The impact of consuming iron from non-food sources on iron status in developing countries

Abstract

Objective: To determine the impact of contaminant iron and geophagy on iron intake and status of persons living in developing countries. Design: Literature for review was identi®ed by searching Medline and Agricola, from appropriate other texts and from three reports from the Opportunities for Micronutrient Interventions (OMNI) Project of USAID. Setting: The dietary intake of iron by people living in developing countries is generally high but iron de®ciency remains prevalent. This apparent paradox is because the iron being consumed is predominantly in the non-haem form, which is poorly absorbed. Some of this non-haem iron is from contamination of food with iron from soil, dust and water; iron leaching into food during storage and cooking; contamination during food processing such as milling; and the practice of geophagy.

A High Prevalence of Zinc- but not Iron-Deficiency among Women in Rural Malawi: a Cross-Sectional Study

“…The low prevalence of depleted iron stores, especially among the Zombwe women (i. e. 3 %), even after adjusting ferritin for infl ammation, suggests that at least some of the contaminant iron may have joined the common non-heme iron pool (i. e. is exchangeable) and thus been available for absorption as postulated in Ethiopia [36], although we recognize that predicting the exchangeability of contaminant iron is diffi cult [39]. Moreover, the low prevalence of iron defi ciency anemia overall (i. e. 6 %) suggests that the few women identifi ed with low iron stores may have upregulated iron absorption from their predominantly cereal-based diets to preserve hemoglobin mass.…”

“…Several factors may account for this discrepancy, including the significantly higher phytate (Table II), and probably higher polyphenol content of the brown fi nger and bullrush millets and brown sorghum consumed in Mikalango, compared to the maize in Zombwe, which has a low polyphenol content [40]. Both phytate and polyphenols inhibit absorption of the non-heme iron intrinsic to food as well as any exchangeable contaminant iron [1,39]. Consumption of polyphenol-containing tea was not an additional inhibitory factor because the women in Mikalango consumed less tea than those in Zombwe.…”

“…Mikalango EPA is characterized by areas of calcareous Eutric Vertisols (median pH = 7.8), whereas in Zombwe EPA soils have a low pH (median 5.2) [9]. Certainly, the proportion of soil contaminant iron that is available for absorption is said to vary widely [39]. Reduction in iron absorption as a consequence of infl ammation [41] is unlikely to be responsible for the discrepancy because there were no differences in the prevalence of elevated concentrations of CRP and AGP in the two EPAs.…”

Iron Deficiency Anemia: A Public Health Problem of Global Proportions

“…In contrast, nonheme iron is not as readily bioavailable absorption is greatly influenced by diet composition (Harvey et al, 2000). Enhancers, such as ascorbic acid, and inhibitors, such as phytates and polyphenols, significantly affect inorganic iron absorption (Baynes & Bothwell, 1990, Tseng et al, 1997.…”

Forests and human health: assessing the evidence

“…The recognized association between iron deficiency and geophagy (pica) has led to debate as to which is cause and which effect. Harvey et al (2000) discuss the complex interactions (and scientific uncertainty) about the possible effects of geophagy on the nutritional availability of soil-derived iron on the body. Iron deficiency, common in developing countries, is often related to consumption of foods that inhibit absorption of iron by the body.…”