The Study
Effects of a high-fiber, low-fat diet intervention on serum concentrations of reproductive steroid hormones in women with a history of breast cancer.
This study found that when women who had breast cancer ate more fiber and less fat, their body made less of a hormone called estradiol. But it doesn't prove that eating this way caused the hormone to drop—just that the two things happened together in this group.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Women who ate more fiber and less fat for a year had lower levels of a hormone linked to breast cancer, even though they didn't lose weight.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 560 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1A 13 pmol/L drop in this hormone may matter for breast cancer risk, since higher levels are linked to worse outcomes.
- 2Fiber intake went up to 29 grams per day; bioavailable estradiol dropped by 13 pmol/L in the fiber group, while it rose by 3 pmol/L in the control group.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of clinical oncology : official journal of the American Society of Clinical Oncology
Year
2004
Authors
Cheryl L. Rock, S. Flatt, Cynthia A. Thomson, Marcia L. Stefanick, V. Newman, Lovell A. Jones, L. Natarajan, C. Ritenbaugh, Kathryn A. Hollenbach, John P. Pierce, R. Jeffrey Chang
Related Content
Claims (3)
Women with a history of breast cancer who follow a high-fiber, low-fat diet for one year have a 13 pmol/L reduction in bioavailable estradiol in their blood, regardless of whether they lose weight.
Women with a history of breast cancer who consume more dietary fiber have lower levels of total estradiol and bioavailable estradiol in their blood.
In women with a history of breast cancer, a high-fiber, low-fat diet for one year does not cause significant weight loss, and any hormonal changes observed are not caused by changes in body weight.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.