How Are Prebiotics Different From Probiotics? Where Can You Find Them?

Medically reviewed by Julie Freeman, RDN, LDN, RYT Julie Freeman Julie FreemanRDN, LDN, RYT facebook_iconinsta_icon
Written by , MSc (Biotechnology), Professional Certificate In Food, Nutrition & Health Swathi Handoo MSc (Biotechnology), Professional Certificate In Food, Nutrition & Health Experience: 4 years

Our digestive system breaks down most complex food molecules into a simple carbon source – glucose. Most of the food gets converted to glucose in the GI tract. Where does the undigested part go? Into the colon, in the small intestine. How does it get digested? With the help of microbes. Yes! As you need these microbes to grow, you need to follow a diet rich in prebiotic foods.

What are prebiotic foods? How do they benefit your body? Where can you find them? All these answers are hidden in the next 1600 words. Read on!

Table Of Contents

What Are Prebiotic Foods?

Prebiotic foods are non-digestible food ingredients that benefit the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon.

Prebiotics are fiber-rich foods that are not easily digestible. That doesn’t mean they go entirely undigested. Prebiotics are redefined as “selectively fermented ingredients that allow specific changes, both in the composition and/or activity in the gastrointestinal microflora, that confer benefits” (1).

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Coming to the most common FAQ…

What Is The Difference Between PRObiotic And PREbiotic?

Probiotics are defined as live microbial organisms that benefit the host by improving intestinal balance. Probiotics could be ‘friendly (or good) bacteria’ and yeast that help in efficient digestion and absorption of the foods we eat daily. For example, Lactobacillus caseii, Bifidobacterium longum, Saccharomyces boulardii, etc.

Prebiotics are foods that cannot be digested entirely by your GI tract. They feed probiotics and help with growth and maintenance of intestinal microflora. These are indigestible, complex carbohydrates (and certain phytochemicals) like psyllium husk, wheat bran, artichokes, berries, etc.

PRObiotics are microbes, and PREbiotics are indigestible, complex carbohydrate-rich foods.

Now that we’ve cleared the major roadblock, let’s get back to the point…

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How Do Prebiotics Work?

You might be aware that as humans, we all house certain strains of microbes in our gut. One of the main responsibilities of the gut microbes (microflora) is to break down dietary fiber or indigestible components of the food we consume. While doing so, the microbes derive energy from such foods and thrive (1).

This means prebiotics are foods that are digestible or fermented by certain gut microbes living in the colon. These foods, in turn, support the growth of the intestinal microflora. The most common targets are bacteria like Lactobacillus, Bifidobacteria, Streptococcus, etc.

Such a beautiful symbiotic relationship in the least habitable location, isn’t it?

Since the gut microbes help us digest difficult molecules, eating prebiotic foods is being encouraged of late. Before you ask, let me start off…


Not all prebiotic foods are fiber and vice versa. An ideal prebiotic should:

  • resist gastric acidity
  • not be hydrolyzed by mammalian cells
  • not be absorbed in the upper GI tract
  • be fermented by intestinal microflora
  • promote activity/survival of beneficial gut microbes

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What Are The Common Prebiotic Foods You Should Try?

Foods containing polysaccharides or fiber like inulin, arabinose, maltodextrin, gums, lactulose, etc. on their label can qualify as prebiotics.

1. Fruits And Vegetables

Fruits and vegetables containing high levels of complex carbs and fiber make good prebiotic foods (2), (3). For example:

  • Leeks
  • Onions
  • Jerusalem artichokes
  • Garlic
  • Chicory root
  • Dandelion greens
  • Asparagus
  • Banana (raw and ripened)
  • Berries
  • Apples
  • Custard apples
  • Pomegranates
  • Watermelon
  • Rambutan
  • Grapefruit
  • White peaches
  • Green peas
  • Shallots
  • Spring onions
  • Beetroot
  • Fennel bulbs
  • Sweet corn
  • Cabbage
  • Dried apricots, figs, dates

2. Grains, Nuts, And Legumes

Some whole grains, legumes, and nuts also contain arabinose (monosaccharides) and wheat dextrin along with dietary fiber (2), (4). Check these out:

