Applied nutritional investigation
Joint association of magnesium and iron intake with anemia among
Zumin Shi, M.D., Ph.D.
*, Xiaoshu Hu, M.D.
, Ka He, M.D., Sc.D.
, Baojun Yuan, M.D.
and Manohar Garg, Ph.D., M.N.D.
Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China
Research Center for Gender, Health and Ageing, Hunter Medical Research Institute, The University of Newcastle, Australia
Departments of Nutrition and Epidemiology, Schools of Public Health and Medicine, University of
North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
Nutraceuticals Research Group, School of Biomedical Sciences, The University of Newcastle, Australia
Manuscript received January 8, 2008; accepted May 9, 2008.
Abstract Objective: Inﬂammation and iron deﬁciency are two important causes of anemia. Magnesium
intake is inversely associated with inﬂammation. However, little is known as to whether magnesium
intake is related to anemia. We assessed the joint association of magnesium and iron intake with
anemia among Chinese adults.
Methods: A cross-sectional household survey of 2849 men and women 20 y of age or older was
conducted in 2002. Nutrient intakes were assessed by 3-d weighed food records. Serum ferritin and
hemoglobin concentrations were measured.
Results: The prevalence of anemia was 18.3% in men and 31.5% in women. Magnesium and iron
intakes were positively associated with hemoglobin levels and inversely related to the prevalence of
anemia. The risks of anemia were reduced by 26% (P for trend ϭ 0.03) and 52% (P Ͻ 0.01),
respectively, for iron and magnesium intake comparing the fourth quartile with the ﬁrst with
adjustment for potential confounders. The lowest risk of anemia was observed among participants
with the highest intakes of magnesium and iron (odds ratio 0.46, 95% conﬁdence interval 0.31–
0.68). The inverse association of iron intake and anemia but not the association of magnesium intake
and anemia was modiﬁed by serum ferritin levels. The observed relations were not appreciably
modiﬁed by gender.
Conclusion: This study suggests that magnesium is a potent predictor of anemia in Chinese
adults. © 2008 Elsevier Inc. All rights reserved.
Keywords: Anemia; Magnesium; Iron; Epidemiology; Chinese
Anemia is a worldwide health problem, especially in
developing countries . According to a Chinese national
survey conducted in 2002, the prevalence of anemia was
15.2% in China . Among various risk factors, iron deﬁ-
ciency and inﬂammation are recognized as two important
causes of anemia . Low iron content in food and low
bioavailability of iron intake from plant-based food are the
main nutritional causes of iron deﬁciency. Iron-fortiﬁed
wheat ﬂour and soy sauce have been recommended for the
prevention of iron deﬁciency anemia (IDA) [1,3].
Studies have suggested that magnesium intake is in-
versely associated with risk of diabetes and metabolic syn-
drome [4–6] and with markers of systemic inﬂammation
[7–9]. Increased magnesium intake may improve dyslipide-
mia, oxidative stress, and insulin sensitivity in type 2 dia-
betes . Magnesium supplementation reduces the risk of
This work was funded by the Jiangsu Provincial Health Bureau. Dr. Shi
is supported by a fellowship from the Newcastle Institute of Public Health–
Hunter Medical Research Institute through the New South Wales Health
Department Capacity Building and Infrastructure Grant.
* Corresponding author. Tel.: ϩ86-25-8375-9341; fax: ϩ86-25-8375-
E-mail address: firstname.lastname@example.org (Z. Shi).
Nutrition 24 (2008) 977–984
0899-9007/08/$ – see front matter © 2008 Elsevier Inc. All rights reserved.