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6 Health Benefits of Prebiotics

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6 Health Benefits of Prebiotics

Prebiotics are substances that aid in a healthy gastrointestinal (GI) tract. The concept of prebiotics was introduced in 1995, and due to significant research findings, the interest in prebiotics has spiked. Once thought to only affect the GI, we now know that prebiotics indirectly affect most body systems. Because of these reseasons, prebiotics are one of the most sought-after supplements; the global market value for prebiotic products was over six billion dollars in 2021, and continued growth in the market is expected.  

This article will discuss prebiotics - what they are, where to find them, how to test for them, and why they are so crucial for your gut health.


What are Prebiotics?

Prebiotics are non-digestible substances that the microbes within our GI microbiome ferment and turn into energy sources called short-chain fatty acids (SCFA). SCFAs feed the microbiome, a group of collective organisms that resides within our large intestine (there are also small amounts in the stomach and small intestine). The microbiome impacts several bodily processes, including digestion and absorption, immune function, hormone synthesis, and more. Because they serve as an energy source, prebiotics can modify the function and makeup of the microbiome.  

In addition to the effects on the microbiome, the SCFAs produced by prebiotics are small enough to enter into the bloodstream and induce their own beneficial effects on numerous body systems, which we will discuss later.

For a compound to be classified as a prebiotic, it must adhere to the following criteria:

  1. It should be resistant to stomach acid and enzymes and be unabsorbable in the gastrointestinal (GI) tract.
  2. It should be fermentable by the microbes in the microbiome.
  3. Microbes in the microbiome should grow and be stimulated by these compounds, and, as a result, the host's (human's) health should be positively impacted.

Prebiotics are found in the following foods:

  • Bananas
  • Garlic
  • Chirocry root
  • Jerusalem artichokes
  • Onions
  • Breast milk
  • Cow milk
  • Sugar beet
  • Beans
  • Seaweed
  • Wheat
  • Honey
  • Tomato
  • Rye
  • Soybean

Prebiotics are also often added to food products, including yogurt, cereals, infant formulas, bread, and desserts.

Prebiotics Vs. Probiotics

While prebiotics and probiotics sound similar, they are actually quite different. Probiotics are supplements that contain strains of beneficial microbes, while prebiotics are the food sources for those microbes. Prebiotics are typically found in high-fiber foods, while probiotics are found in fermented foods such as yogurts, kimchi, sauerkraut, pickles, and tempeh. Probiotics directly affect the cells within the gastrointestinal tract, while prebiotics primarily induce action by their byproducts, SCFAs. Prebiotics can have a beneficial effect on the type and number of probiotic microbes in the microbiome.

Health Benefits of Prebiotics

Prebiotics produce SCFAs that enter the circulation and thus can affect any and every system in the body. SCFAs affect the following body systems and may induce the following benefits:

  • Central Nervous System: they increase recall, memory, learning, and mood, may slow the dementia process and may be a treatment for a brain infection called Hepatic encephalopathy.
  • Cardiovascular system: they may lower cholesterol and triglycerides
  • Gastrointestinal system: they may lower the risk of colorectal cancer, Irritable Bowel Syndrome (IBS), and Crohn's disease
  • Musculoskeletal system: they increase calcium absorption in the bone
  • Immune System: they increase various immune markers
  • Integumentary system: they may reduce the risk of atopic dermatitis, increase collagen and keratin formation, and aid in water retention in the skin

Examples of Prebiotics Commonly Prescribed

Prebiotics can be separated into five main groups: fructans, galacto-oligosaccharides, starch and glucose-derived oligosaccharides, other oligosaccharides, and non-carbohydrate oligosaccharides. The following are the most commonly prescribed:


Inulin and fructo-oligosaccharides (FOS) are two types of fructan prebiotics. Inulin consumption increases the production of Bifidobacterium, which can prevent pathogenic bacteria from cultivating and improve the GI barrier. A study with participants consuming vegetables rich in inulin for two weeks had a 3.8-fold increase in Bifidobacterium bacteria. Previous studies have explicitly shown Jeruselum artichokes, a vegetable high in inulin, to increase Bifidobacterium bacteria as well.  

Inulin also has antioxidant properties specific to the GI. Inulin may serve a protective role against lipopolysaccharide (LPS), a detrimental enzyme that is produced by pathogenic bacteria.  

FOS is added to many food products due to its ability to reduce constipation by increasing the frequency and quality of stool. Research suggests a dose of FOS ranging from 4-15g/day can improve constipation. This effect may be due to the potent ability of FOS to stimulate the growth of good bacteria in the microbiome and increase mineral absorption. FOS has also been shown to lower cholesterol levels, possibly due to the improvement in constipation.  

Galacto-oligosaccharides (GAS)

Primarily found in dairy products and legumes, GAS can also increase levels of Bifidobacterium. In addition, GAS can aid in the breakdown of fats and carbohydrates, perpetuate the growth and function of colonic cells, reduce the number of pathogenic bacteria, and aid in the healthy functioning of the GI tract.  

Resistant Starch (RS)

RS belongs to the starch and glucose-derived Oligosaccharides group of prebiotics. As its name implies, RS is resistant to metabolism in the upper GI tract. When they are metabolized in the large intestine, large amounts of butyrate, the primary fuel for colonic cells, are made. RS can aid in reducing inflammation in the GI tract, reducing the risk of colorectal cancer, aiding in a healthy weight, and regulating blood sugar levels.

There is current research investigating how to synthesize these compounds in labs, as companies know they could be profitable due to their health benefits.  

Investigating GI Health

Comprehensive stool testing can be a valuable tool for investigating GI health. Results can help identify specific foods and supplements that may benefit overall health.

The comprehensive stool tests, GI 360, by Doctor's Data, and GI Effects, by Genova Diagnostics, evaluate many biomarkers related to gastrointestinal functioning. In terms of prebiotics, these tests give the total amount of SCFAs. They also break down the individual SCFAs, acetate, propionate, butyrate, and valerate and report their relative percentages. These tests also screen for many pathogenic and beneficial microbes, including bacteria, viruses, and yeasts. In addition, the pH level is given, which is essential to prevent the overgrowth of harmful microbes. Although different in certain ways, these tests can provide great insight into the complete function of the microbiome, including prebiotic status.


Prebiotics can be a powerful tool to add to your daily regime, whether through food or supplement. If you are still determining if you're getting enough prebiotics, functional medicine comprehensive GI testing can be helpful to assess markers related to prebiotics. Knowing that prebiotics can affect various body systems, prebiotics and their byproducts, SCFAs, are a valuable marker to track for many people.

The information provided is not intended to be a substitute for professional medical advice. Always consult with your doctor or other qualified healthcare provider before taking any dietary supplement or making any changes to your diet or exercise routine.
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