Brown Seaweed as a Breast Cancer Preventive

Phase 1

Completed

• Conditions: Breast Cancer
• Interventions: Dietary Supplement: Placebo and Soy Protein; Dietary Supplement: Seaweed and Soy Protein

• Registration Number: NCT01204957
• Lead Sponsor: University of South Carolina

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.

Study Timeline

• Study Start: 1998-10
• Primary Completion: 1999-03
• Study Completion: 1999-03
• Study First Submitted: 2010-09-16
• Study First Submitted QC: 2010-09-16
• Study First Posted: 2010-09-17
• Status Verified: 2015-04
• Last Update Submitted: 2015-04-02
• Last Update Posted: 2015-04-06

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Female
• Target Recruitment: 33

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Arm 2 Placebo and soy protein	Placebo and Soy Protein	Arm 2 5 g/d Placebo for 6 wk, then 5 g/d Placebo and Soy Protein for 1 wk
Arm 1 Seaweed and Soy Protein	Seaweed and Soy Protein	Arm 1 5 g/d Seaweed for 6 wk, then 5 g/d Seaweed and Soy Protein for 1 wk

Primary Outcome Measures

Name	Time	Method
Thyroid hormones affected by dietary seaweed and soy supplements	14 weeks	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

Secondary Outcome Measures

Name	Time	Method
Serum IGF-1 and IGFBP3 changes associated with seaweed and soy supplementation	14 wk	6 wk seaweed then 1 wk seaweed plus soy OR 6 wk placebo then 1 wk soy plus placebo 3 wk washout then crossover to alternate arm
Serum antioxidant and homocysteine concentrations associated with seaweed and soy	14 wks	6 wks 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
Serum estrogen and urinary phytoestrogen concentrations affected by seaweed and soy	14 wks	6 wk seaweed then 1 wk seaweed plus soy; OR 6 wk placebo then 1 wk soy 3 wk washout period, then crossover to alternate arm

Trial Locations

Locations (1)

University of Massachusetts; 🇺🇸 Worcester, Massachusetts, United States