Flaxseed in Treating Postmenopausal Women With Hot Flashes Who Have a History of Breast Cancer or Other Cancer or Who Do Not Wish to Take Estrogen Therapy

* Bothersome hot flashes, defined by their occurrence ≥ 28 times per week and of sufficient severity to make the patient desire therapeutic intervention * Presence of hot flashes for ≥ 1 month * Meets 1 of the following criteria: * History of breast cancer or other cancer (currently without malignant disease) * No history of breast cancer and wishes to avoid estrogen due to a perceived increased risk of breast cancer * Hormone receptor status not specified * Postmenopausal as defined by 1 of the following*: NOTE: *Women with ≥ 1 ovary but without a uterus should be deemed postmenopausal by either age > 55 OR a combination of estrogen within a postmenopausal range (per local lab) and follicle-stimulating hormone > 40 mIU/mL * Absence of a period in the past 12 months * Bilateral oophorectomy * ECOG performance status 0-1 * Life expectancy ≥ 6 months * Able to complete questionnaire(s) alone or with assistance * No diabetes requiring oral or injectable antihyperglycemics * No hypotension * No history of allergic or other adverse reaction to flaxseed * No irritable bowel syndrome, colitis, Crohn disease, or any gastrointestinal condition where the patient should not consume and/or has an intolerance/allergies to seeds or nuts * At least 4 weeks since prior and no concurrent or planned androgens, estrogens, or progestational agents * Tamoxifen, raloxifene, or aromatase inhibitors are allowed provided the patient has been on a constant dose for ≥ 4 weeks and is not expected to stop the medication during study treatment • At least 4 weeks since prior and no concurrent anti-cancer therapies of any kind * Trastuzumab allowed * No concurrent treatment with other anti-cancer therapies of any kind except for trastuzumab or endocrine therapies * No concurrent (≤ 7 days prior to registration) or planned use of other agents for treating hot flashes (i.e., gabapentin, clonidine, antidepressants, estrogen treatment, megestrol acetate, or Bellergal) * Stable dose of vitamin E (as a general vitamin supplement) allowed provided it is ≤ 800 IU/day, it was started > 30 days before study initiation, and is to be continued through study period * Patients who have been using antidepressants for mood and have been on a stable dose for over a month and meet the eligibility criteria for hot flash frequency and duration are eligible • No concurrent anticoagulants or anti-platelets (1 mg of Coumadin for central line patency allowed) * Aspirin allowed (≤ 81 mg) * No concurrent anti-hypertensives * No other concurrent herbal supplements for any reason, including soy and soy supplements (i.e., powders, pills, or milk)