Serum Hepcidin and Soluble Transferrin Receptor in the Assessment of Iron Metabolism in Children on a Vegetarian Diet
Biol Trace Elem Res
Serum Hepcidin and Soluble Transferrin Receptor in the Assessment of Iron Metabolism in Children on a Vegetarian Diet
Jadwiga Ambroszkiewicz 0 1 2
Witold Klemarczyk 0 1 2
Joanna Mazur 0 1 2
Joanna Gajewska 0 1 2
Grażyna Rowicka 0 1 2
Małgorzata Strucińska 0 1 2
Magdalena Chełchowska 0 1 2
0 Department of Child and Adolescent Health, Institute of Mother and Child , Kasprzaka 17A, 01-211 Warsaw , Poland
1 Department of Nutrition, Institute of Mother and Child , Kasprzaka 17A, 01-211 Warsaw , Poland
2 Screening Department, Institute of Mother and Child , Kasprzaka 17A, 01-211 Warsaw , Poland
3 Jadwiga Ambroszkiewicz
The aim of this study was to assess the effect of vegetarian diet on iron metabolism parameters paying special attention to serum hepcidin and soluble transferrin receptor (sTfR) concentrations in 43 prepubertal children (age range 4.5-9.0 years) on vegetarian and in 46 children on omnivorous diets. There were no significant differences according to age, weight, height, and body mass index (BMI) between vegetarian and omnivorous children. Vegetarians had similar intake of iron and vitamin B12 and a significantly higher intake of vitamin C (p < 0.05) compared with non-vegetarians. Hematologic parameters and serum iron concentrations were within the reference range in both groups of children. Serum transferrin levels were similar in all subjects; however, ferritin concentrations were significantly (p < 0.01) lower in vegetarians than in omnivores. In children on a vegetarian diet, median hepcidin levels were lower (p < 0.05) but sTfR concentrations significantly higher (p < 0.001) compared with omnivorous children. In the multivariate regression model, we observed associations between hepcidin level and ferritin concentration (β = 0.241, p = 0.05) in the whole group of children as well as between hepcidin concentration and CRP level (β = 0.419, p = 0.047) in vegetarians. We did not find significant associations with concentration of sTfR and selected biochemical, anthropometric, and dietary parameters in any of the studied groups of children. As hematologic parameters and iron concentrations in vegetarians and omnivores were comparable and ferritin level was lower in vegetarians, we suggest that inclusion of novel markers, in particular sTfR (not cofounded by inflammation) and hepcidin, can better detect subclinical iron deficiency in children following vegetarian diets.
Hepcidin; Soluble transferin receptor; vegetarian diet; Children
Introduction
Iron deficiency in children has been associated with negative
effects on cognitive and motor development and with
behavioral problems [
1–3
]. Although a range of hematologic and
biochemical iron status indicators have been described in the
past, there is a consensus that no single blood test adequately
reflects iron status in the body. The usual markers might not be
able to adequately distinguish at subclinical levels; therefore,
much attention was paid to the search of novel markers
involved in the regulation of iron metabolism.
Hepcidin is a small cysteine-rich 25 amino acid
antimicrobial peptide that plays a central role in iron homeostasis [
4–6
].
The hepatic cells are a major site of hepcidin production, but
to some extent, hepcidin messenger RNA (mRNA) is also
expressed in other tissues. Hepcidin negatively regulates iron
availability by binding and degrading ferroportin, a
transmembrane iron transporter necessary for iron transfer out of
intestinal epithelial cells and macrophages [
5, 7
]. Low levels of
hepcidin enable increased iron absorption from dietary
sources and its mobilization from hepatocytes and
macrophages, while elevated hepcidin levels inhibit this pathway.
Production of hepcidin is induced by iron overload and
inflammation. Gene expression of this hormone is
downregulated by anemia, hypoxia, erythropoietic activity, and iron
deficiency [
5, 7, 8
].
Serum transferrin receptor (sTfR) is a soluble form of the
membrane receptor derived from its proteolysis. Transferrin
receptor expression on the cell surface and soluble transferrin
receptor concentrations are negatively correlated with
intracellular iron levels [
6
]. It seems that sTfR level is a better marker
of iron status compared with other parameters, because its
concentration is less affected by inflammation but could be
affected by erythropoietic activity [
9
]. It appears that serum
hepcidin and sTfR might provide more information than
ferritin and hematologic parameters in assessing iron status.
Since the health benefits of vegetarian diets were reported,
vegetarianism has been gaining popularity among families as
a lifestyle choice [
10–12
]. In general, the vegetarian dietary
pattern, if well balanced, can be adequate for adults and
children [
13–15
]. However, certain components of these diets and
some required nutrients (including iron) need specific
attention in growing children and adolescents. A very small
number of studies b (...truncated)