  • Wheat bran
  • Whole wheat grains
  • Chickpeas
  • Lentils
  • Soybeans
  • Kidney beans (red)
  • Cashews
  • Baked beans

3. Breakfast Cereals And Snacks

There is a reason these cereals and high fiber foods are consumed in the morning. Breakfast cereals, ideally, alkalize the pH of your stomach and activate the gut microflora (3). Your breakfast should prep your gut for the day’s constant churning. A few good candidates would be:

  • Rye bread
  • Barley
  • Rolled oats
  • Whole wheat pasta
  • Whole wheat bread
  • Rye crackers
  • Psyllium crackers and fritters

By mixing and matching these ingredients, you can create perfect prebiotic meals every day! And they’d turn out tasty, wholesome, and filling.

Not only are these foods nutritious, but they also have a long list of benefits. Wouldn’t you want to know? Scroll down quickly!

How Are Prebiotic Foods Beneficial To You?

1. Aid Appetite Control And Weight Management

Aid Appetite Control And Weight Management
Image: Shutterstock

Fiber gives you a sense of fullness and satiety. This may be a result of the increased time one takes to chew the food (1).

Usually, fibers undergo slow digestion compared to other biomolecules. Certain varieties slow down gastric emptying and decrease the rate of glucose absorption from the duodenum. These factors collectively lead to a slow and steady release of insulin into the bloodstream.

Hence, eating fiber and complex carbs can keep you away from binge eating. A study reported that increasing fiber intake by 1 g per day brought a loss in body weight by 0.25 kg. Prebiotics, therefore, can trigger steady and safe weight loss in overweight individuals (1).

2. Treat Constipation

Fiber increases the stool weight and acts as a bulking agent. It is, therefore, suitable for those suffering from constipation. The fiber holds water and softens the stool. Large and soft stool makes the transit through the intestine less painful and quick (1).

Adding psyllium husk, wheat bran, and other fiber-rich cereals to your diet can relieve irritable bowel syndrome, constipation, and even diarrhea in some cases.

Be mindful of what fiber you eat. Some kinds of fiber that are broken down or fermented in the upper GI tract can cause intolerance in the gut (1). For instance, inulin and fructooligosaccharides can cause discomfort even at low doses. You may need to slowly add these foods to your diet for your gut to adjust to them.

3. Possess Immunity Boosting And Anticancer Properties

Classes of complex fiber, like beta-glucans, support your immune system. Water-soluble fibers can curb inflammation and diseases such as irritable bowel syndrome (IBS), diarrhea, respiratory disturbances, cardiovascular disorders, and epithelial injuries. These carbohydrates improve the activity of T-helper cells, macrophages, neutrophils, and natural killer cells (1).

Another important contribution of prebiotics are the short-chain fatty acids (SCFAs), which are the end products generated by their fermentation. Butyrate, propionate, and acetate are the common products. Research shows these SCFAs interfere with the growth and development of tumor cells (1).

These SCFAs inhibit the proliferation of cancer cell lines in your body, especially those of the liver and colon. Lab studies show that prebiotic polysaccharides from mushrooms, Astragalus, lentils, etc. halt the cell cycle and cause apoptosis (cell death) in several cancer cells (1), (5).

The prebiotics might also alleviate the toxic effects of chemotherapy and radiotherapy in cancer patients (5).

4. Help Manage Anxiety And Stress

Help Manage Anxiety And Stress
Image: Shutterstock

Prebiotics have a positive effect on individuals with anxiety, irrespective of age, per a study on rats (6). This study states that prebiotic foods or supplements can lower the waking cortisol level. Higher activity of cortisol waking is linked to depression and work stress.

Also, the rats on prebiotics had increased attention to positive stimuli.

Since high-fiber foods boost the growth of gut microflora, they tone down the overall inflammatory responses in your body (6). Adding fructooligosaccharides, galactooligosaccharides, and non-digestible and digestible fiber to your diet might give you stress-free mornings and peaceful nights.

Did You Know?

