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What are prebiotics?

The scientific definition of a prebiotic is “a substrate that is selectively utilized by host microorganisms conferring a health benefit”. Often, prebiotics are types of soluble fiber that the human body cannot digest, which serve as ‘food’ for beneficial microbes that already live your colon or elsewhere in your body.

How can I get more prebiotics?

Consuming certain foods and supplements can increase dietary intake of prebiotics. Plants that are rich in prebiotics include onions, garlic, bananas, chicory root, and Jerusalem artichokes. Prebiotics are also added to some food items such as yogurts, cereals, breads, biscuits, desserts, or drinks. The word ‘prebiotic’ is seldom used on the label; instead, look in the ingredients list for galacto-oligosaccharides (GOS), fructo-oligosaccharides (FOS), oligofructose (OF), chicory fiber, or inulin. Consuming at least 5 grams of prebiotics daily is recommended for improved gut health.

Prebiotics are also found in breast milk. Human milk oligosaccharides (HMOs) are prebiotics, which enhance beneficial microbial populations in the infant gut while discouraging pathogens that may cause infections. Many brands of infant formula are now supplemented with oligosaccharide prebiotics to mimic this effect, and HMO-enriched formulas are also available in some places.

What can prebiotics do for health?

Both for healthy people and those with certain health concerns, prebiotics are a promising way to modulate your gut microbiome for better health. While there are more studies to date on probiotics than on prebiotics, research on prebiotics is rapidly expanding. Established health benefits include:

  • Improving calcium absorption
  • Regulating blood sugar
  • Enhancing colonic bacterial fermentation to reduce gut transit time

These physiological benefits may have positive effects in those with osteoporosis, diabetes, and colorectal cancer, respectively.

Newer research is investigating the role of prebiotics in the management of gastrointestinal conditions such as inflammatory bowel diseases (ulcerative colitis and Crohn’s disease), irritable bowel syndrome, and even obesity. In the future, specific prebiotics could be designed to boost numbers of beneficial bacteria known to be less abundant in the systems of people affected by these and other diseases.

Are prebiotics safe?

Clinical trials show the use of prebiotics appears to be very safe.

Are there any downsides to prebiotics?

With high intake of prebiotics, some people experience minor digestive discomfort. It’s a good idea to start with low doses of prebiotics and gradually increase your daily consumption to a level that’s effective. If you have symptoms, they may subside once your body adapts.

Prebiotics are not an alternative to a diverse and healthy diet. Eating a range of whole grains, fruits and vegetables, and other fiber-rich foods in addition to prebiotics can help you enjoy better digestive health and overall health.

Prebiotics and probiotics may be taken at the same time. When one product delivers both, it is called a synbiotic. Although in theory a probiotic could be matched with a prebiotic that will improve the probiotic’s function, few studies have demonstrated this synergy. The specific combination of prebiotic and probiotic has to be carefully considered if the goal is to consume health-benefitting live microorganisms along with the exact substrate that they need to grow.

See here for resources that will help you find a prebiotic product to suit your needs.

Get the facts on prebiotics

This educational infographic gives you the basics of prebiotics in supplements or in foods.

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What effects to prebiotics have on the gut microbiota?

This infographic shows how both probiotics and prebiotics interact with the microbes in your digestive tract.

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Prebiotics and fiber: Are they the same?

It’s a common misconception that prebiotics are the same thing as dietary fiber. This infographic helps you understand the difference between the two categories.

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ISAPP videos

Check out this ISAPP educational video, created by our science translation committee to give a quick overview of prebiotics and how they affect health.

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