The Effect of Soybean Protein on Bone Loss in a Rat Model of Postmenopausal Osteoporosis.

Abstract

SummaryThis study was designed to investigate the modulatory effect of dietary soybean protein on the skeleton of an ovariectomized rat model with postmenopausal osteoporosis. Thirty-two female Sprague-Dawley rats were weight matched and divided into the following four experimental groups: Soy group, ovariectomized and fed soy protein diet; Estrogen group, ovariectomized, fed casein diet and injected with estrogen; Casein group, ovariectomized and fed casein diet; and Sham group, sham-operated and fed casein diet. The diets and estrogen were started two weeks after surgery, and continued for four weeks. Rats in the Sham, Soy and Estrogen groups had significantly higher (p<0.05) femur and tibia ash content than those in the Casein group. Accordingly, the calcium content of the tibia and femur were also significantly higher (p<0.05) in the Soy, Estrogen and Sham groups as compared to the Casein group. Serum total and bone-type alkaline phosphatase levels were both significantly lower (p<0.05) in the Estrogen and Sham groups in relation to the Soy and Casein groups. This study demonstrated that a 22% soybean protein diet could be just as effective as daily estrogen administration in suppressing bone loss due to ovariectomy. However, unlike estrogen, soy protein diet did not have any uterotrophic effect and did not decrease the markers of bone turnover measured, suggesting a possible difference in the mechanism of action. Key Words soy protein, ovariectomy, estrogen, bone loss osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue resulting in an increase in bone fragility and susceptibility to fractures (1).

Soybean isoflavone treatment induces osteoblast differentiation and proliferation by regulating analysis of Wnt/β-catenin pathway

“…Similar benefits have been reported in animal studies (Harrison et al, 1998;Fanti et al, 1998). Moreover, the role of isoflavones in bone health is further supported by in vitro studies investigating the effect of soybean isoflavones on osteoblastic cells, suggesting that this effect is mediated partly through estrogen action (Yamaguchi and Sugimoto, 2000).…”

Soybean isoflavone treatment induces osteoblast differentiation and proliferation by regulating analysis of Wnt/β-catenin pathway

“…Similar benefits have been reported in animal studies (Harrison et al, 1998;Fanti et al, 1998). Moreover, the role of isoflavones in bone health is further supported by in vitro studies investigating the effect of soybean isoflavones on osteoblastic cells, suggesting that this effect is mediated partly through estrogen action (Yamaguchi and Sugimoto, 2000).…”

Bone mass and soy isoflavones in socially housed, premenopausal macaques

“…However, a subgroup analysis in the same trial found that the soy supplement had a bone-sparing effect on the younger postmenopausal women. Studies with relatively young ovariectomized rats also indicate that isoflavonerich soy protein prevents ovariectomy-induced bone loss (42,43). The monkey data are equivocal on this point: the one published study indicated that soy isoflavones do not reduce bone loss after ovariectomy; however, that study did not have a nonsoy protein control (44).…”

Health Benefits of Soy Isoflavones

“…Rats make useful models for evaluating lifetime effects of soy consumption on osteoporosis. Ovarectomized (lacking endogenous esterogen production) rats fed a 22% soy protein diet were found to have a level of bone loss suppression equivalent to that of estrogen supplemented rats (37). Furthermore, in ovarectomized rats fed a regular isoflavone-rich soy or an isoflavone-depleted soy diet, antiosteoporotic effects were only associated with consumption of the isoflavone-rich diet.…”

Soybean isoflavone treatment induces osteoblast differentiation and proliferation by regulating analysis of Wnt/β-catenin pathway

“…Similar benefits have been reported in animal studies (Harrison et al, 1998;Fanti et al, 1998). Moreover, the role of isoflavones in bone health is further supported by in vitro studies investigating the effect of soybean isoflavones on osteoblastic cells, suggesting that this effect is mediated partly through estrogen action (Yamaguchi and Sugimoto, 2000).…”

Bone mass and soy isoflavones in socially housed, premenopausal macaques

“…However, a subgroup analysis in the same trial found that the soy supplement had a bone-sparing effect on the younger postmenopausal women. Studies with relatively young ovariectomized rats also indicate that isoflavonerich soy protein prevents ovariectomy-induced bone loss (42,43). The monkey data are equivocal on this point: the one published study indicated that soy isoflavones do not reduce bone loss after ovariectomy; however, that study did not have a nonsoy protein control (44).…”

Health Benefits of Soy Isoflavones

“…Rats make useful models for evaluating lifetime effects of soy consumption on osteoporosis. Ovarectomized (lacking endogenous esterogen production) rats fed a 22% soy protein diet were found to have a level of bone loss suppression equivalent to that of estrogen supplemented rats (37). Furthermore, in ovarectomized rats fed a regular isoflavone-rich soy or an isoflavone-depleted soy diet, antiosteoporotic effects were only associated with consumption of the isoflavone-rich diet.…”

Soybean isoflavone treatment induces osteoblast differentiation and proliferation by regulating analysis of Wnt/β-catenin pathway

“…Similar benefits have been reported in animal studies (Harrison et al, 1998;Fanti et al, 1998). Moreover, the role of isoflavones in bone health is further supported by in vitro studies investigating the effect of soybean isoflavones on osteoblastic cells, suggesting that this effect is mediated partly through estrogen action (Yamaguchi and Sugimoto, 2000).…”

Bone mass and soy isoflavones in socially housed, premenopausal macaques

“…However, a subgroup analysis in the same trial found that the soy supplement had a bone-sparing effect on the younger postmenopausal women. Studies with relatively young ovariectomized rats also indicate that isoflavonerich soy protein prevents ovariectomy-induced bone loss (42,43). The monkey data are equivocal on this point: the one published study indicated that soy isoflavones do not reduce bone loss after ovariectomy; however, that study did not have a nonsoy protein control (44).…”

Health Benefits of Soy Isoflavones

“…Rats make useful models for evaluating lifetime effects of soy consumption on osteoporosis. Ovarectomized (lacking endogenous esterogen production) rats fed a 22% soy protein diet were found to have a level of bone loss suppression equivalent to that of estrogen supplemented rats (37). Furthermore, in ovarectomized rats fed a regular isoflavone-rich soy or an isoflavone-depleted soy diet, antiosteoporotic effects were only associated with consumption of the isoflavone-rich diet.…”