Dietary Reference Intakes for Protein: Protein Requirement and Estimation Method, AMDR (Amount of Macronutrient Distribution Range), for Protein

This study assessed the current EAR, RDA, and AMDR for protein, which were set in 2005 and revised in 2010 as the DRIs for Koreans. A classical approach to establish the EAR for protein has been the nitrogen balance method. This method has practical limitations and problems in statistical analysis by giving over estimations of nitrogen balance. Thus, the present EAR for protein might be lower than the true requirement. Recent reevaluations of nitrogen balance studies by bilinear regression analysis and the IAAO method have indicated that the EAR of 0.66 g/kg bw/d should be increased by 39% to give 0.92 g/kg bw/d. The AMDR for protein in the Korean DRIs was set at 7-10%, which covers almost the entire population's protein intake. Since the 5th percentile of Korean protein intake is close to 10% of energy and due to the beneficial effects of protein beyond the maintenance of nitrogen equilibrium, the lower range of 7% needs to be increased up to 10%. For practical meal arrangement, 15% of energy as protein, which is close to the average protein intake of Koreans, seems to be proper, although the value is almost two times the EAR.

Effect of a 6-month Low Sodium Diet on the Salt Taste Perception and Pleasantness, Blood Pressure and the Urinary Sodium Excretion in Female College Students

The study aim was to examine the effect of sensory responses of subjects after 6-month dietary sodium reduction with the aid of nutritional education. Fourteen female college students voluntarily restricted their sodium intake for 6 months, during which time they received nutritional education on the low sodium diet. As a control group, 10 students, whose anthropometric measurement, sodium intake behavior, and blood pressure were not different from those of the experimental group, were maintained on a normal diet. For the sensory responses of subjects, the salt taste perception and pleasantness for graded (0.15-1.3%) NaCl solutions were measured by a 9-point hedonic scale. The optimum sodium concentration, urinary sodium excretion, and blood pressure were measured. All the measurements were done at the beginning and end of the experiment. The sensory evaluation revealed an absence of any difference between the two groups in salt taste perception and pleasantness responses at the beginning. After 6-month adaptation, the experimental group subjects showed higher responses to low NaCl solution (0.15, 0.3, 0.5%) in salt taste perception and pleasantness evaluation while the control group subjects exhibited the opposite response. The optimum sodium concentration was reduced from 105.6 mmol to 80.7 mmol (p = 0.015) and the urinary sodium excretion was also reduced from 1,398 mg to 906 mg (p = 0.041) only in the experimental group. Systolic blood pressure was significantly reduced in the experimental group, although there was no correlation between the urinary sodium excretion and blood pressure. The optimum sodium concentration was negatively correlated with the urinary sodium excretion (r = 0.418, p = 0.053), indicating that adaptation to low sodium diet can reduce sodium intake. Further study on the individual responses of subjects on a low sodium diet by periodical evaluation may provide useful data for setting the duration needed to stabilize a lowered appetite for sodium.

Intake of Processed Foods and the Effects of Nutrition Label Education in 5th Grade Children

The effects of nutrition label education on the perception, nutrition knowledge, understanding and applicability of labeling for 81 5th grade students was assessed. Prior to the education, the students' purchasing behavior of processed food was assessed by self-administered questionnaires. The evaluation of subjects' perception and understanding on nutrition label was completed prior to and following four education sessions utilizing materials developed by Korea Food and Drug Administration and Korea Health Industry Development Institute. More than 90% and 15% of subjects purchased processed food weekly and daily, respectively. Considering the nutrition label became an important factor in food purchases following the education sessions. Perception of the value of nutrition label improved from 2.93 to 3.32, although the belief that nutrition labels contributed to the maintenance of good food intake was not significantly increased. The total nutrition knowledge score increased from 5.47 to 7.14 and understanding nutrients composition table was significantly improved (3.17 to 4.80). The results indicate that a school-based nutrition label education program might be an effective aid for adoption of healthier food choices by children.

