• Journal of the East Asian Society of Dietary Life
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• v.15 no.6
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• pp.687-699
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• 2005

In order to investigate the effect of dietary zinc and phytic acid levels on protein metabolism in rats, male rats of Sprague-Dawley strains weighing approximately $60\~74g$ were fed different diets which contained 0, 0.35 and $1.05\%$ phytic acid each at 3 levels of zinc(0, 30 and 1,500 ppm zinc) for 28 days. Result obtained in this experiment are summarized as follows; 1. Body weight gait food consumption food efficiency ratio and protein efficiency ratio were lower in the rats fed zinc deficient diet(0 ppm zinc) than in those consuming 30 or 1,500 ppm dietary zinc, and the additional effect of phytic acid were not observed in all of then 2. Liver weight was lower in the rats fed 30 ppm zinc diet than in those fed 0 or 1,500 ppm-zinc diet but kidney and spleen weights were lower in the rats fed zinc deficient diet than in those fed 30 or 1,500 ppm-zinc diet Among organs measured only the liver appeared to be influenced by dietary phytic acid: the more the dietary phytic acid, the more the weight of liver, 3. Fecal nitrogen was decreased in the rats fed zinc deficient diet compared with those fed 30 or 1,500 ppm dietary zinc. Urinary nitrogen was increased in the rats fed $1.05\%$ dietary phytic acid compared with those fed 0.35 or $0\%$ dietary phytic acid Nitrogen retention of rat was influenced by neither dietary zinc nor phytic acid. 4. Urea nitrogen was decreased with increasing dietary zinc levels, and creatinine and uric acid levels were increased with increasing dietary zinc concentration or with additional quantity of phytic acid. Uric acid appeared to be influenced by zinc x phytic acid interaction; especially, the presence of phytic acid in the 30 ppm-zinc diet had significant effect on uric acid content. 5. Hemoglobin concentrations and hematocrit ratio were higher in the rats fed 30 ppm dietary zinc than in those fed 0 or 1,500 ppm-zinc diet Serum zinc concentration was increased with increasing dietary zinc levels. The content of total protein albumin and BUN and the ratio of albumin to globulin in serum, and protein content in liver were influenced by neither dietary zinc nor phytic acid.

• Nutrition Research and Practice
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• v.7 no.5
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• pp.380-384
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• 2013

Zinc may participate in blood pressure regulation and in the pathogenesis of hypertension. The study examined the relationship between zinc status and blood pressure in obese Korean women. Forty obese women (body mass index (BMI) ${\geq}25kg/m^2$) aged 19-28 years participated in this study. Zinc intake was estimated from one 24 hour recall and 2-day diet records. Serum and urinary zinc concentrations were determined by atomic absorbance spectrophotometry. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using an automatic sphygmometer. Metabolic variables, such as waist circumference, triglyceride, high density lipoprotein (HDL) cholesterol, fasting glucose, and fasting insulin, were also measured. Dietary zinc intake of obese women was averagely 7.5 mg/day. Serum zinc and urinary zinc concentrations were $13.4{\mu}mol/L$ and $378.7{\mu}g/day$, respectively. Averages of SBP and DBP were 119 mmHg and 78 mmHg. Dietary zinc intake was negatively correlated with SBP after adjusting for energy intake (P < 0.05), but serum and urinary zinc concentrations were not found to be correlated with SBP or DBP. Multivariate linear regression analysis showed that dietary zinc intake was inversely associated with SBP in obese women after adjusting for body weight, energy intake and sodium intake (P = 0.0145). The results show that dietary zinc intake may be an independent risk factor of elevated SBP in obese Korean women.

• The Korean Journal of Community Living Science
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• v.16 no.4
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• pp.25-38
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• 2005

In order to investigate the effect of dietary zinc and phytic acid levels on enzyme activity and lipid metabolism in rats, male Sprague-Dawley rats, weighing approximately 60-74g, were fed different diets which contained 0, 0.35 or $1.05\%$ phytic acid each at 3 levels of zinc (0, 30 and 1500ppm zinc) for 28 days. Body weight gain, food consumption, and food efficiency ratio were lower in the rats fed a zinc deficient diet (0ppm zinc) than those consuming 30 or 1500ppm dietary zinc. The activities of GOT, GPT and alkaline phosphatase were lower in the rats consuming 30ppm zinc than those fed 0 or 1500ppm zinc diet. The activity of GOT was increased in rats consuming $0.35\%$ phytic acid, whereas that of alkaline phosphatase was decreased in the rats fed phytic acid-containing diet. The concentration of phospholipid in serum was higher in rats fed $0.35\%$ dietary phytic acid, whereas that of liver phospholipid was higher in zinc deficient groups, and increased by addition of dietary phytic acid. The concentration of triglyceride in serum from rats fed 30ppm zinc was lower than those fed 0 or 1500ppm zinc On the other hand, liver triglyceride was higher in both the rats fed 30ppm zinc and $0.35\%$ phytic acid. The concentration of serum total cholesterol was lower in the rats fed 30ppm zinc diet, and it was increased by addition of dietary phytic acid. But liver total cholesterol was higher in 30ppm zinc group. HDL-cholesterol in serum was the highest in both rats consuming 30ppm zinc and $0.35\%$ dietary phytic acid, and the ratio of HDL-cholesterol to total cholesterol was higher in rats consuming 30ppm zinc diet. In conclusion, we suggest that coronary heart disease or liver disease can be prevented with phytic acid in rats which are fed the high zinc diet.

