• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.948-956
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• 2000

There is growing evidence that soy isoflavone play beneficial roles in the prevention of chronic diseases such as hormone dependent cancers, cardiovascular diseases, osteoporosis and also reduced incidence of menopausal symptoms. However current data are not sufficient to determine the effective doses for beneficial as well as harmful effects and to support dietary recommendation for isoflavones. Since soy products containing isoflavone are one of the common food items that Koreans consume daily basis, assessing consumption of soy isoflavone by Koreans will give a valuable information on making dietary recommendations for isoflavones. the present study was designed to assess dietary intake of isoflavone of Korean middle-aged women who might receive the most beneficial effects from isoflavone consumption thereby prevent post menopausal related symptoms and diseases. In this study isoflavone contents of soy products were analyzed and soy products and isoflavone consumption of these subjects were assessed by a self-reported dietary questionnaire and isoflavone intake data base. Subjects were consisted of 178 Korean women (35~60 y) who live in urban and rural area. All subjects provided detailed information on demographics, anthropometry, health history, menopausal symptoms, health history, menopausal symptoms, and dietary intake using food frequency questionnaire (FFQ) which was developed for Koreans. The average age of the subjects was 46.6 years. The soy products which the subjects frequently consumed were soybean paste soup, braised fried soybean, tofu residue stew, tofu, soy milk, natto stew, bean sprouts, and soybean broth which contained 10.68 mg, 3.34 mg, 2.44 mg, 2.42 mg, 2.42 mg, 1.12 mg, 1.02 mg, 0.33 mg of isoflavone per 100 g, respectively. The estimated daily intake (EDI) of isoflavones ranged from 0 to 144.3 mg, and the mean daily isoflavone (sum of daidzein and genisten) intake of the subjects was 24.41 mg.

• 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.

• 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.

• Korean Journal of Community Nutrition
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• v.5 no.1
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• pp.120-129
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• 2000

Very little is known about the relation between isoflavone intake and menopausal symptoms in Korean woman To find the effects and correlations between these factors, questionnaires(maternal factors, menopausal symptoms) anthropometric measurement, 24hr dietary recalls, and urinary isoflavones analysis were conducted in 100 postmenopausal women residing in the Kyunggi-do rural area. The average age hight and weight of the subject were 61.5 years, 153.6 cm and 56.2kg. The average age at menarche, menopause, and menstrual cycle were 16.7 years, 47.2 years, 29.8 years, respectively. Most of the postmenopausal women experienced mildly menopausal symptoms. The mean calorie, protein and calcium intake were 1417.6 kcal(74.7% of the Korean RDA) 53.2 g(88.6% of the Korean RDA) and 454.0mg(65.6% of the Korean RDA) respectively. The ration of energy from carbohydrate, protein, and fat was 68: 15: 17 The average isoflavone intake from soy foods was 27.27 mg. The major food source of the isoflavone were soybeans and soybean curd. The average urinary isoflavone excretion was 2. 78nmol/mg Cr and showed significant positive correlation with isoflavone intake. Isoflavone intake from soy foods had a negative correlation with the severity of menopausal symptoms. Therefore, soy foods which contain isoflavone may have a protective effect on menopausal symptoms of women in Korea.

• Journal of Nutrition and Health
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• v.36 no.8
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• pp.841-850
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• 2003

