scholarly journals Dietary ascorbic acid raises iron absorption in anaemic rats through enhancing mucosal iron uptake independent of iron solubility in the digesta

1997 ◽  
Vol 77 (1) ◽  
pp. 123-131 ◽  
Author(s):  
K. J. H. Wienk ◽  
J. J. M. Marx ◽  
M. Santos ◽  
A. G. Lemmens ◽  
E. J. Brink ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Iron Uptake ◽  
Iron Absorption ◽  
Iron Solubility ◽  
Fe Uptake ◽  
Isotope Technique ◽  
Proximal Intestine ◽  
Liquid And Solid Phases ◽  
Double Isotope

We studied Fe absorption from FeSO4 in rats with Fe deficiency-induced anaemia that were given an Fe-sufficient purified diet without or with ascorbic acid (10·4 g/kg diet). Attention was focused on mucosal Fe uptake as measured in vivo by a double-isotope technique. Haemoglobin repletion and liver Fe levels were not affected when the ascorbic acid-supplemented diet was given, but apparent Fe absorption and retention of orally administered 59Fe were significantly enhanced. The distribution of Fe between liquid and solid phases of contents of both the stomach and the proximal intestine was not affected by the feeding of the ascorbic acid, but ascorbic acid significantly enhanced mucosal Fe uptake. It is concluded that ascorbic acid in the diet raises mucosal Fe uptake through a mechanism independent of the intestinal Fe solubility.

Maturation, iron deficiency, and ligands in enteric radioiron transport in vitro

1963 ◽  
Vol 204 (1) ◽  
pp. 171-175 ◽  
Author(s):  
W. S. Ruliffson ◽  
J. M. Hopping
Keyword(s):  
Ascorbic Acid ◽  
Iron Deficiency ◽  
Iron Absorption ◽  
Deficiency Anemia ◽  
Anaerobic Incubation ◽  
Reverse Effect ◽  
Factors Affecting ◽  
Everted Gut Sac

The effects in rats, of age, iron-deficiency anemia, and ascorbic acid, citrate, fluoride, and ethylenediaminetetraacetate (EDTA) on enteric radioiron transport were studied in vitro by an everted gut-sac technique. Sacs from young animals transported more than those from older ones. Proximal jejunal sacs from anemic animals transported more than similar sacs from nonanemic rats, but the reverse effect appeared in sacs formed from proximal duodenum. When added to media containing ascorbic acid or citrate, fluoride depressed transport as did anaerobic incubation in the presence of ascorbic acid. Anaerobic incubation in the presence of EDTA appeared to permit elevated transport. Ascorbic acid, citrate, and EDTA all enhanced the level of Fe59 appearing in serosal media. These results appear to agree with previously established in vivo phenomena and tend to validate the in vitro method as one of promise for further studies of factors affecting iron absorption and of the mechanism of iron absorption.

scholarly journals Iron absorption in hepcidin1 knockout mice

2011 ◽  
Vol 105 (11) ◽  
pp. 1583-1591 ◽  
Author(s):  
Patarabutr Masaratana ◽  
Abas H. Laftah ◽  
Gladys O. Latunde-Dada ◽  
Sophie Vaulont ◽  
Robert J. Simpson ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Iron Absorption ◽  
Fe Deficiency ◽  
Acute Effects ◽  
Regulatory Peptide ◽  
Fe Uptake

Hepcidin, the Fe-regulatory peptide, has been shown to inhibit Fe absorption and reticuloendothelial Fe recycling. The present study was conducted to explore the mechanism of in vivo Fe regulation through genetic disruption of hepcidin1 and acute effects of hepcidin treatment in hepcidin1 knockout (Hepc1− / − ) and heterozygous mice. Hepcidin1 disruption resulted in significantly increased intestinal Fe uptake. Hepcidin injection inhibited Fe absorption in both genotypes, but the effects were more evident in the knockout mice. Hepcidin administration was also associated with decreased membrane localisation of ferroportin in the duodenum, liver and, most significantly, in the spleen of Hepc1− / −  mice. Hypoferraemia was induced in heterozygous mice by hepcidin treatment, but not in Hepc1− / −  mice, 4 h after injection. Interestingly, Fe absorption and serum Fe levels in Hepc1− / −  and heterozygous mice fed a low-Fe diet were not affected by hepcidin injection. The present study demonstrates that hepcidin deficiency causes increased Fe absorption. The effects of hepcidin were abolished by dietary Fe deficiency, indicating that the response to hepcidin may be influenced by dietary Fe level or Fe status.

