In our series on the gut microbiome, we explain what constitutes the gut microbiome, signs of compromise, what harms the beneficial bacteria, how to support the gut microbiome and digestive enzymes, indigestion & inflammation. Among the supplements that replenish the gut microbiome are probiotics, including live cultures and fermented foods; prebiotics, including resistant starches; and sporebiotics. In this article we discuss how to help healthy gut bacteria thrive with prebiotics.
Prebiotics Fuel Good Bacteria
Prebiotics provide fiber that is a type of carbohydrate that humans cannot digest. However, gut bacteria thrive on prebiotic fiber, as it allows them to reproduce and enhances their ability to make various products crucial to gut functions and human health.
Food Sources of Prebiotics
Food sources of prebiotics include:
Prebiotic-rich foods like: leek, asparagus, chicory, Jerusalem artichoke, garlic, artichoke, onion, unripe banana, oats, garlic, apple, dandelion and more.
Fermented and home-made vegetables like: kefir, sauerkraut, kombucha, and kimchi. Subscribe to Dr. Axe to see 17 Great Probiotic Foods for Better Gut Health, as fermented foods and live cultures often provide both pro- and pre-biotics.
Resistant starches act as whole-food sources of prebiotics, fiber and carbs.
Resistant Starch As a Prebiotic
From Nutritionist Lesia Atkinson, “Resistant starch shares many properties with fiber, helping food pass through the gut and generally improving digestion. Once it reaches the lower gut, resistant starch feeds our beneficial bacteria, which in turn produce chemicals which can help our immune systems, cardiovascular health and many other benefits.”
Resistant Starch Speeds up Digestion
Resistant starch functions like fermentable insoluble fiber in that it produces the same healthy gases and acids in the large intestine that soluble fiber does. One important difference between the two types of fibers is that soluble fiber tends to slow digestion while insoluble fiber speeds up digestion.
Benefits of Butyrate
Resistant starch feeds the good bacteria in the intestines and increases the production of short chain fatty acids (butyrate). Butyrate is the preferred fuel of cells that line the colon and acts as a powerful anti-inflammatory agent for the colonic cells, and functions to improve the integrity of our gut by decreasing intestinal permeability and therefore keeping toxins in the gut and out of the bloodstream.
Sources of Resistant Starch
Resistant starch is found in starchy plant foods and cooked, cooled and reheated starches like rice, oats, barley, potatoes and pasta.
Consider cooked and cooled potatoes, raw green bananas, plantains, yams, and other root vegetables. Raw potato starch may be convenient, but properly prepared whole foods are more beneficial. (See The Definitive Guide to Resistant Starch).
Diets for Digestive Disorders
Be aware that not everyone’s gut or digestion is created equally: not everyone can break down carbohydrates (or sugars) equally. Individuals with celiac, colitis, IBS, Crohn’s or leaky gut have a compromised GI tract.
If you suffer IBS, your body might not tolerate non-digestible carbohydrates. Consider a low-FODMAP diet and FODMAP 101: A Detailed Beginner’s Guide.
The Gut and Psychology Syndrome Diet (GAPS), like the Specific Carbohydrate Diet (SCD), reduces the intake of the more complex carbohydrates and sugars (disaccharides and polysaccharides) to ease digestion and reduce the presence of undigested foods and complex sugars that feed microbes, bacteria and yeast.
Reducing their overgrowth reduces their resulting toxins and acids that cause irritation and inflammation in the gut that perpetuates malabsorption.
Low-Oxalate Diets Protect from Leaky Gut
If you have a compromised GI tract or are missing any portion of your intestines (from surgical removal), then in addition to considering fermented veggies, live cultures and/or high-quality biotics to increase healthy gut flora, consider limiting oxalates.
Oxalates naturally occur in plant-based foods, not animal foods, but are like tiny “glass chards” in the gut. As you can imagine, if the gut lining is weakened or permeable, these glass chards can cut through, increasing irritation, inflammation and leaky gut. Consider Low Oxalate Diet: Overview, Food Lists, and How It Works