Reframing fruit biofortification for sustainable micronutrient security: from crop innovation to nutritional impact

Micronutrient malnutrition, commonly referred to as "hidden hunger, " remains a persistent global health challenge, particularly in regions with limited dietary diversity. Although agricultural intensification has substantially improved caloric availability, it has not ensured adequate micronutrient density in food systems, highlighting the urgent need for nutrition-sensitive crop improvement strategies. Biofortification has emerged as a sustainable and cost-effective approach to enhance the micronutrient content of food crops through agronomic, genetic, and biotechnological interventions. While biofortification research has predominantly focused on staple cereals and legumes, horticultural fruit crops have received comparatively limited attention despite their widespread consumption, high consumer acceptance, and natural richness in bioactive compounds. This review advances beyond existing overviews by providing a critical and comparative evaluation of agronomic, conventional breeding, and biotechnological approaches for fruit crop biofortification, with particular emphasis on their effectiveness, scalability, limitations, and translational potential. Current advances aimed at enhancing iron, zinc, iodine, selenium, and provitamin A concentrations are comprehensively synthesized. Special attention is given to the physiological and molecular mechanisms regulating micronutrient uptake, transport, accumulation, and storage in fruit tissues. In addition, advanced biotechnological tools, including CRISPR/Cas-mediated genome editing, are critically assessed in relation to biosafety, regulatory considerations, and practical applicability. Evidence from major fruit crops, including apple, banana, mango, pomegranate, strawberry, and papaya, demonstrates that integrated biofortification strategies can improve micronutrient density while maintaining fruit yield and quality. Importantly, this review addresses a major knowledge gap by linking crop-level nutrient enhancement with micronutrient bioavailability and human nutritional outcomes, emphasizing the influence of food matrix interactions and nutrient absorption efficiency. Key constraints, including genotype × environment interactions, postharvest nutrient instability, climate-driven variability, and limited clinical validation, are also discussed. Finally, a systems-level framework integrating plant science, human nutrition, postharvest biology, and policy perspectives is proposed to support the large-scale adoption of nutrition-sensitive fruit biofortification. Collectively, fruit crop biofortification represents a promising strategy for improving global micronutrient security and advancing sustainable food systems.