scholarly journals Solubility and Impact of Ascorbic Acid on the in vitro Bioavailability of Two Casein-Based Iron Fortificants from Reconstituted Milk

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1836-1836
Author(s):  
Magalie Sabatier ◽  
Joeska Husny ◽  
Marine Nicolas ◽  
Stèphane Dubascoux ◽  
Mary Bodis ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Iron Uptake ◽  
Iron Absorption ◽  
In Vitro Digestion ◽  
Iron Level ◽  
Similar Amount ◽  
Soluble Iron ◽  
Reconstituted Milk ◽  
The Impact

Abstract Objectives The two objectives were 1) to evaluate the solubility of two iron casein complexes (ICCs) under a condition mimicking gastric pH, 2) to evaluate the impact of ascorbic acid (AA) on the in vitro iron absorption of ICCs after incorporation in reconstituted whole milk powder. Methods The in vitro solubility was determined over time after addition of diluted HCl (pH 1.7), ultracentrifugation and measurement of iron appearing in the supernatant by ICP-OES (n = 2). The impact of AA on iron uptake from the Fe compounds in reconstituted milk was determined using the in vitro digestion coupled with the Caco-2 cell model and the measurement of ferritin/total protein produced by the cells (n = 3). The molar ratio of AA to iron of 2 to 1 recommended by the WHO for iron absorption optimization has been tested with an iron level corresponding to 3.3 mg Fe/serving of milk. Ferrous sulfate (FeSO4), the reference compound for iron bioavailability and micronized ferric pyrophosphate (FePP), main salt used for milk fortification were used as references. Results The dissolution test showed a rapid solubilization of iron from the ICCs i.e., >75 ± 19.3% at 5 min and >89 ± 0.3% at 90 min. The kinetics of soluble iron from the complexes were like that from FeSO4. The solubility of FePP was only 37.6 ± 4.7% at 90 min. Without AA, the iron uptake from FeSO4 was lower than expected translating into a relative in vitro bioavailability (iRBA) of FePP and of the two ICCs to FeSO4 of 66, 169 and 215%. This might be explained by a rapid conversion of soluble iron from FeSO4 into Fe3+ and insoluble iron hydroxide when the pH increased from 2 to >7 during in vitro digestion. However, with the addition of AA in the milk, iron uptake by the cells was found to be increased to levels of 341.8 ± 8.9, 124 ± 12.2, 403.1 ± 117.8 and 362.9 ± 36.9 ng ferritin/mg protein for FeSO4, FePP and the two ICCs respectively. This translates into iRBAs to FeSO4 of 36% for FePP and of 118 and 106% for the two ICCs. Conclusions The solubility and the demonstrated impact of AA on Fe uptake suggest that ICCs are absorbed to a similar amount as FeSO4 and thus provide an excellent source of Fe. Funding Sources Société des Produits Nestlé, NPTC Konolfingen, Switzerland.

Novel Double-Isotope Technique for Enzymatic Assay of Catecholamines, Permitting High Precision, Sensitivity and Plasma Sample Capacity

1981 ◽  
Vol 61 (5) ◽  
pp. 591-598 ◽  
Author(s):  
M. J. Brown ◽  
D. A. Jenner
Keyword(s):  
Plasma Sample ◽  
Specific Radioactivity ◽  
High Specific Radioactivity ◽  
Coefficients Of Variation ◽  
Isotope Technique ◽  
Noradrenaline And Adrenaline ◽  
Radioenzymatic Assays ◽  
Double Isotope ◽  
Catecholamine Concentration

1. A novel use of a double-isotope method is described which allows radioenzymatic assays to combine precision and sensitivity. 2. In the catechol O-methyltransferase assay separate portions of each plasma sample are incubated with either S-[3H]- or S-[14C]-adenosyl-l-methionine. Standards of noradrenaline and adrenaline are added to the latter portions and are thus converted into standards of [14C]metadrenalines. These are added to the 3H-labelled portions after the incubation, where they function as tracers. 3. The final recovery of 14C radioactivity corrects for (a) the efficiency of methylation in the plasma sample concerned and (b) the recovery of metadrenalines during the extraction procedures. 4. The 3H/14C ratio is constant in each assay for a given catecholamine concentration and is determined for samples to which standards of noradrenaline and adrenaline are added to the 3H- (as well as the I4C-) labelled portions before the initial incubation. 5. The sensitivity of the assay is increased by using high specific radioactivity S-[3H]adenosyl-l-methionine (60-85 Ci/mmol), and low backgrounds are maintained by catecholamine depletion in vivo in the rats used for enzyme preparation. 6. Both catecholamines (1.5 pg/ml; 10 pmol/l) may be detected; the coefficients of variation are 3.0 and 3.2% for noradrenaline and adrenaline respectively (intra-assay) and 4.6 and 5.0% (inter-assay).

