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Brown Seaweed as a Breast Cancer Preventive

Phase 1/Phase 2
18 Years
80 Years
Not Enrolling
Breast Cancer, Thyroid Hormones

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Trial Information

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

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

- 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.

Type of Study:


Study Design:

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Prevention

Outcome Measure:

Thyroid hormones affected by dietary seaweed and soy supplements

Outcome Description:

6 wk seaweed followed by 1 wk seaweed plus soy; Or 6 wk placebo followed by 1 wk soy 3 wk washout period then crossover to alternate arm

Outcome Time Frame:

14 weeks

Safety Issue:


Principal Investigator

Jane Teas, Ph.D.

Investigator Role:

Study Director

Investigator Affiliation:

University of South Carolina


United States: Institutional Review Board

Study ID:




Start Date:

October 1998

Completion Date:

March 1999

Related Keywords:

  • Breast Cancer
  • Thyroid Hormones
  • Homocysteine
  • Insulin-like growth factor
  • Insulin-like growth factor binding protein
  • Serum estrogen
  • Urinary phytoestrogens
  • Thyroid hormones
  • Breast Neoplasms
  • Thyroid Diseases



University of Massachusetts Worcester, Massachusetts  01655