naturally and defend our body from various disease conditions and other common ailments. As such, these bacteria naturally live in our body, and a healthy diet and exercise ensure their availability but in certain cases where an individual has been on antibiotic therapy for too long or has been on Non-steroidal anti-inflammatory drugs (NSAIDs) for too long, lack of physical activity, stress/anxiety, oxidative stress such as the formation of reactive oxygen species (ROS) which damage our healthy cells and tissues by inducing oxidation and generation of free radicals, etc affects the gut microbiome and leads to decrease in their population which ultimately affects overall health and well being of an individual and make them more susceptible to get easily affected with common ailments and health conditions.
As already mentioned, these bacteria naturally harbor in our gut, more specifically called as Gut Microbiome, and need not be taken from any outside source. But, in certain cases such as injudicious and indiscriminate use of antimicrobials, use of NSAIDS, chemotherapy account for a rapid decline in the population of such bacteria, and hence there arises a need to consume them from outside sources called probiotics to maintain their optimal number in the gut.
Probiotics are essentially foods consisting of useful and important bacteria/microorganism which otherwise naturally harbor in one’s body. These beneficial bacteria are naturally present and easily available in most fermented food products such as yogurt (Dahi), paneer, idli/dosa, kefir, fermented soybean, green peas, pickles, buttermilk.
Following are some of the important strains of microbes present in probiotics:-
Lactobacillus Bacteria such as L. acidophilus, L. plantarum, L. casei, L. fermentum, L. rhamnous and brevis.
Bifiobacterium Bacteria such as B. bifidum, B. longum, B. infantis, B. breve.
Yeasts such as Saccharomyces boulardii.
Mechanism of Action:-
A major group of probiotics works by enhancing the epithelial barrier which prevents pathogen entry into submucosa because if the epithelial barrier gets damaged, food pathogens and bacteria (here bad bacteria) can easily enter and induce inflammatory response releasing chemical mediators like histamine, prostaglandins, etc causing intestinal disorders such as IBD.
Increased adhesion to intestinal mucosa is one of the most prominent prerequisites for enhanced colonization and inhibitory effects on pathogens. They compete with pathogens for adhesion site because their surface proteins interact with mucus on the intestinal wall and this competitively excludes pathogenic microorganisms and produce various antimicrobial chemicals such as lactic acid, hippuric acid, acetic acid, and citric acid which in turn produces substances like hydrogen peroxide, diacetyl, and bacteriocin which inhibits pathogens from colonizing and signals immune system to start secreting immune cells and chemical mediators such as T cells, neutrophils, interleukins, TNF alpha, interferon, antibody-producing B cells and ultimately helps the body in eliminating these harmful pathogens.
Anything in excess is ultimately harmful as appropriately said by Paracelsus “Dose makes the poison” and hence if these good intestinal bacteria start harboring excessively in our gut/small intestine it leads to a syndrome called Small Intestinal Bacterial Overgrowth (SIBO) which indicates that the activity and number of the gut microbiome have increased beyond standard leading to mild to chronic diarrhea, weight loss, and malabsorption, nutritional deficiencies, and osteoporosis. Also, it can lead to other conditions such as motility disorder, inflammatory bowel disease(IBD), and metabolic disorders such as diabetes and hypochlorhydria. Intestinal bacteria and enzymes also facilitate the conversion of procarcinogens into their active deleterious forms. Due to this very reason, the use of probiotics such as lactic acid bacillus tablets should be consumed only when prescribed by a medical practitioner.
Mechanism of action
Various health conditions in which these microorganisms play an important role are as follows:-
Antimicrobial properties:-
Our indigenous microbiome has its colonies established throughout the GI tract, right from the esophagus to the large intestine and this is for a very specific reason to prevent growth and colonization of harmful pathogens which easily get access in our body through food, water, and other external factors. Our good bacteria act like a soldier and resist colonization of these detrimental pathogens and eliminate them rapidly by producing lactic acid, hippuric acid, acetic acid, and citric acid. Lactic acid bacteria also produce substances like hydrogen peroxide, diacetyl, and bacteriocin as antimicrobial substances which ultimately degrade harmful extraneous pathogens.
