Estimates of mineral intakes using food composition tables vs measures by inductively-coupled plasma mass spectrometry: Part 2: sodium, potassium, magnesium, copper, zinc

Applicability of food composition tables as a tool to estimate mineral and trace element intake of pre-school children in Japan: a validation study

Because dietary intakes of some minerals (including trace elements), especially iron (Fe), are insufficient for the needs of the general Japanese population, accurate estimation of mineral intake is important. This capability is especially necessary to preserve the health of Japanese children. Therefore, the current version of food composition tables (FCT) in Japan was evaluated for validity as tools to estimate dietary intake of minerals for children. For this purpose, 24h food duplicate samples were collected from 292 pre-school children in Miyagi prefecture, Japan. From the weights of items and food codes, intakes of nine minerals were estimated taking advantage of the FCT. In parallel, amounts of minerals in each duplicate samples were instrumentally measured by ICP-AES for Ca, Cu, Fe, Mg, Mn, P and Zn, and by flame AAS for K and Na, both after wet-ashing. The distributions of the mineral amounts were essentially normal. The comparison of the FCT-based estimates (E) and instrumental measures (M) showed that the E/M ratio was close to 1 for Ca, K, Mn, P and Zn, suggesting that E may be a surrogate of M for Ca, K, Mn, P and Zn on a group basis. The ratio being larger than 1.2 for Cu, Fe, Mg and Na indicates that a risk of over-estimation exists when E is relied upon in place of M. On an individual basis, significant differences were detected for all 9 minerals suggesting that the use of E as a surrogate for M should be practiced with care for the estimation of mineral intake.

Estimation of dietary Pb and Cd intake from Pb and Cd in blood or urine

Successful trials were made to estimate the dietary daily intake of lead (Pb) and cadmium (Cd) via foods from the levels of the metals in blood or urine. In practice, 14 and 15 reports were available for Pb and Cd in blood (Pb-B and Cd-B), urine (Pb-U and Cd-U) and 24-h diet duplicates (Pb-D and Cd-D), respectively, from which 68 pairs each of Pb or Cd in blood and food duplicates [each being geometric mean (GM) values for the survey sites] were obtained. Regression analysis revealed that there was a significant correlation between Pb-B and Pb-D, and also between Cd-B and Cd-D, suggesting that it should be possible to estimate both Pb-D and Cd-D from Pb-B and Cd-B, respectively. For Cd-U, the number of available cases was limited (20 pairs), but a significant correlation was detected between Cd-U (as Cd-U(cr), or Cd levels in urine as corrected for creatinine concentration) and Cd-D. Care should be taken in estimating Pb-D from Pb-B, as the ratio of Pb-D over Pb-B may decrease as a function of increasing Pb-B levels. The Pb-D (μg/day) for typical Japanese women with Pb-B of 15 μg/l was best estimated to be 13.5 μg/day. No Cd-B- or Cd-U(cr)-dependent change was detected in case of Cd. The best estimate of Cd-D for Cd-B at 1.5 μg/l should be about 19.4 μg/day.

Dietary zinc intake and sex differences in taste acuity in healthy young adults

BACKGROUND

Previous research suggests that adequate dietary zinc intake may be important in determining the sensory experience of food, appetite and consequently, dietary quality. The aim of this pilot study was to explore relationships between taste sensitivity and dietary zinc intake in healthy young adults (age 20-40 years: 24 male, mean age +/- SD = 27 +/- 4.86 years; 26 female, mean age +/- SD = 23 +/- 2.10).

METHOD

A signal detection method was used to assess taste acuity for the four basic tastes: sweet (glucose), sour (citric acid), salt (sodium chloride) and bitter (quinine). A 4-day food diary was used to determine dietary intakes of zinc (mg day(-1)) and salt.

RESULTS

Males reported a higher zinc intake than females (P=0.001). Higher dietary zinc intake was associated with better taste acuity for salt in females (P=0.017) but not in males. Acuity for bitter taste appeared to be related to zinc intake in males (P=0.007) but not females. Among those whose average daily zinc intake was below the RNI, males were less sensitive than females to sour (P=0.02) and bitter (P=0.014) taste.

