The Benefits of Prebiotics

You’ve heard about probiotics, but what about prebiotics? What are they, how do you get them, and what are the benefits of prebiotics that you might be missing out on? Let’s find out!

The Basics of Prebiotics

Prebiotics are the fiber that feeds your beneficial gut bacteria. These are the parts of foods you cannot personally digest in the small intestine, but the gut flora in your large intestine can. When you feed your gut flora these yummy prebiotics, they gobble them up and then multiply and prosper.

Prebiotics are different than probiotics in a very basic way: prebiotics feed existing gut bacteria, while probiotics add new helpful bacteria to your gut. Prebiotics come before your gut bacteria can grow (preview before the movie, prenatal care before the baby), while probiotics are an addition (they provide what wasn’t there before).

There is another term you might like to know: synbiotics. Synbiotics are supplements that combine both pre- and probiotics into one. (An example of a synbiotic food is sauerkraut.)

There are many types of fibers that can be counted as prebiotic fibers, with the one basic tenet being that the fiber must bring a beneficial change to your digestive tract. One type of prebiotic is inulin, found in bananas, garlic, and onions. Another is resistant starch, found in legumes, oats, and potatoes. We’ll give you a better rundown of the difference between probiotic foods and prebiotic foods, so you can better visualize just how different they truly are.

The Health Benefits of Prebiotics vs. Probiotics

A few more basic principles here. Keep in mind that probiotics are live beneficial bacteria that you consume to add to your gut microbiome, while prebiotics are substances from carbohydrates like fiber that humans can’t digest, but the friendly bacteria already residing in your gut can. Collectively, your gut bacteria can be referred to as your gut flora, or your gut microbiota, and they all live in the environment that is your gut microbiome, aka your digestive system. You’ll want to eat a balance between pre- and probiotics, as too much of one would be useless or possibly detrimental to the kingdom of gut flora living within you.

Gut Bacteria and Food

The good bacteria in your body helps protect you from harmful fungi and bacteria that may find its way into your digestive tract. They signal your immune system to respond and help regulate inflammation levels. Not only that, some of your gut bacteria form vitamin K and short-chain fatty acids, which are the main food sources for cells living in your colon. These healthy gut bacteria serve as a strong barrier against harmful bacteria and other destructive substances.

The food you eat has a lot to do with the health of your gut. A high-fat, high-sugar diet, for example, has a negative influence and allows harmful species of gut bacteria to grow. If bad bacteria is allowed to proliferate, they will begin to crowd out the beneficial bacteria, leading to (among other issues) absorbing more calories than needed, which contributes to unhealthy weight gain.

Antibiotic intake can have long-lasting impacts on the balance of bacteria, so much so that researchers are studying health problems relating to the gut to generate actionable information doctors can rely on in the future when prescribing treatment. Fiber-rich foods on the other hand? Those can do a lot of good in your gut.

Which Foods Are Probiotic?

To serve as a contrast, here is a list of probiotic foods, those which introduce live, beneficial bacteria to your digestive system. Foods made of cultures like yogurt are probiotics, as are fermented foods such as:

When seeking fermented foods, you’ll want non-pasteurized versions, as pasteurization kills the bacteria in foods. Probiotic supplements can also be taken if you’re interested in the benefits but don’t want to consume the foods.

The benefits of prebiotic foods.

What Are the Best Prebiotic Foods?

Now for a more comprehensive look at what foods are prebiotic and the extra benefits they can provide. All are good for vegetarians, and many of them are suitable for a vegan diet as well.


  • Grapefruit: In addition to prebiotics, grapefruit is high in vitamins A and C, which helps with iron absorption in the gut.
  • WatermelonThis summer favorite has a high-fiber content and plenty of water for hydration (plus the seeds offer up tons of nutrients).
  • BananasThere are 2.6 grams of fiber per 100 grams of banana.
  • Custard apples: A wonderful source of prebiotics, these apples also boast antioxidants for brain health and lowering cholesterol.
  • Berries: Even the most common of berries can bring prebiotic benefits along with antioxidant powers.


