Does zinc deficiency impair antioxidant enzymes, immune regulation, and vascular repair?

Zinc is essential to redox defense, cellular signaling, and immune competence. In a 71-year-old man, deficiency—if present—could therefore have biologically meaningful consequences, although endothelial-repair effects remain primarily experimental rather than established clinical outcomes.

Antioxidant and genomic effects

• Zinc is a structural cofactor for Cu/Zn-superoxide dismutase (SOD1), supporting superoxide detoxification. In healthy older adults, about 7 weeks of zinc 10 mg/day increased plasma and erythrocyte SOD activity, whereas catalase and glutathione peroxidase did not significantly change.
• A meta-analysis of 23 controlled trials found higher SOD, glutathione, and total antioxidant capacity with zinc supplementation, without a significant overall effect on glutathione peroxidase.
• In a controlled depletion–repletion study of nine healthy men, short-term restriction did not significantly alter erythrocyte SOD or F₂-isoprostanes, but increased peripheral-blood DNA strand breaks; damage improved with repletion and was inversely associated with plasma zinc.

Immune regulation

• The strongest evidence concerns cell-mediated immunity. Zinc-dependent LCK/ZAP70, PI3K–AKT, MAPK, NF-κB, and AP-1 signaling supports T-cell development, proliferation, and cytokine transcription.
• Among zinc-deficient nursing-home residents, 30 mg/day elemental zinc for 3 months increased T-cell numbers and stimulated proliferation. In older adults, supplementation increased stimulated IL-2 mRNA, reduced TNF-α generation, and was associated with fewer infections.

Endothelial and repair mechanisms

• Low intracellular zinc impairs endothelial barrier function; physiologic zinc restored barrier integrity in cultured endothelial cells. Deficiency-associated oxidative stress, NF-κB activation, adhesion-molecule expression, monocyte adhesion, apoptosis, reduced nitric-oxide bioavailability, and altered Nrf2/glutathione/Akt signaling provide a coherent explanation for poorer endothelial resilience and repair.
• These findings are mechanistically compelling, but do not establish improved human vascular repair or endothelial function after zinc repletion.

Bottom line

• Zinc deficiency is well supported as harmful to immune regulation and likely compromises SOD-related antioxidant defenses. Its adverse implications for endothelial integrity and vascular repair are plausible and biologically coherent, but require cautious interpretation because direct clinical vascular-outcome evidence remains limited.