Probiotics & Prebiotics: A Beginners Guide

Updated: January 24, 2020

Do you want to improve your gut health? Understanding probiotics and prebiotics is one of the first steps you need to achieve good gut health.

Probiotics and prebiotics have helped many people like you restore their health.

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This post covers the basics of probiotics and prebiotics to get you started on your journey to good gut health, which will result in better overall health.

Table of Contents

By the end of this post, you will have an understanding of the difference between probiotics and prebiotics; why they are important; and what you need to do to improve your gut flora.

Let’s dive right in.

What Are Probiotics?


The friendly bacteria inhabiting the intestines are called friendly flora or probiotics.

Biotic comes from the Greek word that refers to life, so pro-biotic means favorable to life.

Conversely, anti-biotic means against life.

We often think of bacteria as harmful “germs”; however, probiotic bacteria actually helps the body function properly.

There are many different species of beneficial bacteria inhabiting your intestines and many belong to the class (genus) of Lactobacillus.

The three primary types of probiotics are:

  • Lactobacillus acidophilus, which guards the large intestine.
  • Lactobacillus bifidus, also known as bifidobacterium, which protects the small intestine.
  • Lactobacillus bulgaricus, which travels through the entire digestive system and gives the other two, acidophilus and bifidus, a helping hand.

Health Benefits of Probiotics

Your friendly flora are part of your immune system.

How’s that?

Your friendly bacteria enhance the immune system as they form sort of a living blanket that coats the intestinal tract inhibiting other species of microorganisms from gaining foothold on the intestinal mucosa.

About 80 percent of your immune system resides in your gastrointestinal tract in the form of receptor cells, and probiotics support these receptor cells as they form a coating.

Probiotics also prevents Candida albicans, a yeast type fungi, from multiplying out of control after taking a course of antibiotics, which not only kill harmful bacteria, but also kill your friendly bacteria resulting in yeast overgrowth.

Your gut bacteria also compete for food with other microbes resulting in your friendly bacteria inhibiting the growth of infectious organisms.

Your friendly bacteria act as a natural antibiotic agent against harmful bacteria by producing chemicals that are deadly to harmful forms of bacteria.

Your friendly bacteria such as S. thermophilus and L. bulgaricus stimulate your immune system by enticing the activity of lymphocytes, B lymphocytes, and macrophages.

What Are The Best Probiotics?

The best probiotics contain multiple species, preferably at least a dozen, as species diversity has proven to be associated with health.

A good probiotic should contain substantial numbers of organisms (colony-forming units of CFUs), in the order of 50 billion or more to exert an effect.

William Davis, MD, in his book Wheat Belly, recommends the following probiotics supplements for adults:

This probiotics supplement provides a fungus called Saccharomyces boulardii that has the unique property of helping healthy bacterial species proliferate.

The following list is the recommended probiotics supplements for kids:

When Is The Best Time To Take Probiotics?

The best time to take a probiotics supplement is in first thing in the morning on an empty stomach, about 15–30 minutes before breakfast.

This ensures that your probiotic supplement is able to access your digestive track quickly without getting stuck in the stomach behind your breakfast.

Dr. Mercola also suggests having your probiotics after the last meal of your day; however, my preference is first thing in the morning on an empty stomach.

Fermented Foods

Fermentation is “the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat.”

Besides taking probiotics supplements, another way to seed healthy species, such as lactobacillus and leuconostoc, is to include fermented foods in your daily diet.

Sugars ferment into lactate that gives vegetables and fruits a tangy sensation while adding health benefits when you eat them.

Dr. William Davis recommends “seeding” your gut with probiotics and then maintaining your gut flora with fermented foods.

If you want to expand on this topic and know how to ferment foods, I’d recommend William Davis’ book, Undoctored. Check Appendix C and Chapter 10.

What Are Prebiotics?


Once you have seeded your digestive track with probiotics and fermented foods, you can nourish your friendly bacteria with prebiotic fibers!

Prebiotics are fibers that you ingest but cannot digest, leaving them for the microorganisms in your intestines to consume.

Warning: cellulose fibers from bran cereals, bran muffins, and whole grains are not too different from wood fiber.

The awesome benefits of fiber come from your bowel flora digestion of prebiotic fibers converted to fatty acids and vitamins, not by having a larger bowel movement because of the cellulose.

Cellulose is inert and not metabolized by you or bowel flora. It’s not harmful, but it doesn’t provide the benefits of prebiotic fibers.

Foods Rich in Prebiotic Fibers

These are the foods richest in prebiotic fibers:

  • Green bananas and plantains
  • Potatoes
  • Inulin and fructooligosaccharide (FOS) fibers
  • Legumes

Green bananas and plantains have to be green. No yellow anywhere!

Once you buy them at the store, you can either store them in the refrigerator for 4 to 5 days, or peel and chop them and then freeze them for future use, as needed.

You might be wondering why potatoes? Aren’t they high in sugar? Yes, they are but when cooked!

But when white potatoes are raw, they are rich in prebiotic fibers and give you about 10 to 12 grams per half a medium potato.

Sweet potatoes and yams are a different story. You should consider raw white potatoes as a source of prebiotic fibers as they also have a good amount of important nutrients like Vitamin C!

Inulin offers a longer fiber chain whereas FOS a shorter version. However, they both exert similar benefits.

Inulin occurs naturally in leeks, asparagus, onions, wheat, garlic, chicory, oats, soybeans, and Jerusalem artichokes.

Fructooligosaccharides (FOS) are found naturally in plants such as onion, chicory, garlic, asparagus, banana, artichoke, among many others.

Alternatively, inulin and FOS prebiotic fibers can be purchased at health food stores as a purified powder.

Legumes in the form of kidney beans, black beans, white beans, chickpeas (or hummus), and lentils are rich sources of galactooligosaccharide (GOS) prebiotic fibers.

As a word of caution, legumes contain a type of carbohydrate called amylopectin C that opens the potential for blood sugar spikes.

Limit legumes to no more than 15 grams of net carbohydrates (total carbs minus fiber).

You may not want to eat these prebiotic fiber sources raw. However, there are recipes that you can find in Dr. William Davis’ books, Wheat Belly and Undoctored.

Wrapping Up

Keeping your gut healthy is a big deal when you want to regain your health.

Remember that most of your immune system is in your gut, which is the main entry point (immigration border) into your system.

When you swallow something, what you swallowed is still not considered inside of you. What you swallowed is inside of you once it crosses through your intestines and into your bloodstream.

Interesting, right?

Because of that exposure to the external world, your gut barrier holds most of your immune system and you need to strengthen it with probiotics and prebiotic fibers.

Your gut flora keeps candida in check; inhibits the growth of harmful microorganisms; and stimulates your immune system when necessary.

Your friendly bacteria are your friends.

Take care of them!


William Davis, MD. Undoctored. Toronto: HaperColllins, 2017.

William Davis, MD. Wheat Belly – Revised and Expanded. New York: Rodale Books, 2019.

Justin and Erica Sonnenburg, PhDs. The Good Gut. New York: Penguin Books, 2015.

Bernand Jensen, DC. Dr. Jensen’s Guide To Better Bowel Care. New York: Avery, 1999.

I hope this post was informative.

Did you learn anything new?

Please let me know your thoughts in the comments below.

I’d love to hear your experience with probiotics.

Thank you!

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