• Journal of Nutrition and Health
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• 제19권1호
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• pp.32-40
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• 1986

The present study conducted to examine the effects of proteins from different sources on Ca excretion in 6 healthy young adult Korean women. The subjects were given meat protein diet for 5 days and soy protein diet for subsequent 5 days. the two diets were similar in protein and Ca contents. Urinary and fecal samples were collected for the last 2 days of each diet period and were analyzed for Ca and P. The results were as following ; 1) Mean daily urinary calcium excretion was 126.5$\pm$22.70mg for meat protein diet and 83.7$\pm$17.19mg for soy protein diet and the difference was significant (P<0.025). 2) Fecal Ca excretion did not show significant difference between two experimental preiod ; 466.9$\pm$73.68 mg of meat portein diet 284.4$\pm$54.96mg for soy protein diet. 3) Three out of six subjects showed negative balance on meat protein diet, but only one showed negative balance on soy protein diet. The averageof the balances on meat protein diet was -65.4 $\pm$68.19 and that of soy protein diet was 155.3$\pm$52.28 ; the difference was significant(P<0.025). 4) Urinary P excretion tended to be higher on meat protein diet but was not significant compared to soy protein diet . Fecal P excretion was significantly higher (P<0.001) on soy protein diet. Overall P balances for meat protein diet and soy protein diet were 219.94 mg and 229.46mg respectively (P<0.05). The above results show that urinary Ca excretion was significantly higher on meat protein diet but fecal excretion did not show significant difference between meat protein diet and soy protein diet. The overall Ca balance was significantly higher on Soy protein diet compared to meat protein diet.

• Journal of Nutrition and Health
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• 제36권4호
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• pp.359-367
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• 2003

The purpose of this study was to examine the impact of soy protein and soy isoflavones on bone and mineral density in young female Sprague-Dawley rats. Fifty eight rats (body Weight 75 $\pm$ 5 g) were randomly assigned to one of four groups, consuming casein, soy protein concentrate, soy protein isolate (57 mg isoflavones/100 g diet) or casein added isoflavones (57 mg isoflavones /100 g diet). All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. Bone mineral density (BMD) and bone mineral content (BMC) were measured using PIXImus (GE Lunar Co, Wisconsin, USA) in spine and femur on 3, 6, 9 weeks after feeding. The serum and urine concentrations of Ca and P were determined. Diet did not affect weight gain and mean food intake. Food efficiency ratio was lower In soy protein groups. The serum concentration of Ca and P were not changed by soy protein and isoflavones. Urinary Ca and P excretion were not significantly different. Spine BMD was significantly increased by soy protein isolate on 3 and 6 weeks after feeding. Femur BMD was significantly increased in the groups of soy protein isolate and isoflavones adding on after 9 weeks. Therefore, soy protein with rich isoflavones may be beneficial on spine and femur BMD increasement in growing female rats.

• Journal of Nutrition and Health
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• 제36권6호
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• pp.549-558
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• 2003

The purpose of this study was to determine which differences in the source of protein (soy vs casein) and isoflavones in soy protein are responsible for the differential effects of bone marks and hormones in growing female rats. Forty-two 21-day-old Sprague-Dawley female rats were randomly assigned to one of three groups, consuming casein (control group), soy protein isolate (57 mg isoflavones/100 g diet), or soy protein concentrate (about 1.2 mg isoflavones/100 g diet). All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. And bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Serum osteocalcin, growth hormone, estrogen and calcitonin were analyzed using radioimmunoassay kits. Diet did not affect weight gain and mean food intake. Food efficiency ratio was lower in the soy protein groups. The soy isolate group had a higher ALP and osteocalcin concentration and lower crosslinks value than the casein group. Therefore, the soy isolate groups had a higher bone formation/resorption ratio than the casein group. And, the soy group had significantly higher growth hormone than the casein group. The findings of this study suggest that soy protein and isoflavones are beneficial for bone formation in growing female rats. Therefore, exposure to these soy protein and isoflavones early in life may have benefits for osteoporosis prevention.

