Factors involved in the regulation of internal iron exchange

A dissertation submitted to the Faculty of Medicine University of the Witwatersrand, Johannesburg for the Degree of Master of Science in MedicineThe effects of various manoeuvres on the handling of 59 Fe labelled heat damaged red cells (59Fe HDRC) by the reticuloendothelial system were studied in rats. The study demonstrated that prior saturation of transferrin with oral carbonyl iron had little effect on splenic release of 59Fe but markedly inhibited hepatic release . Splenic release was , however, inhibited by the prior administration of unlabelled HDRC.IT201

Iron Bioavailability and Provitamin A from Sweet Potato- and Cereal-Based Complementary Foods

Iron and vitamin A deficiencies in childhood are public health problems in the developing world. Introduction of cereal-based complementary foods, that are often poor sources of both vitamin A and bioavailable iron, increases the risk of deficiency in young children. Alternative foods with higher levels of vitamin A and bioavailable iron could help alleviate these micronutrient deficiencies. The objective of this study was to compare iron bioavailability of β-carotene-rich sweet potato-based complementary foods (orange-flesh based sweet potato (OFSP) ComFa and cream-flesh sweet potato based (CFSP) ComFa with a household cereal-based complementary food (Weanimix) and a commercial cereal (Cerelac®), using the in vitro digestion/Caco-2 cell model. Iron bioavailability relative to total iron, concentrations of iron-uptake inhibitors (fibre, phytates, and polyphenols), and enhancers (ascorbic acid, ß-carotene and fructose) was also evaluated. All foods contained similar amounts of iron, but bioavailability varied: Cerelac® had the highest, followed by OFSP ComFa and Weanimix, which had equivalent bioavailable iron; CFSP ComFa had the lowest bioavailability. The high iron bioavailability from Cerelac® was associated with the highest levels of ascorbic acid, and the lowest levels of inhibitors; polyphenols appeared to limit sweet potato-based food iron bioavailability. Taken together, the results do not support that CFSP- and OFSP ComFa are better sources of bioavailable iron compared with non-commercial/household cereal-based weaning foods; however, they may be a good source of provitamin A in the form of β-carotene

Recurrent Selection to Alter Grain Phytic Acid Concentration and Iron Bioavailability

Iron is an important micronutrient and Fe deficiency is a global health concern. Phytic acid inhibits Fe absorption and cannot be digested by monogastric livestock or humans. High phytate concentration in staple crops may be one of the contributing factors for the high incidence of anemia in developing countries because of its inhibiting effect on Fe absorption. In seeds, it serves as the main storage compound for P. Low phytic acid mutants (lpa) in maize (Zea mays L.) have improved Fe bioavailability, but they have poor germination. Our objective was to develop both low phytic acid (LPA) and high phytic acid (HPA) maize populations using recurrent selection and to compare seed quality and Fe bioavailability among the HPA and LPA populations and lpa mutant lines. Three cycles of selection were performed in two broad-based synthetic populations, BS11 and BS31. The resulting HPA and LPA populations were significantly different in phytic acid concentration in the BS11-derived populations (P \u3c 0.05) but not in the BSS31-derived populations (P \u3e 0.05). The BS11LPA maize population had improved seed germination (13–16%; P \u3c 0.05), and Fe bioavailability was not statistically different (P \u3e 0.05) than the lpa mutant inbred lines. We conclude that recurrent selection for phytic acid levels may be a viable approach for improving Fe bioavailability of grain while maintaining seed quality

Approaches to reduce zinc and iron deficits in food systems

There is a deficit of mineral micronutrients in global food systems, known as ‘hidden hunger’, especially in the global south. This review focuses on zinc (Zn) and iron (Fe), whose entry into food systems depends primarily on soil and crop factors. Approaches to increase dietary supplies of Zn and Fe include: (1) supplementation, (2) food fortification, (3) dietary diversification, and (4) crop biofortification, including breeding and fertilizer-based approaches. Supply-based estimates indicate that Zn deficiency might be more widespread than Fe deficiency in sub-Saharan Africa, although there are major knowledge gaps at an individual biomarker level. Recent analytical advances, including the use of stable isotopes of Zn and Fe, can play an increasing role in improving our understanding of the movement of micronutrients in food systems, and thereby help to reduce the immense human cost of ‘hidden hunger’

The role of ascorbate in antioxidant protection of biomembranes: Interaction with vitamin E and coenzyme Q

One of the vital roles of ascorbic acid (vitamin C) is to act as an antioxidant to protect cellular components from free radical damage. Ascorbic acid has been shown to scavenge free radicals directly in the aqueous phases of cells and the circulatory system. Ascorbic acid has also been proven to protect membrane and other hydrophobic compartments from such damage by regenerating the antioxidant form of vitamin E. In addition, reduced coenzyme Q, also a resident of hydrophobic compartments, interacts with vitamin E to regenerate its antioxidant form. The mechanism of vitamin C antioxidant function, the myriad of pathologies resulting from its clinical deficiency, and the many health benefits it provides, are reviewed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44796/1/10863_2004_Article_BF00762775.pd

Factors involved in the regulation of internal iron exchange

A Dissertation Submitted to the Faculty of Medicine University of the Witwatersrand, Johannesburg for the Degree of Masters of Science in MedicineThe effects of various manoeuvres on the handling of 59pe labelled heat damaged red cells (59pe HDRC) by the reticuloendothelial system were studied in rats. The study demonstrated that prior saturation of transferrin with oral carbonyl iron had little effect on splenic release of 59pe but markedly inhibited hepatic release. Splenic release was, however, inhibited by the prior administration of unlabelled HDRC. The combination of carbonyl iron and unlabelled HDRC exerted a similar effect. When carbonyl iron was administered with unlabelled free haemoglobin, the pattern of 59Fe distribution was the same as that observed when carbonyl iron was given alone.IT201

Factors involved in the regulation of internal iron exchange

A Dissertation Submitted to the Faculty of Medicine University of the Witwatersrand, Johannesburg for the Degree of Masters of Science in MedicineThe effects of various manoeuvres on the handling of 59pe labelled heat damaged red cells (59pe HDRC) by the reticuloendothelial system were studied in rats. The study demonstrated that prior saturation of transferrin with oral carbonyl iron had little effect on splenic release of 59pe but markedly inhibited hepatic release. Splenic release was, however, inhibited by the prior administration of unlabelled HDRC. The combination of carbonyl iron and unlabelled HDRC exerted a similar effect. When carbonyl iron was administered with unlabelled free haemoglobin, the pattern of 59Fe distribution was the same as that observed when carbonyl iron was given alone.IT201