Age-Related Changes in the Kinetics of Iron Absorption across the Guinea Pig Proximal Intestine in vivo

Neonatology ◽  
1988 ◽  
Vol 53 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Surjit K.S. Srai ◽  
Edward S. Debnam ◽  
Margot Boss ◽  
Owen Epstein
Keyword(s):  
Guinea Pig ◽  
Iron Absorption ◽  
Age Related ◽  
Proximal Intestine ◽  
Kinetics Of ◽  
Age Related Changes

Iron Absorption in Chronic Renal Disease

1970 ◽  
Vol 38 (2) ◽  
pp. 191-196 ◽  
Author(s):  
J. W. Eschbach ◽  
J. D. Cook ◽  
C. A. Finch
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Renal Disease ◽  
Iron Overload ◽  
Iron Absorption ◽  
Chronic Renal Disease ◽  
Iron Depletion ◽  
Isotope Technique ◽  
Double Isotope

1. Absorption of inorganic iron was studied in thirty-four patients with chronic renal failure by a double isotope technique. 2. Eight patients with normal iron balance had a mean absorption of 3·5%, ten patients with iron overload had a mean absorption of 3·6%, and sixteen patients with iron depletion had a mean absorption of 58%. Thus, alterations in absorption appeared to be related to disturbances in iron balance. 3. The rate of erythropoiesis had no evident effect on iron absorption nor did the degree of anaemia. 4. The presence of renal disease and the degree of azotaemia likewise did not appear to affect absorption.

Simultaneous Measurement of 59Fe and 51Cr in Iron Absorption Studies Using a Whole-Body Scanner with Mobile Shielding

1980 ◽  
Vol 19 (03) ◽  
pp. 140-145 ◽  
Author(s):  
Bep van den Beld ◽  
R. van Dongen ◽  
L.H. Strackee ◽  
J.J. M. Marx
Keyword(s):  
Iron Absorption ◽  
Background Radiation ◽  
The Body ◽  
Whole Body ◽  
Absorption Studies ◽  
Isotope Technique ◽  
Iron Retention ◽  
Body Scanner ◽  
Mucosal Uptake ◽  
Double Isotope

SummaryA whole-body scanner is described with a mobile shadow shield which affords a considerable reduction in space. The scanner has two Nal(Tl) scintillation crystals of 4 x 6", placed at opposite sites of the subject. Background radiation, efficiency and geometric qualities made the scanner very useful for clinical whole-body counting. The equipment was used in iron absorption studies using a double isotope technique with 59Fe and 51Cr. After ingestion of an oral test dose total body kinetics of 59Fe and 51Cr was followed up to 60 days in 4 volunteers. Between days 3 and 10 the 51Cr, which was used as an non-absorbable indicator, had left the body completely. The 59Fe reached a constant value not before day 10, indicating that iron retention cannot be measured before that time. From repeated measurement of 59Fe and 5lCr directly after ingestion until the first defaecation it could be deduced that the coefficient of variation for 59Fe was less than 1.5% with a scanning time of 600 sec, and for 51Cr less than 5%. Extreme variations in geometry, such as measurement of the activity in a beaker and of the same amount after ingestion in the body, yielded practically the same value for 59Fe. The double isotope technique made it possible to measure not only iron retention but also mucosal uptake and mucosal transfer of iron. It is pointed out that measurement of the last two parameters of iron absorption is not possible in patients with serious obstipation or with very low mucosal uptake values.

Ascorbic Acid can Reverse the Inhibition of Phytic Acid, Sodium Oxalate and Sodium Silicate on Iron Absorption in Caco-2 cells

2018 ◽  
Vol 88 (1-2) ◽  
pp. 65-72 ◽  
Author(s):  
Wanling He ◽  
Xiaoli Li ◽  
Ke Ding ◽  
Yuanxiao Li ◽  
Wang Li
Keyword(s):  
Ascorbic Acid ◽  
Phytic Acid ◽  
Sodium Silicate ◽  
Ferrous Iron ◽  
Iron Uptake ◽  
Iron Absorption ◽  
Cell Model ◽  
Heme Iron ◽  
Iron Bioavailability ◽  
Sodium Oxalate