  • A year-long study with 100 adolescents taking 8 g of long and short-chain inulin fructans per day showed a significant rise in their calcium absorption. As a result, the adolescents showed an increase in bone mineral density. However, this effect was absent in girls consuming a similar amount (9 g/day) of cereal per day (1)! Any guesses why?
  • Prebiotic fibers and complex carbohydrates are fermented at a slower rate. This causes a slow and steady insulin release in your bloodstream and not a sudden spike. Hence, about 10 g/day of inulin, resistant starches, and other prebiotics might benefit those with type 2 diabetes and related metabolic disorders (7).
  • Human milk (breast milk) is one of the richest sources of prebiotics.

What if the proposed dose of 10 g/day of non-digestible fibers backfires? Can you grow intolerant to prebiotics? Let’s find out.

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What Are The Side Effects Of Taking Prebiotics?

Prebiotics have fewer side effects as compared to probiotics. The severity depends on the dosage and varies from person to person. Generally, you can see the following signs (9):

  • Flatulence
  • Abdominal pain
  • Diarrhea (only in large doses)
  • Gastroesophageal reflux
  • Hypersensitivity (allergies/rashes)

Abundant research talks about the gut-, cardio-, and neuro-protective effects of prebiotics. But there is no substantial evidence proving the adverse effects of these foods. We do not have enough data to establish the relationship between prebiotic consumption and clinically measurable effects (10). If you do experience discomfort, start slowly with the addition of prebiotic-rich foods.

Wrapping It Up…

Prebiotics are foods that are fermented by the gut microbes and, in turn, support their growth. Foods rich in complex carbs – inulin, fructooligosaccharides, galactooligosaccharides, xylose, rhamnose, arabinose, dietary fiber, and several polysaccharides – are the ideal prebiotics.

You can find them occurring naturally in artichokes, bananas, chicory roots, dandelion greens, onions, asparagus, and other sources listed in this article.

Create a balanced diet with these prebiotic foods. If you are intolerant to any of these sources, consult your dietitian/nutritionist and physician for alternatives.

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Hope this article helped you understand your gut and its ecosystem. Feel free to give us your constructive feedback and relevant suggestions in the section below.

Frequently Asked Questions

Can you take probiotics and prebiotics together?

Yes, you can. Some prefer having them this way. But you don’t have to take prebiotics to ensure the probiotics work. Prebiotic foods only make probiotics more effective. Consult your nutritionist or physician for the right dosage and time, though. Depending on your sensitivity, having them together might have adverse effects.


  1. Fiber and Prebiotics: Mechanisms and Health Benefits” Nutrients, US National Library of Medicine.
  2. The 10 best food sources of prebiotics” College News, College of Health and Human Sciences, Colorado State University.
  3. Dietary Fibre and natural prebiotics for gut…” FAQs, Medicine, Nursing, and Health Sciences, Monash University.
  4. Prebiotics: How to Feed Your Good Bacteria” PennState Extension, The Pennsylvania State University.
  5. Prebiotics: A Novel Approach to Treat Hepatocellular Carcinoma” Canadian Journal of Gastroenterology and Hepatology, US National Library of Medicine.
  6. Prebiotic intake reduces the waking cortisol response…” Psychopharmacology, US National Library of Medicine.
  7. Prebiotics in the management of components of the…” Maturitas, US National Library of Medicine.
  8. Distant Site Effects of Ingested Prebiotics” Nutrients, US National Library of Medicine.
  9. Tolerance of probiotics and prebiotics.” Journal of Clinical Gastroenterology, US National Library of Medicine.
  10. “Impact of prebiotics on human health.” Digestive and Liver Disease, US National Library of Medicine.
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Julie Freeman

Julie FreemanMA, RDN, LDN, RYT

Julie Freeman is a licensed integrative nutritionist with graduate education in psychology, counseling and education. Her post-graduate certifications include functional medicine, yoga, and mind-body medicine. She works closely with other health professionals to support personal transformation. She has over 35 years’ experience in the field of nutrition, counseling, health promotion and corporate wellness.   She is passionate about clean full bio

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