Digestive Health: Probiotic vs. Prebiotic

Digestive Health: Probiotic vs. Prebiotic


Bacteria are everywhere and that’s a good thing because they help us to stay alive.  In an ideal world we would have an abundance of bacteria covering our skin, inside our mouths, in our nasal tracts, our respiratory system, eyes, and throughout our entire GI tract.  We have evolved to live in a harmonious symbiotic dance with these microscopic creatures, as we keep them alive as much as they keep us alive. Let's talk about all these little specimens that keep us alive and thriving.  

Our microbiome is a whole world unto itself, which is essential for the health of our gut lining; our immune system, proper digestion, and neurological health and overall wellbeing.  The microbiome (meaning the world of bacteria and other organisms that live in your digestive system) are often known as the beneficial gut flora. This gut flora can weigh up to 2 kilos in weight, which just goes to show the enormity of this microbial community.  

Bacteria act as important guardians for our bodies, as they coat the entire digestive tract from where food enters to where food exits.  The GI tract tube is still essentially outside of your body, (despite running through it) as the outside world is still present here in the form of food, toxins, chemicals, or even foreign objects accidentally ingested etc etc.  It is the function of the GI tract to determine what should pass through the gut lining and what should be excreted as waste, as once particles cross the gut lining then they have technically entered your bodily system proper. If harmful particles pass into your system, then cellular damage can be done and problems or disease can manifest. Think of your GI tract as your guardian and best friend, it really deserves to be treated well, as damage to the GI tract can cause the defenses to go down and the gut lining barrier can be breached.

Lines of Defense

The bacteria and other organisms in the microbiome form a protective layer all along the GI tract, which help to act as a line of defense.  Not only does it coat the GI tract with protective bacteria that can neutralize invaders, this layer also helps to nourish and feed cells in your gut, keeping them healthy and alive.  The cells lining your gut shed and reproduce every 3 days, ensuring an optimum performing gut lining teaming with healthy, functioning cells. This means that they need a healthy food supply in order to regenerate rapidly, and the gut bacteria help to provide this.

According to Dr Natasha Campbell McBride who developed the GAPS protocol (gut & psychology syndrome), gut bacteria help to protect the GI tract lining in 3 distinct ways:

  1. They kill unwanted bacteria by producing anti-viral, anti-fungal and antibiotic like substances

  2. They make the pH close to the gut wall very acidic which makes it a very hostile environment for non-beneficial bacteria and other pathogens.  

  3. They absorb and neutralize carcinogenic substances, meaning they are essential for preventing cancer.  

Opportunistic Flora

The gut lining is not only home to a huge amount of beneficial gut bacteria but it is also home to what is known as opportunistic flora which can cause sickness or other health issues if there numbers grow too large.  It is normal to have the non beneficial flora living in your gut but the key is to have an abundance of the good stuff in order to keep the not so nice stuff in check.

So if your beneficial bacteria become depleted, for whatever reason, then this provides a window of opportunity for your opportunistic gut flora to flourish and essentially run amok.  This can lead to IBS symptoms, yeast overgrowth, constipation or diarrhea, skin conditions, and even emotional or psychological imbalances (this is because your gut and brain are directly connected by the vagus nerve, and whatever is going on in your gut can impact on your brain).

A lack of healthy flora can basically lead to inflammation of the digestive system, which can then lead onto system wide inflammation.

Different Types of Beneficial Bacteria

1. Probiotics - these are pro life bacteria that help to populate your gut lining and GI tract in general with some of the most well recognized and researched bacteria out there.  A probiotic is usually a supplement containing freeze dried bacteria, which can be taken daily. There are lots of different types of probiotics on the market aimed at targeting different issues, so it’s often worth talking to a professional who can guide you to buying the best one for you.  Most health food shops have someone who can guide you on this also.

  • As the gut contains a huge variety of species of bacteria it’s important to get a probiotic that has a decent variation of types, and in quantities that can have an impact.

  • A good broad spectrum probiotic should contain bacteria from the Lactobacilli and Bifidobacteria species as well as soil based bacteria. Soil based bacteria act like the bacteria we would ingest if eating food found in an organic environment in nature e.g. picked straight from the ground. As very few people have direct contact with food plucked straight from nature these days, most people are lacking the microorganisms that we would ingest in these circumstances, which are also extremely beneficial to our microbial flora.

  • A decent daily probiotic dose should contain about 8

  • 15-20 billion CFU (colony forming units) or more bacteria and ideally come in a capsule that can withstand stomach acid, only dissolving once in the intestines.

2. Prebiotics - these are components in edible foods that we can’t fully digest but your gut bacteria can.  Your gut flora needs to eat also and certain indigestible prebiotics are able to act as a food source for them. Prebiotics can be just as essential as probiotics as there is no point taking loads of probiotic supplements to populate your gut with bacteria, if the bacteria then suffer from lack of appropriate nourishment.  Easy to access foods containing prebiotics are plantains (which are high in resistant starch), dandelion leaves, onions and raw garlic. If you eat a variety of seasonal fruit and vegetables, you most likely are getting some good prebiotics.