Gut Bacteria and Our Health: Healthy Gut, Healthy You
Each person is like a planet inhabited by a gigantic number of different micro-creatures living inside their body. These microbes in our gut actually dictate a significant amount of our biology, and it’s important to understand the role that our diet and lifestyle have on directly impacting the community of these microbes in our gut.
Scientists and researchers have been able to deep dive into this tiny world and learn about the many features and roles of microbes, but there is still much to be discovered about this complex ecosystem living inside our bodies. Are they really dictating the health of our body and our mind? Let’s see who they are, and what they are doing inside of us.
What are these tiny creatures living inside of us?
There are trillions of microscopic organisms throughout our body, including our digestive system, eyes, skin, excretory and respiratory organs. Their vast numbers and diversity create a rich ecosystem within our body, and help to support our life. Yes, we cannot live without them!
To put it into perspective, we have ten times more bacterial cells in our body than we have cells in our entire body. And we have 100 times more bacterial genes than our own human genome collectively. So we are in fact more microbial than we are human!
The largest of these microscopic colonies live inside our gut. There is approximately 1.5-2 kg of bacteria living inside the gut of a human adult, and are organized into a micro-world with particular species controlling others. This micro-world of microscopic organisms may be collectively referred to as the microbiome, microbiota, or microflora.
The microflora can be divided into 3 primary groups:
1) Beneficial or ‘essential’ flora: this is the most critical group and the largest group in a healthy person. They are ‘indigenous’ and provide a large number of important functions. Examples of these good gut bacteria include Bifidobacteria and Lactobacteria.
2) Opportunistic Flora: these are the bad guys within the gut that can take over if not kept in ‘check’ by the beneficial flora. They are vast in variety, upwards of 500 different species, including Bacteroids, Staphylococci, Streptococci, Clostridia, and Yeasts. Each of these nasty microbes can wreak havoc on our health in a variety of ways if they are not controlled by the good flora.
3) Transitional Flora: These guys just pass through the digestive tract, and are typically found from the food and drinks we consume daily. These are usually non-fermenting bacilli from our environment. As long as the population of the good bacteria (refer to #1) are strong in numbers, then these transitional flora will be unable to do us much harm.
The Role of Good Gut Bacteria in our Health
Without question, it is worth mentioning that the gut contains the largest amount of immune cells in the body (about 70-85%). Substances produced by these immune cells can destroy and inactivate unwelcomed invaders (‘transitional bacteria’) to help protect the vital mucous membrane in the gut. Additionally, these immune cells can communicate with other cells within our gut, as well as with immune cells in areas outside of the gut throughout the body by sending signals to them. They are able to influence immunity within our entire body, and dictate the set-point of how well our body responds to different infections, to immunizations, and to the progression of autoimmune diseases.
The good bacteria actually play a critical role in populating the epithelial wall of the digestive system with immune cells, usually by engaging lymphoid tissue of the gut wall to make vast numbers of immune cells called Lymphocytes and immunoglobulins. But their influential role in immunity doesn’t stop there.
The beneficial bacteria in the gut help to balance the immune system. Consider that there are two major ‘armies’ of the immune system, Th1 and Th2. Th1 can be thought of as the armored soldiers that are defending the outside walls of a castle (our gut walls in this case). These soldiers are well armored and help to keep invaders (microbes and toxins) away from the castle walls and prevent them from entering our body.
If this Th1 army is depleted or compromised, then the invaders may breach the castle wall and enter into the body, which then elicits a response from the secondary immune system inside (Th2). The bigger issue here is that the Th2 army is not well-equipped with weapons and armor to fight off the invaders, so they don’t protect the castle (our body) in the right way. If the Th2 army is bombarded with invaders and becomes overactive, we may see the development of allergic reactions, inflammation, autoimmunity and other health problems in the body as a result.
Without a healthy population of beneficial bacteria in the gut, we may see an underactive Th1 immunity army to protect the gut wall, and an overactive Th2 immunity army in response to the overwhelming intrusion of foreign microbes and toxins.
