Addressing zinc deficiency across the lifespan: A call to action

Zinc is essential for a range of critical life functions due to its catalytic, structural, and regulatory roles. It is vital for metabolic pathways, gene expression, hormone function, and immune defence, impacting health and growth throughout the life course. The manifestations of zinc deficiency are non-specific and vary based on age, duration, and the presence of other diseases. 

This paper explores recent developments in our understanding of zinc's role in health, the prevalence of zinc deficiency, the effects of climate change on zinc intake, and strategies to improve zinc status. 
Zinc deficiency underpins undernutrition, micronutrient deficiencies, overweight, obesity, and non-communicable diseases, and often coexists with other micronutrient deficiencies. The health losses due to zinc deficiency are significant, particularly in children, contributing to 3.7 million disability-adjusted life years (DALYs) lost in China alone. Zinc’s role in glucose regulation links it to non-communicable diseases, accounting for 7.1% of global DALYs lost due to these diseases.

Measuring zinc deficiency remains challenging due to the limitations of current biomarkers. Plasma zinc concentration is the most frequently used measure, but it is affected by daily variations, fasting status, and inflammation. Functional biomarkers and dietary intake assessments offer better estimates of zinc status. Accurate baseline zinc intake estimates are crucial for determining effective and sustainable interventions to address zinc deficiency. 

Combating global zinc deficiency requires a multifaceted approach that includes supplementation, large-scale food fortification, biofortification, and soil zinc repletion. Supplemental zinc, available in various forms, such as organic, inorganic, or zinc complexed to amino acid, can be used to target deficiencies but relies on high compliance. Fortification of staple foods or condiments with zinc enhances population intake and can be cost-effective. Biofortification, which increases zinc content in crops through breeding, agronomic methods, or genetic engineering, holds promise for improving zinc intake, especially in the context of changing environmental conditions. Projected 2050 CO2 levels could lower zinc content in staple crops by 14.6%.

Phytic acid found in plant-based foods significantly reduces zinc absorption by forming insoluble complexes. Improving zinc bioavailability through dietary diversification and reducing the phytic acid to zinc ratio is also crucial, especially in unrefined vegetarian diets, to optimise zinc absorption without compromising consumer preferences.

Zinc biofortification, integrated with smallholder farming and social safety net programmes, delivers essential micronutrients to large populations without requiring behaviour change. It enhances zinc absorption, reduces maternal and childhood morbidity, and supports more nutrient-dense diets. Advocacy for biofortification in national policies is essential for tackling zinc deficiency and improving public health outcomes, including reducing infectious morbidity and preventing non-communicable diseases. Further research on its health impacts in programmatic settings is warranted.