Microbes of all sorts naturally colonize and reside in the human gastrointestinal tract.
This complex ecosystem, when in balance, performs beneficial activities for our health such as helping with digestion, synthesizing enzymes and producing vitamins.
In fact, the estimated 100 trillion microbes who have made your intestines their home is called the gut biome. These microbes have genetic material, as well as release waste products, which can affect our health.
They can modulate our immune responses (recognizing foreign substances), gut barrier function, inflammation and synthesis of neurotransmitters. They may also produce signalling chemicals that regulate our appetites and satiety!
Probiotics are live bacteria which, when taken usually as a dietary supplement, colonize in the intestines and provide health benefits to the host – us!
There’s a “battle” for “dominance” between microorganisms in our bodies. Scientists have reported that Westernized cultures with Westernized diets and pervasive use of antibiotics have experienced a loss of diversity in the internal gut ecosystem. Less diversity usually means less resilience of the gut.
There’s also been a proliferation or overpopulation of certain strains of microorganisms.
This imbalance is also called gut dysbiosis. More and more, scientists are becoming aware that dysbiosis may not only create uncomfortable symptoms, like GI distress, but it may also play a role in autoimmune disorders, allergies, obesity, metabolic syndrome and neuropsychiatric conditions.
One type of gut imbalance is SIBO, or small bowel bacterial overgrowth. SIBO is a condition in which abnormally large numbers of bacteria grow in the small intestine.
The small intestine usually contains a low number of bacteria (and it’s where we absorb most of our nutrients), as compared to the large intestine which contains large numbers. SIBO creates a condition in which the microbes are competing with us for the nutrients we would normally absorb.
In addition to losing out on nutrients, a person with SIBO may experience damage to the cells lining their intestinal walls due to the breakdown of nutrients by the unwanted bacteria in the small intestine.
Except for a few pathogens, most microbes are either harmless or have a mutually positive “relationship” with us.
When our gut ecology is in balance and our immune systems are functioning well, we can generally handle “bad” or “unfriendly” invaders. But when we get out of balance, we often can’t.
And when we get out of balance some microbes take advantage of the opportunity to multiply more and tip the balance further, and are then referred to as “bad.”
I think it’s more complicated than that; most microbes have positive and negative aspects to them. It’s about Balance.
Some of the beneficial bacteria, probiotic strains like Lactobacillus and Bifidobacterium are getting crowded out by the opportunistic resident fungus Candida albicans (yeast).
This crowding out of the beneficial bacteria, or at least disruption of the healthy balance of our gut biome, is becoming more and more common.
When some microbes crowd out other bacteria it can lead to an overgrowth situation.
Yeast Overgrowth and Leaky Gut Syndrome
If you don’t have the right balance of microflora in your gut (ratio of “good” to “bad” microbes), among other things, you can experience yeast overgrowth, which can impact your health and cause uncomfortable symptoms.
Persistent overgrowth of Candida may damage the intestinal walls, weakening the body’s ability to properly absorb nutrients.
The “Leaky Gut” syndrome occurs when intestinal surfaces are damaged, chronically inflamed, causing the cells to separate and the intestinal lining to become more permeable than normal.
Lack of integrity of the gut lining enables things to enter the bloodstream that don’t belong there, such as Candida, bacteria, parasites, toxins, undigested protein, fat, and waste. (Healthy gut lining repels these and the body eliminates them.)
Once the Candida is in the bloodstream, it can travel to other areas of the body and colonize there, especially areas with moist mucous membranes, such as the anus, rectum, vagina, genitourinary tract, lungs and sinuses.
Symptoms of Candida overgrowth in the gut include indigestion, gas, distention, mucus in the bowel.
Women may experience Candida overgrowth in the vagina with vaginal discomfort or itching.
Similarly, people with Candida overgrowth in the rectum may experience rectal itching or discomfort. Diaper rash in children or the incontinent elderly, urinary tract infections and burning upon urination, and oral thrush are other examples of Candida overgrowth. Sinuses may also become inflamed.
People with Candida overgrowth may develop sensitivities to foods (most common are dairy products and foods with dietary yeasts and molds), and to chemicals, including cleaning supplies.
