Food intake survey of kindergarten children in Korea: Part 1 food, energy, and nutrient intake.

OBJECTIVES: Nutrient intakes of children were surveyed at the time when a nation-wide shift took place in the Republic of Korea from agriculture-based to industrialized society. Taking advantage of the survey locations (see below), possible delay in nutritional improvement in rural areas (as compared with that in an urban area) was also examined. METHODS: In total, 108 4- to 6-year-old children (boys and girls in combination) in 4 kindergartens (KGs; 1 in Seoul and 3 in Jeju Island) participated in the survey in 2003-2004. 24-h food duplicate samples were prepared by the mother of each child. Food items in each duplicate sample were separated and coded with reference to the Dietary Reference Intake for Koreans (the 2005 version). Nutrient intake of the day was estimated from the code and weight followed by summation for daily intake. RESULTS: The children in the KG in Seoul studied were younger, and therefore were smaller in body size than those in other KGs. Thus, it was considered necessary to evaluate nutrient intake not only on a daily basis, but after adjustment for body weight. The AM daily intake of energy (protein in parenthesis) for the 108 children was 1479 kcal (55 g)/day or 69.8 kcal (2.6 g)/kg body weight/day. Evaluation by individual nutrient suggested that the intake was sufficient for almost all nutrients except for sodium and potassium. Sodium and potassium intake (2285 and 1840 mg/day, respectively) was in excess and insufficient, respectively, with potential risk of inducing hypertension later in life. CONCLUSIONS: Inter-KG difference was not remarkable and therefore urban-rural difference was not apparent. Nutrient intakes as a whole appeared to be sufficient urban and rural areas. Nevertheless, excess Na intake coupled with insufficient K intake was a common problem.

Food intake survey of kindergarten children in Korea: Part 2 increased dietary intake of tin possibly associated with canned foods.

OBJECTIVES: Dietary intake of tin (Sn) may be increased in some children in kindergartens in Korea. The present study was intended to examine this possibility and clarify the extent of the elevation. METHODS: 24-hour food duplicate and spot urine samples were collected in 2003-2004 from 108 4-6-year-old children (boys and girls combined) in 4 kindergartens (1 in Seoul and 3 in Jeju Island), as reported in a previous publication. These samples were employed in the present analyses to examine tin levels in the diet (including beverages) (Sn-D). A portion of the samples were wet-ashed, and the liquid samples were analyzed for Sn by the ICP-MS method. For statistical evaluation, χ (2) method and Smirnov's test for extreme value were used. RESULTS: Sn-D in the 108 cases distributed as extremely biased, and could be divided into two groups, i.e., those with <10 µg Sn/day (accounting for 90% of the cases), and those with >10 µg/day (for 10%). Sn-D in the former group was distributed quasi-normally with an AM (median) of 2.9 (2.5) µg/day. The maximum in the latter group was 3012 µg/day. No correlation was detected between Sn-D and Sn in urine (Sn-U). Comparison of the findings with published articles strongly suggested that the high Sn-D was due to consumption of foods (including beverages) preserved in tin-plated cans. No positive confirmation was however possible due to insufficient information on food records. CONCLUSIONS: About 10% of children surveyed had elevated Sn-D (up to 3 mg/day). It was quite possible that high Sn-D was associated with tin-canned food intake.

Food intake survey of kindergarten children in Korea: Part 3 cadmium and lead burden.

OBJECTIVES: This study was initiated to elucidate the extent of dietary exposure of children in Korea to two pollutant metals of cadmium (Cd) and lead (Pb). Possible urban-rural difference was also examined. METHODS: Food duplicate and morning spot urine samples were collected from 108 children in 4 kindergartens (KG) (1 KG in Seoul and 3 KGs in Jeju Island), as reported in a previous publication. The samples were analyzed for Cd and Pb by ICP-MS. RESULTS: Cd and Pb in food duplicate and urine samples were distributed approximately log-normally. Geometric means for Cd and Pb in food duplicate samples were 12.4 and 5.8 µg/day, or 0.58 and 0.27 µg/kg body weight/day, respectively, and the values for Cd and Pb in urine (as observed, i.e., with no correction for urine density) were 0.91 and 1.64 µg/L, respectively. 2.41 and 0.30 µg/day of Cd and Pb (accounting for 19.5 and 5.1%) came from boiled rice, the staple food. The levels of Cd and Pb burden among the children in the present survey were essentially the same with the levels reported for children in Pusan. The reasons for difference in the rank in Cd-D and Cd-U among the 4 KGs need further study. CONCLUSIONS: The observed levels of Cd and Pb exposure were more or less similar to what were reported for children in Pusan. No apparent urban-rural difference could be detected.

Food composition table-based estimation of energy and major nutrient intake in comparison with chemical analysis: a validation study in Korea.

This study was initiated to examine the accuracy of conventional food composition table-based estimation of intakes of energy, protein, lipid and carbohydrate, in comparison with chemical analysis. For this purpose, 66 women (at the ages of 29 to 54 years) in three locations in Jeju Island, Republic of Korea, volunteered to offer 24-hour food duplicate samples. A half of them were house-wives, and the remaining half were farmers or fishers. The duplicate samples were subjected 1) to the chemical analysis for daily intake of energy, protein, lipid and carbohydrate after official methods in Korea (measured values), and 2) to the estimation of intakes of the same items taking advantage of Korean Food Composition Tables (estimated values). The two sets of the results, i.e., the measured and estimated values, were compared by paired and unpaired t-test, and linear regression analysis. The estimated values correlated closely with the measured values, irrespective of energy or the three major nutrients. A close agreement was observed for energy intake (the estimated/measured ratio of > 98%), and it was also the case for protein intake (101%). Under- and over-estimation was observed, however, in regard to carbohydrate (by - 8%) and lipid intake (by + 24%), respectively. It was concluded that the Korean Food Composition Tables are sufficiently accurate when applied for estimation of total energy intake as well as protein intake. Cares should be taken, however, in applying the tables for estimation of lipid and carbohydrate intake, because there may be the risk of over- and under-estimation for the former and the latter, respectively.