Table 1.

The concentrations of Zn, Cu, Mn, and Fe in subjects with and without diabetes.

Sample	Trace Metal Elements	Concentration		References
		Healthy People	Diabetic Patients
Plasma	Zinc	12.2–16.9 μmol/L	10.2–16.3 μmol/L	[21,22,23]
	Copper	14.6–19.8 μmol/L	16.4–21.5 μmol/L	[22]
	Manganese	0.77–1.18 μmol/L	0.62–0.93 μmol/L	[22,23,24,25]
	Iron	Male: 11–31 μmol/L, Female: 9–30 μmol/L	Male: 15–33 μmol/L Female: 12–32 μmol/L	[24,26]
Urine	Zinc	300–600 μg/24 h 1	100–300 μg/24 h	[24]
	Copper	15–60 μg/24 h	30–100 μg/24 h	[24]
	Manganese	1–8 μg/24 h	2–15 μg/24 h	[24,25]
	Iron	0.2–1.1 μmol/24 h	0.5–3.5 μmol/24 h	[26]

¹ The 24-h urine specimens were collected.