TABLE 2.
Biochemical, physical, and clinical adverse effects of zinc intake in infants and children aged ≤3 y reported in the included studies1
| Outcome reported | Number of studies2 | References |
|---|---|---|
| Biochemical outcome measures | ||
| Hemoglobin | 34 (32)3 | (8, 12, 13, 18, 19, 26, 28, 29, 31, 33–40, 43, 47, 48, 51, 53, 54, 58, 59, 62, 64, 65, 70–73) (66)4 (52)5 |
| Hematocrit | 6 (6) | (8, 19, 31, 51, 62, 65) |
| Serum ferritin | 21 (20) | (12, 18, 19, 26, 28, 29, 31, 34, 35, 39, 40, 47, 48, 51, 59, 70–72, 74, 75) (52)3 |
| Serum/soluble transferrin receptor | 5 (5) | (12, 28, 36, 47, 74) |
| Iron deficiency | 9 (9) | (12, 31, 34, 39, 47, 53, 59, 70, 71, 73) |
| Anemia | 18 (18) | (12, 19, 29, 34, 36–39, 43, 47, 48, 53–55, 63, 64, 70, 71, 73) |
| Severe anemia | 3 (3) | (12, 63, 64) |
| Iron deficiency anemia | 4 (4) | (29, 34, 47, 71, 74) |
| Serum iron | 2 (2) | (51, 65) |
| Zinc protoporphyrin | 2 (2) | (53, 74) |
| Plasma/serum copper | 13 (13) | (51, 65) |
| Erythrocyte superoxide dismutase | 2 (2) | (18, 72) |
| Elevated C-reactive protein | 3 (3) | (36, 43, 70) |
| Lactulose:mannitol ratio | 2 (2) | (18, 60) |
| Serum total cholesterol | 3 (3) | (8, 17, 72) |
| Physical or clinical descriptive outcomes | ||
| Vomiting | 13 (0) | (8, 27, 30, 36, 41, 44–46, 49, 50, 67, 69) |
| Regurgitation | 5 (0) | (8, 33, 46, 67, 69) |
| Nausea | 2 (0) | (44, 45) |
| Constipation | 4 (0) | (44, 45, 49, 50) |
| Abdominal pain | 3 (0) | (41, 44, 45) |
| Drowsiness | 2 (0) | (44, 45) |
| Mouth irritation | 2 (0) | (44, 45) |
| Taste aversion | 3 (0) | (33, 44, 45) |
| Respiratory infection | 13 (0) | (13, 18, 29, 33, 34, 49, 50, 55, 57–59, 61, 75) |
| URTI | 3 (0) | (33, 34, 50) |
| Bronchiolitis | 2 (0) | (33, 36) |
| Cough | 2 (0) | (29, 72) |
| Diarrhea | 27 (0) | (8, 13, 18, 26, 27, 29–34, 36, 42–45, 49, 50, 55, 56, 58, 59, 61, 63, 67, 72, 75) |
| Dysentery/bloody diarrhea | 3 (0) | (36, 42, 55) |
| ORS use | 2 (0) | (27, 56) |
| Malaria | 9 (0) | (18, 43, 55, 58, 63, 64, 70, 73, 74) |
| Fever | 5 (0) | (29, 34, 59, 72, 74) |
| Death | 7 (0) | (31, 33, 36, 43, 49, 58, 63) |
| Other | 23 (0) | (8, 18, 20, 21, 31–34, 36, 41–45, 50, 51, 56, 62–64, 68, 72, 74) |
1
ORS, oral rehydration solution; URTI, upper respiratory tract infection.
2
Number of studies reporting the outcome in the review (no. studies included in meta-analysis).
3
Includes 2 values converted from hematocrit.
4
No SD values reported.
5
Not included in meta-analysis because same study as that of Rosado et al. (59).