Many of us are familiar with the term “probiotics” which represent the sum of the beneficial bacteria populating our digestive tract and contributing to immunity, nutrient absorption, and good gastrointestinal health.
Less, in my experience, have a full understanding of what the word “prebiotic” means.
Prebiotics are aptly named as such because they are, in essence, food for probiotics.
Their presence in our digestive system supports the growth and flourishing of the healthy gut bacteria that we have all come to appreciate as essential for good health.
The Food & Agricultural Organization Of The United Nations (FAO) formally describes prebiotics as follows:
Which is essentially a slightly more technical definition of the one I just provided.
But how exactly do they function and where do they come from?
These are the questions today’s article will seek to explore.
Where Do We Find Prebiotics?
Just like the bacterial populations, they serve to nourish, there is great variety when it comes to sources of prebiotics.
Perhaps the most well studied that occur naturally in food include:
Beta-glucan: Perhaps most famous for beneficial effects on blood sugar and blood cholesterol, Beta-glucan is a soluble prebiotic fibre found in great supply in cereal grains like oatmeal and barley.
Fructan-based compounds: The allium group of vegetables, including onions, garlic, and leeks, are perhaps the most well known of the Fructan-based prebiotic fibres. Also known for their sulfur-rich antioxidant compounds, foods in this category are not always well tolerated by those living with IBS or GERD.
GOS: Formerly known as Galacto-oligosaccharides, this group of prebiotic fibres are found in good supply in the legume family of foods (lentils, chickpeas, soy). The health benefits of these foods are well known, even if they are not always well-tolerated in large quantities due to their propensity to lead to flatulence.
Isomaltooligosaccharides: This grouping of prebiotic compounds are found in foods that might surprise you including honey, miso and soy sauce.
Maltodextrin: Found naturally occurring in foods such as corn, rice, and potatoes, maltodextrin is also a common additive used in the food industry.
Xylooligosaccharides ( XOS): Known as XOS for short, these compounds are yet another naturally occurring and emerging prebiotic fibre which tends to be found in healthiest fruits and vegetables.
In addition to these natural sources of prebiotics, there are a number of supplemental products that contain these fibers isolated from their food source.
Although consuming them in whole food form offers a number of advantages, some individuals may opt for supplementation.
The top selling prebiotic products currently selling on Amazon can be found here.
Each of these prebiotic compounds interacts with your gut bacteria in a slightly different but generally beneficial way.
It’s important to understand that there are a wide variety of sources of these compounds because certain individuals with gastrointestinal issues like IBS may not be able to consume all of the foods on this list.
Yet the presence of these compounds in your diet, and as much variety as you can get, is important for reasons I’m about to explain.
How They Help
The fermentation of the various types of prebiotic compounds mentioned above leads to the creation of different types of signaling molecules known as short-chain fatty acids.
There are many different types of short-chain fatty acids, and the three most common are acetate, propionate, and butyrate.
Each of these compounds act uniquely as anti-inflammatory messengers in the digestive tract and contributes to a gut environment that is less conducive to the growth of harmful bacteria.
That’s why when it comes to prebiotics and gut health, variety really is the spice of life.
And the benefits don’t end there.
Prebiotics, Gut Microbiota & Human Health
I mentioned earlier in the piece that prebiotics serve as “food” for the healthy bacteria of your gut.
Guess what happens when these healthy bacteria (such as the well studies Bifidobacteria and Lactobacilli) are properly fed?
They proliferate and outcompete harmful bacterial populations.
This ultimately leads to a much healthier gut microbiome, which is increasingly thought to be fundamental to be human health and flourishing.
As we might expect, when you compare individuals with diets high in prebiotic fibres (Mediterranean diet) vs those low in prebiotic fibres (Western diet) there are significant differences in the populations of beneficial vs detrimental gut bacteria.
There are obviously big problems with this as many human illnesses both within and beyond the digestive tract have been increasingly linked with a state known as dysbiosis where your gut may be populated by more “unhealthy” bacteria than it should.
Given all the evidence we have between the relationship between the gut microbiome and diet quality, it is never too late to modify your intake in order to have a positive effect on the state of your digestive tract.
My hope is that you will leave today’s article having found at least a few food sources of prebiotic fibres that you can more regularly incorporate and tolerate in your diet, and in doing so take your gut and overall health to the next level.
When utilized correctly and in a way that fits your needs, there are a number of tangible short-term benefits to increasing the prebiotic content of your diet beyond just long-term health.
- Improved bowel movement frequency/regularity
- Potential improvements to symptoms of constipation and/or diarrhea
- Improvements in blood sugar and blood cholesterol levels
All the best and I sincerely hope today’s article has helped!
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 Carlson JL, Erickson JM, Lloyd BB, Slavin JL. Health Effects and Sources of Prebiotic Dietary Fiber. Curr Dev Nutr. 2018 Jan 29;2(3):nzy005. doi: 10.1093/cdn/nzy005. PMID: 30019028; PMCID: PMC6041804
 Holscher HD. Dietary fiber and prebiotics and the gastrointestinal microbiota. Gut Microbes. 2017 Mar 4;8(2):172-184. doi: 10.1080/19490976.2017.1290756. Epub 2017 Feb 6. PMID: 28165863; PMCID: PMC5390821
 Bibbò S, Ianiro G, Giorgio V, Scaldaferri F, Masucci L, Gasbarrini A, Cammarota G. The role of diet on gut microbiota composition. Eur Rev Med Pharmacol Sci. 2016 Nov;20(22):4742-4749. PMID: 27906427
 Gagliardi A, Totino V, Cacciotti F, Iebba V, Neroni B, Bonfiglio G, Trancassini M, Passariello C, Pantanella F, Schippa S. Rebuilding the Gut Microbiota Ecosystem. Int J Environ Res Public Health. 2018 Aug 7;15(8):1679. doi: 10.3390/ijerph15081679. PMID: 30087270; PMCID: PMC6121872
 Muhammad Shahid Riaz Rajoka, Junling Shi, Hafiza Mahreen Mehwish, Jing Zhu, Qi Li, Dongyan Shao, Qingsheng Huang, Hui Yang, Interaction between diet composition and gut microbiota and its impact on gastrointestinal tract health, Food Science and Human Wellness, Volume 6, Issue 3, 2017, Pages 121-130, ISSN 2213-4530, https://doi.org/10.1016/j.fshw.2017.07.003
 Prebiotics – an added benefit of some fibre types https://onlinelibrary.wiley.com/doi/10.1111/nbu.12366