The iron bioavailability and acute oral toxicity in rats of a ferrous gluconate compound stabilized with glycine (SFG), designed for food fortification, was studied in this work by means of the prophylactic method and the Wilcoxon method, respectively. For the former studies, SFG was homogenously added to a basal diet of low iron content, reaching a final iron concentration of 20.1 ± 2.4 mg Fe/kg diet. A reference standard diet using ferrous sulfate as an iron-fortifying source (19.0 ± 2.1 mg Fe/kg diet) and a control diet without iron additions (9.3 ± 1.4 mg Fe/kg diet) were prepared in the laboratory in a similar way. These diets were administered to three different groups of weaning rats during 23 d as the only type of solid nourishment. The iron bioavailability of SFG was calculated as the relationship between the mass of iron incorporated into hemoglobin during the treatment and the total iron intake per animal. This parameter resulted in 36.6 ± 6.2% for SFG, whereas a value of 35.4 ± 8.0% was obtained for ferrous sulfate. The acute toxicological studies were performed in 2 groups of 70 female and 70 male Sprague–Dawley rats that were administered increasing doses of iron from SFG. The LD50 values of 1775 and 1831 mg SFG/kg body wt were obtained for female and male rats, respectively, evidencing that SFG can be considered as a safe compound from a toxicological point of view.

The purpose of the present work was to evaluate the iron bioavailability of a new
ferric pyrophosphate salt stabilized and solubilized with glycine. The prophylactic–
preventive test in rats, using ferrous sulfate as the reference standard, was applied as the
evaluating methodology both using water and yogurt as vehicles. Fifty female Sprague–
Dawley rats weaned were randomized into five different groups (group 1: FeSO4; group 2:
pyr; group 3: FeSO4 + yogurt; group 4: pyr + yogurt and group 5: control). The iron
bioavailability (BioFe) of each compound was calculated using the formula proposed by
Dutra-de-Oliveira et al. where BioFe %=(HbFef − HbFei) × 100/ToFeIn. Finally, the
iron bioavailability results of each iron source were also given as relative biological
value (RBV) using ferrous sulfate as the reference standard. The results showed that both
BioFe % and RBV % of the new iron source tested is similar to that of the reference
standard independently of the vehicle employed for the fortification procedure (FeSO4
49.46±12.0% and 100%; Pyr 52.66±15.02% and 106%; FeSO4 + yogurth 54.39±13.92%
and 110%; Pyr + yogurt 61.97±13.54% and 125%; Control 25.30±6.60, p<0.05).
Therefore, the stabilized and soluble ferric pyrophosphate may be considered as an optimal
iron source for food fortification.

Food fortification has shown to be an effective strategy to overcome iron malnutrition. When a new iron compound is developed for this purpose, it must be evaluated from a nutritional and technological point of view before adding it into foods. In this way, we have evaluated ferrous gluconate stabilized by glycine as a new iron source to be used in wheat flour fortification. We performed biological studies in rats as well as sensory perceptions by human subjects in wheat flour fortified with this iron source. The productions of pentane as a rancidity indicator as well as the change of the sensorial properties of the biscuits made with stabilized ferrous gluconate-fortified wheat flour were negligible. Iron absorption in water from this iron source was similar to the reference standard ferrous sulfate. Nevertheless, because of the phytic acid content, iron absorption from fortified wheat flour decrease 40% for both iron sources. The addition of zinc from different sources did not modify iron absorption from ferrous sulfate and stabilized ferrous gluconate in water and wheat flour. The iron absorption mechanism as well as the biodistribution studies demonstrate that the biological behavior of this iron source does not differ significantly from the reference standard. These results demonstrate that the iron source under study has adequate properties to be used in wheat flour fortification. Nevertheless, more research is needed before considering this iron source for its massive use in food fortification.

The purpose of this study is to determine the bioavailability, biodistribution and toxicity of Biocal^®, a new source of calcium. Biocal^® is a calcium gluconate stabilized with glycine. A comparative study between this compound and calcium gluconate was conducted in Sprague-Dawley rats. The bioavailability study was carried out by marking both products with ⁴⁵Ca. The dose of 30 mg of Ca per kilo of body weight was administered to two groups of 7 male rats per group. The urine elimination of ⁴⁵Ca, expressed as a total cumulative percentage of ⁴⁵Ca activity in urine (Ae^∞), among rats that received Biocal^® (Ae^∞ = 2.436 ± 1.377%) and the rats that received calcium gluconate (Ae^∞ = 1,241 ± 0.473%) were statistically different (p <0.05). Biodistribution studies showed that Biocal^® calcium follows the same metabolic pathway as calcium gluconate calcium.

Food fortification with a proper zinc compound is an economic and effective strategy to prevent zinc
deficiency. BioZn-AAS, a zinc gluconate stabilized with glycine, was compared with zinc sulfate
(reference standard), zinc hydroxide, and zinc gluconate, all of them labeled with ⁶⁵Zn. This preclinical study was performed on Sprague-Dawley rats of both sexes, and the administered dose was 85 mg/kg of zinc. Bioavailability studies showed that absorption of BioZn-AAS was not statistically different than absorption from other sources in female rats (25.65% 6 2.20% for BioZn AAS, 28.24% 6 4.60% for ZnSO4, 24.91% 6 4.02% for Zn[OH]2, and 25.51% 6 2.70% for Zn gluconate). In the case of the male rats, absorption of BioZn-AAS (27.97% 6 4.20%) was higher (P,0.05) than that from the other compounds (23.15% 6 2.90% for ZnSO4, 22.62% 6 3.90% for Zn[OH]2, and 22.30% 6 3.90% for Zn-gluconate). Biodistribution studies demonstrated that the zinc from BioZn-AAS followed the same metabolic pathway as zinc from the other sources. Toxicity studies were performed with 50 female and 50 male rats. The value of oral lethal dose 50 (LD50) was 2000 mg/kg for female rats and 1900 mg/kg for male rats. Therefore, we conclude that BioZn AAS has adequate properties to be considered a proper zinc compound for food fortification or dietary supplementation.