Table 3.
Zinc and taste disorder
| Author(s), year, and country | Study design and duration | Sample size | Age | Disease or case | Methods | Zinc dose/d | Treatment period | Outcomes |
|---|---|---|---|---|---|---|---|---|
|
Khan [33] Pakistan |
RCT Oct 2017 to Mar 2018 |
17 patients 32.4% females |
46 ± 9.2, 32.4% females | Chemotherapy-related taste alteration (oral cancer) | Detection thresholds, serum zinc level |
Zinc sulphate 50 mg orally 3 times/d |
7–8 MO treatment 1-MO follow-up |
Zinc sulphate was not found to be preventing chemoradiation induced taste alterations Sweet taste was most effected by cancer p = 0.04 |
|
Ripamonti [34] Italy |
RCT 1995–1996 |
18 patients (8 F and 10 M) | Mean (SD) age 55.5 (14.39) | Head and neck cancer | Detection thresholds, serum zinc level |
Zinc sulphate 45 mg orally 3 times/d |
1 MO | A rapid improvement of taste was observed in 64% of patients treated with zinc, compared with 22% of the placebo group |
|
Sakai [35]) Japan |
RCT 1991–1994 |
73 patients 47 F |
23 to 79 years | Idiopathic taste disorder | Filter paper disk method, serum zinc level | 29 mg of zinc picolinate/3 times/d | 3 MO | Zinc level before treatment 69 mg/dl or lower. Patients’ zinc picolinate-treated group had significantly high improvement (x2 test: p = 0.01) compared to placebo |
|
Halyard, Jatoi [36] USA |
RCT 2002–2005 |
169 patients 118 M; 51 F (Co = 84 + Int = 85) |
≥ 18 years | Head and neck cancer | Taste change questionnaire + serum zinc level |
Zinc sulphate 45 mg orally 3 times/d |
6 MO | No significant difference in taste between zinc-treated group and placebo p = 0.09 |
|
Lyckholm [37] USA |
RCT 2002–2005 |
58 cancer patients 41 females |
≥ 18 years | Chemotherapy-related taste (cancer) | Taste change questionnaire + serum zinc level | 50 mg of elemental zinc/2 times/d | 3 MO | There was no statistically significant improvement after zinc supplementation treatment (p < .0001) |
|
Mahajan, Prasad [38] USA |
RCT | 22 patients | 51.3 ± 3.2 | Uremic hypogeusia | Detection thresholds, serum zinc level | 50 mg of elemental zinc as zinc acetate/d | 6 MO | After 6 to 12 weeks of therapy, patients showed significant improvements in taste. The mean plasma zinc level increased from 75 ± 8 to 97 ± 10 ısg/dl (p < 0.001) in patients receiving zinc acetate |
|
Sakagami [39] Japan |
RCT |
109 patients Placebo (n = 28), zinc-treated n = 81 (56 F and 51 M) |
20–80 years | Idiopathic taste disorders | Filter paper disk method, serum zinc level | 17 mg (n = 27), 34 mg (n_26), or 68 mg (n_28) of oral zinc, polaprezinc preparations, daily | 12 weeks |
Zinc level before treatment lower than 69 mg/dl The group of patients given 68 mg zinc showed a significant improvement; 25 patients cured and improved in their gustatory sensitivity, compared with the placebo group p = 0.018 |
|
Ikeda [40] Japan |
1 month |
408 patients 228 females |
49–65 years | Taste disorder in elderly | Filter paper disk method, serum zinc level |
Zinc agent polaprezinc 75 mg, 2 times/day, containing 17 mg of zinc |
1 MO |
Zinc level before treatment 69 mg/dl or lower 1 MO after treatment had significantly increased, to 91.0 mg/dl (p, 0.001) 35 of zinc-deficient patients were cured or improved of taste disorder |
|
Henkin, Schecter [41] Washington |
RCT | 106 patients (53 M and 53 F) | 19–84 years | Taste dysfunction | Detection thresholds, serum zinc level | 100 mg of zinc ion in four divided oral doses | 6 MO | Zinc sulphate was effective in taste treatment |
|
Heckmann, Hujoel [42] Germany |
RCT 1999 to 2001 |
n = 50 patients (7 M and 43 F) | 41–82 years | Dysgeusia | Filter paper strips and serum zinc level |
140 mg/d of zinc gluconate, equivalent to 20 mg/day of elemental Zinc |
3 MO | Intervention group reported improvements of gustatory function after zinc treatment (p < 0.001) taste test—before (mean SD) (17.1, 5.8) and after (9.04, 13.04); zinc in serum before (mg/dl) = (72.78,18.38) and after (81.38,19.61), and rated dysgeusia as being less severe(p < 0.05) |
|
Atkin-Thor, Goddard [43] USA |
RCT | 20 patients | 21–70 years | Hypogeusia | Detection thresholds, serum zinc level, hair zinc |
440 mg ZnSO4 Post-dialysis, 3 times per week |
6 weeks | After supplementation with Zn, taste acuity markedly improved in 95% of patients and Zn concentrations in hair increased in 85% of patients. The patients’ appetites improved |
|
Stewart-Knox, Simpson [44] Tokyo, Japan |
RCT |
199 healthy older F = M |
70–87 years | Taste disorder in elderly | Detection thresholds, serum zinc level | 15 or 30 mg Zn/d | 6 MO | Serum Zn increased post-intervention, intervention. Salt taste acuity was greater in response to Zn (30 mg) supplemented group (0·84 409 (SD 0·13 349) than the placebo group (0·75 045) (SD 0·210) post-intervention, in the Grenoble |
|
Najafizade, Hemati [45] Iran |
RCT | 35 patients (F 14 and M 21) | Age = 59.2 ± 16.5, 60% male | Head and neck cancers | Detection thresholds, serum zinc level | 50 mg/ 3 times/d | 5–9 weeks | There was a significant increase in taste perception threshold for bitter, salty, sweet and sour tastes in placebo group (p = 0.001). Intervention group slightly increased in threshold for perception of salty taste (p = 0.046) |
Summary of 13 studies
3n, number; RCT, randomized controlled trials; SD, standard deviation; M, male; F, Female; MO, month; Zn, zinc; d, day; mg, milligramme; ZnSO4, Zinc sulphate