Powdered vitamins and minerals added to foods at the point-of-use reduces anaemia and iron deficiency in preschool- and school-age children
Background to the question
Approximately one billion people worldwide are deficient in at least one vitamin or mineral (also known of micronutrients). Iron, vitamin A, zinc and iodine deficiencies are very frequent among children of preschool (aged 24 months to less than 5 years) and school age (5 to 12 years of age), limiting their health and daily physical performance. Anaemia, the condition in which red blood cells have limited capacity to carry oxygen, frequently results after prolonged iron deficiency.
Point-of-use fortification with powdered vitamins and minerals has been proposed as a public health intervention to reduce micronutrient deficiencies in children. In this process, a powdered premix containing iron, and possibly other vitamins and minerals, is added to foods either during or after cooking, or immediately before consumption to improve their nutritious value but not their flavour or colour. In some cases, point-of-use fortification is also known as home fortification.
What are the effects of point-of-use fortification of foods with iron-containing micronutrient powders (MNP) alone, or in combination with other vitamins and minerals, on nutrition, health and development among children of preschool and school age (24 months to 12 years of age) compared with no intervention, a placebo (dummy pill) or regular iron-containing supplements (as drops, tablets or syrup)?
This review included 13 trials with 5810 participants from Latin America, Africa and Asia. All trials compared the provision of MNP for point-of-use fortification with no intervention or placebo. Six trials included participants younger than 59 months of age only, four included only children aged 60 months of age or older, and three trials included children both younger and older than 59 months of age. MNPs contained from two to 18 vitamins and minerals. We searched existing clinical trials in December 2016 and ongoing trials in April 2017. We also contacted relevant institutions for additional information upon publication of the protocol and in April 2017.
The review found that children receiving iron-containing MNP for point-of-use fortification of foods were at significantly lower risk of having anaemia and iron deficiency and had higher haemoglobin concentrations. We did not find any positive or negative effect on diarrhoea or mortality, but the data on these two outcomes were very limited.
Quality of the evidence
We rated the overall quality of the evidence for the provision of multiple MNP versus no intervention or placebo as moderate for anaemia, iron deficiency and adverse effects. We judged the evidence to be of low quality for haemoglobin, mortality and diarrhoea, and to be very low-quality for ferritin. In general, the most common risk of bias in the studies was the lack of blinding for participants, personnel and outcome assessors.
Point-of-use fortification of foods with MNPs containing iron reduces anaemia and iron deficiency in preschool- and school-age children and seems feasible for public health purposes. However, future research should aim to increase the body of evidence on mortality, morbidity, developmental outcomes and adverse effects. Due to the lack of trials, we were unable to determine at this time if this intervention has comparable effects to those observed with iron supplements (provided as drops, tablets or syrup).