Soy-based formula has been used for centuries in Korea. Soybeans contain phytochemicals with a biochemically active component, isoflavone. Isoflavone is a kind of phytoestrogens, structurally and functionally similar to estrogen. This study was conducted to investigate the effects of soy-based infant formula on growth, development, and isoflavone concentration in the plasma and urine. Thirty-nine healthy infants who were delivered at K university medical center were recruited. Experimental groups were the breast milk group (n = 15, BM) who were fed breast milk, soy-based formula group (n = 10, SBF) who were fed soy-based infant formula, and the casein-based formula group (n = 14, CBF) who were fed casein-based infant formula for 4 months. HPLC analysis was used to measure the concentration of isoflavones. The measurements of infant weight, length, head circumference and chest circumference were all in the normal growth range and were similar among the experimental groups. No significant differences were found in the scores of total mean of infant development test (Development Quotient, DQ) among the experimental groups. The isoflavone content of soy-based formula was significantly higher than. that of breast milk and casein-based formula. Plasma concentration of daidzein and genistein in the infants fed soy-based formula (daidzein : 264.1 ng/ml, genistein : 392.1 ng/ml) was significantly higher (p<.0001) than that in infants fed breast milk (daidzein : 3.4 ng/ml, genistein : 3.8 ng/ml) and casein-based formula (daidzein: 8.1 ng/ml, genistein: 9.3 ng/ml). Also, urinary daidzein and genistein concentrations in infants fed soy-based formula (daidzein: 19.82 $\mu$g/ml, genistein : 17.89 $\mu$g/ml) were significantly higher (p<.001) than those in infants fed breast milk (daidzein: 0.28 $\mu$g/ml, genistein : 0.22 $\mu$g/ml) and casein-based formula (daidzein : 0.45 $\mu$g/ml, genistein : 0.33 $\mu$g/ml).

• Korean Journal of Community Nutrition
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• v.9 no.5
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• pp.606-614
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• 2004

This study was conducted to investigate the attitude to various soy foods and to estimate dietary isoflavone intake among Korean adolescents. The survey was carried out by self-administered questionnaire with 800 middle and high school students residing in urban and rural areas and 714 questionnaires were collected: resulting in 89% response rate. The dietary isoflavone intake was estimated by food frequency questionnaire developed for rapid assessment of isoflavone intake. Soybean paste, soybean curd, soy milk, bean sprouts and dambuk were recognized as nutritious and healthy food in order. Dambuk got the lowest score in taste and flavor. Bean sprouts, soybean curd and soybean paste were recognized as familiar food in order. Stuffed rice in fried soybean curd got the highest score and Miso soup got the lowest in preference. More than 50% of the subjects consumed soybean paste stew/soup and soybean curd over twice per week and 12.3% of the subjects consumed soybean over once a day. The estimated daily intake of isoflavones ranged from 0 to 227 mg, and the mean daily isoflavone intake of the subjects was 28.1 mg (16.3 mg genistein and 12.0 mg daidzein) whereas the median value of isoflavone intake was 19.7 mg. There was statistically significant relationship among Kyung Gi Do, Chung cheung Do and Seoul residents in their intake of isoflavone. The highest monthly income group consumed isoflavone more than the other groups. These results suggest that Korean adolescent perceived the soybean dishes as high quality foods but they didn't take much because of difficulty to cook or less chance to eat. Nutrition education program is needed to enhance consuming soy foods for prevention of chronic diseases related to dietary isoflavone intake. More detailed information on easy cook method of soy food is also needed.

• Current Research on Agriculture and Life Sciences
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• v.26
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• pp.55-62
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• 2008

To obtain food materials of high isoflavone content from soy-sprouts, 8 soy-sprout varieties, Aga 1, Aga 2, Aga 3, Aga 4, Pungsannamulkong, Eunhakong, Jangkikong and Bosugkong, were grown into soy-sprouts for 7 days under light condition and stored for 5 days at 6 different temperatures; 3, 6, 9, 20, 30, and $40^{\circ}C$ in the dark. The isoflavone content of 7 days grown sprout varieties were highest in the order of Aga 3>Aga 1>Aga 2>Aga 4>Jangkikong>Bosugkong>Eunhakong>Pungsannamulkong. The highest isoflavone content of Aga 3 was $4,619{\mu}g/g$. The isoflavone content of soy-sprouts showed much varietal differences depending on the storage temperatures. Comparative high isoflavone content was obtained at storage temperatures of $6^{\circ}C$ and $20^{\circ}C$ while most of varieties showed low isoflavone content at $9^{\circ}C$ and $30^{\circ}C$. No constant trend in isoflavone content for the tested varieties along with the days to storage but most of varieties showed the highest isoflavone content in 3 days of storage. On the contrary, Aga 4 and Jangkikong showed high isoflavone content even at 5 days of storage. The comparatively high isoflavone content for 4 varieties including of Aga 3 out of 8 varieties was obtained from the treatment of one day storage at $20^{\circ}C$. Out of all treatments, the highest isoflavone content was obtained from one day storage at $20^{\circ}C$ for Aga 3 and the content was as high as $11,705{\mu}g/g$. In this experiment, soy-sprouts were believed to be made continuous growth during the storage because the sprouts were being dipped in water during the temperature treatment to protect soy-sprouts from drying. Thus, it is inferred that additional researches should be made to establish better method to increase isoflavone content in soy-sprouts during the storage.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.479-482
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• 2012

