scholarly journals Obesity-Related Hypoferremia Is Not Explained by Differences in Reported Intake of Heme and Nonheme Iron or Intake of Dietary Factors that Can Affect Iron Absorption

2008 ◽  
Vol 108 (1) ◽  
pp. 145-148 ◽  
Author(s):  
Carolyn M. Menzie ◽  
Lisa B. Yanoff ◽  
Blakeley I. Denkinger ◽  
Teresa McHugh ◽  
Nancy G. Sebring ◽  
...  
Keyword(s):  
Iron Absorption ◽  
Nonheme Iron ◽  
Dietary Factors

Food iron absorption in idiopathic hemochromatosis

Blood ◽  
1989 ◽  
Vol 74 (6) ◽  
pp. 2187-2193 ◽  
Author(s):  
SR Lynch ◽  
BS Skikne ◽  
JD Cook
Keyword(s):  
Serum Ferritin ◽  
Iron Absorption ◽  
Iron Status ◽  
Normal Subjects ◽  
Heme Iron ◽  
Nonheme Iron ◽  
Ferritin Concentration ◽  
Normal Volunteers ◽  
Idiopathic Hemochromatosis ◽  
The Relationship

Abstract The relationship between iron status and food iron absorption was evaluated in 75 normal volunteers, 15 patients with idiopathic hemochromatosis, and 22 heterozygotes by using double extrinsic radioiron tags to label independently the nonheme and heme iron components of a hamburger meal. In normal subjects, absorption from each of these pools was inversely correlated with storage iron, as measured by the serum ferritin concentration. In patients with hemochromatosis, absorption of both forms of iron was far greater than would be predicted from the relationship between absorption and serum ferritin observed in normal volunteers. Nevertheless, there was still a modest but statistically significant reduction in absorption of nonheme iron with increasing serum ferritin. This relationship could not be demonstrated in the case of heme iron absorption. In heterozygotes, nonheme iron absorption from a hamburger meal containing no supplementary iron did not differ significantly from that observed in normal volunteers. However, when this meal was both modified to promote bioavailability and supplemented with iron, absorption of nonheme iron was significantly elevated. These studies confirm the presence of excessive nonheme iron absorption even from unfortified meals in patients with idiopathic hemochromatosis and suggest in addition that they are particularly susceptible to iron loading from diets containing a high proportion of heme iron. Impaired regulation of nonheme iron absorption was also observed in heterozygous individuals, but a statistically significant abnormality was demonstrable only when the test meal contained a large highly bioavailable iron supplement.

scholarly journals Dietary Factors Moderate the Relation between Groundwater Iron and Anemia in Women and Children in Rural Bangladesh

2019 ◽  
Vol 3 (10) ◽  
Author(s):  
Amanda S Wendt ◽  
Jillian L Waid ◽  
Sabine Gabrysch
Keyword(s):  
Iron Deficiency ◽  
Vitamin C ◽  
Fruits And Vegetables ◽  
Iron Absorption ◽  
Cluster Randomized Trial ◽  
Heme Iron ◽  
Dietary Factors ◽  
Baseline Survey ◽  
Women And Children ◽  
Cluster Randomized

ABSTRACT Background Anemia affects ∼1.6 billion people worldwide, often owing to iron deficiency. In Bangladesh, high levels of anemia have been observed alongside little iron deficiency. Elevated concentrations of groundwater iron could constitute a significant source of dietary iron. Objective We aimed to quantify the effect of groundwater iron on anemia in nonpregnant women and young children in Bangladesh, taking into account dietary factors that may affect iron absorption. Methods We analyzed data on 1871 nonpregnant women and 987 children (6–37 mo) from the 2015 baseline survey of the Food and Agricultural Approaches to Reducing Malnutrition cluster-randomized trial in Sylhet, Bangladesh. We used logistic regression with robust standard errors to assess effects of self-reported groundwater iron, dietary intake, and sociodemographic characteristics on anemia, considering interactions between groundwater iron and dietary factors. Results Groundwater iron presence was associated with less anemia in women (OR: 0.74; 95% CI: 0.60, 0.90) and children (OR: 0.58; 95% CI: 0.44, 0.76). This effect was modified by dietary factors. In women, the effect of groundwater iron on anemia was stronger if no vitamin C–rich or heme-iron foods were consumed, and there was a clear dose–response relation. In children, intake of vitamin C–rich foods strengthened the effect of groundwater iron on anemia, and there was no evidence for interaction by intake of iron-rich foods. Conclusions Heme-iron and vitamin C consumption reduced the effect of groundwater iron on anemia among women but not children in Bangladesh, which may be due to higher levels of iron deficiency and lower levels of iron intake among children. Vitamin C consumption appears to enhance iron absorption from groundwater in children and they may thus benefit from consuming more vitamin C–rich fruits and vegetables. Even among women and children consuming heme-iron or vitamin C–rich foods and groundwater iron, anemia prevalence remained elevated, pointing to additional causes of anemia beyond iron deficiency. This trial was registered at clinicaltrials.gov as NCT02505711.

