Climate variability, pastoral and agro-pastoral livestock systems, and human nutrition in African drylands: a PRISMA-based systematic review of evidence, pathways, and policy implications.

Livestock-based livelihoods underpin food security, dietary quality, and resilience in African arid and semi-arid lands (ASALs), yet the mechanisms linking livestock systems, food environments, and human nutrition under climate variability remain fragmented. This PRISMA-based systematic review synthesizes evidence on the nutritional ecology of pastoralist and agro-pastoralist communities in Sub-Saharan Africa, focusing on livestock-mediated nutrition pathways shaped by ecological and socioeconomic change. Literature published between 2006 and 2026 was systematically identified from PubMed, Scopus, AJOL, CABI, and Google Scholar, yielding 60 studies for qualitative synthesis. Nutrition outcomes assessed across the reviewed studies included Household Dietary Diversity Score (HDDS), child wasting and stunting, milk intake, micronutrient adequacy, and food security indicators. The evidence shows that livestock support household nutrition through interconnected biological and economic pathways, including direct consumption of animal-source foods, particularly milk, income generation for food purchases, and buffering against seasonal and climate-related shocks. Larger and more diversified herds are generally associated with higher dietary diversity and improved child nutrition, but benefits are strongly mediated by mobility, market access, gendered control of livestock income, and environmental sustainability. Seasonal dynamics drive marked nutritional variation, with wet seasons supporting improved dietary quality and dry seasons linked to heightened food insecurity and child wasting. Constraints on mobility, sedentarization, market disruptions, and environmental degradation further amplify nutrition risks. The evidence base is dominated by cross-sectional study designs, limiting causal inference and constraining understanding of how livestock ownership, environmental conditions, and nutrition outcomes co-evolve across seasons and shocks. The review identifies key evidence gaps, including limited longitudinal studies, underrepresentation of urbanizing pastoralists, and minimal attention to youth nutrition and livelihood transitions. Drawing on a One Health and food-systems framework, addressing these gaps requires integrated nutrition-livestock surveillance and multisectoral policies to advance climate-resilient, nutrition-sensitive livestock development and support progress toward Sustainable Development Goals related to zero hunger, good health and well-being, and climate action in African drylands.