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  • Bacteria in the gastrointestinal (GI) tract influence many functions in the body.
  • Probiotics and prebiotics work together to balance bacteria in the GI tract. 
  • Prebiotics feed and support the healthy bacteria and cells in the colon.

The topic of gut microbiota and its influence on human health is gaining a lot of attention. Because of this, many health experts are looking at the possible effects of prebiotics and probiotics to prevent disease. 

These supporters of healthy gut bacteria also fall into the category of functional foods. These are just a group of foods that have potential health benefits when consumed regularly. The demand for functional foods such as fruits and vegetables, grains, nuts and fortified foods like yogurt and cereal is growing as the benefits of functional foods are more understood. 

Prebiotics are a type of nutrient (specifically, a carbohydrate) that is broken down and used to support the gut microbiota, which is made up of microorganisms that live within the digestive tract.

The original definition of prebiotics has remained mostly unchanged for many years. This definition uses three “criteria” to classify a nutrient as a prebiotic:

  • Resistant to gastric acidity and hydrolysis by mammalian enzymes and GI absorption. In other words, the compound is not broken down by stomach acid and digestive enzymes. 
  • Can be fermented by intestinal microflora
  • Selectively stimulates the growth and/or activity of intestinal bacteria associated with health and wellbeing. Prebiotics help good gut bacteria flourish.

Prebiotics vs. Probiotics

Before you deep dive into prebiotics, it’s important to understand the difference between prebiotics and probiotics, and how both are needed to optimize gut health. 

The digestive tract, which is colonized with bacteria at birth, is known by some as the body’s “second brain.” The bacteria in the digestive tract influence the body’s metabolism, endocrine and immune functions. Prebiotics and probiotics work symbiotically to balance and support healthy gut bacteria.

Probiotics are live bacteria that balance healthy gut microbiota. Some common strains of probiotics include Lactobacillus acidophilus, Lactobacillus rhamnosus GG, Saccharomyces boulardii, Bifidobacterium bifidum and Bacillus coagulans. You’re likely to see one or more of these live strains listed on probiotic supplement labels. 

Probiotics are relatively easy to find in food as well. They are most commonly found in fermented foods like sauerkraut, kimchi and kombucha. Probiotics may be added to dairy products like kefir and yogurt as well. 

On the other hand, prebiotics feed and support probiotics in the digestive system. Common types of prebiotics include fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), and trans-galacto-oligosaccharides (TOS). They are most commonly found in some foods, such as fruits, vegetables, beans and grains. 

Benefits of Prebiotics

A healthy gut equals a healthier body. Therefore, prebiotics plays a supportive and vital role in many important systems of the body, including the digestive tract, metabolism, immune system, and even the neurological system. 

Prebiotics Support Digestive Health 

A healthy balance of gut microbiota protects the body from harmful types of bacteria, viruses, and fungi. Without prebiotics to support and promote the growth of healthy gut bacteria, harmful substances will grow and flourish. 

Human nutrition is the main factor which influences the growth of healthy bacteria. Giving these cells proper nutrition helps them protect the digestive tract from harmful viruses or bacteria. Prebiotics break down into short-chain fatty acids, which serve as the main source of nutrition for healthy gut bacteria. Short-chain fatty acids also serve as another layer of protection in the digestive tract.  These fatty acids nourish the cells that line the colon. The fermentation of prebiotics may also change the pH of the colon, making it more favorable for certain bacteria.

Prebiotics’ Influence on Your Health

Gut microbiota is considered integral to health, meaning it is associated with many diseases. Prebiotics work symbiotically with probiotics to balance gut bacteria, which has a direct effect on the development and management of obesity, immune disorders, inflammation, gastrointestinal (GI) disorders and neurological disorders.


People with a large amount of harmful gut bacteria may absorb more calories, therefore putting them at higher risk for weight gain and obesity. Prebiotics may have the ability to manipulate gut microbiota to prevent obesity. In fact, one study of overweight or obese children ages 7-12 years found participants who consumed oligofructose-enriched inulin (a prebiotic) had significant decreases in multiple factors including body weight and body fat, compared to participants who consumed a maltodextrin placebo.

Here is a quote summarizing the results from another study: 

“In addition, research was done on four pairs of adult female twins, both lean and obese, from which the microbiota was transferred to germ-free mice. In animals that received microbiota from obese people, obesity developed; whereas mice containing intestinal microorganisms from a lean person had normal body weight” (Ridaura et al., 2013).

Immune System

The bacteria in the digestive system communicate directly with the immune system. Healthy gut bacteria can actually signal the immune system to trigger inflammation if infection is present. Prebiotics also help reduce the colonization of pathogens when they support the growth of healthy probiotics, which have an antimicrobial effect. 


Although inflammation is a normal function of the immune system, chronic inflammation can harm the body. Chronic inflammation has been linked to obesity, heart disease, cancer, and other diseases and conditions. Having a good balance of healthy gut microbiota helps to decrease chronic inflammation and the risk of disease.

GI Diseases and Conditions

When prebiotics are fermented in the colon, they produce short-chain fatty acids, which provide energy for the colon’s epithelial cells. These cells line and protect the colon. Therefore, prebiotics strengthens the protection provided by the epithelial cells, therefore reducing the risk for GI conditions like Irritable Bowel Syndrome (IBS), Crohn’s disease, and even cancer. Prebiotics may also reduce symptoms of GI conditions.

Neurological System

Many know the central nervous system as the brain and spinal cord. However, you may not know about the enteric nervous system, which includes the GI tract. There is a strong link between the enteric and central nervous systems in terms of cognitive and emotional function. Therefore, prebiotics supports healthy gut microbiota to manage mood, learning, memory, and possibly some psychological disorders

How to Incorporate Prebiotics Into Your Diet

The best way to incorporate more prebiotics into the diet is through nutrition. Consuming prebiotic foods delivers these nutrients directly to the colon, where they are broken down, fermented, and put to use. 

Prebiotic Food Sources

Prebiotic foods consist primarily of fruits, vegetables, grains, and beans.

Vegetable Sources

  • Asparagus
  • Sugar Beet
  • Garlic
  • Leek
  • Onion
  • Tomato

Fruit Sources

  • Banana
  • Apple

Other Sources

  • Chicory Root
  • Dandelion Greens
  • Seaweed/Algae
  • Peas
  • Soybean
  • Rye
  • Barley

It’s important to note that cooking may alter any food’s fiber content. In other words, it’s likely best to consume prebiotic foods uncooked. Prebiotics are also sold in the form of supplements to make it easier to make regular consumption less of a hassle.

All in This Together

Prebiotics and probiotics work as a team. Together, they fight off harmful bacteria and create a strong, healthy gut. Without healthy bacteria and an environment to support them, the gut can’t regulate functions that directly influence the immune system, metabolism, and neurological system. To give your body the most benefit, consume a variety of prebiotics and probiotics on a regular basis. 


Breanna Woods is a Registered Dietitian with over 5 years of clinical experience. She is passionate about giving her clients the tools they need to build a healthy lifestyle.

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