Prebiotics

This article is Part One of a two-part piece.  Here we will discuss Prebiotics. Keep a lookout for Part Two, where we will explore Probiotics — the what, why, and ways you can get them into your diet.

Let’s start with a little questionnaire:

1. Are you familiar with the term “prebiotics?”
   1. yes
   2. no
2. Can you describe the difference between Prebiotics and Probiotics?
   1. yes
   2. no
3. Can you name three foods that are good sources of Prebiotics?
   1. yes
   2. no

If you answered “no” to any of the above questions, then in the time it takes you to finish this short article you should have a reasonably good understanding of what prebiotics are and know that while a prebiotic is different from probiotic, they work symbiotically in our gastrointestinal tract.

What are Prebiotics and why do you want to get them into your diet every day?

The World Health Organization (WHO) defines Prebiotics as “living microorganisms that, when administered in adequate amounts, confer a health benefit on the host.”  Who’s the host? You!  So, prebiotics, when consumed, have health benefits for your body.  They are components within food-stuffs  –  including non-digestible carbohydrates –  such as dietary fiber, inulin, and other resistant starches that feed those microbes living in our gut (specifically our large intestine’s or colon’s microbiota) beneficially.  For example, when we ingest probiotics, they and other desirable microorganisms stay around longer with the help of prebiotics, which provide fuel for them (i.e., acting as a food source).

As one’s diet broadens so does the diversity of one’s gut microbiota. However, the variety of microbes residing in your gut can change relatively rapidly.  One of the many reasons why we want to eat a broad range of foods each day is because of the short-lived life of these microbes (a perfect example of “we are what we eat”).

It appears that each prebiotic supports the growth of different gut microbes, so the more diversity we have in our diet, the more diverse and healthier our gut’s environment will be, including a more robust population of probiotics.

Some of the health benefits of Prebiotics include…

…feeding the good bacteria in our gut, such as Bifidobacteria and Lactobacillus strains and Saccharomyces boulardii yeast. These are some of the good guys we want to keep present in our GI tract.

A prebiotic-rich diet can…

…reduce levels of firmicutes (a type of bacteria associated with causing disease); increase bacteroidetes (another bacteria found in our gut), which can have a positive effect on body fat composition; improve glucose and insulin sensitivity; and lessen inflammation and oxidative stress. WOW! Sold on prebiotics yet?

In addition to their being naturally present in a variety of foods, you will see several prebiotics on the supplement shelves as well as added to foods.  Examples of prebiotics include FOS (fructooligosaccharides), Oligofructose, and inulin from native chicory. These fructan carbohydrates impart a positive effect on post-prandial glycemic response. Prebiotics are also a type of fiber, mostly soluble fiber like arabinogalactans (a group of hemicelluloses non-starch carbohydrates) and modified citrus pectins (water-soluble tissues derived from the peel and pulp of fruits like apples, and citrus fruits like oranges and grapefruits).

I am often a proponent of supplements at different times in an individual’s life to support certain conditions or to support achieving individual goals. Specific prebiotics to promote specific goals is no exception.  However, for general health, prebiotics are found in many everyday foods.  To help get your daily dose, if you are not already eating them, here is a partial list of several prebiotic-rich foods you’ll want to add to your diet:  

• Asparagus,
• Bananas
• Burdock root
• Chinese chives
• Cottage cheese
• Eggplant
• Garlic
• Green tea
• Honey
• Jerusalem artichokes
• Kefir
• Leeks
• Legumes
• Maple syrup
• Onions
• Peas
• Soybeans
• Yogurt

Who should not consume prebiotics?

Just about all of us benefit from a prebiotic-rich diet. However, work with your healthcare practitioner if you have bacterial or yeast overgrowth.  It’s likely you will first want to manage any GI bacterial and/or yeast overgrowth issues. For example, if you have small intestinal bacterial overgrowth (SIBO), first treat the SIBO. If you have yeast overgrowth (such as candida), you will want to avoid FOS and have the yeast overgrowth managed first. You will also limit specific prebiotics for a period if you are following a Low FODMAP diet.

If you don’t have any GI issues that warrant avoiding prebiotics for a time, then—as always—for the full beneficial spectrum of the food, stick to fresh, organic, minimally processed local versions whenever possible.

There have been many studies on prebiotics, so we know a fair amount about them. However, we are learning more each day. So much so that in the science and healthcare community, we often say we are still in preschool when talking about matters of precise definitions and the vital role all these food constituents play in our overall health and the well-being of one of the groups of microcosms within us known as our gut microbiome. Therefore, do not be surprised if, as we learn more, the definition evolves, expands, or completely changes.  For now, we do know enough about prebiotics, i.e., these non-digestible carbohydrates, to realize they are significant for us because they support a healthy GI tract and our overall health.

References:

1. Abdallah Ismail, N., Ragab, S. H., Abd ElBaky, A., Shoeib, A. R. S., Alhosary, Y., & Fekry, D. (2011). Frequency of Firmicutes and Bacteroidetes in gut microbiota in obese and normal weight Egyptian children and adults. Archives of Medical Science : AMS, 7(3), 501–507. http://doi.org/10.5114/aoms.2011.23418teri
2. Barrett, J. S., & Gibson, P. R. (2012). “Fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) and nonallergic food intolerance: FODMAPs or food chemicals?” Therapeutic Advances in Gastroenterology, 5(4), 261–268. http://doi.org/10.1177/1756283X11436241
3. Dion, C., Chappuis, E., & Ripoll, C. (2016). “Does larch arabinogalactan enhance immune function? A review of mechanistic and clinical trials.” Nutrition & Metabolism, 13, 28. http://doi.org/10.1186/s12986-016-0086-x
4. Kaur N1, Gupta AK. “Applications of inulin and oligofructose in health and nutrition.” J Biosci. 2002 Dec;27(7):703-14.
5. Macfarlane, G. T., & Cummings, J. H. (1999). “Probiotics and prebiotics: can regulating the activities of intestinal bacteria benefit health?” BMJ : British Medical Journal, 318(7189), 999–1003.
6. Niness, Kathy R.. (1999) “Insulin and Oligofructose: What Are They?” The American Society for Nutritional Sciences
7. Sabater-Molina M1, Larqué E, Torrella F, Zamora S. “Dietary fructooligosaccharides and potential benefits on health.” J Physiol Biochem. 2009 Sep;65(3):315-28. doi:
8. Slavin, J. (2013). Fiber and Prebiotics: Mechanisms and Health Benefits. Nutrients, 5(4), 1417–1435. http://doi.org/10.3390/nu5041417