• Journal of Fisheries and Marine Sciences Education
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• v.28 no.5
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• pp.1220-1230
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• 2016

The purpose of this study is to investigate the effect of 20s university student bodybuilders' protein intake differences with resistant exercise(weight training) by 12 weeks on solt lean mass and body composltion. Natural protein(Chicken breast meat) intake group and Whey protein isolates(WPI) intake group are the experimental groups. Conventional meal intake group is the control group. This study proposes a efficient protein diet for weight training. The results were as follows. In the experimental group(natural protein intake), muscle mass and lean body mass was significantly increased, but body fat percentage was significantly decreased. In the experimental group(WPI intake), muscle mass and lean body mass was significantly increased, but body fat percentage was significantly decreased. In the control group(conventional meal intake), muscle mass and lean body mass was insignificantly increased, but body fat percentage was insignificantly decreased. In addition, there was not a significant difference among intake groups, and also not a differentiated effect between natural protein and WPI intake. In conclusion, natural protein and WPI made muscle mass and lean body mass rise, body fat percentage reduced effectively. Only WPI intake(without natural protein intake) was the efficient mean to increase muscle mass and lean body mass, and to decrease body fat percentage.

• Journal of Korean society of Dental Hygiene
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• v.16 no.6
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• pp.943-953
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• 2016

Objectives: This study aims to evaluate the association between intake of energy, calcium and protein and permanent teeth caries in Korean children. Methods: Research data were obtained from the Fifth Korean National Health and Nutrition Examination Survey (KNHANES) and 1,274 Korean children within 9 to 12 years were selected as subjects for the study. The DMFT index, nutrition factors including total energy and protein intake, and degree of calcium intake were identified Chi-square test was performed to assess the difference of distribution in socioeconomic status, oral health behavior and nutrition factors according to sex. Multilevel linear regression analysis was performed to identify the relationship between DMFT index and the related variables. Results: Significant differences in energy, protein and Ca intake were confirmed according to the sex. Among 10 year-old children who intake total energy less than the recommended had few dental caries (p=0.058, ${\beta}=-0.411$). In addition, 11-year-old children having protein intake more than the recommended experienced dental caries (p=0.02, ${\beta}=0.588$). Conclusions: These results suggest that, there is significant differences between intake of energy and protein and dental caries among Korean children. However, further researches is needed to confirm between intake of energy and protein as a related factor.

• Korean Journal of Community Nutrition
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• v.27 no.1
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• pp.47-60
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• 2022

Objectives: This study aimed to evaluate dietary protein intake and its adequacy among Korean adults during recent 10 years. Methods: Based on the 2010 ~ 2019 Korea National Health and Nutrition Examination Survey (KNHANES) data, a total of 51,296 adults aged 19 years old or more who participated in a one-day 24-hr dietary recall were included. Dietary protein intake was estimated as percentages of total energy (% of energy) and grams per body weight (g/kg/day) and compared with the 2020 Dietary Reference Intakes for Koreans to evaluate the adequacy of protein intake. In addition, proportions of people whose protein intakes were less than the estimated average requirement (EAR) and above the upper limit of the acceptable macronutrient distribution range (AMDR) (> 20% of energy) were calculated according to sociodemographic characteristics. Results: Protein intake was increased from 14.7% of energy in 2010 to 15.6% of energy in 2019 among Korean adults. However, there was no increase in protein intake relative to the recommended nutrient intake (% RNI) during the recent 10 years. Protein intake relative to the RNI was decreased from 130.2% in 2010 to 121.1% in 2019 (P for trend < 0.0001) among total participants, and a significant decreasing trend was observed in all age groups except for over 65 years old. However, protein intake relative to the RNI was lowest in the elderly (98.6%). Proportions of low protein intake (< EAR) and high protein intake (> AMDR) increased in the past 10 years (P for trend < 0.0001 for all), and these were associated with socioeconomic statuses, such as education and household income levels. Conclusions: These findings suggest that protein adequacy in Korean adults has not been improved over the past decade compared with recommended levels. Nutritional education and intervention programs should consider different intake levels according to sociodemographic characteristics.