• Journal of Nutrition and Health
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• v.33 no.5
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• pp.517-523
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• 2000

The effect of dietary zinc deficiency and age on lipid peroxide level was investigaed in rats. Zinc level in serum and liver were also measured. Fifty Sprague-Dawly male rats aging 8 months(older rats) and 2 months(younger rats) were used as experimental animal. Zinc deficient diet(1.1ppm) and normal zinc diet(36.5ppm) were used as experimental diets. Rats in each age group were divided into zinc deficient(ZnDF), zinc pair-fed(ZnPF) and zinc ad-libitum(ZnAL) to remove the variances of food intake. After 4 weeks of experimetal period, rats were sacrificed. Thiobarbituric acid reactive substance(TBARS) levels in plasma and liver, lipofuscin and conjugated diene levels in liver were measured as lipid peroxide index. Food intakes of all groups were not different because zinc deficiency did not reduce food intake in ZnDF group. Younger rats gained weight continuously, while older rats lost weight in the begining of experiment and regained afterwards. In older rats, serum zinc level was decreaed while plasma TBARS. level was increased in ZnDF group. In younger rats, plasma TBARS concentration was increased in dietary zinc deficient rats although serum zinc concentration was not reduced. Liver zinc concentration was significantly higher in older rats comparing to younger rats. However, there was no difference among the three dietary groups. Liver TBARS level was not different by age or dietary zinc level. However it was tended to be higher in older rats. However there was no difference by the dietary zinc level. In both age groups, ZnDF group significantly increased plasma TBARS levels, which suggested dietary zinc deficiency could increase lipid peroxidation in part. Significantly higher levels of lipofuscin and conjugated diene in older rats suggested lipid peroxidation was accelerated by aging.

• Nutrition Research and Practice
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• v.17 no.2
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• pp.257-268
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• 2023

BACKGROUND/OBJECTIVES: Zinc is an essential trace mineral which is important for the growth and development of the human body and immunological and neurological functions. Inadequate zinc intake may cause zinc deficiency with its adverse consequences. In this study, we aimed to estimate the dietary zinc intake levels and sources among Koreans. SUBJECTS/METHODS: For this secondary analysis, we obtained data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016-2019. Individuals aged ≥ 1 yr who had completed a 24-h recall were included. The dietary zinc intake of each individual was calculated by applying data from a newly developed zinc content database to the KNHANES raw data. We also compared the extracted data with the sex-, age-specific reference values suggested in the Korean Dietary Reference Intakes 2020. The prevalence of adequate zinc intake was then evaluated by the proportion of the individuals who met the estimated average requirement (EAR). RESULTS: The mean zinc intake of Koreans aged ≥ 1 yr and adults aged ≥ 19 yrs were 10.2 and 10.4 mg/day, equivalent to 147.4% and 140.8% of the EAR, respectively. Approximately 2 in 3 Koreans met the EAR for zinc, but the zinc intake differed slightly among the different age and sex groups. In children aged 1-2 yrs, 2 out of 5 exceeded the upper level of intake, and nearly half of the younger adults (19-29 yrs) and the elders (≥ 75 yrs) did not meet the EAR. The major contributing food groups were grains (38.9%), meats (20.4%), and vegetables (11.1%). The top 5 food contributors to zinc intake were rice, beef, pork, egg, and baechu kimchi, which accounted for half of the dietary intake. CONCLUSION: The mean zinc intake among Koreans was above the recommended level, but 1 in 3 Koreans had inadequate zinc intake and some children were at risk of excessive zinc intake. Our study included zinc intake from diet only, thus to better understand zinc status, further research to include intake from dietary supplements is needed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.346-353
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• 1995

The dietary requirement for zinc to maintain optimally the various metabolic and physiological funcitons is still under study. Human beings adapt to reductions in zinc intake by reducing the rate of growth or zinc excretion. Reductions in dietary zinc beyond the capacity to maintain homeostasis lead to utilization of zinc from an exchangeable pool. Loss of a small, critical amount of zinc from this pool leads to both biochemical and clinical signs of zinc deficiency. Zinc requirements have been assessed by balance studies and factorial method. As tissue zinc status influences endogenous losses and the dietary needs, individuls in good status may require higher amounts of zinc than those in poor status. While plasma zinc is insensitive to reducitons in dietary zinc, it is regarded as a valid, useful indicator of the exchangeable pool of zinc. Plasma metallothionein concentrations may prove useful for identifying poor zinc status. It has been suggested that functional end point measurement is the new direciton for zinc requirement. However, determination of the functional response to a marginal zinc intake is difficult because of the lack of a specific, sensitive indicator of zinc status. Presently, no good method for assessment of human zinc requirements exists.

