• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.833-839
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• 2005

This study was conducted to demonstrate whether dietary Ca and the soy isoflavones supplementation could reduce the bone loss associated with estrogen deficiency. Nine week-old female rats (SD) were ovariectomized and then fed on diet of low $(0.1\%)$ or normal $(0.5\%)$ Ca supplemented with soy isoflavones (80 and 160 ppm) for 6 weeks. The ovariectomized and sham-operated rats showed normal serum Ca and P levels, and dietary Ca and soy isoflavones did not changed them. The serum alkaline phosphatase activity was increased in all ovariectomized rats, especially in the rats fed low Ca diet regardless of isoflavone supplementation. The serum tartrate-resistance acid phosphatase was not significantly different among the ovariectomized rats and were not changed by dietary Ca and isoflavones. Breaking force of femur was higher in the rats fed the nomral Ca diets and not statistically changed by soy isoflavone supplementation. Femoral and lumbar Ca and P contents decreased in the ovariectomized rats and the soy isoflavones-80 ppm supplementation significantly enhanced bone minerals, but the soy isoflavones-160 ppm supplementation did not. Dietary Ca increased lumbar Ca and P contents. The results of this study have suggested that the soy isoflavones 80 ppm supplementation could be sufficient to prevent bone loss in ovariectomized rats and normal Ca supplementation could enhance the effect of soy isoflavones on bone protection.

• Nutritional Sciences
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• v.9 no.4
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• pp.240-247
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• 2006

In this study we investigated the neuroprotective, antioxidative, and hypocholestrolemic effects of dietary soy protein and soy isoflavone in a rat focal brain ischemia model. Weaning Sprague-Dawley rats were fed a 20% casein-based diet (CA), 20% soy protein-based diet (SP), or 0.2% soy isoflavones-supplemented diet (ISO) for 6 weeks. The cortical infarction volume of the ISO group was significantly lower than that of the SP group. The thiobarbituric acid reactive substances (TBARS) were considerably lower in the ISO group than the CA group. Glutatbione peroxidase activities of the SP group were notably higher than those of the CA group. Acetylcholinesterase (AchE) activities of the SP group were significantly decreased compared to the CA group. LDL cholesterol levels and LDL/HDL ratios of the ISO group were lower than those of the CA and SP groups. Our results collectively suggest that soy isoflavones may contribute to neuroprotection by reducing the TBARS and serum LDL/HDL ratio, whereas soy protein may be associated with the regulation of cognitive functions by modulating AchE activity.

• Preventive Nutrition and Food Science
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• v.10 no.3
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• pp.298-309
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• 2005

As the population of the elderly grows, the prevalence of osteoporosis and its related fractures will increase in both men and women. The etiology, preventive and curative strategies of male osteoporosis are relatively unknown and understudied in comparison with those of female osteoporosis. Even currently approved therapies, e.g. bisphophonates, parathyroid hormone, and testosterone for male osteoporosis are in need of further investigation to test their safety and efficacy. Isoflavones which are found in soy have been shown to positively affect bone by stimulating bone formation while concurrently slowing down bone resorption. These observations mainly come from studies that have employed women or female animal models of osteoporosis. Therefore, there is a need to explore the role of soy and its isoflavones in preventing bone loss or rebuilding bone utilizing men or animal models of .male osteoporosis. From the review of existing literature it is too early to state the extent to which men with osteoporosis can benefit from consumption of soy or its isoflavones. In this review, the efficacy of soy and its isoflavones as alternative and/or adjunctive treatment for male osteoporosis will be discussed.

