Approximately 600 million preschool and school-age children are anaemic worldwide. It is estimated that half of these cases are due to a lack of iron. Iron deficiency anaemia during childhood may slow down growth, reduce motor and brain development, and increase illness and death. If anaemia is not treated promptly, these problems may persist later in life. Taking supplements containing iron (sometimes combined with folic acid and other vitamins and minerals) on a daily basis has shown to improve children's health but its use has been limited because supplements may produce side effects such as nausea, constipation or staining of the teeth. It has been suggested that giving iron one, two or three times a week (known as 'intermittent' supplementation) may reduce these side effects and be easier to remember, and thus encourage children to continue taking the iron supplements.
We analysed 33 trials involving 13,314 children (49% females) from 20 countries in Latin America, Africa and Asia, to assess the effects of intermittent iron supplementation, alone or in combination with other vitamins and minerals, on nutritional and developmental outcomes in children from birth to 12 years of age compared with a placebo, no intervention.or daily supplementation.
The studies were of mixed quality. Overall, the results of this review show that giving children supplements with iron alone or in combination with other vitamins and minerals one, two or three times a week approximately halves their risk of having anaemia in comparison with receiving no iron supplements or a placebo. Giving children supplements on a intermittent basis was as effective as daily supplementation for improving haemoglobin and ferritin concentrations, although, children receiving iron supplements intermittently were at higher risk of having anaemia.
We aimed to examine the effects of intermittent supplementation on illness, death, and school and physical performance, as well as on other side effects, but there was insufficient information to draw firm conclusions.
In summary, intermittent iron supplementation is efficacious to improve haemoglobin concentrations and reduce the risk of having anaemia or iron deficiency in children younger than 12 years of age when compared with a placebo or no intervention, but it is less effective than daily supplementation to prevent or control anaemia. Intermittent supplementation may be a viable public health intervention in settings where daily supplementation has failed or has not been implemented. Information on mortality, morbidity, developmental outcomes and side effects, however, is still lacking.