Cereal Chem. 73 (3):392-398  |  VIEW ARTICLE

Nutrition

Comparison of Large Bowel Function and Calcium Balance During Soft Wheat Bran and Oat Bran Consumption.

Kathryn B. Hosig (1,2), Fred L. Shinnick (3,4), Michelle D. Johnson (3), Jon A. Story (1), and Judith A. Marlett (3,5). (1) Department of Foods and Nutrition, Stone Hall, Purdue University, Lafayette, IN. (2) Present address: University of Arkansas for Medical Sciences, Department of Dietetics & Nutrition, Little Rock, AR. (3) Department of Nutritional Sciences, University of Wisconsin-Madison, WI 53706. (4) Present address: The Quaker Oats Company, Barrington, IL. (5) Corresponding author. E-mail: <jmarlett@nutrisci.wisc.edu> Accepted January 15, 1996. Copyright 1996 by the American Association of Cereal Chemists, Inc. 

This study evaluated the generally accepted concept that dietary fiber from oat bran would have less effect on stool weight than wheat bran fiber. Nine healthy young men participated in two studies, each consisting of 28 days of a low fiber diet and 28 days of a bran diet. Incorporation of 14-16 g of wheat bran or oat bran fiber into basal diets of 14-18 g of fiber increased wet and dry stool weights to the same extent and decreased fecal pH (P < 0.05). Neither bran changed stool moisture, gastrointestinal transit time, calcium balance, or defecation frequency. Most changes were first detected during the period from day 8 to days 12-14 of the study. Incorporation of oat bran only increased the proportion of soluble fiber in the diet from 24 to 33% of the total fiber. We conclude: 1) fiber in oat and wheat brans increases stool weight to the same extent; 2) some measures of bowel function may not change with added fiber if they are within the normal range during low fiber intakes; 3) wheat and oat brans do not adversely affect calcium balance when calcium intake is generous (>=1,200 mg/day); and 4) changes in bowel function may be detected by the second week of a dietary change if intake is rigorously controlled.