• Journal of Nutrition and Health
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• 제27권9호
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• pp.883-891
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• 1994

The number of diabetics in Korea is about 3 to 5 percent of the population, and the incidence is increasing yearly due to changes of life style and food intake. Diet is a key element in the management of diabetes, yet the appropriate diet for diabetes remains controversial. We have recently shown that a diet rich in protein of animal origin(casein) seems beneficial to controling plasma glucose and lipids in streptozotocin-induced diabetic rats. It therefore seemed desirable to find out whether the beneficial effect of high casein diet in experimental diabetes could also be reproduced with a vegetable source of protein(soy). The purpose of this study is to compare these results with the results of our previous study. In the present study, non-diabetic and streptozotocin-induced diabetic rats were studied in order to examine the effects of altering the level(20% vs 60%) of dietary soy protein on blood glucose, lipids, and hormones. Results of the present study showed that a high soy protein diet decreased triglyceride concentration in diabetic rats. However, diabetic rats fed a high soy protein diet were not hypocholesterolemic compared to rats fed a control diet. Moreover, diabetic rats fed a high soy protein diet had significantly increased plasma glucose concentration compared to rats fed a control diet. This study was not able to discern a specific effect of dietary protein level on insulin, glucagon, or insulin/glucagon ratio. Except for the hypotriglyceridemic effect, the results were not similar to the findings of our previous study which showed a beneficial effect on streptozotocin-induced diabetic rats fed a high casein diet.

• Journal of Nutrition and Health
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• 제34권8호
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• pp.833-842
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• 2001

The purpose of this study is to determine the effect of dietary proteins and fats on the hepatic histological changes, membrane stability, and drug-metabolizing enzyme activities during chemically induced rat hepatocarcinogenesis. Weanling Sprague-Dawley rats were fed the diet containing 20% casein or soy protein isolate and 15% perilla or corn oil for 10 weeks. Hepatocarcinogensis was initiated with diethylnitrosamine(DEN), and the rats were fed diets containing 0.02% 2-acetylaminofluorene(AAF) followed by 0.05% phenobarbital (PB). The scores of histological changes were decreased in treated rats fed soy protein diet compared to those find casein diet. Liver weights were significantly increased by AAF and PB treatment in rats fed casein diets in both oil groups. Glucose 6-phosphatase(G6Pase) activities, an index of membrane stability, were significantly reduced by AAF and PB treatment in rats find casein diets, and were lower in casein diet compared to soy protein diet groups. Especially, the activities were the highest in the rats fed soy protein-perilla oil diet. Lipid peroxide values also were increased by AAF and PB treatment in rats fed casein diet. Aniline hydroxylase activities were not influenced by protein and fat sources. Glutathione-dependent enzyme activities were increased by AAF and PB treatment. Linoleic and arachidonic acid content were increased in rats fed corn oil diet, and linolenic and eicosapentaenoic acid contents were increased in rats fed perilla oil diet. Our results suggest that soy protein isolate inhibit the abnormal histological changes in liver, possibly by maintaining the membrane stability during chemically induced rat hepatocarcinogenesis. Soy protein may be protective against the hepatocarcinogenesis induced by chemical carcinogen.

• 동아시아식생활학회지
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• 제7권1호
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• pp.13-20
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• 1997

This study was designed to determine the effects of protein sources on the curation of gastric ulceration, protein metabolism, and nitrogen balance in rats with gastric ulcer induce by restraint and water immersion stress. After the rats were fed 10% casein diet for 3 weeks, four groups of the rats were forced in 5$\times$5$\times$15cm plexiglass cage. The restraint and water immersion stress was carried at 20$\pm$2$^{\circ}C$ for 8-hour. The other one group(control group) was not exposed to stress. After stress 4 kinds of different diets containing 20% protein were given for 5 days. The protein sources were casein, whey protein, soy protein, gluten. The control group was fed to 10% casein diet. The results were as follows ; the weights of rats were not different among the diet groups During the experiment period follows ; the weights of rats were not different among the diet groups during the experiment period (for 5 days). The ulcer index of rats fed 10% gluten and soy protein diet was significantly higher than those of casein and whey protein diet groups(p<0.05). The level of serum albumin was not significantly different among diet groups. But hematocrit and the level of $\alpha$-amino-N, BU and UUN of plant protein diet groups were higher than animal diet groups, the urinary hydroxyproline of soy protein group was the highest and the whey protein was the lowest. The digestibility and BV of nitrogen of gluten diet group were significantly higher than those of casein and whey protein diet groups(p<0.05). The animal proteins had more curative effects of ulcer than plant animals. The results of this study provide useful information concerning diet therapy for the patients with gastrointestinal diseases and the field of enteral diet materials.

