• Journal of Nutrition and Health
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• 제29권10호
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• pp.1096-1104
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• 1996

This study was performed to evaluate the effect of sodium cholride supplementation on bone metabolism in female rats consuming a low calcium diet. Twenty five female rats were divided into three dietary groups (control Na : 0.1038%, 1% Na : 1.036%, 2% Na : 2.072%). All experimental diets contained 0.27% Ca and were fed to rats with deionized water for 7 weeks. Bone mineral density(BMD) and bone mineral content(BMC) of total body, spine and femur were measured using energy x-ray absorptiometry(DEXA) by small animal software. Then Ca efficiency was calculated from BMD and BMC. Serum Ca, P, Na and urine Ca, P, Na were determined. Urinary pyridinoline, serum ALP were measured to monitor bone resorption. Following 7 weeks, sodium cholride supplemented groups had higher urinary Ca excreteion, urinary pyridinoline, crosslinks value and serum ALP. There was no significant difference in case of serum Ca among all groups. Sodium chloride supplemnted groups had lower Ca effciency of total, spine and femur BMD and BMC than that of control group. In conclusion high salt intake not only increases urinary Ca excretion as urinary Na excretion does but also increase bone resorption and decrease Ca efficiency of each bone. It is been suggested that high salt intake may be harmful for bone maintenance. Therfore, the decrease of salt intake to the level of recommendation would be desirable.

• Journal of Nutrition and Health
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• 제31권6호
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• pp.1039-1048
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• 1998

It has been reported that boron may be beneficial for optimal calcium metabolism and, thus, optimal bone metabolism. Therefore, we designed a study to determine the effect of boron supplementation on Ca and bone metabolism in rats. The rats of 80-l40g body weight were given a control(0ug), 5$\mu\textrm{g}$, 10$\mu\textrm{g}$, 20$\mu\textrm{g}$, 40$\mu\textrm{g}$, or 80$\mu\textrm{g}$ boron supplement per Is diet for 4-weeks. The results are summarized as follows. There were no differences in total food intake and weight gain among the experimental groups. fecal Ca excretion, urinary Ca excretion, apparent Ca absorption, Ca retention, serum alkaline phosphatase activity, and urinary hydroxyproline were not affected by boron supplementation. There was no difference in serum creatinine. Whereas, urinary creatinine excretion was increased with increasing boron supplementation, and conse-quently creatinine clearance was increased with boron supplementation. No differences were found in length, weight, density, Ca content of femur and scapular. The findings suggest that boron supplementation was not effective in Ca and bone metabolism in growing rats fed normal Ca diet. (Korean J Nutrition 31(6) : 1039-1048, 1998)

• Journal of Nutrition and Health
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• 제34권1호
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• pp.54-61
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• 2001

The Ca and P balance studies were carried out with two different diets varying Ca levels : the current Korean RDA level(normal Ca diet) and the high level (High Ca diet) which was determined by adding 2SD to mean Ca intake of all subjects. The subjects were sever healthy adult woman, aged from 25 to 32 years old. The metabolic studies were conducted for two weeks with a days recess in between : during the fist week with normal Ca diet and during the second week with high Ca diet. The composition of nutrients excepting Ca of both diets was similar to subjects usual intake. The result were summarized as follows: Mean daily Ca intake was 728.8mg from norma Ca diet and 945.5mg from high Ca diet. Fecal excretion of Ca increased significantly(p<0.05) on high Ca diet, but urinary excretion of Ca did not show any differences between the two diet periods. There were also no significant differences in Ca retention between the two diet periods but it tended to be greater during high Ca diet period: 112.1mg/day during normal Ca diet period vs 208.2mg/day during high Ca diet period. Mean apparent Ca absorption was 41.2% on normal Ca diet and 42.1% on high Ca diet, indicating it was not affected by high Ca intake level used in this study. On the contrary, P retention was significantly increased up to 109.4mg/day with high Ca diet as compared to- 41mg/day with normal Ca diet. There were no significant differences in fecal and urinary excretion of P but those to be lower during high Ca diet period. The above results showed that higher Ca intake more than current RDA(700mg/day), in the level of 945.5mg/day, could increase Ca retention through Ca absorption comparable to the rate appeared on RDA level intake. P retention was also improved by high Ca intake. Therefore, higher Ca intake than the current RDA level seemed to produce favorable effects on bone health in adult women. However, the current RDA level seemed to be relatively appropriate, considering the results that all the subjects but one maintained positive Ca balance with normal Ca diet. (Korean J Nutrition 34(1):54-61, 2001)

