Health Focus: Prebiotics
What is a Prebiotic?
Although the term “prebiotic” is fairly new (coined in 1995), prebiotics themselves are nothing new.1 Prebiotics are an indigestible form of fiber found in some (but not all) fruits, vegetables, and starches. They act as a food source for the friendly bacteria in the gut. It is important to note that though every prebiotic is a fiber, not every fiber is a prebiotic. To be considered "prebiotic" in nature, a fiber must meet the following criteria:2
- Resists digestion and absorption in the upper gastrointestinal tract
- Is fermented by the intestinal microflora
- Selectively stimulates the growth or activity of friendly intestinal bacteria
Prebiotic benefits for optimal health:
Prebiotics and probiotics have a symbiotic relationship. Prebiotic fiber is the main food source of probiotics, and probiotics cannot thrive without it. Ingesting a probiotic supplement or food with prebiotic fiber places the indigestible prebiotics in the gut where probiotics consume them. This helps those beneficial bacteria populate your gut microbiome.3 Conversely, if a probiotic is consumed without prebiotic fiber, it’s less likely to flourish.
Though the scientific understanding of prebiotics is relatively young, promising discoveries have surfaced about their health benefits. The following is just a small sampling of the findings from research into the health benefits of prebiotics.
Encourages Gut Health and Diversity
Per a study published in The Journal of Nutrition, prebiotics and probiotics support gut health diversity and digestive health.4 This is just one of many studies to show that prebiotic fiber is integral fora healthy, balanced gut.5]
Promotes Bone Health
Studies, including those published in The British Journal of Nutrition, show that prebiotic fiber improves absorption of all minerals in the body, including bone-healthy magnesium and calcium.5,6
Supports Cardiovascular Health
Prebiotics have a beneficial effect on lipid metabolism, and they can help ease systemic redness to support normal cardiovascular health.5,7
Helps Control Appetite and Weight Management
Studies published in the British Journal of Medicine and the American Journal of Clinical Nutrition have shown that prebiotics can help with appetite control by increasing satiety hormones, making you feel less hungry.8,9
Regulates Insulin Sensitivity
A study published in The Journal of Nutrition showed consumption of 15 to 30 grams of resistant starch (a type of prebiotic fiber) a day reduced insulin resistance in obese and overweight men.10
Sharpens Brain Function
According to Trends in Neuroscience, prebiotics are considered a form of “psychobiotic,” which exert beneficial effects on gut bacteria and positively impact the gut-brain-axis.11
Brightens Mental and Emotional Health
In addition to their psychobiotic, mental health benifitsthe results of human and animal studies found that prebiotic fibers support normal mental and emotional health and stress response.12
Promotes Restful Sleep
As reported by researchers from the University of Colorado, regular consumption of prebiotics can help boost the amount of REM and non-REM sleep in animals after a stressful event.12,13
What Are the Different Types of Prebiotics?
Prebiotics exist in both food and supplement form. Common examples of prebiotic fiber you will find in supplements and food include:
• Acacia gum
• Oligosaccharides (the best-known prebiotics) including:
- Fructooligosaccharides (FOS)
- Oligofructose (OF)
- Galactooligosaccharides (GOS)
- Transgalactooligosaccharides (TOS)
• Resistant starch (RS)
• Wheat dextrin
Prebiotics in foods:
Since prebiotics are relatively "new" on the health and science scene, there is some debate over which foods qualify as "prebiotic foods" and which don’t. Some health care professionals and scientists believe that any fiber-containing food could have prebiotic benefits. That may be true, but, for now, we'll focus on the "official" best prebiotic foods.14,15
- Asparagus — consumed in its whole, fibrous state.
- Bananas — offer a good serving of resistant starch when consumed slightly unripe.
- Chicory root — rich in inulin and a popular choice among probiotic manufacturers, chicory root also doubles as a delicious coffee substitute.
- Garlic — excellent for supporting the immune system and gut health.
- Jerusalem artichoke — also known as "sunchokes," these potato-like tubers have a delicate flavor and are brimming with prebiotic fiber.
- Leeks — are prized for their health properties and prebiotic value.
- Onions — another immune system and gut-health champion.
- Potato starch — if you’ve ever wondered why potato starch is prevalent in natural food stores, it is partly because of its value as a resistant starch.
