Does zinc deficiency reduce resilience to microvascular injury?

Zinc has established cellular roles in barrier maintenance, redox regulation, and wound repair. The claim is strongest when framed around preventing or correcting deficiency; evidence does not support assuming that zinc supplementation will broadly enhance these functions in zinc-replete individuals.

Barrier, antioxidant, and repair evidence

• In intestinal Caco-2 models, zinc chelation reduces tight-junction proteins and increases permeability; zinc repletion can restore junctional integrity. Peripheral endothelial models are generally directionally consistent, although brain microvascular endothelial cells have shown barrier tightening with depletion, indicating vascular-bed specificity.
• In primary rat endothelial cells, zinc depletion impaired Gclc expression and glutathione biosynthesis, a direct mechanism for weakened antioxidant capacity. Across 25 adult supplementation trials, zinc was associated with lower malondialdehyde and higher total antioxidant capacity, but not a significant glutathione increase; the clinical meaning of these biomarker changes remains uncertain.
• Zinc contributes to keratinocyte migration, re-epithelialization, and matrix metalloproteinase-dependent wound processes. In five small, heterogeneous chronic-ulcer trials, zinc treatment improved healing (RR 1.41, 95% CI 1.04–1.92).

Microvascular implications

• Zinc depletion can increase endothelial oxidative stress and inflammatory signaling, alter eNOS/nitric-oxide signaling, and impair barrier properties in some models—mechanistically consistent with lower resilience to microvascular injury.
• Human findings remain indirect. A short randomized crossover trial in people with type 2 diabetes and microalbuminuria found statistically significant short-term reductions in urinary albumin-to-creatinine ratio with 30 mg/day elemental zinc, but this is a surrogate outcome and does not establish prevention of CKD progression or generalized vascular protection.

Bottom line

• Adequate zinc status is biologically important for barrier integrity, antioxidant defenses, and tissue repair; deficiency plausibly heightens endothelial and microvascular vulnerability. The most evidence-based clinical implication is identifying and correcting deficiency, particularly in chronic-wound contexts, rather than routine zinc use solely to prevent microvascular injury.