Prebiotics vs. Probiotics

by Elizabeth Roberts Patient Expert

Just about the time we've all begun to understand the importance of Probiotics in our diet, a new term has hit the health world - Prebiotics. Today, I'll try my best to answer the question, "Just what are Prebiotics and how are they different from Probiotics?"

Let's start with what we already know. Our gastrointestinal (GI) tract is home to both "good" bacteria and "bad" bacteria and a healthy gut has about a 50/50 ratio of each. This microflora of the gut is what helps our body absorb nutrients while also keeping toxins and foreign bacteria and viruses at bay. It is also this microflora that breaks down vitamins as well as ferments undigested foods and carbohydrates from the upper gastrointestinal tract.

So, in the most simple of terms, Probiotics are what help the "good" bacteria in our gut flourish, which keeps the "bad" bacteria from taking over and becoming harmful to the gut. Probiotics are substances like Bifidobacteria and Lactobacilli and can be found in fermented foods like yogurt and sauerkraut, or in pill form in the refrigerated section of health food stores (look for capsules with at least 10 million live, active cultures). Probiotics are live and active cultures that we absorb in our large intestine.

Prebiotics, then, are a non-digestible food ingredient that promotes the growth and proliferation of "good" gut bacteria, which in turn enhances the effects of Probiotic bacteria. Therefore, the Prebiotic/Probiotic relationship is one of symbiosis and mutual effect. These good bacteria, however, must be fed to the body via our diet because it is the Probiotic bacteria and the short-chain fatty acids that they produce which restrict the overgrowth of "bad" gut bacteria. It is believed that a majority of the gut's energy is provided by short-chain fatty acids, and if the gut does not have enough of these to meet energy requirements a decrease in gut integrity and function will follow, causing illnesses such as IBD and IBS. (To find out the difference between IBD and IBS, please read my previous Sharepost.)

Studies also speculate that the combination of Prebiotics and Probiotics can also have an anticarcinogenic effect, an antimicrobial effect, the ability to lower triglycerides, boost the immune system, stabilize blood sugar, improve the body's ability to absorb minerals, and rid harmful organisms from the gut.

Common sources of Prebiotics include: asparagus, garlic, leeks, onions, Jerusalem artichokes, berries, bananas, tomatoes, chicory, spinach, kale, chard, mustard greens, lentils, navy beans, garbanzo beans, black beans, whole grains, oats, barley, and wheat.

Because Prebiotics are not affected by cooking or baking, many prepared foods like cereal, bread, drinks, and yogurt can also contain Prebiotics in the form of oligosaccharides. There are various forms of oligosaccharides that have been classified as Prebiotics and include: Fructo-oligosaccharides (FOS), Inulins, Isomalto-oligosaccharides, Lactilol, Lactosucrose, Lactulose, Oligofructose, and Transgalacto-oligosaccharides (TOS).

If I look at my own diet - which as you already know from my previous Shareposts I've refined by keeping a food diary and participating in an Elimination diet - I already eat many of the foods listed above under Prebiotic sources. I also eat natural, organic yogurt with live and active Probiotic cultures, and take a Probiotic supplement that includes at least 10 million active cultures. So, I'd have to say it seems I am pretty well set in keep my "good" and "bad" gut bacteria in a symbiotic relationship. However, don't forget that if you must take an antibiotic to fight a bacterial infection you will need to be even more vigilant about keeping up your Prebiotic and Probiotic levels as antibiotics are notorious for killing off "good" bacteria and allowing the "bad" bacteria to take over gut flora, which could lead many IBDers to have more gut problems.

Elizabeth is the author of, Living with IBD & IBS: A Personal Journey of Success -

Elizabeth Roberts
Meet Our Writer
Elizabeth Roberts

Elizabeth wrote for HealthCentral as a patient expert for Digestive Health.