The health effects of phytoestrogens osteoporosis, cardiovascular disease and thyroid function

4 The health effects of phytoestrogens osteoporosis, cardiovascular disease and thyroid function 

The public health implications of dietary phytoestrogens have received a great deal of attention over the last few years. However, despite substantial data from epidemiological and experimental studies, the biological effects of phytoestrogens remain equivocal. 

Studies have demonstrated that treatment with soy or phytoestrogen enriched diets is effective in conserving bone in rodent models of osteoporosis (Anderson and Gamer, 1998 Ishimi et al, 2000 Draper et al, 1997). The mechanism of action of phytoestrogens on bone health is unclear but several mechanisms including inhibition of bone resorption and stimulation of bone formation maybe involved (Fanti etal, 1998 Ishimi e/a/., 1999 Picherit eta/., 2000). Limited data from studies in postmenopausal women have indicated that phytoestrogen supplements have a small, beneficial effect on bone loss in the lumbar spine (Alekel et al, 2000 Potter et al, 1998 Somekawa et al, 2001). 

Cardiovascular disease (CVD) is one of the leading causes of death worldwide. There are a number of established risk factors including serum cholesterol levels, smoking and family history, which are responsible for between 50 and 75% of the CVD cases, with the remainder due to factors that cause atherosclerosis. Estrogen treatment such as hormone replacement therapy is known to protect against CVD by decreasing the levels of low-density 

Mortality rates from CVD are generally lower in Asian populations compared to Western populations (Knight and Eden, 1996). Although many dietary factors are known to play a protective role in CVD and it has been suggested that phytoestrogen content of Asian diets may be responsible for the cardioprotective effect. 

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