• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.677-684
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• 1999

This study has dealt the effect of Ca regulating hormones and dietary Ca levels on Ca metabolism. Animals(BALB/c mice) were divided into three dietary groups(high and medium Ca and Ca free) and hormones including parathyroid hormone(PTH), calcitonin(CT), cholecalciferol(Vit D) were i.p. injected. After feeding experimental diets for five weeks, mice were anaethetized and sacrificed by heart puncture. We found that femur growth of mouse was slightly increased by high dietary Ca without showing statistical significance comparing to low dietary Ca group. The combination of PTH and CT showed the same effect when dietary Ca was high. At the same time, total mineral retention in bone was most affected by dietary Ca. In general, high Ca diet elevated Ca level in the serum. When dietary Ca was low, PTH stimulated Ca release from the bone into the serum, which was shown to be inhibited by CT treatment. Comparing to the control, PTH, Vit D and CT together tended to inhibit serum Ca level at high and medium dietary Ca. PTH and Vit D inhibited Ca reserve in the liver at all dietary levels of Ca. Both PTH and Vit D stimulated bone Ca retention when dietary Ca was low, but this effect was reversed when dietary Ca was high. When PTH, Vit D and CT were administered together, bone Ca level was greatly enhanced at low dietary Ca than at high dietary Ca, which suggests that these hormonal cooperation is needed for proper bone density maintenance especially when dietary minerals are not sufficient.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.2
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• pp.197-202
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• 1999

Three barrows weighing 45.0 kg, fitted with simple T-cannulas in both the duodenum and terminal ileum, were assigned to diets in a $3{\times}3$ Latin Square design experiment to determine the effect of two calcium levels (0.8% vs 0.4%) on phytase activity and nutrient balance in growing pigs. The control diet contained 0.8% calcium, with no added inorganic phosphorus (0.45% total phosphorus) and no added phytase. The two additional experimental diets contained microbial phytase (750 phytase units/kg) and supplied either 0.8% or 0.4% calcium. With added microbial phytase, ileal and total tract digestibility of rotal phosphorus were improved by 20.9 and 13.8 percentage units, respectively (p=0.01). The apparent duodenal and ileal digestibility of phytate phosphorus were increased by 51.8 and 49.7 percentage units (p=0.01). Lowering dietary calcium in the presence of microbial phytase increased the digestibility of phytate phosphorus by an additional 10.9 (p=0.001) and 5.7 percentage units for duodenal and ileal digestibility, respectively. Supplementation with microbial phytase significantly reduced fecal excretion of nitrogen and phosphorus and increased the percentage of these nutrients retained by the pig. Lowering dietary calcium further increased the percentage of dietary phosphorus retained. Overall, reducing dietary calcium appeared to increase the effectiveness of added microbial phytase in degrading phytate phosphorus. As a result, care should be taken to avoid high levels of dietary calcium when supplementing swine diets with microbial phytase.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.3
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• pp.41-49
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• 1994

This study was intended to investigate the effects of nutritional, physical and environmental conditions on the bone status of 102 pre and post menopausal women living in Ulsan area. The results of this study are summarized as follows : when subjects were classified into two groups by bone status, there were significant differences in age, calcium index, serum estrogen and physical activity between two groups. Average daily calcium intake of subjects was 682.9 (149.2)mg, which is almost same as RDA, but 41.1% of the subjects consumed calcium below RDA. Calcium index(p<0.05), serum estrogen(p<0.001), physical activity(p<0.001) of poor bone group were significantly lower than those of good bone group. Although there was not a significant difference between bone status and other influential factors, such as family type, skip meal, alcohol drinking, smoking and BMI, each has been shown to have an effect, if slight, on the bone status.

• Korean Journal of Community Nutrition
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• v.3 no.2
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• pp.218-227
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• 1998

This study was performed to investigate the effects of dietary protein and calcium levels on iron and zinc balance in eight healthy Korean young women. The 20-day metabolic study consisted of a 2-day adaptation period followed by three 6-day experimental periods. Three experimental diets were the low protein-low calcium(LProLCa ; protein 44g, Ca 422mg), the high protein-low calcium(HProLCa ; 'protein 85g, Ca 365mg) and the high protein-high calcium (HProHCa ; protein 84g, Ca 727mg). Apparent absorption and balance of iron and zinc were significantly higher when subjects were fed high protein-low calcium diet than low protein-low calcium diet. The elevation of dietary calcium significantly depressed the apparent absorption of iron and zinc. The levels of serum iron and zinc were likely to be increased with a high protein diet, but the differences were not significant. There was a strong correlation(r=O.99) between the iron intake and serum iron concentration. Serum zinc concentration was not correlated with hair zinc. Study results revealed that the levels of dietary protein and calcium influence iron and zinc balance in Koreans. This study suggests that dietary recommendations for trace minerals, such as iron and zinc, should be carefully examined. In addition, there is a need to evaluate the bioavailability of milk or beverage products enriched with calcium and iron.