• Nutrition Research and Practice
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• v.15 no.1
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• pp.1-11
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• 2021

BACKGROUND/OBJECTIVES: It is difficult to consistently demonstrate the health effects of soy isoflavones owing to the multitude of factors contributing to their bioavailability. To accurately verify these health effects, dietary isoflavone intake should be measured using a biologically active dose rather than an intake dose. This concept has been expanded to the development of new exposure biomarkers in nutrition research. This review aims to provide an overview of the development of exposure biomarkers and suggest a novel research strategy for identifying the health effects of soy isoflavone intake. MATERIALS/METHODS: We cover recent studies on the health effects of soy isoflavones focusing on isoflavone metabolites as exposure biomarkers. RESULTS: Compared to non-fermented soy foods, fermented soy foods cause an increased concentration of isoflavones in the biofluid immediately following ingestion. The correlation between exposure biomarkers in blood and urine and the food frequency questionnaire was slightly lower than that of corresponding 24-h dietary recalls. Urinary and blood isoflavone levels did not show a consistent association with chronic disease and cancer risk. CONCLUSION: It is crucial to understand the variable bioavailabilities of soy isoflavones, which may affect evaluations of soy isoflavone intake in health and disease. Further studies on the development of valid exposure biomarkers are needed to thoroughly investigate the health effects of isoflavone.

• Biomedical Science Letters
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• v.11 no.2
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• pp.175-183
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• 2005

The two major isoflavones in soy, genistein and daidzein, are well known to prevent hormone-dependent cancers by their anti estrogenic activity. The exact molecular mechanisms for the protective action are, however, not provided yet. It has been reported that genistein and daidzein have a potential anticancer activity through their antiproliferative effect in many hormone-dependent cancer cell lines. Transforming growth $factor-\beta1(TGF-\beta1)$ has also been found to have cell growth inhibitory effect, especially in mammary epithelial cells. This knowledge led to a hypothetical mechanism that the soy isoflavones-induced growth inhibitory effect can be derived from the regulation of $TGF-\beta1$ and $TGF-\beta$ receptors. In order to test this hypothesis, the effects of the soy isoflavones at various concentrations and periods on the expression of $TGF-\beta1$and $TGF-\beta$ receptors were investigated by using Northern blot analysis in human breast carcinoma epithelial cell lines, an estrogen receptor positive cell line (MCF-7) and an estrogen receptor negative cell line (MDA-MB-231). As a result, only genistein has shown a profound dose-dependent effect on $TGF-\beta1$ expression in the $ER^+$ cell line within the range of doses tested, and the expression levels are correspondent to their inhibitory activities of cell growth. Moreover, daidzein showed down-regulated $TGF-\beta1$ expression at a low dose, the cell growth proliferation was promoted at the same condition. Therefore, antiproliferative activity of the soy isoflavones can be mediated by $TGF-\beta1$ expression, and the effects are mainly, if not all, occurred by ER dependent pathway. The expression of $TGF-\beta$ receptors was induced at a lower dose than the one for $TGF-{\beta}1$ induction regardless of the presence of ER, and the expression patterns are similar to those of the cell growth inhibition. These results indicated that the regulation of $TGF-\beta$ receptor expression as well, prior to $TGF-\beta1$ expression, may be involved in the antiproliferative activity of soy isoflavones. Little or no expression of $TGF-\beta$ receptors was found in the MCF-7 and MDA-MB-231 cells, suggesting refractory properties of the cells to growth inhibitory effect of the $TGF-\beta$. The soy isoflavones can seemingly restore the sensitivity of growth inhibitory responses to $TGF-\beta1$ by re-inducing $TGF-\beta$ receptors expression. In conclusions, our findings presented in this study show that the antitumorigenic activity of the soy isoflavones could be mediated by not only $TGF-\beta1$induction but $TGF-\beta$ receptor restoration. Thus, soy isoflavones could be good model molecules to develop new nonsteroidal antiestrogenic chemopreventive agents, associated with, regulation of $TGF-\beta$ and its receptors.

