What are the effects of nutritional interventions to increase nutritional status in children living in urban slums in low‐ and middle‐income countries?

UN‐Habitat estimates that there are at least one billion people living in urban slums, that is, places in cities without adequate access to health care, clean water, and sanitation. For this review, we defined low‐income informal settlements or slums as lacking one or more indicators of basic services or infrastructure. More than 90% of these slums are in low‐ and middle‐income nations and the residents are usually living in poverty, with little food security. One consequence of an inadequate diet is growth stunting, that is, very short stature for age. Stunting is associated with greater susceptibility to infection, cognitive (memory and thinking skills) and behavioural problems, and lower adult work performance and earnings. About 25% of children living in urban settings in low‐ and middle‐income countries are stunted. In slum areas, this figure is higher.

Nutritional methods (interventions) to improve infant and young children's growth have not been comprehensively or systematically assessed for urban slums. This review included 15 studies involving 9261 children less than five years old and 3664 pregnant women. About 73% of children were less than one year old. The interventions provided maternal education; nutrient supplementation of mothers, infants, and children; improving nutrition systems; or a combination of these but not dietary modification. The reliability of the studies was very low to moderate overall because studies were not designed to cope with research problems linked to urban slum communities, such as high mobility and high loss of participants to follow‐up. This meant that the effectiveness of the intervention could not be properly assessed at later dates.

There was no effect of giving mothers nutrient supplementation on birth weight and length, there were inconclusive results for nutrient supplementation in infants and children on improving children's height or stunting status, there was a positive impact on birth weight of maternal education interventions where there was a positive difference in birth weight of 478 g in infants exposed to the intervention, and inconclusive results of improving health systems that support nutrition on children's stunting status and a positive effect on height. There were no reported side effects from these interventions.

The review showed the need to better understand urban slum environments and their people as evidence showed that interventions included in this review were successful in other locations outside of urban poor areas. More evidence is needed of the effects of multi‐sectorial interventions, combining nutrition‐specific and sensitive methods and programmes, as well as the effects of 'up‐stream' practices and policies of governmental, non‐governmental organisations (NGOs), and the business sector to improve low birth weight and stunting in poor urban environments.