Probiotics are the good bacteria we ingest to keep our microbiome—the vast pool of live microorganisms in our gut—in balance and our digestive system healthy. Research connects a healthy digestive system to overall wellness, particularly a strong immune system. While probiotics is now a household word linked to better digestion, the term prebiotics isn’t as well known—but it’s just as important to our overall health.
What Are Prebiotics?
Prebiotics are the food for probiotics. Specifically, prebiotics are carbohydrates that can’t be digested by the body. The good bacteria in our gut “feeds” on these undigested carbohydrates. Research into the specific health benefits of prebiotics is in its infancy but experts think that prebiotics may improve gastrointestinal health, as well as potentially enhance calcium absorption.
Prebiotic supplements can be found on store shelves but there’s not yet an official best dose. The ideal way to get prebiotics is by eating plant-based, fiber-rich foods. Excellent sources include asparagus, artichokes, bananas, apples, legumes, garlic, leeks, onions, sweet potatoes, chicory and whole grains, especially gluten-free oats.
The way to maintain a healthy microbiome is eat a variety of prebiotic and probiotic-rich foods. But some people with touchy stomachs need to choose their plant-based foods carefully. Research suggests certain prebiotics may aggravate digestive disorders like small intestinal bacterial overgrowth (SIBO) and irritable bowel syndrome (IBS). Here’s why.
In a healthy digestive tract, most of the microbiome lives in the large intestine, where the bacteria ferment and further digest the foods we eat. When these microorganisms overpopulate the small intestine and fermentation occurs there, symptoms associated with SIBO and IBS (such as abdominal distention, gas, cramping, diarrhea and/or constipation) can develop.
At its worst, SIBO can lead to nutritional deficiencies, fatigue, joint pain and other uncomfortable symptoms.
Experts think SIBO may be responsible for a large percentage of IBS cases. In addition, many people with celiac disease also experience SIBO, even after adopting a strict gluten-free diet.
Preliminary data suggests that avoiding certain hard-to-digest carbohydrates—known by the acronym FODMAPs—may help relieve symptoms of SIBO and/or IBS in susceptible individuals. But here’s the challenge—some FODMAPs are also prebiotics. They include apples, artichokes, garlic, leeks, legumes and onions. If you’re sensitive to FODMAPs, safer bets for prebiotic-rich foods are bananas, sweet potatoes and gluten-free grains like gluten-free oats.
Plan Your Diet
If you have a healthy digestive system or celiac disease with no lingering symptoms, eating a fiber-rich, prebiotic-rich diet is warranted. Many prebiotic foods (fruits, veggies, dairy and legumes) are naturally gluten-free and are part of a nutrient-dense diet. If you’re just starting to focus on prebiotics, increase your intake of prebiotic foods gradually. Ingesting too much fiber too soon can cause gas and bloating. Drink more water, too, as water is essential for moving fiber through the GI tract.
If you have IBS, SIBO or celiac disease with lingering symptoms after going gluten-free, it’s a good idea to see a registered dietitian who can help you identify whether certain prebiotic foods may be an issue for you. While elimination diets like low-FODMAP are all the rage and there are books to help you do it on your own, you’ll get the best results under the supervision of a knowledgeable healthcare professional. Importantly, a low-FODMAP diet isn’t one-size fits all; some FODMAP foods may trigger symptoms in one person but not another. A dietitian can help you more accurately identify your personal trigger foods while customizing a diet that strikes the balance between eliminating symptoms, reversing nutritional deficiencies and rebuilding the gut lining.
We don’t know how much prebiotics are necessary for maintaining healthy digestion, so the best advice is to gradually work up to eating a high-fiber diet (25 to 38 grams per day for adults), adding in whole prebiotic foods as tolerated.
A diet rich in plant-based foods should offer the prebiotics you need to maintain a healthy microbiome. If you’re concerned you’re not getting enough, ask your healthcare provider about taking a prebiotic supplement.