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Publication #FSHN11-10

Go With Your Gut: Understanding Microbiota and Prebiotics1

Wendy J. Dahl and Volker Mai2

What is our microbiota?

All of us have friendly bacteria all over our bodies. A large population of bacteria lives in our gastrointestinal tract, residing mostly in the colon (large intestine). This is known as our gut microbiota.

If we were able to count the bacteria in and on our bodies, they would add up to about 100 trillion. That is 100,000,000,000,000—about 10 times more bacterial cells than human cells making up our body!(1) If we could weigh all the bacteria in our colon, it would amount to about 2 or 3 pounds.

What does our microbiota do for us?

Figure 1. 

FISH image of gut microbiota.


Credit:

Courtesy of the UF/IFAS Department of Microbiology and Cell Science and the Emerging Pathogens Institute


[Click thumbnail to enlarge.]

Our microbiota helps defend against disease—collectively, these resident bacteria help to develop and maintain our immune system's defenses against illness introduced by less friendly, disease-causing bacteria. The bacteria of our microbiota can also make vitamins, such as vitamin K.

The bacteria in our colon break down food residue that escapes digestion in our small intestine. For example, some of the starch and protein we eat, as well as all of the fiber in foods, is not digested and ends up in our colon. The bacteria in the colon break down the food residue for energy and growth. This process is known as fermentation.

We benefit from the fermentation of fiber and starch. However, the fermentation of undigested protein, as a result of high intakes in meat, is much less favorable. (2) Fermentation provides us with some energy (calories) and also helps to keep the colon healthy.(3)

Can microbiota cause disease?

Our microbiota remains quite stable in adulthood. However, the balance of bacteria in our gastrointestinal tract may be disturbed by changes in diet, contaminated food and water, stress, antibiotics, and aging. Inflammatory bowel disease (IBD) and most forms of diarrhea are linked to changes in our gut microbiota.(1) Our gut microbiota may also be related to our health beyond the gut. Research is being carried out to explore possible connections between microbiota and many diseases and conditions. (4)

What is a prebiotic?

A prebiotic is a fiber that benefits health by stimulating the growth or activity of beneficial bacteria in the colon. Prebiotics are found in high amounts in breast milk and work to optimize the numbers of beneficial bacteria in the baby's intestine. Prebiotic fibers are also found naturally in wheat, onions, chicory root, Jerusalem artichoke, and beans.(5) The most well known prebiotic fiber is inulin, also known as chicory root fiber. Chicory root fiber is added to many foods, including snack bars, yogurts, and beverages.

How can we keep our microbiota in balance?

One of the most important things we can do to maintain our normal microbiota is to eat a well-balanced diet. A diet high in fiber from fruits, vegetables, beans, whole grains, and nuts may promote a well-balanced microbiota. Probiotics (good bacteria), taken as capsules or in supplemented foods, also may help maintain or restore microbiota.

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Related EDIS publications include the following:

Endnotes

(1) Dahl, W.J., K.E. Hagen, and T.A. Tompkins. 2009. Human microbiota and the role of probiotics. AgroFood Industry Hi-tech 20: 34–36.

(2) Windey, K., V. De Preter, and K. Verbeke. 2012. Relevance of Mol Nutr Food Res. 56(1):184-96.

(3) Wong J.M., R. de Souza, C.W. Kendall, A. Emam, and D.J. Jenkins. 2006. Colonic health: fermentation and short chain fatty acids. 40(3):235-43.

(4) Belkaid, Y., and T.W. Hand. 2014. Role of the microbiota in immunity and inflammation. Cell 27;157(1):121-41.

(5) Roberfroid, M., G.R. Gibson, et al. 2010. Prebiotic effects: metabolic and health benefitsBr J Nutr 104 Suppl S2: S1–63.

Footnotes

1.

This document is FSHN11-10, one of a series of the Food Science and Human Nutrition Department, UF/IFAS Extension. Original publication date June 2011. Revised October 2014. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Wendy J. Dahl, Ph.D., assistant professor, Food Science and Human Nutrition Department; Volker Mai, Ph.D., assistant professor, Emerging Pathogens Institute; UF/IFAS Extension, Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication do not signify our approval to the exclusion of other products of suitable composition.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.