Review of the Evidence for the Use of Probiotics in Gastrointestinal Disorders

One way of boosting the natural beneficial bacteria in the gastrointestinal tract is by increasing the level of prebiotics in the diet. Prebiotics are forms of carbohydrate that only the gut bacteria can feed upon. Good sources of prebiotics in the diet include bananas, onions, garlic, asparagus, artichoke and chicory. These foods can cause unwanted side effects however e.g. bloating and increased bowel frequency, so some prefer to consume bacteria instead and thus take a probiotic product. Probiotic bacteria are live microorganisms that, when administered in adequate amounts, confer a health benefit to the host [4]. Probiotics may elicit immunomodulatory effects through direct interactions with the intestinal epithelium, especially in the small intestine, which is less densely populated by the commensal microbiota [5]. By contrast, probiotic immunomodulatory effects in the colon, where microbiota are densely populated, are more likely to occur via modulation of the endogenous microbiota [6].