• Journal of Nutrition and Health
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• 제21권1호
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• pp.23-35
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• 1988

This study was designed to find out the effects of aerobic exercise on lipid and Ca metabolism in seven healthy college women, aged 20 to 22 years. Metabolic studies were conducted before and after a 10-weeks exercise period, during which subjects participated in the planned aerobic dance program every day except Sunday. The initial mean time engaged in the exercise was 28 minutes and it was gradually increased up to 45 minutes around the middle point of the exercise period. During both of metabolic study periods, the subjects ate experimental diets which supplied about 120g of protein and 600mg of Ca daily and during the rest of the experimental period they ate their usual diets. The use of alcoholic beverages and drugs were prohibited. The results were summarized as follows. 1) The effect of exercise on lipid metabolism. (1) Mean body weight decreased significantly after exercise(p<0.01) and it did not show a significant decline in skinfold thickness and total body fat contents. (2) Serum total cholesterol level decreased significantly after exercise(p<0.05) and TG level also tended to be lower than that of pre-exercise period. Exercise did not exert any influence on the level of serum HDL-cholesterol in this study. (3) Exercise did not alter total lipid content in feces and apparent lipid absorption rate. 2) The effect of exercise on Ca and P metabolism. (1) After exercise, focal Ca excretion was slightly reduced, however, urinary Ca excretion was not significantly changed. In the results, a slight increase was shown in body Ca retention after exercise. (2) Exercise tended to increase urinary P excretion, but neither P balance nor fecal excretion was significantly changed after exercise. (3) Bone mineral content was not affected by exercise. In summary, aerobic exercise decreased total cholesterol and TG level in serum and tended to increase body Ca retention. With the results, it can be concluded that the additional physical activities beyond the normal daily life in college women might prevent some degenerative diseases-suchas atherosclerosis and osteoporosis.

• Journal of Nutrition and Health
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• 제28권4호
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• pp.298-308
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• 1995

To investigate the effect of estrogen and dietary protein level on Ca metabolism, female rats were undergone ovariectomy or sham-operation. Ovariectomized rate were divided into either estrogen-or vehicle-treated groups. Each treatment group was again divided into 40%-casein(H) or 10%-casein(L) diet groups. All experimental diets contained 0.2% Ca, 0.4% P and fed to rats for 8 weeks. Apparant Ca absorption and Ca balance were not affected by dietary protein level and ovariectomy, however they were increased by estrogen injection and this effect was even higher in low protein groups. Urinary Ca excretion were higher in high protein groups. GFR was not affected by dietary protein level, ovariectomy, or by estrogen injection. Urinary protein excretion was higher in high protein groups, which implies that the kidney funtion was deteriorated by high protein diet, and this may account partly for the higher urinary Ca in high protein groups. Ovariectomy or estrogen treatment had no effect on urinary protein excretion. Urinary hydroxyproline was higher in ovariectomized rats and increased in high protein grous. Elevated value of ovarictomized rats was lowered by estrogen injection, especially in low protein group. Alkaline phosphatase tended to increase in ovariectomized groups and lowered with estrogen treatment, but this difference was not statistically significant. Serum PTH was not affected by ovariectomy and dietary protein level. Therefore the increased hydroxproline excretion does not seem to be attributed to PTH. Dietary protein level, ovariectomy and estrogen treatment did not affect the weights and components of femur, scapular, and 4th vertebra. Ash/wt ratio of femur was, however, lower in ovariectomized rats and increased with estrogen treatment. Therefore, among the bones studied, femur seemed to be the most vulnerable. The results of this study shows that estrogen treatment may alleviate or reduce bone loss in postmenopausal women somewhat, especially for those people with low protein diet.

