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What's Real vs What's Hype? Prebiotics and Probiotics


Knowing what to eat, how much, and building the perfect meals or meal plan all seems like a surefire way to optimize health and wellbeing. There’s another part to the equation that plays a larger role than simply what you have on your plate, and that’s how well you actually digest and absorb it. Imagine intending to reach a protein goal each day, but only actually absorbing and utilizing a fraction of it; you’d always fall short of that goal and maybe spend a lot on foods and supplements without getting the full benefit. Likewise, imagine intending to optimize your health with a change of your diet, activity, and mindset while having a silent roadblock that slows down the process. 

The silent roadblock can be doing more harm to your health and wellbeing than you realize, often because it’s happening without obvious signs and symptoms. We’re talking specifically about the environment along our GI tract that allows digestion and absorption to occur, and which also plays a key role in your overall physical and mental health. (1) This environment is a world of its own, and if it’s not taken care of, that damage can translate to even worse outcomes.

From The Beginning: How Your GI Tract First Develops Its Environment

This environment of your GI tract consists of a variety of coexisting microbes that all want to live in harmony and thrive by feeding on their own nutrient sources from the foods you eat. They don’t just eat from our foods to meet their own needs, they give back helpful metabolites that we use to assist in overall cellular functions throughout our body and brain. It’s the picture of balance and order that supports the overall structure and wellbeing of you, the host of those microbes, and there’s much more to it than any probiotic supplements you may hear about.  

Our GI environment first develops early in life, very early in fact, where from birth through our first 3 years of feeding, we are introducing microbes into our system and establishing our microbiome, which may then change slightly over our lifetime through changes in diet, medications, and overall immune system balance. (2) Over time as you eat a variety of different foods, grow and change through different seasons, your GI environment and the microbiota that inhabit it are adaptable and may change in response to your intake of foods, drinks, your activity level, your stress, and more. This adaptability is key because it means we can survive through different seasons, changes of location, and therefore changes of available foods to eat. We see evidence of evolutionary changes in our microbiota based on overall dietary patterns through human history from ancient and first civilization’s diets to modern and Western diets where changes in microbiota composition seen with modern and Western diets are suggested to contribute to certain diseases. (3)

What To Eat: Feeding Your Microbiota To Thrive  

As we learn more about our GI environment, we have identified that some foods may be supporting or contributing to the health of this GI environment, and some may not. Westernized diets high in refined sugar, saturated fats, and low in fiber are notably the most probable contributors to adverse and maladaptive changes in microbiota where increased inflammation and cytotoxic metabolic byproducts can accumulate. (3) 

It’s important to note that fiber is the key here, and it’s the absence of fiber that sets the stage for an unhealthy environment while the addition of high amounts of sugar and saturated fat increases the potential for excess cell damage and excess growth of some bacteria and unhealthful compounds. With fiber being the key here, it’s also the answer to the problem. 

The Most Important Part May Be Missing From Your Diet

Fiber is the structural part of plants and these indigestible fibers we get from plants that we eat like fruits, vegetables, grains, legumes, nuts, seeds, and more all contribute to the health of your GI environment. If you’ve heard of prebiotic fibers, these are non-digestible food components that are feeding and supporting those microbial populations, and in return those microbes produce compounds like short-chain fatty acids (SCFAs), which provide even more benefits for the gut and the rest of the body. (4)  The most common prebiotic foods include almonds, bananas, onions, garlic, flax, cabbage, lentils, and complex starches and fibers across a variety of fruits, vegetables, beans and legumes.  

When your diet prioritizes those fiber-rich and complex carbohydrates, you’ll be providing your GI environment what it needs to thrive. On the flip side, if instead there’s a lot of refined and high-sugar carbohydrates like sugar-sweetened drinks, juices, and other non-fiber foods and snacks, you'll be feeding your microbes an excessive amount of those sugars but not the all-important fibers they need which can lead to overgrowth of bacteria and yeast which is in itself problematic, as well as not providing those beneficial metabolites you would get from healthy bacteria; like a double-whammy. Choose high-fiber, complex carbohydrates and skip the refined and high sugar items. 

Bringing It All Together: More is Not Better, The “Right Amount” is Best

Prioritizing foods that feed your microbes is the key. The occasional intake of live, active cultures of bacteria can provide an additional layer of support for your GI environment in the form of probiotic-rich foods. Known as probiotics, or live active cultures of bacteria that can be introduced to your GI environment, are most often found in yogurt, kimchi, fermented vegetables, kombucha, and more. Just as we don’t want to feed our GI too much of those sugars leading to an overgrowth of microbes and unhealthy conditions in the environment, we also don’t want to take in a high amount of live active cultures of bacteria if we don’t need them, because an overgrowth spells more trouble than it does a benefit. 

