Phyto-oestrogens and osteoporosis: what is a safe dose?
Hormone replacement therapy (HRT) for preventing loss of bone following the menopause is utilised by only 8-10 % of possible users, largely due to a fear of increased risk of breast cancer. Plant oestrogen-like compounds (phyto-oestrogens) have been proposed as an alternative to HRT to prevent osteoporosis. One class of phyto-oestrogens (the isoflavones) is found in soya foods and red clover. The food industry is developing a wide variety of new foods containing soya to substantially increase isoflavone intake, as well as extracting isoflavones from soya and clover to use as additives to non-soya foods. Pharmaceutical companies are also preparing isoflavone extracts to be used in pill form. In each case the targeted delivery is approximately 50 mg of isoflavones/d. Is this dose of isoflavones safe? In this review of the current literature, it is concluded that isoflavones consumed orally and in doses below 2 mg/kg body weight per d should be considered safe for most population groups. Whether these doses are sufficient to prevent osteoporosis is a separate matter.
Department of Pharmacology & Toxicology, and Comprehensive Cancer Center, University of Alabama at Birmingham, 35294, USA. sbarnes@uab.edu
Stephen
S
Barnes
D001943:Breast Neoplasms / Q000517:prevention & control; D004032:Diet; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000517:prevention & control; D015663:Osteoporosis, Postmenopausal / Q000517:prevention & control*; D013025:Glycine max / Q000737:chemistry
D007529:Isoflavones