• Journal of Nutrition and Health
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• 제25권2호
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• pp.140-149
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• 1992

It was hypothesized that variations within the range of usual calcium(Ca) and sodium(Na) intakes of Korean influence bone mineral density(BMD) in healthy premenopausal women The relationship of nutrient intake urinary excretion physical activity and circulating IGF-1 level with spine({{{{ { L}_{2 } }}}}-{{{{ { L}_{4 } }}}}) and femur BMD was determined in 47 normal premenpausal women. There was a positive relationship between BMD of the lumbar spine and body weight. The BMD of femoral neck was positively correlated with Ca and protein intakes from animal source and circulating IGF-1 level. There was a negative relationship between femur BMD and both Na intake and urinary excretion. The complex interrelations between femur BMD regression analysis, From this analysis. Ca intake from animal origin was the only significnat Premenopausal women of femur BMD. In the basis of femur BMD three groups were divided Premenopausal women of femur BMD$\leq$0.84g/cm2 showed depressed Ca intake of animal origin in later and early life and enhanced urinary Na excretion compared to women of femur study suggests that dietary Ca is a major constituent affecting femur BMD because of a decrease in net Ca absorption and an increase in urinary Ca loss.

• Journal of Nutrition and Health
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• 제34권4호
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• pp.409-416
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• 2001

In order to evaluate the effect of habitual Na and Ca intake on blood pressure regulation, we measured the habitual dietary intakes of Na and Ca, urinary excretion of Ca, Na and K, and plasma level of renin activity, aldosterone, and indices of Ca metabolism in 27 untreated hypertensive women and 30 age-matched normal women on a free diet. Hypertensive and total subjects were divided into four groups according to habitual dietary intakes of Na and Ca as low Na-low Ca(LNLC), low Na-high Ca(LNHC), high Na-low Ca(HNLC), and high Na-high Ca(HNHC). HNLC hypertensive group showed the lowest level of plasma renin activity, 25-(OH) Vit D$_3$, calcitonin and serum total Ca, and presented the highest level of PTH and urinary excretions of Na/K and Ca/Cr. There were no significant difference in plasma level of aldosterone and urinary excretion of Na and K among four hypertensive groups. When all subjects were divided into four groups according to the same method, HNLC group showed the highest level of blood pressure with no statistical significance and the lowest level of calcitonin and total serum Ca. The above results indicated that renin-aldosterone system and Ca regulating hormone has a mutual relationship in hypertension. Na and Ca may interact each other, rather than affecting independently blood pressure control. As a result, considering the fact that daily balance of Na and Ca intakes affects Na and Ca regulating hormones and urinary excretion of Na and Ca, it may be involved in blood pressure control. These results suggest that maintaining an adequate intake of Ca with less intake of Na may prevent from the risk of hypertension. (Korean J Nutrition 34(4) : 409~416, 2001)

• Journal of Nutrition and Health
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• 제26권9호
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• pp.1118-1128
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• 1993

This study was undertaken to investigate the acute effect of caffeine consumption on the change of mineral concentration in serum and urinary mineral excretion in healthy young females. On two separate mornings at one week intervals, each subject drank a coffee which contained no caffeine and 3mg/kg body weight caffeine. To obviate dietary effects on mineral concentration in serum and urine, each subject fasted at least ten hours before consuming the test beverage. At one, two, three and four hours, serum and urine production collected seperately for measurement of sodium, potassium, calcium, phosphorus and magnesium concentration. The results were as following : 1) Mean age of subjects was 20.6$\pm$0.32, Mean body mass index of subjects was 21.64$\pm$0.89, which was within $\pm$10% of ideal body weight. 2) Total urine volume of caffein groups for 4 hour after caffeine consumption was higher than that of decaffeine one, but urine pH was unchanged after caffeine consumption. Total urinary four hour excretion of creatinine was not affected by caffeine consumption and creatinine clearance also was not different from the control value. 3) In serum, mean three hour content of sodium(p<0.01) and phosphorus was higher in the subject given the caffeine. Mean serum magnesium and calcium contents were lower in caffeine group than that of decaffeine one. Mean serum magnesium content for three hour after caffeine ingestion was affected by caffeine consumption(p<0.001). Mean serum content of potassium was unaffected by caffeine consumption. 4) Total urinary four hour excretion of sodium, increased significantly after caffeine consumption(p<0.05), while total urinary four hour excretion of potassium, calcium, phosphorus and magnesium was unchanged after caffeine intake. Urinary excretion of Na, Ca, P and Mg was greatest at one hour after caffeine consumption, especially urinary sodium and potassium excretion was significantly high(p<0.05, p<0.01). The above results show that only 3mg caffeine per kg body weight increase the urinary macro mineral excretion in healthy young females.

