Probiotics and Prebiotics: What’s the Difference?

Probiotics and Prebiotics. They sound the same, but they’re quite different, and have different implications for the gut.

Probiotics are living micro-organisms, often bacterial, that are similar to the bacteria that naturally occur in the human body – particularly the intestine, and even more particularly the intestine of a healthy, breastfed baby. These micro-organisms have been shown to provide health benefits when ingested, and are reported to be especially helpful for those with intestinal and inflammatory disorders, specifically ulcerative colitis.

Prebiotics, on the other hand, are “food” for certain groups of bacteria. They themselves are not living bacteria, but are carbohydrates that are not normally digested (such as fibre), that are contained in many natural food items like fruits and legumes and whole grains. When you ingest prebiotics, you selectively increase certain population of bacteria that consume that prebiotic. In this way, you increase your own probiotic bacteria. 

But do probiotics help those with Crohn’s disease or ulcerative colitis? Dr. Elena Verdu of the Farncombe Family Digestive Health Research Institute at McMaster University is currently studying how a specific probiotic, Bifidobacterium breve, can prevent flares in mice that have a colitis-forming mutation. She is cautious about dramatic claims that specific products containing probiotics can reduce active intestinal inflammation, and notes that not all probiotic bacteria strains are the same, but she says results from animal models on prevention of disease are encouraging. 

“In clinical studies, prevention of IBD (reduction of flares and complications such as pouchitis) seem to be more powerful outcomes of probiotic use in mouse models than ‘curing’ a flare that’s already happening,” says Dr. Verdu. She says there is great variability in results from clinical results that use different formulations, doses and types of probiotics, but that doesn’t mean probiotics are not useful.

Dr Elena Verdu

“To get a clear picture of the benefits, we should examine specific strains of probiotic bacteria in selected populations of IBD patients, and understand their mechanisms of action. This insight should then be taken into clinical trials, and only then, probiotics with credible scientific claims should be marketed.”

Crohn’s and Colitis Canada-funded studies such as the one being undertaken by Dr. Verdu aim to get at the heart of how and why probiotics can help the inflamed gut, but in the meantime, IBD patients naturally want to know whether probiotics are safe to ingest and will help them live better with their disease.

Andrea Firmin, a Registered Dietitian at Mount Sinai Hospital in Toronto, agrees that probiotics can help prevent complications such as pouchitis, and agrees further studies are needed to determine how effective probiotics may be in bringing about remission or maintaining remission in ulcerative colitis. However, she says the safety profile of probiotics seems to be very good.

“Very few adverse effects have been reported with the use of probiotics, with increased gas being the main complaint, so the use of these products is still considered safe,” says Andrea. She does caution IBD patients to be aware of what probiotics supplements they’re taking, however.

“If you choose to use one of these products, make sure the product you choose has a drug information number (DIN), natural product number (NPN) or homeopathic number (DIN-HM) and talk to your doctor before starting the product.”

Probiotics are typically delivered through yogurt and supplements, but there are a number of other natural food sources:

  • Buttermilk is similar to yogurt and can be the basis of a great smoothie. It’s available in the dairy aisle of most grocery stores;
  • Kefir is a drink made of cow, goat or sheep milk fermented with kefir grains. Available in natural food stores, it is bitter on its own but can be mixed with fruit or other sweeteners.
  • Tempeh is a fermented soy product similar to tofu, except that it is chewier. It’s also a high-quality protein and one of the few vegetarian sources of vitamin B12.
  • Miso is a Japanese seasoning produced by fermenting various beans or grains. It is used in soups, sauces, and spreads.
  • Sauerkraut is fermented or pickled cabbage. Probiotic bacteria is formed when fresh cabbage ferments in brine.
  • Kim Chi is somewhat like sauerkraut, but much more pungent and spicy. In Korea, kim chi is served as a side dish or a relish.
  • Brewer’s yeast, a by-product of beer-making, is thought to contain probiotic bacteria.

Some sources of prebiotics are:

  • Raw chicory root
  • Raw jerusalem artichoke
  • Raw dandelion greens
  • Raw garlic
  • Raw leek
  • Raw onion
  • Cooked onion
  • Raw asparagus
  • Raw wheat bran
  • Whole wheat flour, cooked
  • Raw banana

  • Canada has among the highest incidence rates of Crohn's and colitis in the world.
  • 1 in 150 Canadians lives with Crohn’s or colitis.
  • Families new to Canada are developing these diseases for the first time.
  • Incidence of Crohn’s in Canadian kids under 10 has doubled since 1995.
  • People are most commonly diagnosed before age 30.

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