Prebiotic is defined as a nondigestible food ingredient that benefits the host by selectively stimulating the favorable growth and/or activity of 1 or more indigenous probiotic bacteria. (1). Prebiotics are usually in the form of oligosaccharides, which may occur naturally but can also be added as dietary supplements to foods. (2)
Actions of prebiotics
Prebiotics cannot be digested. Prebiotics selectively enhances proliferation of certain probiotic bacteria in the colon, especially Bifidobacteria species. (3) Human milk is a natural prebiotic and the oligosaccharide content of human milk is substantial and is part of the prebiotic components of the human milk. Breastfed infants typically have a preponderance of naturally occurring probiotic bacteria in their digestive systems. Toward the end of the first month of life breastfed infants are found to have Bifidobacteria-predominant colonization. The composition of intestinal microflora does not change significantly after infancy. (3)
Uses of prebiotics
There has been evidence in the last decade for efficacy of prebiotic agents to reduce allergy in atopic children (4). However more randomized controlled trials are needed to confirm the same. It has been shown that the addition of dietary fiber has ameliorated diarrheal stools when added to infant food. (5)
Common prebiotics used
Prebiotic oligosaccharides often contain fructose chains with a terminal glucose and typically consist of 10 or fewer sugar molecules. Examples of prebiotic oligosaccharides include fructo-oligosaccharides (FOSs), inulin, galacto-oligosaccharides (GOSs), and soybean oligosaccharides. Inulin is a composite oligosaccharide that contains several FOS molecules. The complex polysaccharides that constitute dietary fiber can also be considered to be prebiotic agents. (3)
FOS appears to be generally safe. However, they can cause bloating, flatulence, and intestinal discomfort, especially when taken at doses of 15 g or higher daily. (6) People with lactose intolerance may particularly suffer from these side effects. (7)
1. Food and Agriculture Organization of the United Nations; World Health Organization. Guidelines for the evaluation of probiotics in food: joint FAO/WHO Working Group report on drafting guidelines for the evaluation of probiotics in food. Available at: ftp://ftp.fao.org/es/esn/food/wgreport2.pdf. Accessed October 1, 2010.
2. Roberfroid M. Prebiotics: the concept revisited. J Nutr. 2007;137(3 suppl 2):830S?837S
3. Thomas DW, Greer FR; American Academy of Pediatrics Committee on Nutrition; American Academy of Pediatrics Section on Gastroenterology, Hepatology, and Nutrition. Probiotics and prebiotics in pediatrics. Pediatrics. 2010 Dec;126(6):1217-31
4. Arslanoglu S, Moro GE, Schmitt J, Tandoi L, Rizzardi S, Boehm G. Early dietary intervention with a mixture of prebiotic oligosaccharides reduces the incidence of allergic manifestations and infections during the first two years of life. J Nutr. 2008;138(6):1091?1095
5. Brown KH, Perez F, Peerson JM, et al. Effect of dietary fiber (soy polysaccharide) on the severity, duration, and nutritional outcome of acute, watery diarrhea in children. Pediatrics. 1993;92(2):241?247
6. Van Dokkum W, Wezendonk B, Srikumar TS, van den Heuvel EG. Effect of nondigestible oligosaccharides on large-bowel functions, blood lipid concentrations and glucose absorption in young healthy male subjects. Eur J Clin Nutr. 1999;53:1
7. Teuri U, Vapaatalo H, Korpela R. Fructooligosaccharides and lactulose cause more symptoms in lactose maldigesters and subjects with pseudohypolactasia than in control lactose digesters. Am J Clin Nutr. 1999;69:973-979.