Some of the symptoms may be from the Candida itself; others may be from toxins released by the Candida.
The shift in balance of the “good” vs. “bad” bacteria in your gut and other body systems happens over time and usually from a combination of factors.
The chronic use of antibiotics and a high sugar diet may override the body’s ability to re-balance itself.
Taking a Probiotic to Replenish Your “Good” Bacteria
Prepared probiotics will help replenish the microbial balance. They will usually contain bacteria from the Lactobacillus and Bifidobacterium family species. There are many strains of each family.
Members of the Lactobacillus family help repopulate the small intestine where they are naturally found, along with lessor amounts of other bacteria from other families. (Lactobacillus are lactic acid producing bacteria, hence their name.)
Members of the Bifidobacterium family predominate in the large intestine (also known as the colon) which has even more microflora.
That’s why oral probiotics usually contain bacteria from the Lactobacillus and Bifidobacterium family species. Some of the specific strains of the “families” are actually proprietary to the companies who have grown them.
You might also see the word “prebiotic,” which is a food or dietary supplement that is healthful for, stimulates and modulates the microbiota already colonized in your intestines but does not provide bacteria directly.
Some examples of prebiotics are fibers (but not all fibers) such as fructose oligosaccharide or galactose oligosaccharide. Just like us, microbes need food to exist and reproduce, and prebiotics provide healthy food for “good” bacteria.
Some dietary supplements contain prebiotics and probiotics. If they work synergistically to improve overall gut health, (produce an effect different from or greater than the sum of their individual effects), they are often called synbiotics.
The probiotic has the challenge of getting past your stomach acids and arriving in the small and large intestines, alive and active, in order to benefit the host, you!
That’s why the delivery system of the probiotic is key. For example, some probiotics supplements are made with a special encapsulating process (coating system) that protects the probiotic bacteria from stomach acids as well as other environmental factors such as heat, moisture or oxygen on the shelf.
Probiotics are measured in CFUs or Colony Forming Units. CFUs measure the number of viable microbes or live bacteria in a probiotic.
Sometimes a person with symptoms will start off with a probiotic with more CFUs and then taper down to a maintenance dose with fewer CFUs. Some probiotic supplements have CFUs in the millions, others 1 billion, 5 billion, etc. The ideal number of CFUs has not been determined.
The Many Roles of Probiotics
- Probiotics perform beneficial activities for our health, like supporting healthy digestion through fermentation of the byproducts of the food we eat.
(The acidic environment, like lactic acid, created by the fermentation, also creates an environment that’s more hostile to yeast.)
- In the digestive process, probiotics help assimilate nutrients.
- Probiotics can ease gas and bloating.
- Probiotics support regularity of normal bowel movements – easing diarrhea or constipation.
- Probiotics produce their own enzymes that help process our food.
- Probiotics manufacture essential vitamins such as B and K.
- Probiotics keep our immune systems healthy by stimulating some components of our immune system and by protecting the body from unfriendly organisms.
- Probiotics help prevent the overgrowth of yeast and fungi and harmful bacteria and their harmful by-products. These harmful by-products can also interfere with the production of neurotransmitters by the gut.
- Probiotics play a role in the manufacture of neurotransmitters like serotonin.
- Probiotics play a role in the manufacture of amino acids and short chain fatty acids.
- Many scientists believe that the probiotic microorganisms live symbiotically in us and function as an auxiliary DNA. (Their DNA may influence the expression of our DNA.)
- Probiotics “communicate” with our brain and can affect our mood and memory through the gut-brain axis.
There has been exciting new research about the Gut-Brain Axis. In addition to our brain, we have an enteric nervous system (ENS). The ENS is composed of millions of neurons and neurohormones produced in our gut that communicate with our brain.
The ENS sends chemicals and electrical message signals to the brain that directly affect feelings (sadness, stress, anxiety, fear), memory, learning and decision making.
While the ENS may be called a “second brain,” the communication between the gut bacteria and the brain is actually one part of a single nervous system.
If dysbiosis is present and the gut is unhealthy, it can adversely affect the nervous system. Probiotics, so important to the integrity of our gut, are also intricately connected to the Gut-Brain Axis.