New research has expanded the relevance of zinc deficiency across the life course. Zinc deficiency is well known for its impact on child growth and resistance to infections. Now, growing evidence shows it is also a key player in the emergent global burden of diabetes and cardiovascular disease in adulthood.

A recent narrative review published in Advances in Nutrition summarizes developments in our understanding of zinc’s role in health, the impact of the changing climate and global context on zinc intake, and solutions for improving population zinc intake.

The Roles of Zinc in Health

Zinc determines a greater number of critical life functions than any other single micronutrient. It is essential to metabolic pathways, gene expression, hormone function, immune defense mechanisms, and much more—making it vitally important to healththroughout life.

In children, zinc is a significant limiting factor for growth; inadequate zinc in the diet is an important contributor to stunting. The impacts of severe zinc deficiency include cognitive impairment, recurrent infections, and skin and bone repair disfunction.

In adults, growing evidence links zinc deficiency with an increased risk of cardiometabolic disorders. Specifically, low zinc status has been associated with more severe type 2 diabetes mellitus and may increase the risk of cardiovascular disease.

The Burden of Zinc Deficiency

Zinc deficiency is one of the most common forms of micronutrient malnutrition globally. An estimated 17% of the global population is at risk of inadequate zinc intake, with the prevalence as high as 19% and 24% in Asia and Africa, respectively.

Evidence now shows that the global estimate of the burden of health disparity attributable to zinc deficiency is more significant than previously thought, when accounting for its contribution to elevated fasting blood glucose and related noncommunicable diseases in adulthood and later life.

The Impact of Complex and Changing Environments on Dietary Zinc Intake

The ever-changing environments in which we live and in which our food grows impact our dietary zinc intake. Experiments with plants cultivated in growth chambers and under field conditions have shown that when crops are grown at elevated atmospheric CO₂—at levels projected for 2050—there is a decline in the zinc concentrations in the grains of many staple cereal crops. The performance of new biofortified varieties of crops, bred with increased grain nutrient concentration, are influenced by the complex and changing environments in which they are grown, and can be optimized by the site-specific crop management approaches adopted by farmers. Strategies to improve soil health and function (for example, by adding organic matter into soils) have been reported to moderately improve the zinc composition of grains of crops grown on them.

Assessment of Human Zinc Status

Progress attenuating the prevalence of zinc deficiency has been limited due, in part, to the lack of sensitive and specific methods to assess human zinc status.

Novel functional biomarkers are demonstrating potential in research studies and show promise for the monitoring of population-level interventions. Examples include essential fatty acid desaturation, DNA damage, and zinc transporter gene expression. Data from animal models further suggest that changes in gut microbiota may be used towards the evaluation of zinc status. Expanding the use of these measures in future zinc intervention studies is key to exposing subclinical zinc deficiency and curtailing its contribution to the burden of malnutrition.

Solutions: Evidence-Based Interventions to Increase Population Zinc Intake

There are readily available and deployable solutions proven to prevent zinc deficiency, including zinc supplementation, large-scale food fortification, and food and agricultural strategies such as soil zinc repletion and biofortification. Increasing zinc intake and combatting global zinc deficiency requires context-specific strategies that combine these complementary evidence-based interventions where appropriate.

Inclusive nutrition strategies based on smallholder farming systems such as zinc biofortification are endorsed because they deliver essential micronutrients to large segments of the population without the need for behavior change. They can help transform food systems to produce diets that are inherently and sustainably more nutrient-dense, and better equipped to offset climate-related shortfalls in food nutrient concentrations.

As drivers of food and nutrition insecurity such as conflict, climate change, and unfavorable socioeconomic conditions rise globally, it is vital that solutions to address malnutrition in all its forms (including micronutrient deficiencies) are prioritized.

The impact of holistic national policies and adequately resourced programs that tackle zinc deficiency and its underlying causes is measurable, albeit imperfectly. Improvements in child and maternal infectious morbidity and related disability and in adult-onset non-communicable diseases await bold action.