Maximising benefits and minimising adverse effects of micronutrient interventions in low- and middle-income countries.

Micronutrient deficiencies are widespread and disproportionately affect women and children in low- and middle-income countries (LMIC). Among various interventions, food fortification and supplementation with micronutrients have been proven to be cost-effective. The aim of the present paper is to review existing literature to assess risks of excessive intake in LMIC to then highlight programmatic changes required to maximise benefits of micronutrient interventions while minimising risks of adverse effects. While very few LMIC have national food consumption surveys that can inform fortification programmes, many more are implementing mandatory fortification programmes. The risks of inadequate micronutrient intakes were common, but risks of excessive intakes were also present for iodine, vitamin A, folic acid and iron. Excessive salt consumption, high concentrations of iodine in ground-water and excessive levels of iodisation were linked with excessive iodine intake. For vitamin A, overlapping interventions were the main risk for excessive intake; whereas for iron, contamination with iron from soil and screw-wares of millers and high iron concentration in drinking-water increased the risk of excessive intake, which could be further exacerbated with fortification. Before implementing micronutrient interventions, adherence to the basic principles of documenting evidence confirming that the deficiency in question exists and that fortification will correct this deficiency is needed. This can be supported with dietary intake assessments and biochemical screening that help diagnose nutrient deficiencies. Targeting micronutrient interventions, although programmatically challenging, should be considered whenever possible. Moreover, closer monitoring of appropriate fortification of foods and overlapping interventions is needed.