• Journal of the Korean Dietetic Association
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• v.29 no.1
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• pp.49-64
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• 2023

Osteoporosis is a major health problem confronting middle-aged women today. Enhancing calcium intake in early adulthood can increase the rate of calcium gain in bone. In this study, we investigated the association of bone health-related nutritional knowledge levels with calcium-related dietary behavior and nutrition education among women. Data were collected using questionnaires from 347 women aged 20~30 residing in Gyeonggi-do. Subjects were categorized into two groups according to their bone health-related nutritional knowledge (high or low-knowledge group). Knowledge related to bone health and calcium, and dietary habits was assessed, and the preference for and intake frequency of calcium-rich food were collected and analyzed using food frequency questionnaires. The high-knowledge group showed a significantly higher rate of nutritional education experience (33.9%) when compared with the low-knowledge group (18.9%). Not only were the perceptions regarding milk and dairy products more positive in the high-knowledge group (P<0.05), but the intake frequency of calcium-rich foods, such as tofu, soybean, and anchovies, was also higher in this group compared to the low-knowledge group (P<0.05). Overall, the preference for all calcium-rich foods was positively correlated to their intake frequency (P<0.05). Nutrition education experience and the recognition of the need for such education were positively correlated with the bone health-related nutrition knowledge score (P<0.05). In conclusion, bone health-related nutritional knowledge can affect calcium-related dietary behavior and increase the intake of calcium-rich food of 20~30-year-old women and this can contribute to the prevention of osteoporosis. To improve bone health-related nutritional knowledge among young women, it may be important to provide nutrition education.

• Journal of the Korean Dietetic Association
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• v.7 no.2
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• pp.159-166
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• 2001

This study was conducted to investigate the relationship of calcium intake , serum calcium level to calcium supplementation and the effect of nutritional education in middle-aged women. The age distribution of the subjects was 49-55 years. Daily nutrient intakes and dietary sources of calcium were analyzed by convenient method and food frequency questionnaire. At the same time, fasting blood samples were collected and serum calcium and magnesium concentrations were measured before and after nutritional education. The BMD of subjects were measured by Dual Energy X-ray Absorptiometry(DEXA). Serum calcium and magnesium concentrations were significantly(p<0.05) different between pre and post nutritional education. After nutritional education, nutrient intakes were significantly increased(p<0.05), especially calcium. This results suggested that dietary calcium intake as well as nutritional education seem to be important in preventing in middle-aged women.

• Journal of Nutrition and Health
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• v.30 no.3
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• pp.266-276
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• 1997

To investigate the effects of dietary protein and calcium levels on calcium and bone metabolism Sprague-Dawley male growing rats weighting approximately 91.4g were divided into four groups and fed one of the following four experimental diets-15% protein 0.2% calcium ; 15% protein 0.5% calcium ; 30% protein 0.2% calcium ; 30% protein 0.5% calcium-for five weeks. Calcium intake and excretion, apparent calcium absorption were measured and bone densities and mineral contents of femur and scapula were analyzed. Calcium excretion through feces and urine was significantly greater in animals receiving diets of higher calcium. Fecal calcium but not urinary calcium excretion was greater when the protein level was increased from 15% to 30%. Apparent calcium absorption rate was significantly higher with lower calcium intakes. Serum alkaline phosphatase activity was significantly higher in 0.2% calcium group than in 0.5% calcium group, while urinary hydroxyproline excretion was essentially same among all experimental groups. Weights and mineral contents or protein. Bone weights were greater, but calcium and ash contents of femur and scapula were lower in animals on the diet containing low calcium and high protein, which suggests that bone metabolism may be affected by the interaction between calcium and protein intake. These results indicate that during growth high protein intake might be beneficial to bone health if the diet is sufficient in calcium, however, if the diet fails to provide an optimum amount of calcium, such practice might be detrimental.

• Journal of Nutrition and Health
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• v.27 no.1
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• pp.90-99
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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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• v.27 no.1
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• pp.46-52
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• 1994

Recently it is reported that RBC membrane fluidity decreases and RBC calcium levels increase with age. The aim of this study was to analyze changes in lipid and calcium metabolism with age, and to seek relationship of diet and metabolism. With clinically normal Korean adults(male 60, female 63), this study was carried out in three phases : 1) to analyze fatty acid percentage of RBC membrane, 2) to analyze calcium levels of RBC with age, and 3) to compare the effects of dietary fatty acid intake on blood fatty acid profiles. The results are as follows : The P/S ratio of RBC membrane fatty acid decreased with age. The RBC calcium content increased according to age, with women having a higher level than men. The higher intake groups of linolenic acid(C18:3) has statistically higher serum linolenic acid levels. But dietary effects of membrane fatty acid were not found. Therefore, the further research to seek the possible relationship of diet and membrane fatty acid should be continued.

• Journal of the Korean Dietetic Association
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• v.17 no.3
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• pp.313-326
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• 2011

This study was performed to investigate the relationship between milk and milk product consumption and dietary nutrient intake among Korean adolescents. Questionnaire survey and 3-day diet survey using the food record method were completed by a total of 664 subjects. Subjects were divided into three groups, Q1 (low group), Q2 (middle group), and Q3 (high group), according to dairy equivalent of calcium. Dairy equivalent of calcium was determined by the amount of calcium eaten from milk and milk products by individual subjects. As a result, the ratio of school milk service was higher in Q3 (P<0.001). The most frequent answer about the reason for consuming milk and milk products was 'to be taller' followed by 'good taste' and 'health promotion'. Preference for all types of milk such as white-, enriched-, and flavored-milk was higher in Q3 followed by Q2>Q1 (P<0.05). Ratio of mean daily dietary nutrient intakes of dietary fiber, vitamin C, folate, and calcium to RNI was lower than 2/3 for all of the groups. These mean daily dietary nutrient intakes were significantly higher in Q3 (P<0.05), and in particular, mean daily dietary calcium intake, which was the lowest nutrient consumed by Korean adolescents, was also the highest in Q3 followed by Q2>Q1 (P<0.05). The above results suggest that the school milk program is very helpful in encouraging adolescents to consume milk and milk products and consequently ensure their optimal nutrition. Therefore, we should try to encourage adolescents to participate in the school milk program more actively through nutritional education and government policy.