Abstract. The objective of the present study is to determine the effect of phytic acid (PA), sodium oxalate (SO) and sodium silicate (SS) on non-heme iron bioavailability in both the presence and absence of ascorbic acid (AA) using an in vitro digestion/Caco-2 cell model, and the levels of AA needed to promote Fe absorption from Fe complexed with PA, SO or SS were also determined. The results indicated that adding PA at 1:1, 3:1, 5:1 and 10:1 molar as compared to Fe decreased ferrous iron uptake by 55.80 %(P < 0.05), 72.33 % (P < 0.05), 73.32 % (P < 0.05), and 73.26 % (P < 0.05), respectively. Adding SS at 1:1, 3:1, 5:1 and 10:1 molar as compared to Fe also decreased ferrous iron uptake by 51.40 % (P < 0.05), 66.12 %(P < 0.05), 60.19 % (P < 0.05) and 45.11 % (P < 0.05), respectively. Adding SO at 5:1 and 10:1 molar as compared to Fe decreased ferrous iron uptake by 40.81 % (P < 0.05) and 33.14 % (P < 0.05), respectively. When adding AA to iron plus organic acid medias reached molar ratios of 5:5:1 AA:PA:Fe, 3:5:1 AA:SO:Fe and 5:5:1 AA:SS:Fe, iron absorption from FeSO4 were significantly increased (P < 0.05). However, no significant effect was observed in iron absorption from FeCl3 when adding AA to the media. The results showed that PA, SS or SO decreases iron uptake from ferrous Fe, and AA can counteract their inhibiting effect on ferrous iron absorption and thus increase ferrous iron uptake. The results may be important for elucidating factors affecting iron bioavailability in the small intestine and for the development of foods with improved iron bioavailability.

Role of hydrochloric acid in iron absorption

1964 ◽  
Vol 19 (2) ◽  
pp. 187-188 ◽  
Author(s):  
Peter Jacobs ◽  
Thomas Bothwell ◽  
Robert W. Charlton
Keyword(s):  
Hydrochloric Acid ◽  
Pernicious Anemia ◽  
Iron Absorption ◽  
Gastric Ph ◽  
Ferrous Ascorbate ◽  
Isotope Technique ◽  
The Mean ◽  
The Difference ◽  
Double Isotope

The absorption of 5 mg iron administered in 300 ml water was compared with absorption from 300 ml 0.05 n HCL in 24 subjects with histamine-fast achlorhydria, using a double isotope technique. In ten individuals given ferric chloride the mean absorptions were 2.2% with water and 9.2% in acid; the difference was less marked in the case of the seven subjects to whom ferrous ascorbate was administered (10.9% and 19.3%, respectively). In contrast, acid did not increase the absorption of hemoglobin iron, the mean figures being 13.4% with water and 9.6% with HCL. pernicious anemia; achlorhydria; gastric pH Fe55 and Fe59; radioactive hemoglobin iron Submitted on June 17, 1963

Active transport of iron by intestine: mucosal iron pools

1964 ◽  
Vol 207 (4) ◽  
pp. 893-900 ◽  
Author(s):  
James Manis ◽  
David Schachter
Keyword(s):  
Active Transport ◽  
Hemagglutination Inhibition ◽  
Iron Uptake ◽  
Iron Transport ◽  
Iron Absorption ◽  
Duodenal Mucosa ◽  
Serosal Surface ◽  
Normal Rat

Methods were developed for the specific estimation of Fe++, Fe+++, Fe59++ and Fe59+++ in homogenates of rat duodenal mucosa and applied to studies of iron transport by everted gut sacs in vitro and duodenal loops in vivo. In the course of active transport in vitro Fe++ is absorbed into a mucosal ferrous pool which turns over relatively rapidly by a) transport of Fe++ to the serosal surface and b) formation of a mucosal Fe+++ pool. The latter turns over more slowly and appears to be a storage depot for excess mineral. When rats are pretreated with oral iron, uptake of Fe++ at the mucosal surface is decreased, diversion of mucosal Fe++ to mucosal Fe+++ is increased, and transport toward the serosal surface is reduced. Corresponding effects, which tend to limit iron absorption in vivo, are observed with duodenal loops. A sensitive hemagglutination-inhibition method was developed to estimate apoferritin in normal rat mucosa, and this protein was detected and quantified. Ferritin could account for only 8.0% of the trivalent mucosal pool and appeared to play an insignificant role in the present studies.

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