CONCLUSION

These findings suggest that zinc is more important for taste acuity in males than females and indicate the importance of taking sex differences into account when studying taste acuity.

Effects of revision of Japanese food composition tables on estimation of nutrient intakes, with reference to age-dependent differences

OBJECTIVE

To identify effects of revision of the Japanese food composition tables from the fourth version to the fifth version on nutrient intake estimation.

DESIGN

A database on 783 samples of 24-hour food duplicate portions was re-visited. Nutrients in the duplicate portions were estimated by use of the fourth and fifth versions of the Japanese food composition tables in parallel, together with supplemental use of other databases. The two sets of estimates were subjected to comparison.

SETTING

The sample collection was conducted at 31 sites all over Japan.

SUBJECTS

The sample donors were 783 women aged 20-78 years.

RESULTS

Compared with the estimates by use of the fourth version of the tables, the estimates by the fifth version were substantially higher for intakes of energy, carbohydrate, dietary fibre, vitamin A and niacin, and lower for iron intake. The increase in carbohydrate intake estimates was more evident in older women than in young women, whereas the decrease in the intake estimation of iron and the increase in that of dietary fibre were more marked in young women than in older women.

CONCLUSION

The recent revision of food composition tables in Japan induced substantial changes in the estimation of nutrient intakes, i.e. an increase in energy, carbohydrate, dietary fibre, vitamin A and niacin, and a decrease in iron. The extent of the changes varied depending on age.

Effects of life away from home and physical exercise on nutrient intake and blood/serum parameters among girl students in Japan

This study was initiated to examine if the life away from home and participation in sport activities affect nutritional health among girl university students. For this purpose, anthropometric data, peripheral blood and spot urine samples, 24-hour food duplicate samples, and answers to questionnaires were collected from 71 girl students at 19 to 23 years of ages who provided informed consent to participate in the study. Of the 71 participants, 29 and 42 participants lived in their homes or outside, respectively, and 23 subjects participated in sport activities whereas 48 subjects did not. Hematology, serum biochemistry and nutrient intakes were evaluated in comparison with the life conditions (home vs. dormitory, boarding house, etc.) and participation in sport activities. The population studied had insufficient intake of energy, protein, and minerals such as Ca and Fe. Those who lived in home or participated in sport activities took more energy and protein (although not the two minerals) than others. Skipping of breakfast was more common among those who lived away from home and had no sport activity. Thus, two social factors of life in home and participation in sport clubs contribute favorably for better food habits, but not necessarily improved intakes of Ca and Fe.

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.

Estimation of nutrient intake by the new version of Japanese food composition tables in comparison with that by the previous version

This study was initiated to examine if the revision of the food composition tables from the 4th version to the 5th version has induced any substantial changes in nutrient intake estimation, and if so, in which nutrient item and to what extent. For this purpose, 24-hour duplicates of food samples were collected in 1996 to 1998 from 71 girl university students, together with food menus of the day. The nutrients in the duplicates were estimated by use of the 4th and the 5th version food composition tables in parallel, with supplements of other databases. The results of the estimation with the two databases were compared by Student's paired t-test. Compared with the results with the 4th version, the estimation utilizing the 5th version gave 3 to 8% increases in intakes of major nutrients including energy (except for protein), a 20% increase in vitamin A, and decreases in iron (-13%) and NaCl (-3%), whereas there were only small or essentially no changes in other minerals and vitamins. The largest increment in energy through the re-calculation came from the cereals (especially rice), and it was meats for the increment in lipid intake. The increment in vitamin A with the 5th version is primarily due to the re-evaluation of fruits and vegetables. The present observation suggests that care should be practiced in examining secular trends in nutrition when the basis of estimation is shifted from one database of the 4th version of food composition tables to another of the 5th version. Further study of a larger scale is apparently warranted to confirm the conclusions.