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This research project aims to investigate the effect of phytoestrogens on prostate cancer, DNA damage in blood cells, cholesterol levels in the blood and sperm production.
Study Duration : January 1997 to June 2000
Contractor : Rowett Research Institute
It has been suggested that phytoestrogens possess hormonal and antioxidant properties. This project is investigating what effects consumption of phytoestrogens may have on biological markers of hormonal and antioxidant activity in cell based systems and also in a few male subjects.
The project is divided into two stages. The first stage will determine what effect exposure to phytoestrogens has on human prostate tumour cells and will measure the ability of phytoestrogens to act as antioxidants. The second stage will investigate what effect supplementation of the diet with phytoestrogens has on DNA damage in blood cells and on cholesterol levels in blood taken from 16 healthy men. The effects of supplementing the diet with phytoestrogens on sperm production will also be investigated in a group of 14 healthy men. In addition, the effects of dietary supplementation with phytoestrogens on the progression of prostate cancer in 3 men will be studied.
The phytoestrogens genistein, daidzein, coumestrol and equol were found to inhibit the growth of human prostate cancer cells in culture. In addition, genistein was found to act as an antioxidant, protecting the cells against DNA damage, although it was not as potent as other recognised antioxidants such as the vitamins C and E.
The antioxidant activity was also evident when 16 healthy men were given tablets containing about 50 mg of phytoestrogens (genistein, daidzein and glycitein) daily for 3 months. However, this treatment produced no changes in hormone (follicle stimulating hormone or testosterone) concentrations or in the levels of cholesterol (total, high density lipoprotein or low density lipoprotein).
In a separate experiment, there were no effects on sperm number or quality when 14 healthy men were given tablets containing 40 mg of phytoestrogens (genistein, daidzein and glycitein) daily for 2 months.
In a final experiment, dietary supplementation with a total of 100 mg of phytoestrogens (genistein, daidzein and glycitein) in tablet form daily for 1 month produced a similar effect on prostate cancer progression in 3 men with prostate cancer as that observed by oestrogen treatment.
The results of this project were evaluated by the Committee on Toxicity (COT) as part of its review on phytoestrogens and health .
Final report is available from the FSA Library and Information centre.
To obtain a copy, please contact the Enquiry Desk, Dr Elsie Widdowson Library and Information Services, Food Standards Agency tel: 020 7276 8181/8182 or email:
library&info@foodstandards.gsi.gov.uk
).
Publications
Mitchell, J.H. et al (1998). Antioxidant efficacy of phytoestrogens in chemical and biological model systems. Arch biochem biophys 360 , 142-148.
Mitchell, J.H. et al (1999). Effects of a soy milk supplement on plasma cholesterol levels and oxidative DNA damage in men - a pilot study. Eur J Nutr 38 , 143-148.
Mitchell, J.H. (2000). Effects of phytoestrogens on growth and DNA integrity in human prostate tumour cell lines: PC-3 and LNCaP. Nutr Cancer 38 , 223-8.
Contact
: For any enquiries concerning this research project, please contact the relevant Programme contact or email:
science@foodstandards.gsi.gov.uk
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