- Soybeans — though I generally recommend avoiding soy products, whole soybeans are a good source of prebiotic fiber. If you do eat soy, consume it sparingly and look for organic, non-GMO, fermented soy products like tempeh and miso.
- Whole grain corn — look for organic, non-GMO, sprouted corn products.
- Whole grains — such as oats.
It is worth noting that prebiotics are also abundant in breast milk and help babies build good gut bacteria, a benefit that’s thought to help protect infants from infections.12,14,15 Remember, organic is best.
Prebiotics are the primary food source for probiotics and are just as important as probiotics (if not more so). Probiotics cannot flourish in your gut without prebiotics.15Prebiotic supplements may be taken as stand-alone products, or combined with a probiotic formula.
1. Patel, Seema, and Arun Goyal. "The Current Trends and Future Perspectives of Prebiotics Research: A Review." 3 Biotech 2.2 (2012): 115–125. PMC. Web. 22 Sept. 2017
2. Slavin, Joanne. "Fiber and Prebiotics: Mechanisms and Health Benefits." Nutrients 5.4 (2013): 1417–1435. PMC. Web. 22 Sept. 2017.
3. Cummings, J.H. and G.T. Macfarlane. "Gastrointestinal Effects of Prebiotics." The British Journal of Nutrition., U.S. National Library of Medicine, May 2002
4. Collins, M. David, and Glenn R. Gibson. "Probiotics, Prebiotics, and Synbiotics: Approaches for Modulating the Microbial Ecology of the Gut." American Journal of Clinical Nutrition, vol. 69, no.5, 1052s-1057s, May 1999.
5. Roberfroid, M., et al. "Prebiotic Effects: Metabolic and Health Benefits." The British Journal of Nutrition, Aug. 2010. Suppl 2:S1-63.
6. Scholz-Ahrens, K.E., Ade, P., Marten, B., Weber, P., Timm, W., Açil, Y., Glüer, C.C., Schrezenmeir, J. "Prebiotics, Probiotics, and Synbiotics Affect Mineral Absorption, Bone Mineral Content, and Bone Structure." The Journal of Nutrition. U.S. National Library of Medicine, Mar. 2007. Web. 22 Sept. 2017.
7. Gibson, G.R., and M.B. Roberfroid. "Dietary Modulation of the Human Colonic Microbiota: Introducing the Concept of Prebiotics." The Journal of Nutrition. U.S. National Library of Medicine, June 1995. Web. 22 Sept. 2017.
8. Hume, Megan P., and and Alissa C. Nicolucci. "Prebiotic supplementation improves appetite control in children with overweight and obesity: a randomized controlled trial." The American Journal of Clinical Nutrition, DOI: 10.3945/ajcn.116.140947.
9. Parnell, J.A., and R.A. Reimer. "Prebiotic Fibres Dose-Dependently Increase Satiety Hormones and Alter Bacteroidetes and Firmicutes in Lean and Obese JCR:LA-Cp Rats." The British Journal of Nutrition., U.S. National Library of Medicine, Feb. 2012.
10. Maki, Kevin C., et al. "Resistant Starch from High-Amylose Maize Increases Insulin Sensitivity in Overweight and Obese Men." The Journal of Nutrition, February 22, 2012, doi: 10.3945/jn.111.152975.
11. Sarkar, Amar, et al. "Psychobiotics and the Manipulation of Bacteria–Gut–Brain Signals." Trends in Neurosciences, Elsevier Applied Science Publishing, Nov. 2016.
12. Thompson, Robert S., et al. "Dietary Prebiotics and Bioactive Milk Fractions Improve NREM Sleep, Enhance REM Sleep Rebound and Attenuate the Stress-Induced Decrease in Diurnal Temperature and Gut Microbial Alpha Diversity." Frontiers, Frontiers, 9 Dec. 2016.
13. Leach, J.D., and K.D. Sobolik. "High Dietary Intake of Prebiotic Inulin-Type Fructans in the Prehistoric Chihuahuan Desert." The British Journal of Nutrition., U.S. National Library of Medicine, June 2010.
14. "Prebiotics and Probiotics: Creating a Healthier You.” www.eatright.org, Academy of Dietetics and Nutrition, 10 Oct. 2016.
15. Scott, Karen. "Prebiotics." International Scientific Association for Probiotics and Prebiotics (ISAPP).