• Korean Journal of Human Ecology
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• v.23 no.1
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• pp.137-148
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• 2014

The aim of this study was to determine whether the addition of soy isoflavones to dairy ice cream modifies diabetic biomarkers in the type 2 diabetic model mice. Forty male C57BL/6J-ob/ob mice were randomly divided into 4 groups and fed control diet (basal, 7% fat), MS diet (milk ice cream with sugar, 20% fat), MS-SI diet (MS ice cream with 0.01% soy isoflavones, 20% fat), or MF-SI diet (milk ice cream with 0.01% soy isoflavones, 5% fructooligosaccharide, 20% fat) for 12 weeks. Blood response area by glucose tolerance test, plasma levels of glucose, insulin, C-peptide, leptin, and blood $HbA_{1c}$ were not significantly different among all the groups. Concentrations of interleukin-6 and tumor necrosis factor-${\alpha}$ secreted from splenocytes induced by Concanavalin A were not significantly different among all the groups. In conclusion, soy isoflavones supplemented to ice cream did not alter diabetic biomarkers in diabetic type 2 model mice.

• Journal of Nutrition and Health
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• v.38 no.4
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• pp.279-288
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• 2005

The purpose of this study was to examine whether soybean protein isolate with rich isoflavones which was the same amount as used for earlier study prevents bone induced by ovarian hormone deficiency. Forty female Sprague-Dawley rats (body weight 210 $\pm$ 5 g) were divided into two groups, ovariectomy (OVX) and sham surgery groups, which were each randomly divided into two subgroups that were fed casein and soybean protein isolate with rich isoflavones (isoflavones 3_4 mg/g protein). The diets were fed for 9 weeks after operation. The results of this study indicate that body weight gain and food intake were higher in OVX groups than in SHAM groups regardless of diets. Weight gain were higher in soy isolate groups than in casein groups. Serum Ca concentration was lower in OVX rats than in SHAM rats when fed casein diet. Within the OVX groups, serum Ca concentration was higher in rats fed soy isolate diet than in rats fed casein diet. Serum ALP were higher in OVX groups than in SHAM groups. Within the OVX, soy isolate groups, indices of serum osteocalcin, were a trend for greater than those of the OVX casein group. Crosslink value were increased in ovariectomy groups. Spine BMD and femur BMD of ovariectomy groups were significantly lower than SHAM groups. However, soy isolate with rich isoflavones group in ovariectomy groups, spine BMC and femur BMC were significantly increased after 9 weeks. In conclusion, the soy protein with rich isoflavones was beneficial for bone in ovareiectomized rats and the results were similar to the findings of our previous study which showed a beneficial effect on bone in growing rats.

• Journal of Nutrition and Health
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• v.35 no.4
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• pp.409-413
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• 2002

The purpose of this study was to determine to which differences in the source of protein (soy vs casein) and of isoflavones in soy protein are responsible for differential effects of bone mineral density and bone mineral content. Thirty 21-d-old Sprague-Dawley young rats were divided into 3 groups: the control group was find a casein-based diet, the soy concentrate group was fed soy protein with totally reduced isoflavones content (isoflavone 0.07 mg/g protein), and soy isolate group was fed with a higher isoflavone content (isoflavone 3.4 mg/g protein) than normal. The animal was scanned to determine the BMD and BMC using dual energy X-ray absorptiometry (DEXA, Lunar Corporation, Madison, WI). The soy concentrate group had significantly higher total body calcium/weight and total mineral content/weight than the casein group. The soy isolate group had significantly greater total bone mineral density/weight, spine bone mineral density/weight, and femoral bone mineral density (in g/$\textrm{cm}^2$ than the control and soy concentrate group. The findings of this study suggest that soy protein and isoflavones in soy protein are beneficial for bone-formation in growing male rats. Therefore exposure to these soy protein and isoflavones early in life may have long-term health benefits for bone diseases such as osteoporosis.

