Iron Bioavailability Studied in Infants: The Influence of Phytic Acid and Ascorbic Acid in Infant Formulas Based on Soy Isolate

Phytic acid is a potent inhibitor of native and fortification iron absorption and low absorption of iron from cereal- and/or legume-based complementary foods is a major factor in the etiology of iron deficiency in infants. Dephytinization of complementary foods or soy-based infant formulas is technically possible but, as phytic acid is strongly inhibitory at low concentrations, complete enzymatic degradation is recommended. If this is not possible, the phytic acid to iron molar ratio should be decreased to below 1:1 and preferably below 0.4:1. Complete dephytinization of cereal- and legume-based complementary foods has been shown to increase the percentage of iron absorption by as much as 12-fold (0.99% to 11.54%) in a single-meal study when the foods were reconstituted with water. The addition of milk, however, inhibits iron absorption and overcomes the enhancing effect of phytic acid degradation. Dephytinization can therefore be strongly recommended only for cereal/legume mixtures reconstituted with water, especially low-cost complementary foods destined for infants in developing countries. In countries where infant cereals are consumed with milk, ascorbic acid addition can more easily be used to overcome the negative effect of phytic acid on iron absorption. Similarly with soy-based infant formulas, especially if manufactured from low-phytate isolates, ascorbic acid can be used to ensure adequate iron absorption.

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A comparison of iron absorption in adults and infants consuming identical infant formulas

British Journal Of Nutrition ◽

10.1079/bjn19980006 ◽

1998 ◽

Vol 79 (1) ◽

pp. 31-36 ◽

Cited By ~ 27

Author(s):

Richard F. Hurrell ◽

Lena Davidsson ◽

Manju Reddy ◽

Peter Kastenmayer ◽

James D. Cook

Keyword(s):

Ascorbic Acid ◽

Phytic Acid ◽

Geometric Mean ◽

Inhibitory Effect ◽

Meal Size ◽

Infant Formulas ◽

Phytic Acid Content ◽

Fe Isotopes ◽

Absorption Studies ◽

Isotope Technique

Fe absorption was estimated in adults and infants from the erythrocyte incorporation of Fe isotopes added to infant formula. Fe absorption was measured in adults using radioisotopes, and in infants with a stable-isotope technique. In adults, the geometric mean Fe absorption from a ready-to-feed soya formula with its native phytic acid content was 2·4%. This increased to 6·0% (P< 0·05) after almost complete dephytinization. In infants, mean Fe absorption values were 3·9 and 8·7% respectively from the same products (P<0·05). In adults, mean Fe absorption from a spray-dried soya formula containing 110mg ascorbic acid/I was 4·1%, increasing to 5·3% (P< 0·05) when ascorbic acid was doubled to 220 mg/l. In infants, mean Fe absorption values were 5·7 and 9·5% (P< 0·05) from the same products. Mean Fe absorption from a milk-based formula was 6·5% in adults compared with 6·7% in infants. All meals in the adult and infant studies were fed using an identical meal size of 217g. Increasing the meal size threefold in adults did not change fractional Fe absorption. Mean Fe absorption values for each meal were lower in adults than in infants, but the relative inhibitory effect of phytic acid and the enhancing effect of ascorbic acid were similar. We conclude that Fe absorption studies in adults can be used to assess the influence of enhancers and inhibitors of Fe absorption in infant formulas fed to infants. Further studies, however, are required to extend these findings to weaning foods and complete meals.

