Increase in Cruciferous Vegetable Intake in Women Previously Treated for Breast Cancer Participating in a Dietary Intervention Trial

Abstract

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.

Acknowledgments and Notes

This work was supported by National Cancer Institute Grants CA69375 and K07-CA093658-05; University of California, San Diego, General Clinical Research Center National Institutes of Health Grant M01-RR00827; University of California, San Francisco, General Clinical Research Center National Institutes of Health Grant M01-RR00079; Stanford University General Clinical Research Center National Institutes of Health Grant M01-RR00070; and the Walton Family Foundation.

The authors acknowledge The Women's Healthy Eating and Living Study Group, who was involved in recruitment, intervention, and data collection for this publication: University of California, San Diego, Cancer Prevention and Control Program, LaJolla, CA: John P. Pierce, PhD (Principal Investigator); Cheryl L. Rock, PhD, RD; Susan Faerber, BA; Vicky A. Newman, MS, RD; Shirley W. Flatt, MS; Sheila Kealey, MPH; Loki Natarajan, PhD; Barbara Parker, MD; Center for Health Research, Portland, OR: Njeri Karanja, PhD; Mark Rarick, MD; Kaiser Permanente Northern California, Oakland, CA: Bette J. Caan, DrPH; Lou Fehrenbacher, MD; Stanford University/University of California, San Francisco, Palo Alto, CA: Marcia L. Stefanick, PhD; Robert Carlson, MD; The University of Arizona, Tucson and Phoenix, AZ: Cynthia Thomson, PhD, RD; James Warnecke, MD; University of California, Davis, Davis, CA: Ellen B. Gold, PhD; Sidney Scudder, MD; University of California, San Diego Cancer Center, San Diego, CA: Linda Wasserman, MD, PhD; Kathryn A. Hollenbach, PhD; The University of Texas M.D. Anderson Cancer Center, Houston, TX: Lovell A. Jones, PhD; and Richard Theriault, DO. The authors acknowledge Shirley Flatt, Phyllis Reid, Vernon Hartz, and Ellen Cussler, who assisted in data analyses for this publication. Address correspondence to Cynthia A. Thomson, PhD, RD, The University of Arizona, Department of Nutritional Sciences, 1177 E. 4th Street, Tucson, AZ 85721. Phone: [phone]. FAX: [phone]. E-mail: [email protected].