Table 1 Description of the included studies

Afkhami-Ardekani et al., [19] 2008, Iran

R, DB, P;

T2DM (n=40); age 52.7 8.6year;

2 groups; 612weeks;

BMI; SBP; DBP; FBG; 2-h PPBS;

HbA1c; TG; TC; HDL-c;

LDL-c; Urea; Creatinine; ALT; AST

ZnSO₄;

660mg/day^#

None

Reduction in TG, TC, LDL

and HbA1C

Al-Maroof et al., [20] 2006, Iraq

R, B, P;

T2DM (n=86); age 54.6 9.2year;

2 groups; 3months

HbA1c; FBG

ZnSO₄;

30mg/day*

None

Reduction in HbA1C

Anderson et al., [27] 2001, Tunisia

R, DB, P;

T2DM (n=110); age 57.9 6.2year;

4 groups; 6months

Plasma and Urinary Zinc;

Antioxidant effects

Zn gluconate;

30mg/day^#

Chromium

Positive antioxidant effect

Blostein-Fujii et al., [38] 1997, USA

R, B, P;

T2DM (n=60); age 60.0 12.0year;

2 groups; 3weeks

Plasma Zinc; 5-nucleotidase;

lipoprotein oxidation; IGF-1

30mg/day^#

None

Raised IGF-1

(only if low at initiation)

De Sena et al., [39] 2005, Brazil

Casecontrol;

T1DM (n=37); age 4.1 16.5year;

2 groups; 4months

FBG; HbA1c; Urine sugar;

Plasma and red cell Zn

7.5-15mg/day*

None

Increased erythrocyte

Zinc concentration

Farvid et al., [28] 2011, Iran

R, DB, P;

T2DM (n=67); age 52.5 8.2year;

3 groups; 4months

Plasma Zinc; FBG; HbA1c;

Fructosamine; Antioxidant effects;

Neuropathy symptoms;

Nerve conduction; Peripheral blood flow

ZnSO₄;

20mg/day*

Mg²⁺; Vitamin B1,B2,

B6,B12, C,E; Folate

Reduced severity of neuropathy

symptoms in patients with

mild-moderate neuropathy

Farvid et al., [29] 2005, Iran

R, DB, P;

T2DM (n=69); age 50.0 9.0year;

4 groups; 3months

Plasma and Urinary Zinc; SBP;

DBP; MAP; FBG; HbA1c; TC;

TG; HDL-c; LDL-c; Apo-A1;

Apo B; Fructosamine;

Urinary Microalbumin and protein

ZnSO₄;

30mg/day*

Mg²⁺; Vitamin C,E

Lowered urinary

albumin excretion

Farvid et al., [30] 2004a, Iran

R, DB, P;

T2DM (n=69); age 50.3 8.2year;

4 groups; 3months

Plasma and Urinary Zinc; SBP;

DBP; MAP

ZnSO₄;

30mg/day*

Mg²⁺; Vitamin C,E

Combination of vitamins and

minerals decreases blood pressure

Farvid et al., [31] 2004b, Iran

R, DB, P;

T2DM (n=69); age 50.3 8.2year;

4 groups; 3months

Plasma and Urinary Zinc; TC;

HDL-c; LDL-c; TG; Apo-A1; Apo B

ZnSO₄;

30mg/day*

Mg²⁺; Vitamin C,E

co-supplementation of Mg, Zn,

Vitamins C and E,

increases HDL and Apo-A1

Faure et al., [17] 1995, France

Casecontrol;

T1DM (n=18); age 32.2 8.1year;

2 groups; 3months

Plasma Zinc; Antioxidant effects

Zn gluconate;

30mg/day*

None

Reduced lipid peroxidation

Garcia-Medina et al., [32] 2011, Spain

R; P;

T2DM (n=97); age 54.8 11.6year;

2 groups; 60months

Antioxidant effects; Visual acuity;

Slit-lamp examination; IOP;

Fundoscopy

27mg/day*

Cu²⁺, Mn²⁺, Se²⁺,

Vitamin C, E, Niacin

Retardation of retinopathy

progression; improved antioxidant

status

Gunasekara et al., [33] 2011, Sri Lanka

R, B, P;

T2DM (n=96); age 53.4 7.2year;

3 groups; 4months

FBG; 2-h PPBS; HbA1c;

Creatinine; Insulin; Plasma and

Urinary Zinc; TC; TG; HDL-c; LDL-c

ZnSO₄;

22mg/day*

Mg²⁺, Cu²⁺, Se²⁺,

Multivitamin

Reduced HbA1C, FBG, 2-h PPBS,

TC and TC/HDL ration.

