I have been a loyal devotee of probiotics ever since my internist first introduced me to the idea many years ago after a strong round of necessary antibiotics.

After experiencing the benefits for myself, I was hooked. So apart from taking probiotics, I have made it part of my daily routine to consume food sources of prebiotics and probiotics.

Now that probiotics seem to be a household name, we are hearing much reference to something called the microbiome. In short, the microbiome is made up of microorganisms that include bacteria, viruses, and fungi. The largest microbiome resides in the gastrointestinal tract. Just to give you an idea of the magnitude of this, we have more bacterial cells and genes in our body than human cells and genes, with most of the bacteria living in our gut.

A healthy gut microbiome supports a strong immune system, improves digestion and absorption, as well as lowers levels of chronic inflammation associated with several chronic diseases. So feed these microorganisms right and you will see some good health effects. 


Our guts are home to trillions of good bacteria and some yeasts, which support good health. They are not only associated with immunity, digestive health, and anti-inflammatory effects, but there is growing research on lower BMI, weight loss, and even the anti-aging effects of probiotics. We acquire our probiotics naturally when we are born, but many life events affect their composition and quantity over the years. Some of these include illness, stress, antibiotic use, and of course diet.

Probiotics are found in cultured dairy products, such as yogurt and kefir; fermented foods like unpasteurized sauerkraut, miso, tempeh, and naturally fermented sour pickles (not in vinegar); and acidophilus milk and buttermilk. So it doesn’t hurt to consume these foods as often as you can, as there is no down side to eating these healthy food sources.

Probiotic Supplements                     

Aside from food, probiotics come in supplements in capsule, tablet, powder, and liquid forms and are a convenient way to take probiotics, but keep in mind they are not providing the nutrition foods can offer. If you take probiotic supplements, bacterial survival is best when taken within 30 minutes before a meal or simultaneously with a meal or beverage that contains some fat content.

Feed your good bacteria with fiber

Prebiotics, components of fiber, are also beneficial to the microbiota and digestive system. They are not bacteria, but indigestible plant fibers that stimulate the growth of healthy bacteria by feeding probiotics. They are referred to as fermentable ingredients or fermentable dietary fiber. So in order to nurture friendly bacteria, we need fiber-rich foods with prebiotics.

You can increase your total fiber intake by eating foods from plant sources including whole grains, lentils, beans, peas, fruits, vegetables, nuts and seeds to feed your good bacteria, create a healthy gut environment, and decrease inflammation in the colon. Other benefits may include lowering cholesterol and controlling blood sugar levels, which are no surprise since they are components of fiber. 

While there are no current recommendations for prebiotic intake, the recommendations for a high fiber intake are out there. Women should strive for 21 to 25 grams per day and men 30 to 38 grams. When we are not consuming enough fiber, and that’s most Americans, this translates into the bacteria actually eating away at your mucus layer of the gut to get what they need. This leads to the inflammation often tagged as a cause of all sorts of diseases and conditions. 

In addition, the foods high in prebiotics have additional beneficial components in the form of phytochemicals. So this is just one more reason why fruits, vegetables, and whole grains such as whole grain breads should be incorporated daily into our diet. Some specific top sources of prebiotics include: apples, asparagus, barley, dandelion greens, garlic, leeks, raisins, jicama, onions, bananas, artichokes, Jerusalem artichoke, chicory, oats, rice, potatoes, pasta, and legumes.

Bottom line

While we wait for the evidence to build, there is no down side to eating these foods. A plant-based high fiber diet is the best way to enhance your gut microflora. Eat a lot of fiber from diverse natural sources. The positive effects of fiber and whole grains in the diet on gut microflora were recently outlined in a study published in the American Journal of Nutrition out of Tufts University. They support that the gains of eating these foods include an increase in gut microbial diversity along with enhanced immune and inflammatory response. To top it all off, some evidence has emerged that taking probiotics reduced BMI (body mass index) and body weight with the greatest reduction in BMI occurring in overweight adults. The best news is, improving your gut bacteria through diet driven changes can happen in a matter of days, so get to it!

Lela Iliopoulos is a Registered Dietitian and Certified Diabetes Educator and an expert in nutrition therapy, health promotion, and education. She is passionate about impacting nutritional health through the practical application of science-based information.