Increase in cruciferous vegetable intake in women previously treated for breast cancer participating in a dietary intervention trial.

Consumption of cruciferous vegetables has been associated with reduced breast cancer risk mechanistically and in population-based studies, although evidence has been inconsistent. This inconsistency may be related to limitations in quantifying and qualifying cruciferous vegetable exposure using standard instruments for dietary assessment (for example, food-frequency questionnaires, FFQs) or due to low levels of intake demonstrated among U.S. population samples. Cruciferous vegetable intake data are presented from a longitudinal study of a high-vegetable dietary intervention to reduce breast cancer recurrence among breast cancer survivors (n=1,156; 536 intervention and 620 comparison group subjects). Intake was assessed using repeat administration of an FFQ and cross-sectional administration of a cruciferous vegetable-specific FFQ (CVFFQ). Mean intake in the intervention group assessed using the standard FFQ was 37.7 g/day at baseline and increased to 57.1 g/day at 12 mo (P=0.0001) and was sustained through 48 mo. Broccoli and cabbage were the most commonly consumed cruciferous vegetables, regardless of the instrument used to assess intake. Differences in intake by group assignment were shown for raw cruciferous vegetables (30.2 g/day vs. 24.6 g/day, assessed using the CVFFQ), suggesting increased exposure to biologically active, cancer-preventive food constituents. These data suggest that this study population will be the first U.S. population sample to provide ample quantity and variety in cruciferous intake to examine whether these vegetables are protective against breast cancer recurrence.