PRIMARY OBJECTIVES:
I. Evaluate whether a dietary flaxseed intervention among post-menopausal women influences circulating levels of sex steroid hormones and estrogen metabolites (including estradiol, estrone, 2-hydroxy(OH)-/16-OH-estrone ratio, SHBG, testosterone, 2-MeOH-E1\&-E2, 4-MeOH-E1\&-E2) thought to be involved in the development of breast cancer.
SECONDARY OBJECTIVES:
II. Assess a) the effect of flaxseed intake on serum enterolignan levels (lignan biomarker), b) the relationship between serum enterolignan and sex hormone levels.
III. Describe adherence to the flaxseed intervention.
OUTLINE: Participants are randomized to 1 of 2 arms.
ARM 1: Participants take 2 tablespoons of ground flaxseed daily for approximately 50 days.
ARM 2: Participants maintain their usual diet for approximately 50 days.
All participants will complete a questionnaire and have their blood drawn at the beginning of the study (Day 0) and at the end of the study period (approximately Day 50).