High specific activity heme-Fe and its application for studying heme-Fe metabolism in Caco-2 cell monolayers

2002 ◽  
Vol 283 (5) ◽  
pp. G1125-G1131 ◽  
Author(s):  
Jennifer R. Follett ◽  
Yasushi A. Suzuki ◽  
Bo Lönnerdal
Keyword(s):  
Iron Absorption ◽  
Specific Activity ◽  
Iron Status ◽  
Basolateral Membrane ◽  
High Specific Activity ◽  
Heme Iron ◽  
Nonheme Iron ◽  
Serum Free Medium ◽  
Factors Affecting ◽  
Cell Monolayers

Heme-Fe is an important source of dietary iron in humans. Caco-2 cells have been used extensively to study human iron absorption with an emphasis on factors affecting nonheme iron absorption. Therefore, we examined several factors known to affect heme iron absorption. Cells grown in bicameral chambers were incubated with high specific activity [59Fe]heme alone or with 1% globin, BSA, or fatty acid-free BSA (BSA-FA) to examine the effect of protein source on absorption. Heme iron absorption was enhanced by globin and inhibited by BSA and BSA-FA. Absorption of heme iron in cells pretreated for 7 days with serum-free medium containing 1, 25, 50, or 100 μM Fe was higher in the 1-μM-Fe pretreatment group than in all other groups ( P < 0.05), showing an effect of iron status. Increased heme concentrations resulted in decreased percent absorbed but increased total heme iron absorption and increased transport rate across the basolateral membrane. Finally, cells treated with 10 μM CdCl2, which induces heme oxygenase, demonstrated higher absorption of [59Fe]heme than control cells ( P < 0.05). Our results from Caco-2 cells are in agreement with human studies and make this a promising model for examining intestinal heme iron absorption.

Alternative pathways for absorption of iron from foods

2010 ◽  
Vol 82 (2) ◽  
pp. 429-436 ◽  
Author(s):  
Bo Lönnerdal
Keyword(s):  
Iron Absorption ◽  
Iron Status ◽  
Age Groups ◽  
Heme Iron ◽  
Dietary Factors ◽  
Iron Binding ◽  
Alternative Pathways ◽  
Non Heme Iron ◽  
Lactoferrin Receptor ◽  
Iron Binding Proteins

Iron is known to be absorbed from foods in two major forms, heme iron and non-heme iron. Iron status as well as dietary factors known to affect iron absorption has limited effect on heme iron absorption, whereas inhibitors and enhancers of iron absorption have pronounced effects on non-heme iron absorption. The enterocyte transporter for non-heme iron, DMT1, is strongly up-regulated during iron deficiency and down-regulated during iron overload. A transporter for heme iron, HCP1, was recently characterized and is present on the apical membrane of enterocytes. Two other pathways for iron absorption have been discovered and may serve to facilitate uptake of iron from two unique iron-binding proteins, lactoferrin and ferritin. Lactoferrin is an iron-binding protein in human milk and known to survive proteolytic digestion. It mediates iron uptake in breast-fed infants through endocytosis via a specific lactoferrin receptor (LfR). Recently, lactoferrin has become popular as a food additive and may enhance iron status in several age groups. Ferritin is present in meat, but also in plants. The ferritin content of plants can be enhanced by conventional breeding or genetic engineering, and thereby increase iron intake of populations consuming plant-based diets. Ferritin is a bioavailable source of iron, as shown in recent human studies. Ferritin can be taken up by intestinal cells via endocytosis, suggesting a receptor-mediated mechanism.

Copper deficiency increases iron absorption in the rat

2003 ◽  
Vol 285 (5) ◽  
pp. G789-G795 ◽  
Author(s):  
Carla Thomas ◽  
Phillip S. Oates
Keyword(s):  
Kupffer Cells ◽  
Oxidase Activity ◽  
Copper Deficiency ◽  
Iron Absorption ◽  
Nonheme Iron ◽  
Iron Accumulation ◽  
Strong Correlations ◽  
Liver Iron ◽  
Iron Deficient ◽  
Ferroxidase Activity

Release of iron from enterocytes and hepatocytes is thought to require the copper-dependent ferroxidase activity of hephaestin (Hp) and ceruloplasmin (Cp), respectively. In swine, copper deficiency (CD) impairs iron absorption, but whether this occurs in rats is unclear. By feeding a diet deficient in copper, CD was produced, as evidenced by the loss of copper-dependent plasma ferroxidase I activity, and in enterocytes, CD reduced copper levels and copper-dependent oxidase activity. Hematocrit was reduced, and liver iron was doubled. CD reduced duodenal mucosal iron and ferritin, whereas CD increased iron absorption. Duodenal mucosal DMT1-IRE and ferroportin1 expression remained constant with CD. When absorption in CD rats was compared with that seen normally and in iron-deficient anemic animals, strong correlations were found among mucosal iron, ferritin, and iron absorption, suggesting that the level of iron absorption was appropriate given that the erythroid and stores stimulators of iron absorption are opposed in CD. Because CD reduced the activity of Cp, as evidenced by copper-dependent plasma ferroxidase I activity and hepatocyte iron accumulation, but iron absorption increased, it is unlikely that the ferroxidase activity of Hp is important and suggests another function for this protein in the export of iron from the enterocyte during iron absorption. Also, the copper-dependent ferroxidase activity of Cp does not appear important for iron efflux from macrophages, because Kupffer cells of the liver and nonheme iron levels of the spleen were normal during copper deficiency, suggesting another role for Cp in these cells.

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