Climate-associated nutritional variability of maize across agroecological zones in Cameroon: implications for food security

Abstract Background Maize is a major staple crop in Cameroon and throughout sub-Saharan Africa, contributing to food security, though the impact of climate on its nutritional composition remains insufficiently understood. This study examined how climate variability, proxied by four agroecological zones (AEZs) of Cameroon, is associated with maize nutritional and biochemical composition, while statistically accounting for agronomic and postharvest practices. Results A total of 261 maize grain samples, drawn from a broader survey of 303 smallholder households, were analysed for eighteen biochemical parameters. Principal Component Analysis identified three key nutritional markers explaining 52.7% of total variance, including an antioxidant and sucrose profile, a mineral profile, and a phytochemical and alternative carbohydrate profile. Factor Analysis of Mixed Data confirmed these markers remained structured by AEZ even after accounting for twelve agronomic and postharvest variables, and Multiple Linear Regression isolated AEZ's independent contribution to each. Maize from the Sudano-Sahelian zone showed a coordinated stress signature, significantly higher antioxidant compounds and sucrose alongside lower mineral concentrations ( p  ≤ 0.05), consistent with heat and drought stress. Maize from the Western Highlands showed the opposite pattern, the lowest antioxidant activity and the highest simple sugars, consistent with cooler growing conditions, while maize from the humid Bimodal and Monomodal zones carried the strongest mineral profiles. AEZ was the strongest and most consistent predictor across all three nutrient profiles ( p  ≤ 0.001), alongside growing duration, cropping system, fertiliser rate, variety (proxied by kernel colour), and postharvest handling. Conclusion Climate variability is strongly associated with nutritional differences in maize grown across Cameroon's AEZs, independent of farm management practices. Maize is therefore not a nutritionally uniform staple, and safeguarding its nutritional quality under a changing climate will require regionally tailored breeding, agronomic, and postharvest interventions rather than a single, nationwide approach.