Journal of Advances in Food Science & Technology

Rising atmospheric carbon dioxide (CO₂) is increasingly recognized as a determinant of crop nutritional quality, with implications that extend beyond yield alone. This review brings together mechanistic, experimental, and epidemiological evidence to examine how elevated CO₂ alters the micronutrient composition of staple crops and what this means for population health. Drawing on plant physiology, field-based enrichment studies, controlled experiments, and dietary modeling, it outlines the pathways through which atmospheric change influences food quality. Elevated CO₂ enhances carbon assimilation and promotes the accumulation of carbohydrates, leading to a relative dilution of other nutrients. At the same time, reduced transpiration and changes in nitrogen metabolism constrain the uptake and incorporation of key nutrients, including iron, zinc, protein, and selected vitamins, particularly in major crops such as rice and wheat. Across different study designs, a consistent pattern emerges, with declines in nutrient density shaped by crop type, genotype, and environmental conditions. For populations that rely heavily on staple foods, these changes translate into lower dietary intake of essential micronutrients. Model-based projections suggest that continued increases in CO₂ could substantially increase the global burden of iron and zinc deficiencies by mid-century. Taken together, the evidence points to a widening gap between food quantity and food quality. Addressing this challenge will require coordinated approaches that link crop improvement, soil and agronomic management, dietary diversification, and nutrition-sensitive policy within broader climate and food system strategies.