1996 Fiscal Year Final Research Report Summary
Estimation of dietary allowance of magnesium and trace alements using stable isotopes
| Project/Area Number |
07407012
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Hygiene
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
ITOKAWA Yoshinori KYOTO UNIVERSITY,Graduate School of Medicine, Professor, 医学研究科, 教授 (80025593)
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| Co-Investigator(Kenkyū-buntansha) |
HATSUDA Naoki KYOTO UNIVERSITY,Graduate School of Medicine, Instructor, 医学研究科, 助手 (80283620)
KIMURA Mieko KYOTO UNIVERSITY,Graduate School of Medicine, Associate Professor, 医学研究科, 助教授 (60025658)
EZASHI Takatoshi National Institute of Health and Nutrition, Head, 栄養研究所, 部長 (80191922)
YOKOI Katsuhiko KYOTO UNIVERSITY,Graduate School of Medicine, Instructor, 医学研究科, 助手 (10200883)
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| Project Period (FY) |
1995 – 1996
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| Keywords | dietary allowance of magnesium / zinc deficienty / stable isotope / plasma zinc disappearance / serum ferritin concentration / cluster analysis / ICP mass spectroscopy / plasma zinc concentration |
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| Research Abstract |
Aim of this research is to clarify the dietary allowance of magnesium and trace elements using stable isotopes as this method is very sensitive to detect marginal deficiency status of minerals. However, unfortunately, stable isotope of magnesium did not available within a definite period of time, we investigated dietary allowance of magnesiumusing atomic absorption spectrophotometer. A study was undertaken in long-term hospitalized patients aged 70-90 years and healthy young adults aged 19-40 years. The magnesium status were assessed by plasma levels and the dietary intake of magnesium. Significant correlation was observed between dietary intake and plasma levels of magnesium and it was found that plasma magnesium was decreased below the normal range in some subjects when daily intake of magnesium was below 150mg. Therefore, we assumed that the minimum requirement of magnesium for Japanese adults including aged peoples were 150mg/day. The dietary allowance should be set around 300mg/da
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y by adding safety coefficients. In future, these values should be re-estimated using stable isotope method.
To clarify the nutritional status of zinc and iron, we carried out a series of experiments in American subjects using the stable isotope ^<67>Zn. Food frequency history, serum ferritin, plasma zinc, plasma zinc disappearance, and zinc turnover rate were measured in these subjects. Plasma zinc disappearance and turnover rate were determined by inductively coupled plasma mass spectroscopic analysis of the plasma ratio of zinc 67 to zinc 68 before and 30 to 60 minutes after intravenous injection of ^<67>Zn. Data were applied the cluster analysis. The results were as follows. Frequent meat intake and vitamin C supplements were associated with hgher serum ferritin concentration and a normal plasma zinc disappearance. Serum ferritin concentration and plsma zinc disappearance constant were inversely and non-linearly related. Lower serum ferritin was associated with the faster disappearance of plasma zinc. These findings suggest that avoidance of meat increases the risk of iron and zinc deficiencies, and low serum ferritin concentrations suggest the possibility of low zinc nutriture. The problem that whether these findings in Americans are also adapted to Japanese or not are remain to be clafiried. Less
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