Anticarcinogenic properties:-
Scientists have suggested that the introduction of Lactobacillus acidophilus which is one of the most prevalent bacteria in the human body significantly lowers the incidence of colon tumors in rats. Later on, same group of scientists reported that the inclusion of food rich with probiotics containing L. acidophilus lowers the generation of carcinogens in the colon and reduces the incidence of chemically induced tumors. A putative mechanism for their anticancer effect could be that they inhibit intestinal enzymes which are responsible for converting procarcinogens into the active cancer-causing agent, enhance individual’s immune system, alters the metabolic activity of intestinal enzymes, binds and degrades carcinogens, production of antimutagenic compounds, and alter physiochemical conditions in the colon. Our normal intestinal flora influences the pathogenesis of cancer by producing enzymes such as glycosidase, B glucuronidase, azoreductase, and nitroreductase transform procarcinogen into active tumor causing ones. L. acidophilus and L. casei supplementation help in preventing such incidences.
Immunogenic Enhancement:-
There have been several reports suggesting the role of L. acidophilus, L. casei, found in dairy products in enhancing the host’s immune response by supporting the immune system to produce prominent immune cells and chemical mediators. Probiotics strengthen the immune system by enhancing phagocytic activity of granulocytes, lymphocyte proliferation, interleukin 1,2,6 and tumor necrosis factor (TNF) production, albumin, globulin, interferon, increased immunoglobulin secreting cells. Scientists have also observed increased lymphocyte proliferation in the spleen, in peripheral blood, in Peyer’s patches, and also increased INF gamma production in Peyer’s patches and spleen when rats were fed food rich in L. bulgaricus and S. thermophilus. Immunity majorly declines in old age and thus elderly people are advised to consume probiotic-rich food. Probiotics are capable of stimulating both specific and nonspecific immune responses. They are very useful in prophylaxis and have therapeutic applications in the treatment of infections, common ailments, and cancer.
Antiatherogenic and Cholesterol-lowering potential:-
Individuals with cardiovascular diseases, atherosclerosis, and hypercholesteremia having elevated levels of Low-density lipoprotein (LDL) and triacylglycerol, and the treatment aims at decreasing their levels and elevating High-density lipoprotein (HDL). Several experiments conducted by researchers suggest that probiotics consisting of L. acidophilus and Bifidobacterium (fermented products) have cholesterol-lowering potential. The possible mechanism through which they exert anticholesteremic action could be cholesterol assimilation of bacteria, deconjugation of bile salts, binding of cholesterol to the bacterial cell wall, and most importantly reduction in cholesterol biosynthesis.
Role in diabetes and obesity:-
The capability of probiotics (Dahi) in reducing insulin resistance and controlling obesity has been well documented. Studies suggest that consumption of probiotic-rich products (Dahi) has markedly suppressed food-induced insulin resistance and protected from streptozotocin-induced diabetes. It has also been found that they also suppress diabetic progression and associated complications by enhancing the antioxidant system. Some specific strains of Bifidobacterium and Lactobacillus have the potential to control obesity to a good extent. Although animal studies have shown promising results, indicating the role of probiotic-mediated diabetes and obesity suppression, still substantial data collection and clinical studies need to be done on humans to valid their beneficial health potentials.
Amid the pandemic, when we constantly talk and hear about the immune system, ways to make it more strong so that it can easily knock down any bacteria, virus, fungi and hence one of the ways to prepare ourselves and our body is to take utmost care of our gut microbiome, consuming probiotic-rich food which amplifies their colonies and yes most importantly is to balance their number (anything in excess is harmful) because our gut microflora is capable enough to ward off several harmful pathogens and prevent progression of critical health conditions even without we knowing it.