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Review: Effect of Some Components of Milk- and Soy-Based Infant Formulas on Mineral Bioavailability

Food Science and Technology International ◽

10.1106/r4eb-xxla-9mlp-bqyk ◽

2001 ◽

Vol 7 (3) ◽

pp. 191-198 ◽

Cited By ~ 7

Author(s):

M. Jovaní ◽

R. Barberá ◽

R. Farré

Keyword(s):

Ascorbic Acid ◽

Citric Acid ◽

Phytic Acid ◽

Iron Absorption ◽

Mineral Elements ◽

Molar Ratio ◽

Zinc Absorption ◽

Infant Formulas ◽

Mineral Bioavailability ◽

Negative Effect

Infants’ high nutritional needs are fulfilled by mother’s milk or infant formulas to provide all the necessary nutrients, among them minerals. Minerals uptake depends not only on mineral content but also on their bioavailability which, in turn, is affected by the different components of the infant formulas. An understanding of these effects would help to improve mineral bioavailability. This work reviews the influence of endogenous (proteins and phytates) and added (ascorbic and citric acid) components in infant formulas on the bioavailability of nutritionally important mineral elements (calcium, zinc, iron and copper) and their interactions. Special attention is given to the influence of protein, which is positive for calcium and negative for iron absorption. The marked negative effect of phytates on iron and zinc absorption can be counteracted by a dephytinization process. Of the added compounds, ascorbic acid has a positive effect on iron absorption that depends on the molar ratio between ascorbic acid and iron. In fact, adding ascorbic acid can counteract the negative effect of phytic acid on iron absorption but does not alter the effect of phytic acid on zinc absorption. The null effect of an increase in citric acid content can be ascribed to the fact that the citrate contents of infant formulas are already high. One of the most important element interactions is the negative effect of calcium on zinc and iron intestinal absorption and also the interaction between zinc and iron. These interactions deserve our attention because these minerals are essential to infants’ growth and development.

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Iron absorption from experimental infant formulas based on pea (Pisum sativum)-protein isolate: the effect of phytic acid and ascorbic acid

British Journal Of Nutrition ◽

10.1079/bjn2000232 ◽

2001 ◽

Vol 85 (1) ◽

pp. 59-63 ◽

Cited By ~ 24

Author(s):

Lena Davidsson ◽

Triantafillia Dimitriou ◽

Thomas Walczyk ◽

Richard F. Hurrell

Keyword(s):

Ascorbic Acid ◽

Stable Isotope ◽

Pisum Sativum ◽

Phytic Acid ◽

Infant Formula ◽

Geometric Mean ◽

Protein Isolate ◽

Infant Formulas ◽

Phytic Acid Content ◽

Pea Protein

Infant formula based on pea (Pisum sativum)-protein isolate has been suggested as an alternative to soyabean formula in countries where soyabean is not a native crop, or when soyabean protein cannot be used due to allergic reactions or intolerances. In the present study, Fe absorption from experimental infant formulas based on pea-protein isolate was measured in healthy non-anaemic young women. The influence of phytic acid and ascorbic acid on Fe absorption was evaluated, using a stable-isotope technique based on incorporation of Fe stable-isotope labels into erythrocytes 14 d after administration. Geometric mean Fe absorption increased from 20·7 (+1SD 41·6, -1sd 10·3) % to 33·1 (+1sd 58·6, -1sd 18·7) %; (P<0·0001; n 10) after enzymic degradation of virtually all phytic acid. Doubling the molar ratio Fe : ascorbic acid from 1 : 2·1 to 1 : 4·2 in the infant formula with native phytic acid content also increased Fe absorption significantly (P<0·0001; n 10); geometric mean Fe absorption increased from 14·8 (+1sd 32·1, -1sd 6·8) % to 22·1 (+1sd 47·2, -1sd 10·4) %. These results confirm the inhibitory and enhancing effects of phytic acid and ascorbic acid respectively on Fe absorption, but also indicate relatively high fractional Fe absorption from the pea-protein-based formulas. After adjusting for differences in Fe status, our data indicate that Fe absorption from dephytinised pea protein might be less inhibitory than dephytinised soyabean protein as measured in a previous study ().

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

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000503 ◽

2018 ◽

Vol 88 (1-2) ◽

pp. 65-72 ◽

Cited By ~ 1

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.