• Nutrition Research and Practice
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• v.2 no.1
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• pp.41-45
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• 2008

The purpose of this study was to analyze the relationships among zinc status, diet quality, glycemic control and self-rated physical activity level of type 2 diabetic patients. Dietary intakes for two non-consecutive days were measured by 24-hour recall method for seventy-six diabetic patients. Fasting blood glucose and HbA1c were measured for the assessment of glycemic control. We evaluated the extent of dietary adequacy by the percentage of subjects with a dietary intake of a nutrient less than the estimated average requirement(EAR), the dietary diversity score(DDS) and the dietary variety score(DVS). Zinc status was assessed from serum levels and urinary excretion. Dietary inadequacy was serious for five nutrients: riboflavin, calcium, thiamin, zinc and vitamin C. Dietary intakes from the meat, fish, and egg food groups and the milk food group were below the recommended level. We found that subjects with high levels of physical activities had significantly higher DVS and serum zinc levels compared to others (p

• Korean Journal of Community Nutrition
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• v.2 no.1
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• pp.52-62
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• 1997

This study was intended to examine the zinc status of free-living adult women living in the Taegu region. Zine intake of 102 female subjects was measured by food frequency method for 3 consecutive days. Urinary zine was assessed from urine samples collected fir twenty four hours. Average dietary zinc intake of adult female subjects using food record was 5.9$\pm$1.8mg which was 49$\%$of Korean RDA. When zine intake by frequency method was higher than by food record. Average urinary zine intake by frequency method was higher than that by food record. Thus, it appeared that zinc intake by frequency method was higher than that by food record. Average urinary zinc excretion of 102 adult female subjects was 0.28$\pm$0.16mg, which belonged to marginal zinc deficiency range. Fifty nine of 102 subjects showed marginal zinc deficiency as assessed by urinary zinc excretion. If we compare the zinc status of adult female subjects by age group, zinc intake in the 50s was significantly higher than any other age groups. However, there were no significant differences in zinc status according to BMI groups and BMI groups. Significant correlations were found between zinc intake and energy, protein, carbohydrate and fat intake. Based on dietary zinc intake and urinary zinc, we concluded that zinc status of adult female living in the Taegu region is marginally deficient.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.325-330
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• 2001

The purpose of this study was to evaluate the obesity index and effect of dietary zinc and iron levels on serum trace minerals status in the high fat diet-induced obese rats. Male Sprague-Dawley rats were randomly assigned to control and high fat diet groups. Ten weeks later, the control and high fat diet group were rearranged into six groups by zinc and iron levels. After 16 wk serum zinc, iron, copper and manganese was analyzed. Obesity index was significantly higher in the group fed high fat diet (20% lard) than that of control group (5% corn oil). Body fat content was 12.10$\pm$4.51g/100g BW in high fat diet group and 7.64$\pm$4.18g/100g BW in control group. So, the obese rats were successfully induced by high fat diet. The trace mineral concentration of obese rats in serum were affected by zinc levels. Serum zinc concentration was increased by dietary zinc overload, whereas the iron, copper and manganese were decreased. Specially the manganese concentration was significantly affected by zinc levels. In both groups, serum trace mineral concentration was not changed significantly by the dietary iron levels. There were positive correlations between zinc, iron and manganese concentration according to dietary zinc and iron levels.

• Journal of the Korean Dietetic Association
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• v.7 no.3
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• pp.258-266
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• 2001

The purpose of this study was to investigate the effect of dietary zinc on the carbohydrate metabolism and the serum content of magnesium and chromium in rats fed normal diet. Animals were divided into three groups by different dietary zinc levels which were low(15ppm), normal(30ppm) or high(60ppm). Serum glucose and Insulin concentrations were assessed by the glucose method and the radio immuno assay respectively. Serum zinc. magnesium and chromium contents were measured by Indectively Coupled Plasma(ICP). Results of the study were as follows : 1. Feed intake in a zinc deficiency group was significantly higher than that in other group, but the weight gain in high zinc diet group was significantly lower than in other groups. 2. There were no significant differences in liver, kidney and spleen weight. 3. Serum glucose, insulin and zinc concentrations were not significantly different among different dietary zinc groups, However serum magnesium and chromium concentrations were significantly decreased as the level of dietary zinc was increased.