Evaluation of lipid peroxidation and antioxidant system in healthy iron-replete infants receiving iron prophylaxis

Scientific opinion on the tolerable upper intake level for iron

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the tolerable upper intake level (UL) for iron. Systematic reviews were conducted to identify evidence regarding high iron intakes and risk of chronic diseases, adverse gastrointestinal effects and adverse effects of iron supplementation in infancy, young childhood and pregnancy. It is established that systemic iron overload leads to organ toxicity, but no UL could be established. The only indicator for which a dose-response could be established was black stools, which reflect the presence of large amounts of unabsorbed iron in the gut. This is a conservative endpoint among the chain of events that may lead to systemic iron overload but is not adverse per se. Based on interventions in which black stools did not occur at supplemental iron intakes of 20-25 mg/day (added to a background intake of 15 mg/day), a safe level of intake for iron of 40 mg/day for adults (including pregnant and lactating women) was established. Using allometric scaling (body weight0.75), this value was scaled down to children and adolescents and safe levels of intakes between 10 mg/day (1-3 years) and 35 mg/day (15-17 years) were derived. For infants 7-11 months of age who have a higher iron requirement than young children, allometric scaling was applied to the supplemental iron intakes (i.e. 25 mg/day) and resulted in a safe level of supplemental iron intake of 5 mg/day. This value was extended to 4-6 month-old infants and refers to iron intakes from fortified foods and food supplements, not from infant and follow-on formulae. The application of the safe level of intake is more limited than a UL because the intake level at which the risk of adverse effects starts to increase is not defined.

Oxidative Stress and Genomic Damage Induced In Vitro in Human Peripheral Blood by Two Preventive Treatments of Iron Deficiency Anemia

Iron deficiency is the most prevalent nutritional deficiency and the main cause of anemia worldwide. Since children aged 6-24 months are among the most vulnerable groups at risk, daily supplementation with ferrous sulfate is recommended by the Argentine Society of Pediatrics as preventive treatment of anemia. However, a single weekly dose would have fewer adverse side effects and has been therefore proposed as an alternative treatment. Ferrous sulfate is known by its pro-oxidative properties, which may lead to increased oxidative stress as well as lipid, protein, and DNA damage. We analyzed the effect of daily and weekly preventive treatment of iron deficiency anemia (IDA) on cell viability, oxidative stress, chromosome, and cytomolecular damage in peripheral blood cultured in vitro. The study protocol included the following: untreated negative control; bleomycin, hydrogen peroxide, or ethanol-treated positive control; daily 0.14 mg ferrous sulfate-supplemented group; and weekly 0.55 mg ferrous sulfate-supplemented group. We assessed cell viability (methyl-thiazolyl-tetrazolium and neutral red assays), lipid peroxidation (thiobarbituric acid reactive substances assay), antioxidant response (superoxide dismutase and catalase enzyme analysis), chromosome damage (cytokinesis-blocked micronucleus cytome assay), and cytomolecular damage (comet assay). Lipid peroxidation, antioxidant response, and chromosome and cytomolecular damage decreased after weekly ferrous sulfate supplementation (p < 0.05), suggesting less oxygen free radical production and decreased oxidative stress and genomic damage. Such a decrease in oxidative stress and genomic damage in vitro positions weekly supplementation as a better alternative for IDA treatment. Further studies in vivo would be necessary to corroborate whether weekly supplementation could improve IDA preventive treatment compliance in children.

Protective effects of naringenin on iron-overload-induced cerebral cortex neurotoxicity correlated with oxidative stress

Iron is a component of several metalloproteins involved in crucial metabolic processes such as oxygen sensing and transport, energy metabolism, and DNA synthesis. This metal progressively accumulates in the pathogenesis of Alzheimer's (AD) and Parkinson's (PD) diseases. Naringenin (NGEN), a natural flavonoid compound, has been reported to possess neuroprotective effect against PD-related pathology, however, the mechanisms underlying its beneficial effects are poorly defined. Thus, the aim of this study is to investigate the potential mechanism involved in the cytoprotection of NGEN against iron-induced neurotoxicity in the cerebral cortex of Wistar rats. Animals that were given repetitive injections of iron dextran for a total of 4 weeks showed a significant increase in lipid and protein markers such as thiobarbituric reactive acid substances, protein carbonyl product content levels, and DNA apoptosis in the cerebral cortex. These changes were accompanied by a decrease of enzymatic antioxidants like superoxide dismutase and catalase and in the levels of nonenzymatic antioxidants like total thiols and ascorbic acid. The activity of glutathione peroxidase remained unchanged in rats. A significant decrease in acetylcholinesterase and Na(+)/K(+)-ATPase activities was also shown, with a substantial rise in the nitric oxide levels. Coadministration of NGEN to iron-treated rats significantly improved antioxidant enzyme activities and attenuated oxidative damages observed in the cerebral cortex. The potential effect of NGEN to prevent iron-induced neurotoxicity was also reflected by the microscopic study, indicative of its neuroprotective effects.