Flaxseed Intervention Study to Assess Sex Hormone Levels Among Post-Menopausal Women

Effect of Dietary Flaxseed on Circulating Sex Hormone Levels Among Post-menopausal Women - an Intervention Trial to Explore Flaxseed Intake as a Possible Breast Cancer Prevention Strategy

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT02501031

Enrollment

Registered

2015-07-17

Start date

2015-09-30

Completion date

2018-01-31

Last updated

2018-01-12

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Healthy

Keywords

Flaxseed, Postmenopause, Hormones, Lignans, No Evidence of Disease

Brief summary

The purpose of this study is to understand whether consuming flaxseed for approximately 50 days may beneficially affect the level of certain hormones in the blood thought to be involved in the development of breast cancer. This study will address the first steps toward the development of possible breast cancer prevention strategies. Differences in hormone levels (from blood samples) will be compared between two groups of women - those in the group assigned to eating ground flaxseed daily and those in the control group (with no change in diet).

Detailed description

PRIMARY OBJECTIVES: I. Evaluate whether a dietary flaxseed intervention among post-menopausal women influences circulating levels of sex steroid hormones and estrogen metabolites (including estradiol, estrone, 2-hydroxy(OH)-/16-OH-estrone ratio, SHBG, testosterone, 2-MeOH-E1&-E2, 4-MeOH-E1&-E2) thought to be involved in the development of breast cancer. SECONDARY OBJECTIVES: II. Assess a) the effect of flaxseed intake on serum enterolignan levels (lignan biomarker), b) the relationship between serum enterolignan and sex hormone levels. III. Describe adherence to the flaxseed intervention. OUTLINE: Participants are randomized to 1 of 2 arms. ARM 1: Participants take 2 tablespoons of ground flaxseed daily for approximately 50 days. ARM 2: Participants maintain their usual diet for approximately 50 days. All participants will complete a questionnaire and have their blood drawn at the beginning of the study (Day 0) and at the end of the study period (approximately Day 50).

Interventions

DIETARY_SUPPLEMENTGround flaxseed

2 tablespoons of ground flaxseed taken daily for approximately 50 days.

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

PREVENTION

Masking

SINGLE (Outcomes Assessor)

Eligibility

Sex/Gender

FEMALE

Age

57 Years to 64 Years

Healthy volunteers

Yes

Inclusion criteria

1\. Women residing in Toronto aged 57-64 years old, and post-menopausal.

Exclusion criteria

1. Consumers of flaxseed and soy (including supplements) in the past 6 months. 2. Consumers of sesame oil and sesame seeds in the past 6 months. 3. Women who took antibiotics orally in the past 6 months. 4. Women who took hormone replacement therapy or corticosteroids in the past month. 5. Non-English speaking. 6. Current chronic illnesses such as bowel disease (e.g. IBS - irritable bowel syndrome, or IBD - inflammatory bowel disease, such as Crohn's or ulcerative colitis), diabetes, heart disease (e.g. high cholesterol or high blood pressure and on medication for it), cancer, or another chronic illness. 7. Women who are currently taking blood thinners, such as Warfarin.

Design outcomes

Primary

Measure	Time frame
Change in circulating levels of sex steroid hormones at Day 0 (baseline) compared with ~Day 50 (end of study period)	Day 0 and ~Day 50

Secondary

Measure	Time frame
Change in serum enterolignan levels at Day 0 (baseline) compared with ~Day 50 (end of study period)	Day 0 and ~Day 50

Countries

Canada

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026