Brown Seaweed as a Breast Cancer Preventive

33 healthy postmenopausal women were randomized to 6 wk seaweed then 1 wk seaweed plus soy or 6 wk placebo then 1 wk placebo plus soy. Blood and urine samples were collected at the end of each treatment period and analyzed for estrogen, homocysteine, antioxidants, insulin-like growth factors and thyroid hormones. Urine was analyzed for phytoestrogens and iodine.

Inclusion criteria

• Postmenopausal (self-reported cessation of menstruation 1 y prior to enrollment)
• If breast cancer survivor, all therapy completed at least 6 months prior to enrollment
• Agreed to eat their normal diet, avoiding seaweeds and phytoestrogen-rich foods,
• Restricting alcoholic intake to #2 drinks (24 g alcohol)/wk -Continuing habitual intake of vitamins, supplements, and medications during the study. -

Exclusion criteria

• No allergies to seaweed, soy, shellfish, or iodine
• No current use of tobacco;
• No thyroid dysfunction or treatment within the previous 5 y;
• Negative thyroid peroxidase antibodies as determined by screening;
• No hormone replacement therapy or for breast cancer survivors, no chemotherapy or radiation treatments within the preceding 6 mo
• No history of cancer (other than breast cancer)
• No current gastrointestinal disorders or diabetes; omnivorous eating habits, including meat and dairy products at least twice/wk
• No oral antibiotics, iodine containing medications, or corticosteroids treatment within the previous 3 mo.