Gupta et al., [40] 1998, India

R, DB, P;

T2DM (n=50); age 49.9 11.0year;

3 groups; 6weeks

Plasma Zinc; FBG; 2-h PPBS;

Nerve conduction tests

ZnSO₄;

660mg/day^#

None

Reduced FBG and 2h-PPBS,

improved motor nerve conduction

velocity

Hayee et al., [41]

2005, Bangladesh

R, DB, P;

T2DM (n=60); age 50.9 11.1year;

3 groups; 6weeks

Plasma Zinc; FBG; 2-h PPBS;

Nerve conduction tests

ZnSO₄;

660mg/day^#

None

Reduced FBG and 2h-PPBS,

improved motor nerve conduction

velocity

Hegazi et al., [42]

1992, Egypt

Casecontrol;

T2DM (n=56); age 26 62year;

2 groups; 3weeks

FBG; Plasma Zinc; Insulin; Glucagon;

Glucose-6-Phosphatase

Zn₃(PO₄)₂;

28mg/day^#

None

Increased serum Insulin. Reduced

FBG and Glucagon

Heidarian et al., [43]

2009, Iran

R, DB, C;

T2DM (n=50); age 53.2 9.2year;

2 groups; 3months

Plasma Zinc; Folate;

Vitamin B12; Homocysteine

ZnSO₄;

30mg/day^#

None

Reduced serum Homocysteine,

increase folate and Vitamin B12

Hussain et al., [34] 2006, Iraq

R, DB, P;

T2DM (n=46); age 49.1 6.0year;

3 groups; 3months

FBG; 2-h PPBS; HbA1c;

C-Peptide

Zn acetate;

50mg/day^#

Melatonin

Reduced FBG and 2-h PPBS

Kadhim et al., [35]

2006, Iraq

R, DB, P;

T2DM (n=46); age 49.1 6.0year;

3 groups; 3months

TC; TG; HDL-c; LDL-c;

Creatinine; Urea; Urinary

Microalbumin

Zn acetate;

50mg/day^#

Melatonin

Reduced TC, TG and LDL

Niewoehner et al., [44]

1986, USA

Cohort study;

T2DM (n=13); age 61.0 2.0year;

2 groups; 68weeks

Plasma Zinc; HbA1c;

Immune function

ZnSO₄;

660mg/day^#

None

No beneficial effects observed

Parham et al., [36]

2008, Iran

R, DB, C;

T2DM (n=39); age 53.2 9.2year;

2 groups; 6months

FBG; HbA1c; GFR; SBP; DBP;

TC; TG; HDL-c; LDL-c;

Urinary Albumin; Plasma Zinc

ZnSO₄;

30mg/day*

None

Reduced urinary albumin excretion

Partida-Hernndez et al., [37]

2006, Mexico

R, DB, C;

T2DM (n=27); age 35 65year;

2 groups; 4months

FBG; HbA1c; Plasma Zinc; TG;

TC; LDL-c; HDL-c

ZnSO₄;

100mg/day^#

None

Reduced TC and TG.

Increased HDL

Raz et al., [45]

1989, Israel

Cohort study;

T2DM (n=13); age 55.0 2.4year;

1 group; 2months

Plasma Zinc; FBG; Fructosamine;

HbA1c; TC; TG; HDL-c;

immune function; IV GTT

ZnSO₄;

660mg/day^#

None

Increased glucose intolerance

Roussel et al., [46]

2003, Tunisia

R, DB, P;

T2DM (n=56); age 53.6 1.5year;

2 groups; 6months

Plasma and Urinary Zinc;

Antioxidant effects

Zn gluconate

30mg/day*

None

Positive antioxidant effect

Seet et al., [47]

2011, Singapore

R, B, P;

T2DM (n=40); age 56.0 7.5year;

2 groups; 3months

FBG; Insulin; TC; LDL-c; HDL-c;

TAG; PAF-AH; PLA₂

Zn gluconate;

240mg/day^#

None

No beneficial effects observed

Shidfar et al., [18]

2010, Iran

R, DB, P;

T1DM (n=48); age 720year;

2 groups; 3months

BMI; Apo A-1 and B; FBG; Insulin

ZnSO₄;

10mg/day*

Vitamin A

Increase in serum Apo-A1 and

Decrease in Apo-B/Apo-A1 ratio