A prebiotic is defined as a nondigestible food ingredient that stimulates the growth and/or activity of one or a limited number of bacteria in the colon with the purpose of improving the host's health. Basically, it’s food for our good bacteria! 

Prebiotics of various types are found as natural components in plants such as onion, chicory, leek, almonds, chia seeds, garlic, artichoke, banana, rye, and barley. Xylooligosaccharide (XOS) is a specific prebiotic that is found in bamboo shoots, fruits, vegetables, milk, and honey. Inulin, guar gum, and maltodextrin are other common prebiotic fibers.

How do they work? 

Unlike probiotics, prebiotics have no issue surviving its journey through the digestive tract. These fibers ferment in the gut to fertilize the good bacteria as they stifle production of the bad, disease-causing bacteria. The “bad” bacteria are mostly fed simple sugars and the junk we eat, so they don’t thrive when fed these complex fibers.  We can help populate our gut with the good bacteria in two ways: starving the bad guys of their preferred food and by feeding the good guys so they can crowd out the bad guys!

How does it benefit us? 

Health benefits of prebiotic dietary fibers:

• Increases in Bifidobacteria and Lactobacilli

• Increases in calcium absorption

• Decreases in protein fermentation and pathogenic bacteria populations

• Decreases in allergy risk

• Improved gut permeability and immune system functions

(Carlson, Erickson, Lloyd, & Slavin, 2018)

Prebiotics are nutrients that have the potential to considerably influence the physiology of the whole body and, consequently, health, and well-being. However, because prebiotics specifically and selectively affect the gut microflora, their importance is likely to become greater and greater. As biomedical research progresses, it is proposed to go further and to classify a “prebiotic” as an essential, specific colonic nutrient! Future generations may see prebiotic fibers listed on nutrition fact labels and discussed in nutrition lessons!

TLDR: Prebiotics are food for bacteria. Specifically, foodstuffs that feed our more helpful bacteria. 

Sources and helpful info:

Aachary, A. A., Prapulla, S. G. (2011, January). Xylooligosaccharides (XOS) as an emerging prebiotic: Microbial synthesis, utilization, structural characterization, bioactive properties, and applications. Comprehensive review in food science and food safety, 10(1), 2-16. https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1541-4337.2010.00135.x 

Carlson, J. L., Erickson, J. M., Lloyd, B. B., & Slavin, J. L. (2018). Health Effects and Sources of Prebiotic Dietary Fiber. Current developments in nutrition, 2(3), nzy005. https://doi.org/10.1093/cdn/nzy005 

Kaur, A. P., Bhardwaj, S., Dhanjal, D. S., Nepovimova, E., Cruz-Martins, N., Kuča, K., Chopra, C., Singh, R., Kumar, H., Șen, F., Kumar, V., Verma, R., & Kumar, D. (2021). Plant Prebiotics and Their Role in the Amelioration of Diseases. Biomolecules, 11(3), 440. https://doi.org/10.3390/biom11030440