Common Gastrointestinal Conditions
Medscape: Dr. Thomas, can you summarize some of the major findings in the report in each of the therapeutic areas discussed? First, what is the role of these agents in prevention and treatment of acute gastroenteritis (AGE)?
Dr. Thomas: A number of randomized controlled trials (RCT) of probiotics in AGE have been conducted. Rotavirus was the most common cause of acute diarrhea in these studies. While the results indicate that there is modest benefit with use of probiotics to prevent AGE in infants and children, the available data do not support routine use to prevent nosocomial rotavirus diarrhea in children attending daycare. Rotavirus vaccine is likely to be a much more effective agent in preventing rotavirus infection although there may be special circumstances, such as long-term care facilities, where use of probiotics may be useful in prevention. In the treatment of AGE, however, the data are positive. There is evidence from well-conducted RCTs to support the use of probiotics, specifically LGG, in the management of acute infectious diarrhea. Probiotics have been found to shorten the duration of diarrhea by about 1 day and to decrease the number of diarrheal stools. They also shorten the time necessary for intravenous hydration when this is required. Probiotics seem to be more effective when given early in the course of diarrhea and are most effective in healthy infants and young children with watery diarrhea due to viral gastroenteritis, such as rotavirus, but not invasive bacterial infections.
Medscape: Another common cause of diarrhea in young children is the use of antibiotics. What does the report say about use of probiotics in the prevention and treatment of antibiotic-associated diarrhea?
Dr. Thomas: Prevention of diarrhea due to antibiotic use is another area where a meta-analysis of RCTs indicates a benefit from probiotics. In most of the studies, a probiotic was initiated at the same time as the antibiotic, resulting in a substantial reduction in development of diarrhea. Approximately 1 in 7 cases of antibiotic-associated diarrhea was prevented by the use of a probiotic. However, there have been no published RCTs examining probiotics for the treatment of antibiotic-associated diarrhea in children, including Clostridium difficile antibiotic-associated diarrhea, and therefore their use presently cannot be recommended for pediatric patients.
Dr. Thomas: Prebiotics are supplements or foods that contain viable microorganisms that cause alterations in the microflora of the host and stimulate favorable growth of probiotic bacteria. Human milk contains substantial quantities of prebiotics, and prebiotics and probiotics have also recently been added to infant formulas. Human milk and formula therefore are examples of functional foods -- a modified food that provides a health benefit that cannot be attributed to the nutrients in that food (see the Table for terms). The most studied probiotic bacteria to date include Lactobacillus rhamnosus GG (LGG), Bifidobacterium lactis, and Streptococcus thermophilus. Live yogurt, which contains probiotics, is the most common example of a functional food. The list of products containing probiotics is rapidly expanding and clinicians can access the most up-to-date information at www.usprobiotics.org. It should be noted that this is an industry-maintained Website.
Table. Definitions of Agents
Probiotic A supplement or food containing a sufficient number of viable microorganisms to alter microflora and has the potential for health benefit
Prebiotic A nondigestible food ingredient that selectively stimulates favorable growth and/or activity of 1 or more indigenous probiotic bacteria
Synbiotic A product containing both probiotics and prebiotics. Synergy of a specific probiotic for a probiotic in the product is not essential. May be separate supplements or added to food
Postbiotic A metabolic byproduct generated by a probiotic microorganism that influences biologic functions
Functional food Any modified food that provides a health benefit beyond that ascribed to any specific nutrients it contains