Do Flavonoid Intakes of Postmenopausal Women With Breast Cancer Vary on Very Low Fat Diets?

Abstract

In the Women's Intervention Nutrition Study (WINS), a very low-fat eating pattern decreased breast cancer recurrence. We assessed whether the women's flavonoid intakes varied on the very low fat diet. A total of 550 randomly selected WINS participants who had been treated with conventional therapy (surgery, chemotherapy, and/or radiation) for primary breast cancer were randomized to either a very low fat diet (15% of calories from fat, N = 218) or their usual diets (30% calories from fat, N = 332). We compared their intakes of total flavonoids and 6 flavonoid classes (isoflavones, flavones, flavanones, flavonols, flavan-3-ols, and anthocyanins) for these 2 groups using the U.S. Department of Agriculture food flavonoid database and a flavonoid dietary supplement database on three 24-h dietary recalls at baseline and 12 mo after randomization. At baseline, neither mean fat intakes (31.7% ± 6.8 SD of calories, n = 332 in the usual diet group and 31.6% ± 6.8 SD of calories, n = 218 in the very low fat diet group; P = NS) nor flavonoid intakes (218 ± 283 SD mg/day, n = 332 in the usual diet group and 236 ± 393 SD mg/day, n = 218 in the very low fat diet group; P = NS) differed. Over half of the women's flavonoid intakes were from the flavan-3-ols. After 12 months of intervention, with 39 participants lost to follow-up, dietary fat intakes were 30.7 ± 8.4 SD calories (n = 316) among those on their usual diets but were significantly lower among those on the very low fat diet intervention: 21.4 ± 8.3 SD calories (n = 195), P = < 0.05. However, flavonoid intakes remained similar in both groups (201 ± 252 SD mg/day, n = 316 in the usual diet group vs. 235 ± 425 SD mg/day, n = 195 in the very low fat group; P = NS). In this random sample of WINS participants, neither total flavonoid intakes nor intakes of subclasses of flavonoids differed between those who had dramatically decreased their fat intakes and those who had not. Flavonoid intakes are therefore unlikely to account for WINS results on differences between the groups in cancer recurrence.

ACKNOWLEDGMENTS

We thank the following institutions for partial support of this work: American Institute for Cancer Research to Dr. Dwyer, Massachusetts Department of Public Health's Breast Cancer Research Grants Program, and the National Research Initiative of the USDA Cooperative State Research, Education and Extension Service, Grant 2006-35200-17259 to Dr. Peterson. This project was also supported in part by the USDA, under agreement No. 58-1950-4-401 at the Jean Mayer USDA HNRC on Aging at Tufts University. The contents of this publication do not necessarily reflect the views or policies of the USDA, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. government. We also thank Dr. Ritva Butrum who first stimulated our thinking about bioactive compounds. Note that information on the supplement flavonoid dataset is available from the authors.

Notes

^a Abbreviation is as follows: WINS, Women's Intervention Nutrition Study.

^a Abbreviation is as follows: WINS, Women's Intervention Nutrition Study. Key: d, quantitative data; p, qualitative data; g, quantitative data available only on genus, or products of the genus; f, quantitative data available only on family; i, investigated not present; blank, not expected, not investigated.

^a Abbreviation is as follows: WINS, Women's Intervention Nutrition Study. Items with the same subscript are significantly different from each other at P ≤ 0.05 using Mann–Whitney test.

^b P < 0.0001 for comparison of the very low fat group from baseline to 12 mo using 2-tailed t-test of means.

^a Abbreviation is as follows: WINS, Women's Intervention Nutrition Study. Items with the same subscript are significantly different from each other. Subscripts a, c, and e, P < 0.05; subscripts b and d, P < 0.001; Wilcoxon signed ranks test.

^a Abbreviation is as follows: WINS, Women's Intervention Nutrition Study. Items with the same subscript are significantly different from each other. P < 0.01 for subscripts a and b, p ≤ 0.05 for subscripts c and d; Mann–Whitney test.