In my On Nutrition column in today’s Seattle Times, I talk about the difference between prebiotics (foods that contain substances that the beneficial bacteria in your gut (a.k.a. your intestines) can ferment and use as food) and probiotics (food that contains actual live specimens of beneficial bacteria that can add to your existing population or possibly alter it for the better).

The prebiotic/probiotic issue is a gorgeous example of how a healthful diet can yield benefits that are hard to fathom. The types of fiber that feed our “good” bacteria are found in a number of vegetables, fruits, whole grains and beans (legumes). Probiotics are found in yogurt that contains “live active cultures.” Eating a diet full of a variety of healthful whole or minimally-processed foods not only provides you with the nutrients you need, but it feeds the beneficial bacteria that you rely on for certain aspects of good health. Yes, rely on. You need those healthy little “freeloaders.”

The research is ongoing, but it appears that our beneficial bacteria (collectively known as your microbiome) perform an untold number of functions for us. They affect our metabolism (i.e., how we turn the food we eat into energy) and can make certain nutrients in our food available to our bodies. When they ferment the fiber we feed them, they produce, certain substances that contribute to our health.

With any hot area of research, there tends to be a desire by both scientists and your average Joe and Jane (once news of research findings trickle down to the general public) to find and grab onto a “magic bullet” that holds the secret to improved health. With the Mediterranean diet it was olive oil. With research into antioxidants or other vitamins and minerals it’s supplements. Downing a gallon of olive oil a day is not a good idea, nor is taking mega doses of vitamin and minerals in pill form. Similarly, the hope and the promise of research on the gut microbiome does not mean we should all run out and buy probiotic supplements!

As with many supplements, probiotic supplements tend to carry health claims that aren’t exactly supported by the current evidence. And I don’t have a crystal ball, do you? Plus, not all probiotic supplements contain the same bacterial species. You could end up dosing yourself with species that you don’t need more of. If you have a health condition that affects your intestines, or if you’ve been on a course of broad-spectrum antibiotics and you’re concerned about the state of your microbiota, it’s well worth talking to your doctor or to a Registered Dietitian. If you might be a good candidate for probiotic supplements, it’s important to take one that will actually benefit you.

Tomorrow, I’ll include some links to informational resources on probiotics, prebiotics and the gut microbiota, for those of you who are itching to know more. It’s a fascinating subject!