Dietary Intake, Supplement Use, and Survival Among Women Diagnosed With Early-Stage Breast Cancer

Abstract

Previous studies examining the relationship between micronutrient intakes and survival following diagnosis of breast cancer have reported mixed results. This may be partly due to considerable variance in amounts of micronutrients consumed from diet and supplements across studies. Early-stage breast cancer survivors (N = 3081) completed four 24-h dietary and supplement recalls at the baseline assessment (1995 to 2000) and were followed for a median of 9.0 yr. Mean micronutrient intakes were compared to dietary reference intakes (DRI) to assess micronutrient adequacy for both users and nonusers of supplements. Cox regressions were performed to assess whether intakes of selected micronutrients were associated with all-cause mortality. Four hundred and twelve deaths occurred between baseline and August 2009. Among these women, more supplement users had adequate micronutrient intakes than nonusers for 15 out of 17 micronutrients. Less than 10% of supplement users (<2% of nonsupplement users) reported levels that exceeded the tolerable upper limit for each micronutrient except magnesium. After adjusting for age, tumor characteristics, and health status variables, micronutrient intakes were not significantly associated with all-cause mortality. Dietary supplements may improve overall micronutrient intakes of breast cancer survivors. However, vitamin and mineral intakes were not associated with all-cause mortality.

ACKNOWLEDGMENTS

The Women's Healthy Eating and Living (WHEL) Study was initiated with the support of the Walton Family Foundation and continued with funding from NCI grant CA 69375. Some of the data were collected from General Clinical Research Centers, NIH grants M01-RR00070, M01-RR00079, and M01-RR00827. Research related to the development of this article was funded with support from NRSA National Center for Complementary and Alternative Medicine Fellowship Award 5F31AT004652-02.

Notes

^a Adequate intake levels were substituted for RDA for vitamin D, vitamin K, and calcium.

^a Cox regression models were adjusted for age at randomization, tumor stage, tumor grade, time since diagnosis, body mass index, smoking, randomization group, hot flashes, group by hot flash interaction, and physical health.

^b Reference group for each survival analysis includes those with adequate micronutrient intake, which is set between the recommended dietary intake and the upper limit for each micronutrient.