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Effects of ascorbic acid, phytic acid and tannic acid on iron bioavailability from reconstituted ferritin measured by anin vitrodigestion–Caco-2 cell model

British Journal Of Nutrition ◽

10.1017/s0007114508055621 ◽

2008 ◽

Vol 101 (7) ◽

pp. 972-981 ◽

Cited By ~ 36

Author(s):

Fuxia Jin ◽

Charles Frohman ◽

Theodore W. Thannhauser ◽

Ross M. Welch ◽

Raymond P. Glahn

Keyword(s):

Ascorbic Acid ◽

Phytic Acid ◽

Tannic Acid ◽

Cell Model ◽

Iron Bioavailability ◽

Molar Ratio ◽

Plant Type ◽

Inhibiting Effect ◽

Negative Effect

The effects of ascorbic acid (AA), phytate and tannic acid (TA) on Fe bioavailability from Fe supplied as reconstituted ferritin were compared with FeSO4using anin vitrodigestion–Caco-2 cell model. Horse spleen apoferritin was chemically reconstituted into an animal-type ferritin (HSF) and a plant-type ferritin (P-HSF) according to the typical ratios of Fe:P found in these molecules. In the presence of AA (Fe:AA molar ratio of 1:20), significantly more Fe was absorbed from FeSO4(about 303 %), HSF (about 454 %) and P-HSF (about 371 %) when compared with ferrous sulfate or ferritin without AA. Phytic acid (PA; Fe:PA molar ratio of 1:20) significantly reduced Fe bioavailability from FeSO4(about 86 %), HSF (about 82 %) and P-HSF (about 93 %) relative to FeSO4and the ferritin controls. Treatment with TA (Fe:TA molar ratio of 1:1) significantly decreased Fe bioavailability (about 97 %) from both FeSO4and the ferritin samples. AA was able to partially reverse the negative effect of PA (Fe:PA:AA molar ratio of 1:20:20) on Fe bioavailability but did not reverse the inhibiting effect of TA (Fe:TA:AA molar ratio of 1:1:20) on Fe bioavailability from ferritin and FeSO4. Overall, there were no significant differences in bioavailable Fe between P-HSF, HSF or FeSO4. Furthermore, the addition of AA (a known promoter) or the inhibitors, PA and TA, or both, did not result in significant differences in bioavailable Fe from ferritin relative to FeSO4. The results suggest that Fe in the reconstituted ferritin molecule is easily released duringin vitrodigestion and interacts with known promoters and inhibitors.

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Lactoferrin and Its Possible Role in Iron Enrichment of Infant Formulas

Food Science and Technology International ◽

10.1177/108201320100700201 ◽

2001 ◽

Vol 7 (2) ◽

pp. 97-103 ◽

Cited By ~ 6

Author(s):

M. Jovani ◽

R. Barbera ◽

R. Farre

Keyword(s):

Ascorbic Acid ◽

Iron Absorption ◽

Antioxidant Activities ◽

Iron Bioavailability ◽

Bovine Lactoferrin ◽

Infant Formulas ◽

Toxicological Evaluation ◽

Additional Improvement ◽

Free Radical Formation ◽

The Moment

The properties and functions of lactoferrin in relation to its use in the supplementation of infant formulas are discussed. Special attention is paid to lactoferrin functions directly related to its ability to bind iron, that is, its effect on iron absorption and bacteriostatic and antioxidant activities. From the results obtained by different authors, it can be concluded that the addition of lactoferrin, usually bovine, to infant formulas, does not affect iron absorption. However, given its ability to bind iron, its use in infant formulas could be useful for protecting the gut of infants against infections from microbial-requiring iron, its ability to reduce interelemental interactions and especially to protect infant formulas supplemented with iron and ascorbic acid against free radical formation. Although bovine lactoferrin is at the moment the most easily available, today it is possible to have human recombinant lactoferrin. The possibility of adding it to infant formulas should be considered, if and when the toxicological evaluation proves favorable, because of the possible additional improvement of iron bioavailability.

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