Safety of NaFeEDTA as an iron fortificant: effects of fortification using NaFeEDTA on status of zinc and other nutritionally important mineral elements in Kenyan school children

Abstract

Food fortification is an effective strategy for reaching populations with micronutrient deficiencies. Fortification with iron presents a major challenge because of the presence of phytates and other iron absorption inhibitors in diets of poor people. Addition of iron does not necessarily mean that it is absorbed. Because of its low cost and its relative stability in food vehicles, electrolytic iron has been the fortificant of choice in many national programmes, despite its low bioavailability compared to fortificants such as ferrous salts. NaFeEDTA may be a more effective iron fortificant in high-phytate foods. Concerns about its cost and safety, however, have delayed its application in fortification programmes. This thesis is based on a 5-month randomised placebo-controlled trial conducted among school children (n = 516) aged 3-8 years in Kenya in May-November 2005. It aimed to measure the benefits of fortification with NaFeEDTA or electrolytic iron, and to assess the safety of using NaFeEDTA as an iron fortificant. The specific objectives were to assess a) the efficacy of fortifying whole maize flour with NaFeEDTA (28 mg iron/kg flour or 56 mg/kg) or electrolytic iron (56 mg/kg); b) the effect of the intervention on cognitive and motor function; c) response to the intervention of individuals with α+ -thalassaemia genotype relative to their counterparts with a normal genotype; d) and the effect of NaFeEDTA on the status of zinc, calcium, copper, magnesium and manganese. Fortification with NaFeEDTA at high levels (56 mg iron per kg flour), or low levels (28 mg/kg) reduced the prevalence of iron deficiency anaemia by 89% (95% CI 49% to 97%) and 48% (-20% to 77%), respectively. High-dose fortification with NaFeEDTA led to larger gains in iron status than low-dose level, and was more efficacious in children with iron deficiency at baseline. By contrast, electrolytic iron did not improve iron status. There was no evidence that the iron intervention improved either cognitive or motor function of these children; or that children with the α+ -thalassaemia genotype responded differently to the iron intervention than their peers with a normal genotype. There was also no evidence that NaFeEDTA adversely affected the status of the nutritionally important mineral elements assessed. The thesis concludes that in high-phytate flours, NaFeEDTA is more suitable than electrolytic iron for supplementation of iron in the diet. Governments should act and implement national programmes to fortify industrially processed flour, whereby NaFeEDTA should be considered the preferred fortificant in high-phytate food vehicles.