• Journal of Nutrition and Health
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• 제28권5호
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• pp.415-425
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• 1995

This study was performed to investigate the effect of dietary protein level on the metabolic changes of Ca and skeletons in postmenopausal women, using ovariecotomized rats as an animal model. The female rats of 200∼250g were fed either 8%(L) or 50%(H) casein diet for 15 weeks(1st experiment). At 15th week, the rats of each diet group were undergone ovariectomy or sham-operation and they were continued to feed the same experimantal diet for 9 more months(2nd experiment). Ca metabolism, kidney function and bone composition were determined at the end of 1st experiment, 3rd and 9th month of 2nd experiment. After 1st experiment, high protein group showed higher urinary Ca and protein excretion, however, there was no difference in GFR and urinary hydroxyproline excretion. The weights, ash and Ca content of femur, scapular and vertebra tended to be higher in high protein groups which tells that high protein promoted skeletal growth. In 2nd experiment, high protein group showed higher urinary Ca and protein excretion and lower Ca absorption and balance. GFR was not affected by dietary protein and ovariectomy but increased with time, as well as kidney weight which shows the continuous development of kidney at this age of 15 month in rats. There were no difference in urinary hydroxyproline, serum ALP, and PTH among experimental groups. The weights of femur, scapular, 4th vertebra increased with time, showing the skeleton continues to grow at this age in rats. However, Ca contents, Ca/wt, Ca/ash were decreased with time and tended to be lower in high protein group especially in femur. In conclusion, prolonged feeding of high protein diet deteriorated Ca metabolism and induced bone loss as time after menopause is extended.

• Journal of Nutrition and Health
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• 제26권6호
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• pp.728-742
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• 1993

The effects of dietary calcium levels on the blood pressure and calcium metabolism were investigated. Nine normotensive female college students having hypertention family history were participated in 4-week dietary expeiments. They were provided with either high Ca diet (HCa, average 797mg/day) or low Ca diet(LCa, average 225mg/day) during two weeks, each, consecutively. Sodium amounts of the body diets were 3566~4022mg/day, which were ordinary sodium intake levels in Korea. After the HCa, systolic blood pressures(SBR) in both seated and isogrip-seated postitions were decreased by about 2.5mgHg, comparing with those after the LCa(p<.05). Diastoilc blood pressures(DBP) were not changed by dietary calcium levels. Serum total Ca, ionized Ca, Mg and P levels and Ca/Mg ratio were not different between the HCa and the LCa. Serum parathyroid hormone(PTH) levels were similar between two diets, but individually in seven of nine subjects, the slightly lower values of PTH were observed after the HCa than after the LCa. Urinary excretion of Ca(p<.01), Mg(p<.05) and P(p<.1) were increased after the HCa comparing with the LCa, but Ca/Mg ratio were not different between the two diets. SBP was in positive correlations with boty urinary excretion of Ca(supine, r=.7356, p<.05) and urinary Ca/Mg ratio(isogrip-seated, r=.7483, p<.05). SBP was also negatively correlated with serum P level(supine, r=-.6930, p<.05) and DBP was in negative correlation with urinary P excretion(seated, r=-.8586, p<.01). Serum total and ionized Ca, Mg, Ca/Mg ratio were not significantly correlated with blood pressures.