Eating prebiotic foods, which provide the nutrients that healthy types of bacteria in your digestive tract need to thrive and grow, may help improve your immune function and lower your risk for diarrhea and cancer, according to an article published in 2008 in the journal, "Advances in Biochemical Engineering/Biotechnology." Prebiotic foods contain certain types of fiber, including inulin, oligofructose and trans-galactooligosaccharides.
Both bananas and berries provide you with prebiotics. These fruits are good sources of fiber and also contain other essential nutrients, such as the high amounts of potassium in bananas and vitamin C in berries. Add these fruits to salads, yogurt, oatmeal or sandwiches, or simply consume them alone as snacks to include them in your diet.
A number of vegetables provide prebiotics, including jicama, artichokes, asparagus, garlic, leeks, onions, chicory root, Jerusalem artichokes and dandelion greens, as well as other leafy greens. These foods are all low in energy density, meaning they don't contain many calories per gram, so eating more of them is a great way to increase your prebiotic intake without consuming too many additional calories.
If you replace part or all of your animal protein with soybeans and other beans, you'll lower your fat and cholesterol intake while increasing your prebiotic intake. Beans also provide other essential nutrients, including copper, fiber, iron, magnesium, manganese, phosphorus, potassium and protein. Toss them on top of salads, puree them to replace part of the fat in your baked goods, mix them into your favorite pasta recipe or make them into a tasty dip to have with baked pita chips or vegetables.
Wheat is the main source of prebiotics for most of the U.S. population, according to an article published in "The Journal of Nutrition" in 1999. However, other grains including rye, barley, flax seeds and oatmeal also provide prebiotics. Whole grains are better sources than refined grains, since they contain more fiber, and as such, more prebiotics.