What Is the Microbiome?

Your body is host to many trillions of bacteria, fungi and viruses, which are collectively known as the microbiome, and the individual constituents thereof are called microbiota. Your gut acts as the frontline of your immune system, and it is continuously exposed to new microbes and molecules that come from the things you eat and drink. The processes that take place in the gut are involved in the central nervous system, brain, and even influence your mood. The role of the microbiome is so central to the body’s operations that it essentially acts as an organ. The microbiome impacts ageing, digestion, the immune system, mood, and cognitive function, and a healthy microbiome is the foundation of your immune system. In discussing how probiotics promote a healthy gut microbiome, we first need to understand what a healthy gut microbiome is.

Quoting from a research paper entitled Defining a Healthy Human Gut Microbiome: Current Concepts, Future Directions, and Clinical Applications:

Indigenous microbiota are an essential component in the modern concept of human health, but the composition and functional characteristics of a healthy microbiome remain to be precisely defined. Patterns of microbial colonization associated with disease states have been documented, but the health-associated microbial patterns and their functional characteristics are less clear.

What is a Healthy Microbiome

A healthy microbiome, considered in the context of body habitat or body site, could be described in terms of ecologic stability (i.e., ability to resist community structure change under stress or to rapidly return to baseline following a stress-related change), by an idealized (presumably health-associated) composition or by a desirable functional profile (including metabolic and trophic provisions to the host).

Definition of a Healthy Microbiome

The article goes on to define a healthy microbiome:

How is a healthy microbiome defined? From the ecologic standpoint, the stability of a community (bacterial or otherwise) can be thought of as a functional property descriptive of the health of that community. Stability refers to the ability of a community to resist change in the setting of an ecologic stress (resistance) or to return to an equilibrium state following a stress-related perturbation (resilience). These concepts of resistance and resilience as key features of healthy microbiome are consistent with established views of microbial ecology. However, the concept that a healthy microbiome can be defined by some idealized community composed of defined populations of specific microbes is too simplistic in light of the consistent interindividual differences observed in many studies.

Stability of the Microbiome

The article further elucidates on the importance of maintaining microbiome stability:

That microbial community stability is important in maintaining health is indirectly supported by the nonbeneficial consequences of altering the normal intestinal ecosystem. Consistent with this, alterations of the indigenous microbiota have been associated with many diseases.

Microbiome Dysbiosis

The concept of dysbiosis emerged from studies comparing the composition of the microbial community obtained from a person with a given disease and that of a control which could be obtained from a person without such a disease. Dysbiosis may be understood as an imbalanced microbiome.

Antibiotics and the Microbiome

For example, disrupting microbial colonization by antibiotics is frequently associated with diarrhea, altered gastrointestinal physiology, and abnormal carbohydrate metabolism. Antibiotic-mediated disruption of the microbiome may also result in the proliferation of C. difficile and can lead to aggressive bacterial toxin-induced colitis (Reeves et al., 2011).

Probiotics and the Microbiome

Probiotics promote a healthy gut microbiome by supplementing the gut with beneficial intestinal flora or bacteria that can displace harmful intestinal flora or bacteria and influence our metabolism, digestion and overall health. The probiotic bacteria used in most supplements are typically members of the genera Lactobacillus and Bifidobacterium.

Accumulated data from clinical trials indicate that certain intestinal disease conditions associated with intestinal dysbiosis—such as antibiotic-associated diarrhea, NEC, pouchitis, ulcerative colitis, and IBS—have yielded clinical benefits with some probiotic interventions (Ringel et al., 2012). Because probiotics largely act directly or indirectly on the intestinal microbiota (O’Toole and Cooney, 2008), a possible hypothesis is that some probiotics correct or reduce the effect of dysbiosis. However, the mechanisms underlying the beneficial effects of probiotics remain incompletely understood, especially as they relate to modifying the gut microbiota and associated microbial functions.

Supporting the Microbiome

You rely on your microbiome for many processes, including digestion and immune system function, and the stronger it is, the better off you’ll be. To positively shape your microbiome, eat a diverse diet rich in complex carbohydrates and fibre. Probiotic supplements can also help strengthen the microbiota. Choosing the best probiotic supplement is subject on its own, but the best probiotic supplements contain an assortment of probiotic strains and prebiotics. Prebiotics are foods that help probiotics flourish.

More than 65 scientific studies and published articles have been written in support of probiotic strains, documenting the ability of these strains to:

• Possess a high tolerance to survive stomach acids and bile salts
• Support the body’s natural defences and the intestinal tract’s immune system
• Help alleviate occasional diarrhoea and constipation
• Address lactose metabolism issues
• Adhere to and colonise the GI mucosal membrane
• Assist with regulating intestinal mobility and normal bowel function
• Possibly help create an inhibitory effect on free radical activity in the colon.