Red Clover Clinical Evidence

Cancer Epidemiology, Biomarkers & Prevention. 
Jarred RA, et al. Induction of apoptosis in low to moderate-grade human prostate carcinoma by red clover-derived dietary isoflavones. 2002 Dec;11(12):1689-96. 

Topic: 
Do isoflavones have cancer-preventative properties?

Background:

Population studies indicate that isoflavone consumption may be linked to reduced incidence of prostate cancer. Will the association hold up in a clinical trial?

Study Type:
Human clinical intervention trial

Study Design:
Controlled: Prostate tumor cells from radical prostatectomy specimens were compared between 18 treated and 18 untreated control tissues.

Subjects:
36 men with prostate cancer

Dosage:
160 mg red clover-derived isoflavones per day

Results:
Apoptosis (cell death) in radical prostatectomy specimens from patients taking red clover supplements was significantly higher than in untreated men.

Conclusion:
This report suggests that dietary isoflavones may halt the progression of prostate cancer by inducing apoptosis in low to moderate-grade tumors, potentially contributing to lower incidence of clinically significant disease in Asian men.

Urology. 
Engelhardt PF, Riedl CR. Effects of one-year treatment with isoflavone extract from red clover on prostate, liver function, sexual function, and quality of life in men with elevated PSA levels and negative prostate biopsy findings. 2008 Feb;71(2):185-90. 

Topic: 
How do isoflavones affect prostate health, liver function, sexual function and quality of life in men with elevated PSA levels?

Background:
Prostate-specific androgen (PSA) is a biomarker used to detect disease; elevated levels of PSA may be indicative of prostate cancer, benign prostatic hyperplasia or prostatitis.

Study Type:
Human clinical intervention trial

Study Design:
Open label: Several indices of prostate health, liver health, erectile function and quality of life were measured at baseline and then every 3 months for 1 year.

Subjects:
20 men with elevated levels of (PSA), but a negative prostate biopsy finding

Dosage:
60 mg red clover-derived isoflavones per day for 1 year

Results:
After one year of taking red clover isoflavones, PSA levels dropped 33% and the mean prostate volume decreased slightly. Sexual function was not affected. Liver enzymes were elevated.

Conclusion:
The significant increase in liver transaminases and the significant decrease in total PSA levels by >30% indicates that patients, general practitioners, and urologists should be informed about these potential effects of red clover extracts and possibly other phytoestrogens, on liver transaminases and elevated total PSA levels.

 

 

Red Clover Mechanism of Action

Isoflavones such as Biochanin A, found in red clover, may halt the progression of prostate cancer by stopping cancer cells from proliferating and inducing cell death in low to moderate-grade tumors. Biochanin A affects many genes and pathways involved in the progression of the cancer cell cycle, specifically during stage G1 and mitosis, or cell division. DNA analysis found that Biochanin A down-regulated 29 genes related to the prostate cancer, with 6 below detection limits of the test. Biochanin A also significantly reduced tumor incidence and size.