Iron physiological requirements in Chinese adults assessed by the stable isotope labeling technique

Jie Cai,Lingyan Gou,Xiaoguang Yang,Jianhua Piao,Zhengwu Huang,Zhilin Wang,Jun Wang,Tongxiang Ren,Lichen Yang,Yuhui Zhang

doi:10.1186/s12986-018-0262-2

Abstract

BackgroundIron is a kind of essential trace mineral in the human body, while the studies on its physiological requirement are very limited recently, especially in China. And most studies were performed with the radioisotope tracer technique, which was harmful to health. This study aimed to first get the value of iron physiological requirements in Chinese adults assessed by the stable isotope labeling technique.MethodsForty-four eligible young Chinese healthy adults were randomly recruited from the Bethune Military Medical College (Shijiazhuang, Hebei, China) between January 2010 and March 2011, and 19 subjects were included in the final data analysis. After adaptive diets and observation, subjects received 58Fe intravenously. The baseline venous blood sample and general information were collected on day 0. Venous blood samples were also collected on day 14, 30, 60, 100, 120, 150, 240, 330, 425, 515, 605, 767, 1155, respectively. The blood samples were acid digested by a Microwave Digestion System and then analyzed by the MC-ICP-MS and Atomic Absorption Spectroscopy to get the abundance of Fe isotopes and the total iron concentration respectively. The circulation rate (the proportion of blood iron to whole body iron) could be calculated by the intake amount, background content and the peak isotope content. When the abundance changed stably, the iron physiological requirement could be calculated by the iron loss in a period of time.ResultsThe abundance of 58Fe reached its peak on day 14, and changed stably from day 425. The average circulation rate was 84%, with no significance difference between the 2 genders. The mean iron requirement in females was 1101.68 μg/d, and the mean requirement adjusted by body weight was 20.69 μg/kg.d. For males, the mean iron requirement was 959.9 μg/d, and the requirement adjusted by body weight was 14.04 μg/kg.d.ConclusionOur study has obtained the data about the iron physiological requirements of Chinese adults using stable isotope labeling technique, which could provide the basis for adjusting iron DRIs of Chinese people in the future.Trial registrationThe trial was registered at the Chinese Clinical Trial Registry (No: ChiCTR-TRC-09000581).

Highlights

Iron is a kind of essential trace mineral in the human body, while the studies on its physiological requirement are very limited recently, especially in China
The factorial calculation is an indirect method based on calculation which adds up all aspects of iron requirements
On day 0, the mean abundance of 58Fe was 0.002809, which was very close to the natural abundance

Summary

Introduction

Iron is a kind of essential trace mineral in the human body, while the studies on its physiological requirement are very limited recently, especially in China. This study aimed to first get the value of iron physiological requirements in Chinese adults assessed by the stable isotope labeling technique. Since 1939, a series of studies on the iron requirements in human adults using the radioisotope tracer method have been carried out in western countries [14]. With the development of technology, the stable isotope labeling technique, with its advantage of no radioactive health hazards to subjects, has been used for studying absorption and utilization rate of iron in recent years [15, 16], while rarely used in iron physiological requirements. In China, there is no direct experimental data from the domestic population and the values related to DRIs are all calculated based on experimental data from other countries

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