The Evaluation of Nutrients and Health Functional Elements Presented at Nutrition Labels of Various Beverages in the Market

On the basis of the increasing interest for the selection of beverages, this study aimed to evaluate the contents of nutrients and health functional elements in the beverages. Total 161 beverages that bear nutrition lable (NL) as nutrition table and health functional elements information were collected and classified to 8 groups. The evaluated nutrients that are obligatory for NL in Korea were total calorie, carbohydrate, protein, fat, and sodium. Presented values showed that milk & yogurt and soy milk are the most wholesome beverages while the total caloric contents also were higher among 8 groups. Sodium contents in soy milk were higher than any other groups. The caloric contents of other beverage groups come mainly from carbohydrate presumably simple sugar. The caloric content of sports drinks is the lowest but the sodium content is variable among products showing the range of 0 - 100 mg/100 ml. Nonobligatory nutrients for NL frequently expressed are Ca, Fe, vitamin C, folate, and dietary fiber. Their content per serving size does not exceed the tolerable upper intake level, however, habitual multiple intakes of certain product require attention for the prevention of overintakes. Many health functional elements as catechin, carnitine, polyphenol, and nucleic acids etc were listed in NL without presenting the content and their functions appear to be exaggerated compared to the known scientific evidence.

The Amount of Sodium in the Processed Foods, the Use of Sodium Information on the Nutrition Label and the Acceptance of Sodium Reduced Ramen in the Female College Students

The amount of sodium in the processed foods was evaluated by the information on the nutrition label. One-meal type foods as Ramen, Woodong, Naengmyon provide the most sodium reaching 30 - 70% DV per serving size. In Ramen not much difference was observed for the sodium content by food companies though each company provides various amount of sodium reducing as much as 25% DV. The proportion of female college students who read the nutrition information reached 62% but it remained 32% on the sodium information. They purchase low sodium foods rarely however their intention to buy low sodium foods increased up to 40% in condition that sodium information is given on the food label. Neverthless 50% of them would not buy low sodium food if the taste is undesirable. Low sodium ramen cooked with 80% soup-base was acceptable by the subjects. Majority of them responded the soup was rather salty indicating the reduction of sodium in ramyeon is possible.

The Effect of Excess Calcium on the Iron Bioavailability and Bone Growth of Marginally Iron Deficient Rats

This study examined the effect of excess calcium (Ca) on the iron (Fe) bioavailability and bone growth of marginally Fe deficient animals. Two groups of weanling female SD rats were fed either normal Fe (35 ppm) or Fe deficient diet (8 ppm) for 3 weeks. Then each group of animals were assigned randomly to one of three groups and were fed one of six experimental diets additionally for 4 weeks, containing normal (35 ppm) or low (15 ppm) Fe and one of three levels of Ca as normal (0.5%), high (1.0%), or excess (1.5%). Feces and urine were collected during the last 3 days of treatment. After sacrifice blood, organs, and femur bone were collected for analysis. Final body weight and average food intake were not affected by either the levels of dietary Ca or Fe. Low Fe diet significantly reduced the level of serum ferritin, however, for Hb, Hct, and TIBC no difference was shown than those in the normal Fe group. TIBC increased slightly by high and excess Ca intake in low Fe groups. For both normal and low Fe groups, high and excess Ca intakes reduced the apparent absorption of Fe and Fe contents of liver significantly (p < 0.05). Calcium contents in kidney and Femur of rats that were fed high and excess levels of Ca were significantly greater than those of normal Ca groups. However, weight, length, and breaking force of the bone were not affected by increased Ca intakes. Both in control and low Fe groups, high and excess intakes of Ca decreased the apparent absorption of Ca. These results indicate that the excess intakes of calcium than the normal needs would be undesirable for Fe bioavailability and that the adverse effects be more serious in marginally iron deficient growing animals. In addition bone growth and strength would not be favorably affected by high Ca intakes, though, the long term effect of increased Ca contents in bone requires further examination.

