Prebiotics are complex carbohydrates such as inulin and short-chain sugars, called oligosaccharides, that pass undigested from the lower intestine to the colon. There, the carbohydrates are consumed by Bifidobacterium and other beneficial bacteria that release vitamins, minerals and nutrients that might not otherwise be available to their hosts--human and animal. The bacteria may also change the colon environment such that pathogens like Salmonella are curtailed.

In this case, ARS chemist Greg Côté and cooperators found that an enzyme-based process for making alternan--a promising bulking agent--also yielded oligosaccharides that stimulate the growth of Bifidobacterium bacteria.

In Europe and Asia, consumers seeking to improve their gastrointestinal health can now buy prebiotic products specifically formulated to bolster populations of these and other bacterial gut colonists. The U.S. market for prebiotics is comparatively young, but growing. Côté's fermentation studies at ARS' National Center for Agricultural Utilization Research in Peoria, Ill., eventually could offer U.S. makers a way to mass-produce the oligosaccharides from a domestic commodity: carbohydrate-rich corn, soybean, beet and cane crops. Arland Hotchkiss, at ARS' Eastern Regional Research Center in Wyndmoor, Penn., has similar aspirations--but for pectin from citrus peels and other crop byproducts.

Early lab results from Côté 's collaborators, Scott Holt and Candace Miller-Fosmore of Western Illinois University in Macomb, indicate the oligosaccharides nourish several beneficial strains of Bifidobacterium, but not pathogens such as Salmonella, Escherichia coli and Clostridium. Côté discussed the results last spring at the American Chemical Society's national meeting.

This April, ARS applied for patent protection covering the synthesis and potential use of some of the prebiotics as food additives for both people and livestock animals.

The research comes at a time when 10 million Americans annually require hospitalized care for gastrointestinal problems ranging from constipation and diarrhea to ulcers, irritable bowel syndrome and colon cancer.

ARS is the U.S. Department of Agriculture's chief scientific research agency.