• Journal of Nutrition and Health
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• v.21 no.2
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• pp.99-112
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• 1988

This study was performed to investigate the effects of dietary protein and calcium levels on calcium metabolism in eight healthy Korean adult females. The 2-day metabolic study consisted of a 2 day adaptation period and three 6-day experimental periods. Three experimental diets were low protein low calcium(LPLCa : protein 44g, Ca 422mg), higher protein low calcium(HPLCa : protein 85g, Ca 365mg), and high protein high calcium (HPHCa : protein 84g, Ca 727mg). The apparent calcium absorption was likely to be affected by the calcium intake rather than by the protein intake. Average calcium absorption rate was about 23-29% of calcium intake. The calcium balance was -21.44mg for LPCa, -25.02mg for HPLCa, and -3.22mg for HPHCa. Avergae urinary calcium excretion was 127.7mg for LPLCa, 108.6mg for HPLCa, and 215.4mg for HPHCa. Urinary calcium excretion was more closely related to the changes of calcium intake rather than of protein intake. These results seemed to be due to the interactions between the high phosphours contained in the high protein diet and the little discrepancy of protein intake levels.

• Journal of Nutrition and Health
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• v.30 no.7
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• pp.840-847
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• 1997

In order to investigate the protein intake of breast-fed infants, we examined sixty infants during the first 5 months of lactation. Human milk intake infants increased during lactation with the respective values of 525, 671, 734, 744 , 765 and 768g/day t 0.5, 1, 2, 3, , 4 and 5 months postpartum. The average protein contents of human milk showed 1.58, 1.38, 1.23, 1.11, 1.08and 1.07g/100g respectively. The protein intake of boys during the first 5 months of lactation averaged 9.11g/day which was higher than the 7.71g/day average for girls. Body weight of infants at birth was 3337g, which increased significantly during lactation. The protein intake per body weight of breast-fed infants in boys was significantly higher than that in girls(p<0.01). Protein intake of breast-fed infants had survey, a revaluation of the protein intake and recommended dietary allowance of protein during early infancy should be considered.

• Nutrition Research and Practice
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• v.17 no.5
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• pp.969-983
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• 2023

BACKGROUND/OBJECTIVES: We investigated the association of plant and animal protein intake with grip strength in Koreans aged ≥ 50 yrs. SUBJECTS/METHODS: The data was collected from 3,610 men and 4,691 women (≥ 50 yrs) from the 2016-2018 Korea National Health and Nutrition Examination Survey. We calculated the total energy intake, and the intake of animal and plant protein and collected dietary data using 1-day 24-h dietary recalls. Low grip strength (LGS) was defined as the lowest quintile (men: up to 26.8 kg, women: up to 15.7 kg). The association of protein intake with grip strength was examined using Pearson's correlation and multiple linear regression analysis. RESULTS: The results proved that participants with LGS had lower daily energy, protein and fat intake, and percent energy from protein than those with normal or high grip strength (P < 0.0001). Total energy intake, animal protein, and plant protein were positively associated with grip strength. A higher intake of total plant protein (P for trend = 0.004 for men, 0.05 for women) and legumes, nuts, and seeds (LNS) protein (P for trend = 0.01 for men, 0.02 for women) was significantly associated with a lower prevalence of LGS. However, non-LNS plant protein intake was not associated with LGS (P for trend = 0.10 for men, 0.15 for women). In women, a higher total animal protein intake was significantly associated with decreased LGS (P for trend = 0.03). CONCLUSIONS: Higher total plant protein and LNS protein intake are negatively associated with LGS.

• Journal of Nutrition and Health
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• v.21 no.1
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• pp.47-60
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• 1988

This study was performed to investigate the effect of dietary levels on protein metabolism in eight healthy Korean adult females. The 20-day metabolic study consisted of 2 day adaptation period and three 6-day experimental. Three experimental diets were low protein (LP : protein 44g), high protein(HP : protein 85g) and high animal protein (HAP : protein-84g). The apparent absorption and balance on nitrogen were significantly higher in high protein than in low protein diet. Nitrogen, absorption rate was about 75% for low protein and about 85% for high protein intake. The mean values of nitrogen balance were -1.28% for low protein and 0.78% for high protein diet. All the subjects were in negative nitrogen balance at the low protein intake while they were in positive nitrogen balance at the high protein intake. The mean daily urinary nitrogen excretion increased with increased level of protein intake. Urea nitrogen was the largest part of the urinary nitrogen. The ratio of urea nitrogen to total urinary nitrogen increased significantly for 79 to 85% as protein intake was doubled.

