Dietary change in an intervention trial of wheat bran fiber and colorectal adenoma recurrence.
OBJECTIVE
The objectives of this study were to determine whether participants in the Wheat Bran Fiber (WBF) trial exhibited changes in diet over time, and whether these changes were differential by assigned treatment group.


METHODS
The WBF trial was a randomized trial with participants assigned to one of two groups: a low-fiber (2.0 g/d) or high-fiber (13.5 g/d) wheat bran fiber cereal supplement. A total of 685 participants from both treatment groups completed the Arizona Food Frequency Questionnaire (AFFQ) at baseline, year one, and year three of the trial. Means were calculated for nutrient intake, change in nutrient intake, number of food group servings, and change in number of food group servings.


RESULTS
For both treatment groups combined, significant increases were observed for most micronutrients and vitamins at years one and three, while fat intake significantly decreased. Participants from both groups significantly increased their consumption of cereals, breads, and crackers, but decreased the number of servings from the meat, poultry, and egg group, the fats group, and the salty snacks group. The only differential changes in intake between the treatment groups were for sugar and iron, which increased to a lesser extent among those assigned to the high-fiber treatment as compared with the low-fiber group.


CONCLUSIONS
Although differential dietary intake was not appreciable in the WBF trial, participants exhibited longitudinal changes. Future intervention studies should carefully monitor dietary changes during the trial with multiple dietary assessment tools to assess potential secular and treatment-related diet changes.
Jacobs
Elizabeth T
ET
Arizona Cancer Center, University of Arizona, Tucson, Arizona 85724-5024, USA. jacobse@u.arizona.edu
Giuliano
Anna R
AR
Roe
Denise J
DJ
Guillén-Rodríguez
José M
JM
Hartz
Vernon L
VL
Whitacre
Robin C
RC
Alberts
David S
DS
Martínez
María Elena
ME
D000236:Adenoma / Q000517:prevention & control*; D015179:Colorectal Neoplasms / Q000517:prevention & control*; D004041:Dietary Fats; D004043:Dietary Fiber / Q000008:administration & dosage* / Q000145:classification; D004311:Double-Blind Method; D002523:Edible Grain; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D015596:Nutrition Assessment; D010919:Placebos; D014815:Vitamins / Q000008:administration & dosage
D004041:Dietary Fats; D004043:Dietary Fiber; D010919:Placebos; D014815:Vitamins