Insights & Discussion
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.
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.
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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.
2021 EClinicalMedicine Threshold ferritin and hepcidin concentrations indicating early iron deficiency in young women based on upregulation of iron absorption Galetti V, Stoffel NU, Sieber C, Zeder C, Moretti D, Zimmermann MB
Cohort Study Ferritin Hepcidin Iron Absorption
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.
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.
Bovine meats exhibit low variations in total iron content, with more than 60% of it consisting of heme iron.
2009 Biological Trace Element Research Total Iron and Heme Iron Content and their Distribution in Beef Meat and Viscera Valenzuela C, López de Romaña D, Olivares M, Morales MS, Pizarro F
Experimental Study Haem Iron Iron Deficiency
Two 4-month-year-old calves were injected with radioactive iron (55Fe), and then, samples were taken from the principal cuts of meat and major organs. The collected samples underwent acid digestion and their iron content was observed using atomic absorption spectrophotometry. In an overlapping process, another set of duplicate samples were analyzed for the concentration of 55Fe via a double isotopic method.
In the discussion of results, it was observed that the all cuts of meat had a consistent level of total iron (TFe). The amount of heme iron (HeFe) was found to represent more than 60% of TFe in meat, and varying larger proportions in different organs. The spleen held the highest HeFe proportion, whilst the liver contained the lowest. There was a notable amount of the radioisotope found in the blood, with minimal amounts found in muscle and organs.