This scenario is often seen in people who suffer from health problems such as asthma, eczema, allergies, chronic fatigue syndrome, chronic viral infections, candidiasis, and autism.
We can easily see how the amount of healthy activity of beneficial bacteria in the gut can act as a puppeteer for the body’s entire immune system.
The beneficial gut bacteria work in other ways to protect our body:
They help to neutralize harmful toxic substances, poisons and heavy metals that enter our body, or are produced by harmful microbes.
The cell walls of these ‘good’ bacteria also have the capacity to absorb cancer-causing carcinogenic compounds to make them less harmful.
They help protect our digestive system against damage and inflammation by diminishing the growth of bad pathogenic microbes that can wreak havoc in our gut.
Harmful gut microbes (ex: candida yeast) are capable of producing a variety of neurotoxins that can enter our bloodstream from the gut, and migrate up to our brain. This can cause a wide array of neurological and cognitive symptoms, ranging from mood disorders, behavioral changes, to learning difficulties. The good bacteria in our gut help both to reduce the number of bad pathogens, as well as neutralize many of the toxins they produce.
These healthy bacteria also nourish the cells that line and protect the gut wall (‘epithelial cells’). They do this by converting certain foods they digest into nourishing substances that these epithelial cells can use to function well and keep the gut wall healthy.
As the good bacteria help to keep the epithelial cells of the gut wall healthy, this will allow for proper digestion and absorption of food and its vital nutrients. Unhealthy epithelial cells can lead to malabsorption, food intolerances, and nutritional deficiencies, which can have numerous consequences for our health.
They also take an active role in the digestion and absorption of food. They will digest proteins, break down fibre and lipids, as well as ferment carbohydrates. The byproducts of their activity can help to transport important minerals, water, and vitamins across the gut wall and into the bloodstream. We need these good bacteria to break down and absorb even the best foods and supplements in the world.
Certain strains of healthy bacteria (physiological strains of E.coli.) can assist to digest lactose, which is the sugar in milk. People who lack these lactose-digesting strains of bacteria may experience more sensitivities to dairy.
Certain strains of healthy bacteria can also actively make various nutrients, including Vitamin K2, vitamins B1, B2, B3, B6, B12, pantothenic acid and folic acid. This is an important ‘survival’ feature of the body when food may be scarce, and since vitamins have a fairly short life in the body.
As we can see, our good gut microflora provides a plethora of determinants and benefits for our health, and there will likely be more to discover still. We can think of the human body as a tree, with our roots found in the digestive system. The soil in which these roots grow and thrive is the gut flora, offering protection, nourishment and support. So just as a tree with sick roots is unable to thrive, a human body cannot thrive when it is void of a healthy-performing digestive system.
What is the best diet for gut bacteria?
Certain foods provide nourishment specifically for these gut microbes. Dietary fibre (‘complex carbohydrates’) is especially important to feed these gut microbes. We also require healthy functioning gut microbes to be able to properly break down this dietary fibre.
Dietary fibre is unable to be broken down in the early part of the gut, which allows it to make it to the distal part of our gut, where a lot of these microbes live. There, beneficial microbes will break down this dietary fibre to produce other substances (ex: short-chain fatty acids). You can think of these substances as the ‘feces’ produced by microbial breakdown of dietary fibre, which can be utilized by other cells and microbes to regulate activity and carry out a variety of important functions for our health.
Fibre is a nutrient that comes from plants. So in theory, the more plant foods you consume, the more fibre you will ingest. Good healthy sources of fibre include fresh fruit and vegetables, nuts and seeds, whole grains, beans and lentils. Adults should aim to consume 30 grams of fibre per day, and should include a variety of different fibre sources so that you can grow and nourish a more diverse and robust population of microflora in the gut.
If you are struggling with chronic digestive issues and other health concerns that may be related to your gut health, contact me for an individual plan to help you rebalance the foundation of your health.
In Good Health,
Naomi