Probiotics, prebiotics, and the bacteria that call you home

By Tina Patnode, RDN, LD, registered dietitian nutritionist specializing in gastrointestinal medical nutrition therapy, Providence Nutrition Services

You are not alone. 

Making themselves at home, deep inside your intestinal tract, are some 100 trillion living microorganisms. These gut bacteria, collectively known as your “microbiome,” are so abundant that they outnumber all the cells in your body by 10 to one.

Before you send out an eviction notice, however, it's important to understand that these bacteria aren't just squatters looking for a free ride – they provide some very important services in exchange for their room and board. The 400 or so different strains of bacteria that inhabit your gastrointestinal tract help you digest food, for one. They also defend against infections caused by harmful bacteria that attempt to set up camp in your body. 

In addition, your health and the health of your resident microbes appear to be linked in a number of other ways that we don't yet fully understand. Although more studies are needed, emerging research suggests that our microbiome may exert a wide-ranging influence on our early development, our behavior, our susceptibility to disease and our ability to recover from disease. Imbalances in our gut bacteria may play a potential role in everything from diarrhea and stomach upset to conditions such as allergies and asthma, autism, attention deficit hyperactivity disorder, mood disorders, acne, obesity, inflammatory bowel diseases and esophageal cancer.

The more we learn, the more clear it becomes that maintaining this delicate balance is crucial to our health. Here are a few things you can do to support your resident microbes.

Eat foods that contain probiotics. Probiotics are live bacteria that are either the same as or similar to the ones found naturally in your gastrointestinal tract. You can help replenish your beneficial bacteria by eating probiotic dairy foods such as cultured yogurt, kefir, buttermilk, acidophilus milk, and cheese with added probiotics. Many fermented foods, such as miso, tempeh, soy sauce, kimchi and fresh sauerkraut also contain probiotics. 

Feed your probiotics some prebiotics. Prebiotics are high-fiber foods that feed the good bacteria in your intestines and help them to flourish. Give your probiotics something to chew on by eating whole grains, oatmeal, root vegetables, nuts, onions, garlic, beans, avocados and asparagus. 

Consider a probiotic supplement. Research on the benefits of probiotic supplements is promising, but there are still many unknowns about what quantities and bacterial strains work best for different people and conditions. If you suffer from recurring diarrhea or antibiotic-associated diarrhea, a probiotic supplement may very well help. Other gastrointestinal symptoms, such as those associated with irritable bowel syndrome, ulcerative colitis and pouchitis, also may respond to probiotic supplements. Talk with your physician or dietitian about whether a probiotic supplement is right for you. 

In the near future, we may be reaching for probiotics to reduce childhood respiratory infections, atopic eczema, tooth decay, high cholesterol, obesity and inflammatory bowel disease, among other ills. Research is looking into all of these now. But until we have more definitive answers, it's best to work with your doctor or dietitian before purchasing a supplement off the shelf. Health claims for probiotics have not been approved by the Food and Drug Administration. And while most people tolerate probiotics without ill effects, some people experience gas, bloating and other gastrointestinal side effects. Immune-compromised people should not use probiotics unless directed by their physician. 

For now, consider this food for thought and fodder for a future conversation with your doctor or dietitian. Just as your health care team works to keep you healthy, so do the bacteria that call you home – so ask about the probiotics and prebiotics that you can incorporate into your daily diet to keep your inner residents feeling healthy, happy and welcome.


Learn more in our Health Library: 
Probiotics