Research Article

The Effectiveness of Zinc Supplementation in Taste Disorder Treatment: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Table 1

The main patient characteristics of the included studies.

Author (s), year (study duration)CountryStudy typeTotal no. of patientsNo. of patients receiving zincNo. of patients receiving placeboGenderAge (year)Zinc supplementDisease or case-induced taste disorder

Ikeda et al., 2013 [23] (12 weeks)JapanDouble-blind RCT w/placebo21910811187 M and 132 FAverage for intervention: 43.3
Control: 47.1
Polaprezinc, 34 mg/dZinc deficiency and idiopathic taste disorder
Sakagami et al., 2009 [24] (12 weeks)JapanDouble-blind RCT w/placebo. Multicentre1098128M and 56 F 5120–80Polaprezinc, (group 1) 17 mg (n = 27), (group 2) 34 mg (n = 26) or (group 3) 68 mg (n = 28) dailyIdiopathic taste disorder
Stewart-Knox et al., 2007 [25] (6 months)JapanDouble-blind RCT w/placebo199NRNR103 M and 96 F70–78Zinc gluconate, elemental zinc gluconate (group 1) 15 mg/d and (group 2) 30 mg/dIdiopathic taste disorder in elderly people
Heckmann et al., 2005 [26] (3 months)GermanyRCT w/placebo5024267 M and 43 F41–82Zinc gluconate (140 mg/d, equivalent to 20 mg/d of elemental zinc)Idiopathic taste disorder
Matson et al., 2003 [27] (6 weeks)UKDouble-blind RCT w/placebo241212M and F30 to 72Zinc sulphateChronic renal failure
Sakai et al., 2002 [28] (3 months)JapanDouble-blind RCT w/placebo733736M/NR and 47 F23–79Picolinate, 28.9 mg of elemental zinc three times/dZinc deficiency and idiopathic taste disorder
Yoshida et al., 1991 [29] (4 months)JapanDouble-blind RCT w/placebo522824M to F ratio was 1 : 1.8Mean age for group 55.1 & 59.2 for placeboZinc gluconate, 158 mg zinc gluconate; zinc content: 22.59 mgZinc deficiency and idiopathic taste disorder
Mahajan et al., 1982 [30] (6 months)USADouble-blind RCT w/placebo241212Only malesTreatment 46 ± 8
Control 49 ± 12
Zinc acetate, zinc acetate (50 mg of elemental zinc/d)Chronic renal failure
Mahajan et al., 1980 [31] (6 months)USADouble-blind RCT w/placebo221111NRTreatment: 51.3 ± 3.2
Control: 55.1 ± 2.8
Zinc acetate, zinc acetate (50 mg of elemental zinc/d)Chronic renal failure
Mahajan et al., 1979 [32] (6 months)USADouble-blind RCT w/placebo311120NRNRZinc acetate, zinc acetate (50 mg of elemental zinc/d)Chronic renal failure
Atkin-Thor et al., 1978 [33] (6 weeks)USADouble-blind crossover RCT w/placebo29209NR21–70Zinc sulphate, 440 mg ZnSO4 postdialysis, 3 times per weekChronic renal failure
Henkin et al., 1976 [34] (6 months)USADouble-blind crossover RCT w/placebo106Not clearNot clear53 M and 53 F19–84Zinc sulphate, 100 mg of zinc ion in four oral dosesIdiopathic taste disorder

NR: not reported, M: male, F: female, RCT: randomized controlled trial, w: with.