Aim: Soy foods are the major source of isoflavones, which are believed to play important roles in genesis of breast cancer and its progression. We here conducted a prospective study to evaluate the association of soy isoflavone food consumption with breast cancer prognosis. Methods: A prospective study was performed from January 2004 and January 2006 in China. Trained interviewers conducted face-to-face interviews using a structured questionnaire to collect information on dietary habits and potential confounding factors. The relative risk [hazard ratio (HR)] and 95% CI were calculated from the Cox regression model for all significant predictors from cancer diagnosis to the endpoint of the study (event). Results: After a median follow up of 52.1 months (range, 9-60 months), a total of 79 breast cancer related deaths were recorded in our study, risk being inversely associated with a high intake of soy isoflavone. With an average intake of soy isoflavone above 17.3 mg/day, the mortality of breast cancer can be reduced by about 38-36%. We also found the decreased breast cancer death with high soy protein intake, with a HR (95% CI) of 0.71 (0.52-0.98). Stratified analysis with reference to the ER status, further demonstrated a better prognosis of ER positive breast cancer with a high intake of soy isoflavone (HR 0.59, 0.40-0.93). Conclusion: Our study shows the soy food intake is associated with longer survival and low recurrence among breast cancer patients. A cohort study with a larger sample size and long term follow-up is now needed.

• Food Science and Biotechnology
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• v.15 no.6
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• pp.931-936
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• 2006

This study sought to investigate any additive or interactive effects that soy isoflavones may have on the ecosystem of the gut, which is influenced by fructooligosaccharide (FOS) in colon-cancer model rats. Male Sprague-Dawley rats treated with 1,2-dimethylhydrazine were given experimental diets containing 0, 3, 6, or 9% FOS with or without 0.1% soy isoflavone for 12 weeks. In addition to the effects of FOS dosage on the gut ecosystem, dietary supplementation with soy isoflavone reduced the number of colonic aberrant crypts (ACs). The fecal weight, fecal pH, and gut transit time significantly decreased in a dose-dependent manner in rats fed FOS and the fecal concentration of bifidobacteria was higher in rats fed FOS than in control rats. The fecal output of total short-chain fatty acids, acetate, and propionate was significantly increased by the presence of FOS and was negatively correlated with the number of ACs, whereas the fecal output of butyrate showed no significant correlation with FOS dosage. The addition of soy isoflavone to the diet did not result in any significant differences in gut ecosystem parameters. Therefore, we conclude that the suppressive effect of soy isoflavone on ACs was not associated with the intestinal ecosystem, which was significantly altered by the dosage of FOS.

• Journal of Nutrition and Health
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• v.38 no.6
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• pp.411-418
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• 2005

To elucidate the effect of soy isoflavone supplementation and exercise on serum lipids in normolipidemic and mildly hyperlipidemic postmenopausal period, 54 women residing in Seoul area were recruited. The subjects were divided into 4 groups: control group (n=13), isoflavone group (n=14), exercise group (n=14), isoflavone + exercise group (n=13). The control group was given placebo capsules, isoflavone group was given soy isoflavone supplements (90 mg/day), exercise group was given placebo capsules and exercised 3 times/week, over 30 min/time, and isoflavone + exercise group took soy isoflavone supplement and exercised. The duration of study were 8 weeks. The average age of the subjects was 57.0 years, 56.0 years, 54.4 years, and 55.2 years, respectively. There were no significant differences among the four groups in terms of height, weight, and body mass index. There were no significant differences among the four groups in terms of serum, total cholesterol, HDL-cholesterol. But the subjects indicated a significant difference in serum LDL-cholesterol (110.5 mg/day in before versus 74.6 mg/day in after) in the isoflavone + exercise group at the levels of p<0.05. In conclusion, the isoflavone supplementation and exercise may be helpful to decrease serum lipids of normolipidemic and mildly hyperlipidemic postmenopausal women.