Improved iron bioavailability in an oat-based beverage: the combined effect of citric acid addition, dephytinization and iron supplementation

Zhang, Huanmei; Önning, Gunilla; Öste, Rickard; Gramatkovski, Elisabeth; Hulthén, Lena

doi:10.1007/s00394-006-0637-4

Cited by 37 publications

(32 citation statements)

References 35 publications

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“…5c). Citrate, which was used as a buffer in the kinetics experiments above, is a known dietary chelator that supports iron uptake from the gut 30 . As an excess of citrate may reasonably be expected to occupy the relatively accessible binding site for Fe 3+ and ascorbate, the effect of soluble chelators on Fe 3+ reduction was evaluated in nonchelating buffers.…”

Section: Resultsmentioning

confidence: 99%

Structural basis for promotion of duodenal iron absorption by enteric ferric reductase with ascorbate

et al. 2018

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Dietary iron absorption is regulated by duodenal cytochrome b (Dcytb), an integral membrane protein that catalyzes reduction of nonheme Fe3+ by electron transfer from ascorbate across the membrane. This step is essential to enable iron uptake by the divalent metal transporter. Here we report the crystallographic structures of human Dcytb and its complex with ascorbate and Zn2+. Each monomer of the homodimeric protein possesses cytoplasmic and apical heme groups, as well as cytoplasmic and apical ascorbate-binding sites located adjacent to each heme. Zn2+ coordinates to two hydroxyl groups of the apical ascorbate and to a histidine residue. Biochemical analysis indicates that Fe3+ competes with Zn2+ for this binding site. These results provide a structural basis for the mechanism by which Fe3+ uptake is promoted by reducing agents and should facilitate structure-based development of improved agents for absorption of orally administered iron.

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Section: Resultsmentioning

confidence: 99%

Structural basis for promotion of duodenal iron absorption by enteric ferric reductase with ascorbate

et al. 2018

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“…First, some seeds and beans have a high content of potassium (see Table 1), which may contribute to worsening hyperkalemia in patients with CKD. Second, yeast-based phytase in whole grains makes the P content of leavened breads more prone to intestinal absorption than cereals or flat breads (40). Finally, the effect of probiotics on enhancing phytateassociated P release and absorption is not clear.…”

Section: P Intake From Plant Foods: the Role Of Phytatementioning

confidence: 99%

Understanding Sources of Dietary Phosphorus in the Treatment of Patients with Chronic Kidney Disease

Kalantar-Zadeh

Gutekunst²,

Mehrotra³

et al. 2010

Clinical Journal of the American Society of Nephrology

430

321

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In individuals with chronic kidney disease, high dietary phosphorus (P) burden may worsen hyperparathyroidism and renal osteodystrophy, promote vascular calcification and cardiovascular events, and increase mortality. In addition to the absolute amount of dietary P, its type (organic versus inorganic), source (animal versus plant derived), and ratio to dietary protein may be important. Organic P in such plant foods as seeds and legumes is less bioavailable because of limited gastrointestinal absorption of phytate-based P. Inorganic P is more readily absorbed by intestine, and its presence in processed, preserved, or enhanced foods or soft drinks that contain additives may be underreported and not distinguished from the less readily absorbed organic P in nutrient databases. Hence, P burden from food additives is disproportionately high relative to its dietary content as compared with natural sources that are derived from organic (animal and vegetable) food proteins. Observational and metabolic studies indicate nutritional and longevity benefits of higher protein intake in dialysis patients. This presents challenges to providing appropriate nutrition because protein and P intakes are closely correlated. During dietary counseling of patients with chronic kidney disease, the absolute dietary P content as well as the P-to-protein ratio in foods should be addressed. Foods with the least amount of inorganic P, low P-to-protein ratios, and adequate protein content that are consistent with acceptable palatability and enjoyment to the individual patient should be recommended along with appropriate prescription of P binders. Provision of in-center and monitored meals during hemodialysis treatment sessions in the dialysis clinic may facilitate the achievement of these goals.

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“…Effect of phytase-mediated pretreatment of cereal-based foods has been documented as increases in in vivo iron absorption from 78% up to as much as 1066% in single meal studies [12,101] (Table 3). However, a four-month intervention study with 41 women did not show an effect of phytase pretreatment [5] (Table 3).…”

Section: Potential Of Phytase-mediated Iron Release From Plant Foodsmentioning

confidence: 99%

Potential of Phytase-Mediated Iron Release from Cereal-Based Foods: A Quantitative View

2013

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The major part of iron present in plant foods such as cereals is largely unavailable for direct absorption in humans due to complexation with the negatively charged phosphate groups of phytate (myo-inositol (1,2,3,4,5,6)-hexakisphosphate). Human biology has not evolved an efficient mechanism to naturally release iron from iron phytate complexes. This narrative review will evaluate the quantitative significance of phytase-catalysed iron release from cereal foods. In vivo studies have shown how addition of microbially derived phytases to cereal-based foods has produced increased iron absorption via enzyme-catalysed dephosphorylation of phytate, indicating the potential of this strategy for preventing and treating iron deficiency anaemia. Despite the immense promise of this strategy and the prevalence of iron deficiency worldwide, the number of human studies elucidating the significance of phytase-mediated improvements in iron absorption and ultimately in iron status in particularly vulnerable groups is still low. A more detailed understanding of (1) the uptake mechanism for iron released from partially dephosphorylated phytate chelates, (2) the affinity of microbially derived phytases towards insoluble iron phytate complexes, and (3) the extent of phytate dephosphorylation required for iron release from inositol phosphates is warranted. Phytase-mediated iron release can improve iron absorption from plant foods. There is a need for development of innovative strategies to obtain better effects.

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Improved iron bioavailability in an oat-based beverage: the combined effect of citric acid addition, dephytinization and iron supplementation

Abstract: A combination of citric acid addition, dephytinization and iron supplementation significantly increased the iron absorption in an oat-based beverage. Such a beverage can be useful in the prevention of iron deficiency in 1- to 3-year-old children.

Cited by 37 publications

References 35 publications

Structural basis for promotion of duodenal iron absorption by enteric ferric reductase with ascorbate

Structural basis for promotion of duodenal iron absorption by enteric ferric reductase with ascorbate

Understanding Sources of Dietary Phosphorus in the Treatment of Patients with Chronic Kidney Disease

Potential of Phytase-Mediated Iron Release from Cereal-Based Foods: A Quantitative View

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