Table 2.

Trace metal elements (Zn, Cu, Mn, Fe) and diabetes.

Metal Elements	Association with Diabetes Mellitus	References
Zinc	Plasma zinc levels are decreased in diabetes. Increasing zinc levels reduces the risk of T2D 1. Low zinc levels aggravate diabetes. Zinc has curative effects on diabetes.	[33,35]
Copper	Plasma copper levels are increased in people with diabetes. High plasma copper levels increase the risk of T2D. Copper reduction can alleviate diabetic symptoms.	[54,55]
Manganese	Plasma manganese levels are reduced in T2D patients. Manganese supplementation can effectively protect against T2D.	[56,57]
Iron	Iron and ferritin levels are increased in diabetes. Iron overload increases the incidence of T2D. Iron depletion restores insulin sensitivity and reduces plasma glucose levels.	[58,59,60]

¹ T2D: type 2 diabetes.