Daily dietary intakes of trace elements of importance in nutrition

A comparison of daily dietary intakes of essential trace elements from nine Asian countries is shown in Table 38. Results for intakes of various essential elements are discussed below.

Iron

Iron is an important trace element whose deficiency can lead to iron deficiency anaemia. Its daily dietary intakes were studied in 8 countries and they ranged from 5.4 mg for Japan to 30.3 mg for Pakistan. The results are shown in Table 38. The higher intake in Pakistan is perhaps due to large consumption of wheat (staple food of the population) which is rich in Fe. The intakes by the populations in various countries are well represented in box plots (Fig. 8). The intakes vary by a factor of five within the Asian region. Daily intakes of Fe in some Asian countries, for example Japan, are quite low in comparison with the ICRP-23 value of 16.0 mg. On the other hand, when comparing the average body weight of 73 kg of Caucasian population with the average body weight of about 60 kg for the Asian population, the Asian median intake of 11 mg Fe may not appear significantly low in comparison with the US RDA value of 12 mg.

Source of information in the above table: ICRP reference Man Data, ICRP-23 [3]

(*) Data extracted from the final report on phase-1 of the reference Asian Man Project [10]

(1) Assumes 10% waste from those purchased (2) Actual consumption

(3) Assumes 15% waste from those purchased.

TABLE 38: DAILY INTAKES OF THE ELEMENTS OF IMPORTANCE IN NUTRITION IN A FEW ASIAN COUNTRIES (MEDIAN VALUES AND RANGES)

Country Cu (mg) Fe (mg) Mn (mg) Mg (g) P (g) Na (g) Zn (mg)

Asian Range 0.68-1.95 4.22-30.10 2.34-11.75 0.13-0.52 0.56-0.79 1.88-4.13 5.21-14.25

Asian Median (rounded)

1.1 11.0 3.5 0.30 0.75 3.5 8.5

Daily Intake (mg)

Country

BGD CPR IND JPN PHI PAK VIE 0

10 20 30 40 50 60

FIG. 8. Daily dietary intakes of Fe by adult population in some Asian countries.

Zinc

Zn is an essential trace element for the growth as well as maintenance of the human system. It is a co-factor in a number of metallo-enzymes. Carbonic anhydrase, alcohol dehydrogenase, and alkaline phosphatase are a few examples of Zn enzymes. Its deficiency is reported to be associated with hypo-gonadism, dwarfism, and the reduction of body’s auto-immune response. The daily intakes were estimated in all participating Asian countries. The comparative intakes in different Asian countries are shown in Table 38. The daily intakes varied from 5.21 mg for Vietnam to the highest intake of 13.6 mg for the population of Pakistan. Although the intake appears high in Pakistan among the participating countries, even this intake is just comparable to the nutritionally defined requirement value of 15 mg per day. The possible reason for the adequate intake of Zn in Pakistan is the consumption of a large quantity of wheat (the staple food). Wheat has high concentration of Zn, Fe and Mn in comparison with their relatively low concentration in rice. Only in Pakistan and China, the intakes were adequate. In the Philippines, Vietnam, India and even in Japan, the intakes were significantly lower than the US RDA for Zn and also much lower than 15 mg cited in ICRP-23 [3]. It is interesting to note (see Table 38) that the Asian median intake of 8.5 mg Zn (Fig. 9) is not much lower than the global average intake value of 10.0 mg (see Table 35).

Daily Intake (mg)

Country

BGD CPR IND JPN ROK PHI PAK VIE 0

4 8 12 16 20

FIG. 9. Daily dietary intakes of Zn by adult population in some Asian countries.

Manganese

Intake of Mn was studied in six Asian countries. The intakes varied from a minimum of 2.34 mg for the Philippines to maximum intake of 11.75 mg for the population of Pakistan. The highest intake of Mn by the population of Pakistan is also due to the consumption of a large quantity of wheat which is rich in Mn. The Asian median intake was found to be 3.5 mg. Mn is one of the few essential elements whose intake in Asian population was found to be similar to the value as seen from ICRP-23 [3] and US RDA (Table 35). Except for the population of Pakistan, the inter-country variations for the intake of Mn in various Asian countries is not very high as may become clear from the box-plots (Fig.10).

Daily Intake (mg)

Country

BGD CPR JPN PHI PAK VIE 0

3 6 9 12 15

FIG. 10. Daily dietary intakes of Mn by adult population in some Asian countries.

Copper

Cu is an essential trace element and is associated with the metallo-protein, ceruloplasmin present in blood. Its deficiency is known to cause secondary anaemia. It has also been recognized as a co-factor in a number of other metallo-enzymes such as cytochrome-c-oxidase, superoxide dismutase etc. Its intakes were studied in only five Asian countries. The range of daily intakes varied from 0.87 mg for Vietnam to 1.8 mg for Bangladesh. The median intake of 1.1 mg for Cu in the Asian region is much lower than the ICRP-23 value. It is also low when compared to US RDA value of 2.0–3.0 mg (Table 35). The variation in the intake of Cu in the Asian region was observed to be small as may be seen from box-plots for the intake of copper (Fig. 11).

Daily Intake (mg)

Country

BGD CPR JPN PHI VIE

0 0.4 0.8 1.2 1.6 2 2.4

FIG. 11. Daily dietary intakes of Cu by adult population in some Asian countries.

Magnesium

Magnesium is an essential minor element. Its deficiency is known to be associated with heart disease.

The intake of Mg was studied in six Asian countries. Intakes varied by a factor of 5. As may be seen from Table 38 and Fig. 12, the minimum intake of 0.13 g was for the Philippine population and the maximum of 0.52 g was for Pakistan. The median intake of 0.30 g was comparable to ICRP-23 value of 0.34 g. No RDA value is available for comparing intake of Mg in the Asian region.

Daily Intake (g)

Country

BGD CPR JPN PHI PAK VIE 0

0.2 0.4 0.6 0.8

FIG. 12. Daily dietary intakes of Mg by adult population in some Asian countries.

Phosphorus

Phosphorus along with Calcium, belongs to the category of structural elements and forms an integral part of the human bone (skeleton). As may be seen from Table 38, only three countries studied the intake of P, which varied by a very small factor (<1.5). The Asian median intake of 0.75 g phosphorus (Fig. 13) was much lower than 1.4 g mentioned in ICRP-23, but it was comparable to the US RDA value of 0.7 g. It was, however, lower than the global average value of 1.3 g.

Daily Intake (g)

Country

JPN PHI VIE

0 0.3 0.6 0.9 1.2 1.5

FIG. 13. Daily dietary intakes of P by adult population in some Asian countries.

Sodium

The main source of intake of Na is common salt used for cooking purpose. Only four countries studied its intake. It ranged between 1.88 g for Philippines and 4.13 g for Japan. The intake of Na in Pakistan was found to be 3.43 g. The Asian median intake was 3.5 which, although less than ICRP-23 value of 4.4 g, is adequate according to US RDA. The intakes pattern of Na in various Asian countries is shown in the Fig. 14.

FIG. 14. Daily dietary intakes of Na by adult population in some Asian countries.