Osteoporosis isoflavones

It has been shown that in postmenopausal women habitually high intakes of dietary isoflavones are associated with higher bone mineral density (BMD) values at both the spine and hip region (Mei et al, 2001). It is conceivable that an isoflavone-rich diet may help to reverse the state of secondary hyperparathyroidism associated with estrogen withdrawal and hence lower the rate of bone turnover in postmenopausal women, thus reducing the risk of osteoporosis (Valtuena et al, 2003). Phytoestrogens could be used as natural SERMs (Brzezinski and Debi, 1999) and some studies (Setchell, 2001 and refs therein) support such an idea since the molecular targets of... 

Soy protein doses of 20 to 60 g daily are used to reduce hot flashes and to lower elevated cholesterol. Higher doses of isoflavones (2.25 mg/g soy protein) or more than 60 g soy protein may help prevent osteoporosis. 

Although there is some controversy about how much soy must be consumed to benefit from its phytoestrogen effect, it is beheved that two servings per day will modestly reduce menopausal symptoms and the risk of breast cancer. More than three servings may reduce cholesterol. Although it has yet to be proved that dietary soy will stop osteoporosis, a synthetic isoflavone, ipriflavone, has been used in Japan and Europe to treat osteoporosis. Large doses of soy (6-8 servings per day) are believed by some to help this condition as well. 

Consumption of soy foods (providing 60mg/day isoflavones) for 12 weeks by postmenopausal women has been found to significantly decrease clinical risk factors for osteoporosis (short-term markers of bone turnover) including decreased urinary M-telopeptide excretion (bone resorption marker) and increased serum osteocalcin (bone formation marker). Furthermore, consumption of a soy isoflavone supplement containing 61.8 mg of isoflavones for 4 weeks by postmenopausal Japanese women significantly decreased excretion of bone resorption markers. ... 

Considerable evidence exists from epidemiological and experimental studies for preventive effects of soy or isoflavones against chronic diseases including cancer (breast, prostate, colorectal, lung), osteoporosis, cardiovascular disorders, and menopausal symptoms, but this is not always consistent [Adlercreutz... 

Bone is composed mainly of calcium and phosphorous, as well as collagen and proteoglycans. A major disease of bone is osteoporosis, which is characterized by low bone mass and structural deterioration leading to fragility and fracture. The disease occurs with increasing age in both sexes, but also due to estrogen deficiency in women around menopause, resulting in calcium loss. The major nutraceuticals used for the treatment of osteoporosis are soy products, particularly isoflavones, but also n-3-fatty acids and tea. 

Coumarins are active molecules against osteoporosis, they also behaves as estrogens, therefore, termed phytoestrogens as isoflavones and lignans. 

Epidemiological studies (Aldercreutz et al., 1991 Aldercreutz, 1998) indicate that consumption of tofu and other soy foods may be associated with the low incidence of breast cancer in Japanese women. This discovery has led numerous researchers in recent years to search for the biochemical components in soybean that are responsible for the cancer risk-lowering effect. Aside from the potential cancer prevention effect (Wu et al., 1996 Cline and Hughes, 1998 Griffiths et al., 1998 Messina and Bennink, 1998 Stephens, 1999), isoflavones also have been found to have other potential health benefits, including heart disease prevention (Anthony et al., 1998), bone mass density increase to prevent osteoporosis (Anderson and Camer, 1997) and the reduction of postmenopausal syndromes in women (Knight et al., 1996). 

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