Physiological requirements for iron in women of reproductive age assessed by the stable isotope tracer technique

Jiaxi Lu; Jie Cai; Tongxiang Ren; Jinghuan Wu; Deqian Mao; Weidong Li; Yu Zhang; Jianhua Piao; Jun Wang; Lichen Yang; Xiaoguang Yang; Yuxia Ma

doi:10.1186/s12986-019-0384-1

Physiological requirements for iron in women of reproductive age assessed by the stable isotope tracer technique

Nutr Metab (Lond). 2019 Aug 19:16:55. doi: 10.1186/s12986-019-0384-1. eCollection 2019.

Authors

Jiaxi Lu^#¹, Jie Cai^#², Tongxiang Ren³, Jinghuan Wu¹, Deqian Mao¹, Weidong Li¹, Yu Zhang¹, Jianhua Piao¹, Jun Wang³, Lichen Yang¹, Xiaoguang Yang¹, Yuxia Ma⁴

Affiliations

¹ 1The Key Laboratory of Trace Element Nutrition of The Ministry of Health, National Institute for Nutrition and Health, Chinese center for disease control and prevention, 29 Nan Wei Road, Xicheng District, Beijing, 100050 People's Republic of China.
² 2Hospital Management Institute, Zhongnan Hospital of Wuhan University, 169 Donghu Road, Wuchang District, Wuhan, Hubei 430071 People's Republic of China.
³ National Institute of Metrology, National Research Center for Certified Reference Material, No.18, Bei San Huan Dong Lu, Chaoyang District, Beijing, 10050 People's Republic of China.
⁴ 4Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, Hebei 050017 People's Republic of China.

^# Contributed equally.

Abstract

Background: Iron nutrition is important for the health of women of reproductive age, and defining the physiologic requirement for iron can help them accurately plan the iron intake. However, research on the physiologic requirement for iron in women is insufficient worldwide. This study aimed to further improve the methodology and get more precise data for the physiological requirements for iron in women of reproductive age on the basis of our previous study.

Method: Sixty-one women of reproductive age who had not been pregnant before and during the whole study were included from Hebei province, China in 2015. Each subject participated in a 2-week metabolic trial with consuming 50 mg of the stable isotope ⁵⁸Fe, and were then followed for ~ 800 days. The abundance of ⁵⁸Fe and the total iron concentration in the circulation were measured using multi-collector inductively-coupled plasma mass spectrometry and atomic absorption spectroscopy. The physiologic requirement for iron in women of reproductive age was then calculated.

Results: The average iron circulation rate was 80.4%, and the steady period started from about 1 year. The average physiological requirement for iron of 21 subjects obtained by formula calculation was 1.55 mg/d and 23.63 μg.kg^{- 1}.d^{- 1} after adjustment for body mass, and that of 33 subjects obtained by linear regression was 1.29 mg/d, 20.98 μg.kg^{- 1}.d^{- 1} after adjustment for body mass. The results by two methods showed no significant difference. The EAR and RNI calculated from this results was 11-13 mg/d and 15-18 mg/d, respectively, both of which were slightly lower than the recommended value in Chinese Dietary Reference Intake (2013).

Conclusion: The physiological requirements for iron in women of reproductive age were in accordance with other studies, while the EAR and RNI calculated from which were slightly lower than Chinese present recommended value.

Trial registration: ChiCTR, ChiCTR-OCH-14004302. Registered 14 February 2014, http://www.chictr.org.cn/enindex.aspx.

Keywords: Iron; Physiological requirement; Stable isotope tracer technique; Women of reproductive age.