• Journal of Nutrition and Health
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• v.35 no.8
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• pp.863-869
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• 2002

Soy isoflavones have been hypothesized to exert hormonal effects and to enhance bone mineral density in postmenopausal women. To test this hypothesis, we studied the effects of soy isoflavones supplements on bone mineral density and sex hormones (serum estradiol, sex hormone-binding globulin and testosterone) in 47 postmenopausal women. There were 24 participants in the treatment group and 23 in the control group. The treatment group consumed the isoftavones extract capsule daily (which contained 90 mg of soy isoflavones) for 12 weeks. The study compared pre- and post-isoflavones intake in the following areas: physical examination, diet survey, bone mineral density and serum sex hormone levels. The average age of the treatment group was 64.63 years and that of the control group was 66.48 years. There were no significant differences between the two groups in terms of height, weight, and body mass index. Both groups maintained regular diet patterns in terms of their average daily nutrient intake. There was no significant difference between the treatment group (18.49 mg) and the control group (21.27 mg) in terms of daily isoflavones intake based on diet. The 12-week analysis of bone mineral density change after taking isoflavones supplements demonstrated no significant differences in the following : lumbar spine BMD (0.82 g/$\textrm{cm}^2$ in pre versus 0.81 g/$\textrm{cm}^2$ in post), femoral neck BMD (0.58 g/$\textrm{cm}^2$ in pre versus 0.57 g/$\textrm{cm}^2$ in post) in the treatment group. There was no significant difference in serum estradiol in the isoflavones treatment group. The subjects indicated no significant difference in serum testosterone in the isoflavones treatment group. But the subjects indicated a significant difference in sex hormone-binding globulin (60.04 nmol/L in pre versus 52.39 nmol/L in post) in the isoflavones treatment group at the levels of p < 0.05. The significant decrease in sex hormone-binding globulin did indicate the need for long-term study on isoflavones supplementation as well as its positive effect on bone mineral density.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.spc1
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• pp.25-45
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• 1996

Soyfoods have potential roles in the prevention and treatment of chronic diseases, most notably cancer, osteoporosis, and heart disease. There is evidence that carcinogenesis are supressed by isolated soybean derived products in vivo such as a protease inhibitor, phytic acid, saponins and isoflavones. It is believed that supplementation of human diets with soybean products markedly reduces human cancer mortality rates. Especially, recent papers recognize the potential benefit of soybean isoflavone components for reducing the risk of various cancers. Isoflavones exhibit a multitude of medicinal effects that influence cell growth and regulation, which may have potential value in the prevention and treatment of cancer. In addition to potential biological effects, soybean isoflavones have the important physiological functions such as the induction of Bradyrizobium japonicum nod genes and the responses of soybean tissues to infection by Phytophthora megasperma as well as biochemical activities such as antifungal and antibacterial actions. Genistin, daidzin, glycitin and their aglycone (genistein, daidzein, glycitein) are the principal isoflavones found in soybean. Malonyl and acetyl forms have also been detected but they are thermally unstable and are usually transformed during the processing in glucoside form. Most soy products, with the exception of soy sauce, alcohol-extracted soy protein concentrate, and soy protein isolate, have total isoflavone concentrations similar to those in the whole soybean. Soybean-containing diets inhibit mammary tumorigenesis in animal models of breast cancer, therefore, it is possible that dietary isoflavones are an important factor accounting for the lower incidence and mortality from breast cancer. Of the total soybean seed isoflavones, $80\~90\%$ were located in cotyledons, with the remainder in the hypocotyls. The hypocotyls had a higher concentrations of isoflavones on a weight basis compared with cotyledons. Isoflavone contents were influenced by genetics, crop years, and growth locations. The effect of crop year had a greater impact on the isoflavone contents than that of location. The climate condition might be the attribution factor to variation in isoflavone contents. Also, while the isoflavone content of cotyledons exhibited large variations in response to high temperature during seed development, hypocotyls showed high concentration in isoflavone content. So, it is concluded that one of the factors affecting isoflavone content in soybean seeds is temperature during seed development. High temperature, especially in maturity stage, causes lower isoflavone content in soybean seed. It is also suggested that there may exist a different mechanism to maintain isoflavone contents between cotyledon and seed hypocotyls. In a conclusion, soy foods may be able to have a significant beneficial impact on public health.