Clinical trial NCT01204957: Brown Seaweed as a Breast Cancer Preventive
Official title: Brown Seaweed as a Breast Cancer Preventive
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE1
PHASE2
Conditions: Breast Cancer
Keywords: Homocysteine
Insulin-like growth factor
Insulin-like growth factor binding protein
Serum estrogen
Urinary phytoestrogens
Thyroid hormones
Lead sponsor: University of South Carolina
Sponsor class: OTHER
Collaborators: name: Susan G. Komen Breast Cancer Foundation
First posted: 2010-09-17
Enrollment: 33
Sex: FEMALE
Minimum age (years): 18
Maximum age (years): 80
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: PREVENTION

Brief summary: Japanese postmenopausal women in Japan have about one ninth the rate of American postmenopausal women. Rates of breast cancer double even after just ten years among Japanese women who migrate to the US. Diet is thought to be an important factor, and the investigators were interested in whether dietary seaweed, with and without soy supplements, could influence known biomarkers of breast cancer risk in American women.

Detailed description: 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.

Eligibility criteria: 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.

Primary outcomes:
measure: Thyroid hormones affected by dietary seaweed and soy supplements
timeFrame: 14 weeks
Secondary outcomes:
measure: Serum estrogen and urinary phytoestrogen concentrations affected by seaweed and soy
timeFrame: 14 wks
measure: Serum antioxidant and homocysteine concentrations associated with seaweed and soy
timeFrame: 14 wks
measure: Serum IGF-1 and IGFBP3 changes associated with seaweed and soy supplementation
timeFrame: 14 wk
Other outcomes:
Locations:
city: Worcester
country: United States
facility: University of Massachusetts
state: Massachusetts
Study officials:
affiliation: University of South Carolina
name: Jane Teas, Ph.D.
role: STUDY_DIRECTOR
References:
citation: Teas J, Hurley TG, Hebert JR, Franke AA, Sepkovic DW, Kurzer MS. Dietary seaweed modifies estrogen and phytoestrogen metabolism in healthy postmenopausal women. J Nutr. 2009 May;139(5):939-44. doi: 10.3945/jn.108.100834. Epub 2009 Mar 25.
citation: Teas J, Braverman LE, Kurzer MS, Pino S, Hurley TG, Hebert JR. Seaweed and soy: companion foods in Asian cuisine and their effects on thyroid function in American women. J Med Food. 2007 Mar;10(1):90-100. doi: 10.1089/jmf.2005.056.
citation: Teas J, Pino S, Critchley A, Braverman LE. Variability of iodine content in common commercially available edible seaweeds. Thyroid. 2004 Oct;14(10):836-41. doi: 10.1089/thy.2004.14.836.