By Laura Kruskall, PhD, RD, CSSD, FACSM

What’s all this I hear about my digestive tract?

If you are a casual reader of popular magazines or watch television commercials then you are well aware of the growing popularity of products that promise to improve the health of your digestive system.  Several recent studies suggest that a healthy gut (intestines) contributes to improved health and well-being and reduces the severity and incidence of many conditions, including irritable bowel syndrome (IBS), diarrhea, high cholesterol, colon cancer, lactose intolerance, and hypertension.

So, the big question is how do I make my digestive tract healthier?  You do this by consuming foods and supplements that stimulate the growth and activity of healthy bacteria that normally reside in your intestines.  Healthy gut bacteria are beneficial because they repress the growth of harmful bacteria and train the immune system to defend against diseases, even those diseases not affiliated directly with the digestive tract.

Benefits of probiotics and prebiotics

Taken collectively prebiotics and probiotics are substances that you consume that result in more plentiful and active healthy gut bacteria.  Whereas probiotics are actual live microorganisms, prebiotics are essentially the food that gut bacteria eats to help it flourish.  Whether you choose prebiotics or probiotics is up to you as both sources have similar benefits despite their different mechanisms of action.  Probiotics are readily found in fortified foods and supplements and can be purchased in large concentrations to enhance their effectiveness.  Prebiotics are naturally occurring in many foods and help existing gut bacteria to flourish, so they may be safer and more effective than probiotics, which introduce live bacteria into your system.

Major sources of prebiotics and probiotics

Probiotics are most commonly found in fermented foods with additional active live cultures; such as in enhanced yoghurt, cheese, and smoothies.  The most common strains of bacteria in probiotics are Bifidobacterium and Lactobacillus, so if you see these names or the words “active live cultures” on the label then you can assume that the product is designed to be a probiotic.

Prebiotics are mostly comprised of soluble fiber and are found in many fortified foods, beverages, and supplements.  In addition, the following foods contain naturally occurring prebiotics in relatively high quantities, so if you like these foods then feel free to include them in your diet: chicory, onions, whole grains, bananas, garlic, leeks, and artichokes.

Words of caution

If you are unhealthy or have significantly weakened immunity then you should consult with your physician before taking probiotics because the living microorganisms can potentially cause infection.  If you are healthy enough to consume probiotics and have decided to take them in the form of a supplement rather than in fortified foods then you should be aware that dietary supplements are not regulated by the Food and Drug Administration, so you can never be sure that you are getting what is written on the package.  To increase the likelihood that you are getting a high-quality probiotic supplement, you should choose a manufacturer whose reputation is trustworthy.