Zinc and Copper Metallic Instability: Investigating Altered Metal Functionality in both Human and Animal Studies

Homeostasis is the regulatory mechanism for the expression of all genes, the function of all metabolic pathways, the utilization of any essential trace element (TEs), while its disruptions lead to many pathological states. The pathologies include cardiovascular disease, anaemia, diabetes, neurological disorders, and cell death. For this, copper and zinc are two of the major TEs involved in controlling the physiological and pathological processes in both humans and animals. Zinc deficiency, for instance, is linked with decreased body weight, decreased ability to metabolize glucose, and impaired immune function. By contrast, deficiency of copper can lead to several neurological disorders, oxidative stress, mitochondrial dysfunction, and changes in lipid metabolism. On the other hand, there excessive exposure can have adverse effects on health, including the development of epilepsy, neuronal excitability, genotoxic effects, and cellular toxicity. Moreover, dual biological functions of zinc further complicate the understanding of their roles in both health and disease. Such as, zinc has a neuromodulatory function and helps to control excitably in neurons, but sometimes zinc in the synapse, inhibit the functioning of inhibitory neurotransmitter and cause damage to the neurons. Likewise, in metabolic diseases, particularly diabetes mellitus, there is often dysregulation of the levels of zinc and copper, resulting in steel-like interactions; elevated levels of copper and reduced levels of zinc contribute towards the pathogenesis of both the disease and the progression of dementia. Despite this antagonistic relationship, both trace metals act synergistically as necessary derivatives of superoxide dismutase; therefore, both play a vital role in maintaining cellular antioxidant defense systems. Therefore, this review covers published articles from 1992-2025 with regard to zinc and copper in their dietary and nanoparticle forms in animal and human models to demonstrate their differing roles and how they complement one another, or conflict with one another.