The effect of nutrition-specific and nutrition-sensitive interventions on the double burden of malnutrition in low-income and middle-income countries: a systematic review

Background: Low-income and middle-income countries (LMICs) experiencing nutrition transition face an increasing double burden of malnutrition (DBM). WHO has urged the identification of risks and opportunities in nutrition interventions to mitigate the DBM, but robust evidence is missing. This review summarises the effect of nutrition-specific and nutrition-sensitive interventions on undernutrition and overnutrition in LMICs. Methods: We searched four major databases and grey literature for publications in English, French, Portuguese, and Spanish from Jan 1, 2000, to Aug 14, 2023. Eligible studies evaluated nutrition-specific or nutrition-sensitive interventions on both undernutrition and overnutrition, employing robust study designs (individually randomised, cluster randomised, and non-randomised trials; interrupted time series; controlled before–after; and prospective cohort studies). Studies were synthesised narratively, and classified as DBM-beneficial, potentially DBM-beneficial, DBM-neutral, potentially DBM-harmful, and DBM-harmful, using vote counting. This review is registered with PROSPERO (CRD42022320131). Findings: We identified 26 studies evaluating 20 nutrition-specific (maternal and child health [MCH] and school-based programmes) and six nutrition-sensitive (conditional cash transfers and other social policies) interventions. Seven of eight MCH interventions providing food-based or nutritional supplements indicated possible DBM-harmful effects, associated with increased maternal or child overweight. Most school-based programmes and MCH interventions that target behavioural change were considered potentially DBM-beneficial. Two studies of conditional cash transfers suggested DBM-beneficial effects in children, whereas one indicated potentially harmful effects on maternal overweight. A study on a family planning service and one on an education reform revealed possible long-term harmful effects on obesity. Interpretation: There is considerable scope to repurpose existing nutrition interventions to reduce the growing burden of the DBM in LMICs. In settings undergoing rapid nutrition transition, specific policy attention is required to ensure that food-based or supplement-based MCH programmes do not unintentionally increase maternal or child overweight. Consistent reporting of undernutrition and overnutrition outcomes in all nutrition interventions is essential to expand the evidence base to identify and promote interventions maximising benefits and minimising harms on the DBM. Funding: President's Scholarship (Imperial College London) and National Institute for Health and Care Research. Translations: For the Portuguese, Spanish and French translations of the abstract see Supplementary Materials section.