Insights & Discussion
The body begins to upregulate iron absorption at a ferritin concentration of less than 50 µg/L, indicating an incipient iron deficiency in young women.
In the methodology, this study utilizes a pooled analysis of stable iron isotope studies conducted between 2006 and 2019 on healthy women aged 18 to 50. These studies quantified iron absorption from meals providing physiological quantities of iron. A mathematical model known as generalized additive modeling was employed to ascertain the relationships between iron absorption, ferritin, and a molecule called hepcidin. By estimating the first derivatives of the trend created by the model, inflection points (or thresholds) in these relationships were established.
The results revealed that hepcidin increased in a linear fashion parallel to ferritin. Iron absorption increased when hepcidin reached a threshold value and when a threshold ferritin value was detected, beyond which iron absorption remained stable. An auxiliary validation within the results found that a hepcidin of approximately 3 nmol/l corresponded to a ferritin level of approximately 51 µg/l. These findings collectively suggest that if the body's ferritin concentration falls below 50 µg/L—corresponding to a hepcidin level of less than 3 nmol/l—the body will respond by absorbing more iron from the diet, signaling an emerging iron deficiency.
Discover Related Insights
Pomegranate juice has potential beyond ascorbic acid alone in enhancing iron absorption and assimilation, supporting Ayurveda's proposition of managing iron deficiency anemia with pomegranate.
2020 Plant Foods for Human Nutrition Pomegranate Juice Enhances Iron Dialysability and Assimilation in In-Vitro Cell Free and Cell-Based Models Balasubramani SP, Varghese RK, Vishnuprasad CN, Venkatasubramanian P
Experimental Study Iron Absorption Iron Deficiency Pomegranate
The study applied a cell-free model imitating gastric and intestinal digestive procedures, along with cell-based models (in the form of Caco-2 and HepG2 cells), to evaluate iron dialysability in the presence of pomegranate juice. This method was utilized to observe iron uptake into cells, assessed via cellular ferritin content measures.
Pomegranate juice highly improved iron dialysability in the cell-free model and increased iron uptake and ferritin content in the cells’ models far more than ascorbic acid alone. This result corroborates Ayurveda's claim regarding the beneficial usage of pomegranate in managing iron deficiency anemia, proposing a straightforward remedy to a global health issue. The betterment of iron bioavailability could be due to the synergistic action of various phytochemicals in pomegranate juice, suggesting a multifunctional utility for this natural product.
Children with attention-deficit hyperactivity disorder are found to have lower ferritin levels and are more likely to have iron deficiency.
2018 Scientific Reports Peripheral iron levels in children with attention-deficit hyperactivity disorder: a systematic review and meta-analysis Tseng PT, Cheng YS, Yen CF, Chen YW, Stubbs B, Whiteley P, et al.
Meta-Analysis Ferritin Iron Deficiency
For the methodology of this meta-analysis, numerous databases such as PubMed, ScienceDirect, Cochrane CENTRAL, and ClinicalTrials.gov were searched for relevant studies up until August 9, 2017. The principal outcomes were the differences in peripheral iron levels between children diagnosed with ADHD and healthy controls, and the severity of ADHD symptoms in children with and without iron deficiency. Seventeen articles met the strict inclusion criteria and were therefore included in the meta-analysis.
Discussing the results, peripheral serum ferritin levels (a measure of iron storage) were found to be significantly lower in children with ADHD. However, no notable difference was found in serum iron or transferrin levels (measures of iron transport). In addition, children with iron deficiency displayed more severe ADHD symptoms. Importantly, a significant link between ADHD and iron deficiency was also established.
Black soyabean seed coat extract significantly decreases hepcidin expression, leading to improved iron metabolism and potential treatment for iron-deficiency anaemia.
2014 British Journal of Nutrition Black soyabean seed coat extract regulates iron metabolism by inhibiting the expression of hepcidin Mu M, Wu A, An P, Du X, Wu Q, Shen X, et al.
Experimental Study Anaemia Black Soybean Hepcidin
The research employed both in vitro and in vivo experimental designs using cells treated with black soyabean seed coat extract (BSSCE) and 8-week-old male mice fed with a diet containing 2% BSSCE respectively. The study measured the effect of this extract on the expression of hepcidin, which is known to regulate iron homeostasis. In addition to this, its impact on splenic iron concentrations, serum iron concentrations and the phosphorylation levels of specific proteins was assessed.
The study found that BSSCE effectively inhibited the expression of hepcidin in both the in vitro and in vivo investigations. The mice given a diet containing BSSCE showed a decrease in hepatic hepcidin expression and splenic iron concentrations, while at the same time, an increase was observed in serum iron concentrations. The BSSCE induced this change through a decrease in the phosphorylation of mothers against decapentaplegic homolog proteins. There were marked increases in erythrocyte counts, hemoglobin concentrations, and hematocrit values in the test mice, indicating improved iron metabolism. This suggest that black soyabean extract has potential in regulating iron metabolism, presenting possibilities for the treatment of hepcidin-related diseases, including iron-deficiency anaemia.
Healthy individuals, including those with low iron stores, show reduced nonheme-iron absorption after iron supplementation, leading to larger iron stores that are sustained over time.
2000 The American Journal of Clinical Nutrition Adaptation in iron absorption: iron supplementation reduces nonheme-iron but not heme-iron absorption from food Roughead ZK, Hunt JR
Randomised Controlled Trial Heme-Iron Iron Absorption Iron Deficiency
This research was conducted via a randomized, placebo-controlled trial with 57 healthy volunteers (comprising of men and women). The participants' absorption of heme and nonheme iron was measured both prior and subsequent to a 12-week course of iron supplementation achieved through the provision of 50mg iron everyday as ferrous sulphate. Alongside, serum and fecal ferritin were observed during the supplementation period and for six months thereafter.
In the initial phase, both heme and nonheme iron absorption had an inverse relation with serum ferritin concentration. With the passage of the 12 week period of iron supplementation, participants, even those with serum ferritin less than 21 microg/L, showed evidence of absorbing less nonheme iron from their diet, but no such change was observed with respect to heme iron from a beef-based meal. Serum ferritin concentration was higher after the supplementation period than after placebo, and this increase remained for more than half a year, barring individuals with low iron stores, in whom the serum ferritin levels returned to their initial numbers within three months. A 2.5-fold increase in fecal ferritin excretion was noted during the supplementation. It becomes evident from these findings that even people with low iron stores adapt by lowering their nonheme iron absorption from food in response to iron supplementation. Despite this adaptation, iron stores appeared to be greater after iron supplementation when compared to placebo, and the difference was sustained across the board, except in the case of people with the lowest iron stores.