• Journal of the Korean Society of Food Culture
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• v.11 no.5
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• pp.643-649
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• 1996

This study was performed to investigate the adequacy of dietary fat and protein intakes among female college students. Daily intakes of energy, fat, protein, major amino acids and other nutrients were measured in 52 female college students. Daily energy intake was 75.8% of the recommended intake. Fat and protein consist 19.2% and 16.7% of the total calorie, respectively. The average protein consumption per day was 105% of the recommended intake. Essential amino acids intakes were more than the recommended amounts which appears in the 6th edition of Recommended Dietary Allowances for Koreans. However, when the intake of each essential amino acid was compared to the recommended amino acid requirement pattern, these subjects did not meet the estimated requirements. There was a highly significant correlation between daily protein intake and lipid intake implying the major sources of protein in the diet were also major sources of fat. Daily intakes of dietary fiber, vitamin C, iron, and phosphorous were above the recommended levels of intake. However, blood hemoglobin concentration was marginal indicating dietary iron consumption is not a good marker for iron status. Also, calcium intake was only 63.5% of the recommended intake. Therefore, these results imply that main problems for these subjects are low energy consumption, low calcium intake, and the quality of protein. However, as opposed to the hypothesis, the main energy sources were not the food items high in saturated fats such as instant foods, which should be emphasized further.

• Korean Journal of Community Nutrition
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• v.21 no.4
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• pp.366-377
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• 2016

Objectives: The purpose of the study was to compare intake of energy nutrients, physical characteristics, and the prevalence of metabolic syndrome according to protein intake group. Methods: Subjects were 827 men aged 40-65 years. The results presented were based on data from the 2012-2013 National Health and Nutrition Examination Survey and analyzed using SPSS. The odds ratio (OR) of metabolic syndrome was assessed according to the protein intake group and intake pattern of protein-rich foods. Results: The mean of protein intake was $73.96{\pm}0.71g$. According to level of protein intake, four groups (deficient, normal, excess 1, excess 2) were created and their percentages were 8.3%, 39.6%, 37.1%, and 15.0% respectively. The mean of daily energy intake was $2,312.33{\pm}24.08kcal$. It was higher in excess group 2 than in the deficiency group (p < 0.001). Moreover, the intake of all energy nutrients increased significantly with protein intake group (p < 0.001). The main contribution to daily protein included mixed grains ($10.96{\pm}0.32g$), milled rice ($7.14{\pm}0.30g$), chicken ($3.50{\pm}0.21g$), and grilled pork belly ($3.04{\pm}0.16g$). With regard to physical characteristics, and blood pressure and blood test results, only body mass index increased significantly according to protein intake groups (p < 0.05). The prevalence of metabolic syndrome in subjects was 38.5%, and there was no significant correlation with protein intake group. The OR of metabolic syndrome increased with protein intake, and was higher 4.452 times in excess group 2 than in the normal group (p < 0.05). Conversely, the OR of metabolic syndrome according to the frequency of protein-rich food intake did not show a significant correlation. Conclusions: The results of this study can be used as significant supporting data to establish guidelines for protein intake in middle-aged men.

• Journal of Nutrition and Health
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• v.26 no.9
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• pp.1033-1048
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• 1993

This study was designed to describe the effect of the protein quality at different intake level of protein on the protein metabolism in the whole body of growing pigs with a simulation model. Varying to the protein level in feeds, four simulations were conducted. The feed protein level, represented as proportions of digestible protein to the metabolic energy (DP/ME, g/MJ), were 6-8, 11-13, 17-19, and 23-25 DP/ME, respectively. Two protein quality and six weeks of growth time were used at each simulation. The objective function for the simulations was protein deposition in the whole body, which was calculated from the experimental results. The parameters in the simulation were determined by the parameter estimation technique. The results obtained from the simulation were as follows: The protein synthesis and breakdown rates(g/day) in the whole body was increased with the increase of protein quality only at lower or required level of protein intake. They showed a parallel behavior in the course of growth, irrespective of quality and level of feed protein intake. The simulated protein deposition and protein synthesis showed a linear relationship between them at different protein quality and level. The affinity parameter showed a linear relationship between them at different protein quality and level. The affinity parameter showed that arginine, tryptophan and isoleucine were more efficient in the stimulation ofbody protein synthesis. Lysine and phenylalanine+tyrosine were less efficient. The oxidation parameter showed that histidine, pheyalanine+tyrosine were less efficient. The oxidation parameter showed that histidine, phenyalanine+tyrosine, and methionine+cystine were oxidized in larger magnitude than lysine and threonine. The oxidation parameter of most amino acids increased with the increase of protein intake beyond the requirement level, but not any more at highest protein intake level. Finally it was found that the improvement of feed protein quality at the lower or required level of protein intake increase protein deposition through a parallel increase of protein synthesis and breakdown.