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D. T. GORDON, Department of Cereal Science, North Dakota State University, Harris Hall 10, Fargo, ND 58105

There is no official definition of dietary fiber (DF), but there is a working description. This description has been discussed through an American Association of Cereal Chemist initiative in 1999 with the idea of finding a modern and near consensus description/definition (D/D). A proposed D/D for DF, which includes physiological effects, is "Dietary fiber is the edible part of plants and analogous carbohydrates that are resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the large intestine. Dietary fiber includes polysaccharides, oligosaccharides, lignin and associated plant substances. Dietary fiber promotes beneficial physiological effects, such as laxation, blood cholesterol attenuation, and/or blood glucose attenuation." There are 13 authorized health claims and five are associated with DF. Two DF health claims are associated with cancer and three are associated with cardiovascular disease. Two soluble DF, b-glucan and psyllium, are believed to lower blood cholesterol levels through their viscous effects in the intestine. The ability of any DF to attenuate blood glucose levels is highly controversial and any health claims associating DF with diabetes and/or blood glucose regulation may be difficult to achieve. Demonstrating this physiological response is further complicated by the variability of the "glycemic index" method to measure the effects of any DF on blood glucose levels. Possibly the most significant physiological aspect of DF is its ability to maintain normal bowel function. However, the idea of having a health claim associating DF with "fecal bulking and softening; increased frequency; and/or regularity" in preventing and/or treating diverticulosis and hemorrhoids could be considered. There is strong scientific evidence that DF is effective in preventing these two disorders. The available data showing a correlation between DF, bowel function, and colon-rectal cancer are tenuous.