Food iron absorption in human subjects. III. Comparison of the effect of animal proteins on nonheme iron absorption

1976 ◽  
Vol 29 (8) ◽  
pp. 859-867 ◽  
Author(s):  
J D Cook ◽  
E R Monsen
Keyword(s):  
Iron Absorption ◽  
Human Subjects ◽  
Nonheme Iron

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

scholarly journals Improved zinc and iron absorption from breakfast meals containing malted oats with reduced phytate content

1996 ◽  
Vol 76 (5) ◽  
pp. 677-688 ◽  
Author(s):  
Marie Larsson ◽  
Lena Rossander-Hulthén ◽  
Brittmarie Sandström ◽  
Ann-Sofie Sandberg
Keyword(s):  
Iron Absorption ◽  
Human Subjects ◽  
Vulnerable Groups ◽  
Whole Body ◽  
Absolute Amount ◽  
Average Increase ◽  
Mineral Deficiency ◽  
Breakfast Meal ◽  
Body Retention ◽  
Phytate Content

The absorption of Zn or Fe from breakfast meals containing oat porridge prepared from malted and soaked oats and a control porridge made from untreated oats was measured in human subjects. The effect on Zn and Fe absorption of reducing the phytate content of oat-porridge meals was examined in each subject by extrinsic labelling of porridge with 65Zn and of bread rolls with 55Fe and 59Fe, and measuring whole-body retention and the erythrocyte uptake of isotopes. Each experiment comprised nine to ten subjects. The absorption of Zn from malted-oat porridge with a phytate (inositol hexaphosphate) content of 107 μmol was 18·3%, and significantly higher (P < 0·05) than from the control porridge containing 432 μmol phytate (11·8%). Fe absorption from the meal containing malted-oat porridge with 107 μmol phytate (Expt 2) was also significantly improved (P < 0·05) compared with that from the meal containing control porridge with 437 μmol phytate. The average increase in Fe absorption was 47%, or from 4·4 to 6·0%. In the breakfast meal containing malted porridge with 198 μmol phytate (Expt 3) the increase in Fe absorption was not significantly improved. Even though the phytate content was reduced to a greater extent in Expt 3 than Expt 2, the average increase in Fe absorption in Expt 3 was only 25% more than that from the meal containing control porridge (with 599 μmol phytate), depending on the higher absolute amount of phytate. In conclusion, an improvement in Zn and Fe absorption from oat products can be achieved by practising malting and soaking in the processing of oats. This may be of importance in the prevention of mineral deficiency in vulnerable groups.

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.

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.

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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