Across 3 studies, findings are mixed: 1 large beneficial effect (lower zinc levels in vitiligo patients vs. controls, MD -0.642, p <0.001), 1 neutral finding with no significant difference in zinc deficiencies across bariatric surgery revision types, and 1 large harmful effect (lower zinc levels in mild cognitive impairment patients, SMD -0.77, p <0.05). The evidence is too sparse and heterogeneous to identify a consistent direction of effect, and no dose range or population can be generalized.
Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Results conflict in direction: one study shows benefit, one shows harm, and one is neutral, suggesting effect may be context-dependent or driven by population differences. Study durations and forms were not reported, limiting interpretability.
zinc (MD, -0.642; 95% CI, -0.731--0.554; p <0.001) levels were lower in the vitiligo group than in the control group.
Deficiencies in key micronutrients such as vitamin D, vitamin B12, albumin, calcium, zinc and iron were reported across revision types.
Zn (SMD: -0.77, 95%CI: -1.22-0.33) were significantly lower