Red clover isoflavones are safe and well tolerated in women with a family history of breast cancer.
OBJECTIVE
To assess the safety and tolerability of a standardized 40 mg red clover isoflavone dietary supplement (Promensil, Novogen) in women with a family history of breast cancer to evaluate the feasibility of using the supplement for prevention of breast cancer in healthy women.


METHODS
Healthy women aged 35-70 years (n = 401) with at least one first-degree relative with breast cancer received red clover isoflavones or placebo for three years in a randomized, double-blind, placebo-controlled pilot trial. Participants were assessed clinically and blood samples taken for biochemical analysis every six months. In addition, study participants underwent mammography, bone density and transvaginal ultrasound (postmenopausal women only) once per year.


RESULTS
No significant differences in breast density, endometrial thickness, serum cholesterol, follicle stimulating hormone levels and bone mineral density were detected between those taking red clover isoflavones and placebo. In postmenopausal women, some significant differences in bone marker levels were seen between active and placebo groups, at six months and at 12 months. The adverse event profile was similar across all red clover isoflavone and placebo groups.


CONCLUSIONS
This three-year study supports the growing body of evidence that treatment with red clover isoflavones is safe and well tolerated in healthy women. Supplements containing red clover isoflavones did not adversely affect breast density, skeletal strength or cardiovascular status. In postmenopausal women, endometrial status was not adversely affected. The adverse event profile was similar between red clover isoflavones, and placebo and endocrine status did not differ.
Powles
Trevor J
TJ
Breast Unit, Parkside Oncology Clinic, Wimbledon, London, UK. trevorpowles@aol.com
Howell
Anthony
A
Evans
D Gareth
DG
McCloskey
Eugene V
EV
Ashley
Sue
S
Greenhalgh
Rosemary
R
Affen
Jenny
J
Flook
Lesley Ann
LA
Tidy
Alwynne
A
D000368:Aged; D001943:Breast Neoplasms / Q000235:genetics / Q000517:prevention & control*; D019587:Dietary Supplements / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D048789:Phytoestrogens / Q000009:adverse effects / Q000627:therapeutic use*; D008517:Phytotherapy; D017698:Postmenopause / Q000187:drug effects; D017697:Premenopause / Q000187:drug effects; D029921:Trifolium
D007529:Isoflavones; D048789:Phytoestrogens; C487928:Promensil