• Journal of Nutrition and Health
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• 제27권1호
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• pp.3-11
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• 1994

This study was carried out to examine how dietary protein and calcium levels in rats fed fat-enriched diet affect the total lipid and cholesterol contents of blood and tissues. Male Sprauge-Dawley rats weighing approximately 200g were fed six purified diets which contained 18%(w/w) beef tallow, 1% (w/w) cholesterol, two source of protein, casein or isolated soy protein (ISP) and three levels of dietary calcium, 0.1%, 0.4% and 1.0%, first, for four weeks, and second, for eight weeks. The contents of the total lipid, cholesterol and triglyceride in blood, liver, heart and feces were determined. After four weeks feeding serum lipid and cholesterol concentrations significantly decreased in rats fed 1.0% (w/w) level calcium, regardless of dietrary protein sources. After eight weeks, these concentrations were significantly lower in the rats fed soy protein than in casein-fed rats. As dietary calcium level increased serum and tissue lipid and cholesterol contents were decreased and fecal lipid excretion increased. It is concluded that hypolipidemic and/or hypocholesterolemic effects of soy protein and calcium were partly due to decrease in lipid absorption.

• Journal of Nutrition and Health
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• 제37권2호
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• pp.100-107
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• 2004

This study was performed to evaluate the effect of dietary protein source and sulfur amino acid content on bone metabolism in ra. Thirty male rats (body weight 145$\pm$2g) were divided into three groups. The rats in the first group were fed on casein 20% diet as animal protein source and those in the second group were fed on soy 20% diet as plant protein source. Sulfur amino acid ratio of these group was 1.07:1. The rats in the third group were fed on soy 20% diet and the sulfur amino acid were supplemented with the amount contained as much in the soy 20% diet. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks, The total body, spine, femur bone mineral density and bone mineral content were measured using Dual Energy X-ray Absorptiometry Calcium, phosphate, pyridinoline, creatinine in urine and calcium, phosphate, alkaline phosphatase, osteocalcin in serum were measured. During the experimental period, plant protein (soy protein) group had a lower urinary Ca excretion, urine pyridinoline ＆ crosslinks value and had a higher Ca efficiency in total bone and femur bone mineral density than animal protein (casein) group. There were no significant differences in serum calcium, phosphate, alkaline phosphatase and osteocalcin among the three groups of the rats. The findings from this study demonstrated that plant protein (soy protein) is beneficial of bone mineral density because it had a higher Ca efficiency in total bone and femur bone mineral density than animal protein (casein). However, the supplementation of sulfur amino acid on soy results were consistent with prior studies that dietary sulfur amino acid load had a negative effect on calcium balance. The rats fed sulfur amino acid supplementation diet increased urinary calcium excretion and decreased calcium efficiency for total and femur mineral density. Therefore, dietary protein source and sulfur amino acid content influence bone metabolism. (Korean J Nutrition 37(2): 100-107, 2004)

• Nutritional Sciences
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• 제9권4호
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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.

• 대한지역사회영양학회:학술대회논문집
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• 대한지역사회영양학회 2004년도 춘계학술대회
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• pp.437.2-438
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• 2004

The purpose of this study was to investigate the effects of garlic, soy protein and taurine on blood lipid profiles in postmenopausal hyperlipidemic model rats. Seventy-two female Sprague-Dawley rats weighing 200g were fed a commercial diet for one week. All rats were ovariectomized and then were randomly assigned to eight groups (high fat diet group; HFD group, 2% garlic powder group; GP group, taurine group; TR group, soy protein group; SP group, 2% garlic powder ＋ taurine group; GP＋TR group, 2% garlic powder+ soy protein group; GP＋SP group, taurine＋soy protein group; TR＋SP group, 2% garlic powder＋taurine＋soy protein group; GP＋TR＋SP group).(omitted)