  • Chicory rootBelonging to the sunflower and daisy family, chicory root is high in inulin and helpful at relieving constipation.
  • AsparagusEveryone’s favorite veggie side is full of vitamin K and antioxidants.
  • Jerusalem artichokesWith 1.6 grams of fiber per 100 grams, Jerusalem artichoke is great for digestive health.
  • GarlicA flavor agent for all genres of meals, garlic also contains vitamin B6, important in brain health and function.
  • Onions, leeks, and shallots: Members of the Allium family, onions, leeks, and shallots share antioxidant properties.
  • Savoy cabbage: This winter vegetable contains vitamins B and C on top of a dose of prebiotics.
  • Dandelion greensThe leaves and roughage of dandelion plants, these dark, leafy greens are as powerful as spinach.


  • Chickpeas: Rich in iron, protein, and B vitamins, chickpeas are also the key ingredient in hummus.
  • Lentils: Whether pink or red, these legumes have 10.8 grams of fiber per 100 grams of lentils.
  • Red kidney beans: An excellent source of potassium, red kidney beans are good for heart health.
  • SoybeansFull of protein and nutrients, soy products are a staple of vegan and vegetarian diets.


  • Bran: Bran is famous for promoting digestive well-being and regular bowel movements.
  • Barley: An immune-booster and an antioxidant, barley is also an excellent high-fiber food.
  • Oats: With their own anti-inflammatory properties, oats help to promote healthy bacteria in the gut.
  • Wheat: Whole-grain bread can be an easy way to gain the prebiotic properties of wheat.

Nuts and Seeds

  • AlmondsAn easy snack and full of dietary fiber, almonds are a great source of calcium for those on a vegan diet.
  • Pistachio nuts: With fiber, vitamins, minerals, and vegetable proteins, pistachio nuts are excellent stimulants of gut bacteria.
  • Flaxseeds: Flaxseeds are versatile seeds that can be included in various dishes to up your prebiotic intake without much effort.

As a general rule, raw foods provide more prebiotic fibers than cooked foods do, but nevertheless the benefits of prebiotics can come from any of the above foods.

Are There Side Effects to Prebiotics?

Yes, there are some side effects, but they are specifically for those with certain medical conditions, like irritable bowel syndrome, inflammatory bowel disease, Crohn’s disease, or FODMAPs intolerance (referring to Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols, the names of certain food molecules that are poorly absorbed by some digestive systems).

Too much fiber in these conditions can cause serious abdominal pain and cramping, so much so that some people are placed on a temporary fiber-restricted diet for the sake of resting their digestive tract. While no one can forgo fiber indefinitely, these conditions may need to managed by removing even beneficial prebiotic fiber from the diet.

Prebiotic Beneficial Effects

Here are some final notes on the benefits of prebiotics.

Calcium Absorption

Among the healthful effects of prebiotics is the hidden gem of an increase in calcium absorption. More calcium absorbed means better bone mineral density, which means a lower risk of osteoporosis as we age. That means that above and beyond the promotion of gut health, in the large intestine and beyond, prebiotics also come with bone-health-promoting potential.

Colon Health

Beneficial bacteria in your digestive tract helps to acidify your colon, which is a good thing. It’s a perfect symbiotic relationship: as long as good bacteria do well, they provide food for the cells of the colon itself. As the colon gets stronger, it provides a better gut microbiome. When this system is operating at an ideal balance, you’ll literally feel better: you’ll eat well, digest well, and expel your waste comfortably.

Trust Your Gut

It’s often noted that those eating non-Westernized diets full of fiber-rich traditional food ingredients, tend to have healthier gut flora than those in North American and European nations. While prebiotic supplements may not be right for everyone, the foods listed above are safe, natural ways to get this valuable form of fiber.

The term “prebiotic” was only coined in 1995, which means we still have a lot to learn about the details of our gut health. At the end of the day, you’ll know better than anyone what foods work best for you, because you’ll literally know it in your gut.

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