As much as this contradicts some mainstream marketing pitches that everyone benefits from constantly taking probiotics for a healthy GI environment, the reality is you already have bacterial populations and need to focus on the types and varieties of foods you are feeding them. The occasional addition of probiotic-rich foods can further support by adding bacteria, especially if recent antibiotic use or illness may have disrupted the environment, but more is not better, which means probiotic supplements may not be worth it.

Do I Need a Probiotic Supplement?

While there is a lot of information out there, it’s important to note that not everything you see or hear is accurate, realistic, safe, or applicable to you and so using discernment is key. (5) Probiotic supplements are much higher concentrations than what is naturally occurring in foods, much of which might go to waste anyway as the interactions of stomach acid and bile salts in the intestine can destroy that bacteria, and these supplements may even introduce antibiotic-resistant strains into the gut.(6)

Most importantly to note is the fact that there is an entire industry of probiotics products and the claims being made can seem encouraging with one big caveat: they are simply claims. The use and utility of taking a probiotic supplement should only ever be considered if and when a proper assessment has been done to show your current microbiota populations, and only if your food and drink intake are sufficient to meet your nutritional needs but you require additional supplementation. 

To put this in perspective, if after a proper microbiome assessment your results show that you have an imbalance, maybe overgrowth of some species, you would then require a protocol provided by your healthcare provider to support the removal, repair, reintegration, and reinoculation of your gut microbiota and your gut environment. None of this would be possible from taking a probiotic supplement alone, and in fact taking that probiotic blind or without knowledge of our current populations of that particular bacteria can lead to unintentional overgrowth, worsening any gut dysbiosis, and further damaging the gut environment and even passing those compounds along to other cells and systems. When in doubt, speak with your healthcare provider, discuss your diet with a dietitian, and test with a microbiome assessment before trying any supplement. 


Some important things to consider when it comes to pre and probiotics:

  • Food first! Prebiotic foods, aka those high fiber foods, should be the focus with occasional probiotic-rich foods like yogurt, kefir, kimchi, and fermented vegetables

  • Adaptability is key, and variety is the spice of life! Variety across your food choices allows for the much-needed support across the diversity of microorganisms you are hosting; be a good host and support the diversity of your GI community so those microbes can live in harmony

  • More is not better, the right balance is

  • If you aren’t sure, talk to your healthcare provider, your dietitian, and test your microbiome before supplementing

Disclaimer for those who are highly active, especially for endurance athletes: If you are continually taking in different quick-digesting carbohydrates to support your activity like sports drinks, gels, chews, bars, and more while exercising, it is strongly advised that you seek out GI microbial testing to ensure you are avoiding a bacterial overgrowth, and even catch it in time to correct if needed. During exercise your digestive function decreases which means what you take in by mouth during this time may not be fully and properly absorbed the way you intend, but rather may sit in your GI environment and feed bacteria with that exact sugar or simple carbohydrate you intended to use for your activity. This can spell danger with bacterial overgrowth occuring along the GI tract, and potentially carcinogenic compounds accumulating as a byproduct of these bacteria feasting on this excess sugar, especially if this is occurring on a regular basis.  

Conclusion: The Reality vs The Hype

Choosing foods in your overall diet, and lifestyle factors to complement a healthy microbiome will set the stage for a balanced and harmonious community of diverse microbes that benefit you. Focus on protecting the health and integrity of your gut and microbiome with intentional choices to allow those microorganisms to thrive and for your gut lining to maintain its integrity and health. A natural gut health protocol may be in order to allow for your microbiome to establish balance while also protecting the health and integrity of your gut lining. 

  1. Appleton J. The Gut-Brain Axis: Influence of Microbiota on Mood and Mental Health. Integr Med (Encinitas). 2018;17(4):28-32. 

  2. Leeming ER, Johnson AJ, Spector TD, Le Roy CI. Effect of Diet on the Gut Microbiota: Rethinking Intervention Duration. Nutrients. 2019;11(12):2862. Published 2019 Nov 22. doi:10.3390/nu11122862. 

  3. Moles L, Otaegui D. The Impact of Diet on Microbiota Evolution and Human Health. Is Diet an Adequate Tool for Microbiota Modulation?. Nutrients. 2020;12(6):1654. Published 2020 Jun 2. doi:10.3390/nu12061654

  1. Davani-Davari D, Negahdaripour M, Karimzadeh I, et al. Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications. Foods. 2019;8(3):92. Published 2019 Mar 9. doi:10.3390/foods8030092

  1. Neunez M, Goldman M, Gheezi P. Online Information on Probiotics: Does it Match Scientific Evidence? Frontiers in Medicine. Section Regulatory Science. 2020; 6. 

  2. Wang Y, Jiang Y, Deng Y, et al. Probiotic Supplements: Hope or Hype? Frontiers in Medicine. Section Food Microbiology. 2020; 11. 


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