A Study on the Calcium Bioavailability of Eggshell Powder in the Growing Rats

This study has investigated the bioavailability of calcium in eggshell powder (ESP) for the purpose of reutilizing eggshells as the calcium source. The experiment was designed 2 X 2 factorial method with two sources, CaCO3 and ESP, and two levels, 0.2% and 0.4% calcium. Weanling SD rats were assigned randomly to one of 4 groups and provided by one of the isocaloric, 20% casein based 4 different experimental diets for 4weeks. Deionized water was given and environment was kept from any contamination of minerals. The body weight, diet intake, feed efficiency ratio (FER), bone growth, Ca contents of bones, and apparent absorption were measured. FER (0.38 - 0.40) and kidney weight were not different among groups and the weight and length, Ca content, strength of two bones Tibia and Femur were not affected by Ca sources except Femur Ca content. Ca content of Femur was greater in ESP groups than that of CaCO3 groups. The body weight gain, bone growth, the Ca contents and strength of bones were significantly greater in 0.4% calcium groups suggesting 0.2% calcium is not sufficient for the optimum growth in the growing rats. These results indicate that ESP be a proper Ca source comparable or superior to CaCO3. However the apparent absorption rate of final 3 days of feeding did not support the observed results showing lower rate in ESP than CaCO3 groups. Further study be needed in the absorption aspect.

Current Status of Nutrient Fortification in Processed Foods and Food Fortification Policies in Other Countries

Nutrition fortification of processed foods with microelements is a popular practice in many countries to improve nutritional status of target population. In this study the current food fortification in Korea was evaluated and the regulations and guidelines for food fortification in other countries were presented. Most commonly added nutrients were calcium, vit.C, fiber, vit.Bs and iron. The level of fortified nutrients and the vehicle foods were variable. vit.C and fiber appeared to be overfortified in some foods and the necessity of fortification of these nutrients needs to be examined since the intakes of these elements appears to meet the RDA. Most of other nutrients such as vit.A, vit.B1, vit.B2, and iron were added at the level of 10~25% RDA per serving size. The vehicle foods for fortification were snacks, milk, ramyun, breakfast cereal, juices, candies and ready-to-eat retort pouch foods but not rice which is a staple food in Korea. The guideline and regulation for food fortification is required to ensure safe and proper supplementation of needed nutrients in processed foods.

Current Status of Nutrient Fortification in Processed Foods and Nutrition Labeling

Current status of nutrient fortification in processed food in Korea were presented by analyzing the information shown on food labels. The obtained information was assessed by the regulations on food fortification in both Korea and other countries including Codex. The most current regulations were gathered from internet. The results are summarized as follows. 1. Major nutrients fortified were calcium, Vit C, Vit B complex, iron and fiber. The forfified foods were not limitted to certain food group with more frequent fortification in snackfoods, cereal, ramyun, retort pouch foods, milk, and youguart. The descriptive terms of nutrition label for the fortification were various including high, supplemented, added, source, fortified, and abundance though the difference among these terms were not distinct. 2. Current regulation on nutrition laber requires to give the content of the fortified nutrient and % RDA. However not all of food items carry above information. Also some ingredients such as chitosan, DHA, taurine, omega-3 fatty acid, chondrichin, bifidus were supplemented mainly to the snack foods which FDA(USA) does not allow to be fortified. 3. The nutrient most frequently fortified was calcium and general practice of fortification appears to follow the regulation in Korea. Presently the regulation itself is not well described, this nutient fortification can cause toxic effect. Since calcium was supplemented to wide range of food group consumers who are not conscious of the safe upper limit may intake the fortified food up to the level of 2g/day. 4. For the effective fortification in Korea, the regulation on fortification should be reformed in accordance with the international guideline Codex and the regulations in other countries especially in America and Japan.