The role of nutrition-sensitive interventions in improving nutritional outcomes: findings from a systematic review and meta-analysis.

BACKGROUND: Maternal and child undernutrition remains a major global health concern despite modest progress. Accelerating reductions in stunting and wasting will require increased investments in nutrition-sensitive interventions, which target nutrition impacts outside of the healthcare setting. This review examines the effects of four types of nutrition-sensitive interventions -cash/food transfers, nutrition-sensitive agriculture, water/sanitation/hygiene, and school nutrition- on maternal and child nutrition outcomes and dietary diversity. METHODS: We synthesized the evidence using an initial broad search and synthesis for nutrition-sensitive interventions, followed by targeted searches and syntheses for specific interventions and nutrition outcomes. Meta-analyses were performed to evaluate the impacts of cash transfers and agricultural interventions, while a narrative synthesis was produced for additional nutrition-sensitive interventions. Additionally, qualitative synthesis was incorporated to provide insights into the relationship between implementation context and program effectiveness. RESULTS: Our initial evidence synthesis included 260 quantitative studies, and additional targeted searches produced 72 eligible articles. Meta-analyses reveal positive impacts on dietary diversity for cash transfers without nutrition-specific components (0.14 SMD; 95% CI: 0.06-0.22), and some nutrition-sensitive agricultural interventions (0.24 SMD; 95% CI: 0.11-0.37). Cash transfers have larger effects on dietary diversity when they include behavior change communication or other nutrition-specific elements (0.41 SMD; 95% CI; 0.15-0.66), whereas agriculture programs with nutrition-specific elements do not show larger effects on dietary diversity than those without. Narrative syntheses indicate that homestead food production interventions may reduce anemia, school feeding interventions may improve anthropometric outcomes, and WASH interventions are most effective when combined with other nutrition initiatives. CONCLUSIONS: We find consistent evidence that nutrition-sensitive programs contribute to dietary diversity and may have small but positive effects on nutrition outcomes, such as anthropometric outcomes and anemia. Integrating nutrition into social protection, agriculture, and education sectors is essential for addressing the underlying causes of malnutrition, such as dietary diversity. REGISTRATION: Our review protocols were pre-registered at AIR.org [ https://www.air.org/sites/default/files/2024-01/Synthesis-of-evidence-nutrition-sensitive-interventions-maternal-childrens-nutrition-outcomes-research-protocol-Nov-2023.pdf ] and PROSPERO [ https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024552449 ].