Prebiotic Side Effects

Prebiotics are indigestible substances in foods that promote the beneficial growth and activity of certain microorganisms in the large intestine. The term "prebiotics" was introduced, along with "probiotics," in the mid-1990s to describe the effects of certain food ingredients in the promotion of healthy bacterial growth in the intestinal tract. Prebiotics also have a few side effects that may discourage some people from using them.

History

• Nutritionists G.R. Gibson and M.B. Roberfroid introduced the concept of prebiotics and probiotics in a paper they published in the June 1995 issue of the Journal of Nutrition. They observed that the level of beneficial bacterial flora in the human intestinal tract plays a critical role in overall health. Gibson and Roberfroid suggested that the selective use of probiotics and prebiotics could help to promote an optimal level of good bacterial flora. They defined probiotics as "microbial food supplements that beneficially affect the host by improving its intestinal microbial balance" but noted that the effects of probiotics alone may be transient. They theorized that the use of "synbiotics"---mixtures of probiotics and prebiotics---might have the greatest benefit for overall health.

Examples of Prebiotics

• Prebiotics consist mostly---but not exclusively---of indigestible carbohydrates. General classifications of prebiotics include inulin, fructo-oligosaccharides, polydextrose, arabinogalactan, and the polyols lactulose and lactitol. These can be found in dietary supplements and in such natural foods as artichokes, bananas, garlic, honey, leeks, onions and whole grains, as well as foods that have been fortified with these substances.

Benefits

• The benefits of prebiotics are many, according to the website of Food-Info.net. These include restoration of a healthy bacterial balance in the intestines, lowering of blood cholesterol levels, boosting of the body's immune function, reduction of intestinal pH, relief of constipation and a reduction in the risk of colorectal cancer. Because high levels of intestinal pH are linked to such disorders as Crohn's disease and irritable bowel syndrome, the reduction of pH levels through prebiotics can ease the symptoms of those conditions.

Side Effects

• Excessive consumption of prebiotics---particularly those in the oligosaccharides category---may cause abdominal discomfort and distension, as well as significant levels of flatulence. The Nutrition Information Centre of South Africa's University of Stellenbosch recommends that daily consumption of prebiotics be held below 20 grams, a level that seems to minimize the side effects described here.

Bottom Line

• Food-Info.net reports that the level of tolerance for prebiotics varies considerably from person to person with some reporting significant bloating and flatulence after consuming 5 grams of prebiotics, while others reported no ill effects after consuming as much as 40 grams. You will have to see what side effects, if any, that they have on you and then weigh those side effects against the potential benefits of prebiotics to decide whether to add them to your diet.