Combined zinc and iron compared with iron supplementation of diets of 6- to 12-year old village schoolchildren in southern Iran

Abstract

The effects of supplementation of the diets of 6- to 12-year-old children in a village near Shiraz in Iran with zinc plus iron or iron alone, together with the indispensable amino acids in the form of egg white protein, vitamins, minerals, and corn oil have been evaluated. Initially 48 of 59 children had zinc concentrations below the minimum found in well-nourished persons. Eight months of supplementation with zinc plus iron (20 mg daily of elemental zinc as carbonate and 20 mg ferrous iron as fumarate) failed to stimulate growth or bone development or to bring about an increase in plasma zinc concentrations. However, supplementation with iron in the above amount was associated with an acceleration of growth in height and weight. The persistence of low concentrations of zinc in plasma and the failure of supplemental zinc to stimulate growth are attributed to the poor availability of both dietary and supplemental zinc resulting from sequestering action of fiber and phytate present in large amounts in the unleavened whole meal bread consumed by villagers. In addition, the results suggest that simultaneous administration of iron and zinc supplements may impair utilization of the metals.

Bioavailability of Zinc in Infant Cereals

“…This observa tion does not explain the low bioavailability of zinc in the muted infant cereal reported earlier (12). Moreover, it does not agree with the suggestion made by Mahloudji et al (8) that simultaneous administration of iron and zinc supple ments given to 6-to 12-year-old Iranian children may have impaired the utilization of the metals. Dietary levels of iron up to 80 mg/kg were reported to have no effect on the zinc and copper concentrations in the liver and spleen of rats after 10 weeks of feeding (1).…”

“…This was an unexpected observation because fibre and phytate which are reported to have an adverse effect on bioavailability of divalent cations (2,17) were probably higher in the breakfast cereal than in the mixed infant cereal as indicated by the ingredients. In view of the zinc-iron antagonism reported earlier (8), another factor which could have led to the low bioavailability of zinc in the infant cereal was the high level of fortification with iron (1,000/ag Fe per gram infant cereal vs. 183/ag/g Bureau of Nutritional Sciences publication No. 72. breakfast cereal).…”

The Relationship between Zinc Intake and Serum/Plasma Zinc Concentration in Children: A Systematic Review and Dose-Response Meta-Analysis

“…In 11 studies zinc was supplemented alone at doses ranging from 3 to 70 mg/day and in 7 studies participants also received other micronutrients. Zinc was provided with iron supplements [23] or iron fortified milk [36], as part of a fortified meal [24,35], and with other micronutrients [27,31,37]. The zinc dose ranged from 10 to 20 mg/day when combined with other vitamin/minerals and 2.57 to 9 mg/day when provided in fortified meals.…”

“…The zinc dose ranged from 10 to 20 mg/day when combined with other vitamin/minerals and 2.57 to 9 mg/day when provided in fortified meals. Most studies ( n = 7) provided the zinc supplements in the form of zinc sulphate, but others used zinc citrate [32], zinc gluconate [33], zinc carbonate [23], zinc methionine [29,34], amino acid chelate [27], and elemental zinc in a syrup [28,40]. Studies were conducted in Latin America ( n = 9), North America ( n = 4), Asia ( n = 3), Africa ( n = 1) and Europe ( n = 1).…”

Availability of lactoferrin as a natural solubilizer of iron for food products

“…Ascorbic acid maintains the normally ferric form of food iron in the more soluble ferrous state, and forms a complex with iron that remains soluble as the pH increases in the upper small intestine (Mahloudji et al, 1975).…”