Table 4.
Key findings on managing cold severity with micronutrients`
| Study (author, year) | Severity scale used | Key findings* |
|---|---|---|
| Vitamin D | ||
| Goodall, 2014 | WURSS-21† | Mean severity score per episode is 48.2 ± 27.92 points higher in the vitamin D group than in the placebo group (P = 0.09). |
| Li-Ng, 2009 | 5-point scale (1 = healthy, 5 = “very ill” ) | Mean severity score is 0.2 ± 0.24 points lower in the vitamin D group than in the placebo group (P = 0.4). |
| Murdoch, 2012 | WURSS-24‡ and WURSS-21 | Mean severity score per episode is lower in vitamin D the group (162 ± 1,142.2) than in the placebo group (167.5 ± 147.4) (P = 0.48). |
| Shimizu, 2018 | WURSS-21 | Mean severity score per day while ill is 4.5 ± 3.13 points lower in the vitamin D group than in the placebo group (P = 0.154). |
| Simpson, 2016 | 6-point scale (0–5, where 0 is no presence of that symptom and 5 is most severe) | Mean severity score per episode is 2.87 ± 11.38 points lower in the vitamin D group than in the placebo group (P = 0.4). |
| Zinc | ||
| Douglas, 1987 | 4-point scale§ | Mean severity score per episode is 1.9 ± 2.80 points higher in the zinc group than in the placebo group. |
| Eby, 1984 | 4-point scale§‖ | Average total severity scores dropped significantly faster in the zinc group than in the placebo group (half-lives of exponential decay curves 1.9 ± 0.3 for the zinc group vs. 4.5 ± 1.0 for the placebo group). However, initial severity was significantly lower in the zinc group. |
| Frequency and severity score was consistently lower for all symptoms in the zinc group than in the placebo group, after 7 days of zinc administration. | ||
| Godfrey, 1992 | 4-point scale§‖ | By day 7 of zinc administration: |
| Symptoms left: three mild symptoms (symptom severity score of 1 for each symptom) in one subject in the zinc group, compared with an average of 2.4 moderate symptoms (average severity score of 2.6) in eight subjects in the placebo group. | ||
| Nasal drainage incidence: 5% in the zinc group vs. 33% in the placebo group. | ||
| Nasal congestion: 0% in the zinc group vs. 31% in the placebo group. | ||
| Mossad, 1996 | 4-point scale§‖ | Zinc group had significantly fewer days with any symptoms than the placebo group. |
| Petrus, 1998 | 4-point scale§‖¶ | Mean severity score per day while ill is 0.09 ± 0.06 points lower in the vitamin D group than in the placebo group. |
| Prasad, 2000 | 4-point scale§‖ | Severity scores were significantly different between the zinc and placebo groups after 10 days of zinc administration (P = 0.0002). |
| Average severity scores decreased from 8.32 (baseline) to 3.45 (day 4) in the zinc group and from 7.78 (baseline) to 5.61 (day 4) in the placebo group. | ||
| Prasad, 2008 | 4-point scale§‖ | Severity scores were significantly different between the zinc and placebo groups after 12 days of zinc administration (P = 0.0002). |
| Average severity scores decreased from 10.8 (baseline) to 2.7 (day 4) in the zinc group and from 8.9 (baseline) to 5.4 (day 4) in the placebo group. | ||
| Turner, 2000 | 4-point scale§‖ | No significant differences between zinc and placebo groups for the total symptom score or severity of any individual symptoms over the first 3 days of zinc administration or on any of the individual days, regardless of zinc formulations provided. |
| Weismann, 1990 | Visual analogue scale (11 cm horizontal line) for overall condition | No significant difference in severity in both groups, even on days with largest severity difference between the zinc and placebo groups. |
| No significant differences in cold severity compared with prior episodes, in both the zinc and placebo groups (P = 0.64) | ||
*
Scores are presented as mean score ± SEM.
†
Wisconsin Upper Respiratory Symptom Survey-21 (WURSS-21) consists of 21 questions rated on a 0–7 Likert scale. Symptoms rated for physical severity include runny nose, plugged nose, sneezing, sore throat, scratchy throat, cough, hoarseness, head congestion, chest congestion, and feeling tired.
‡
Wisconsin Upper Respiratory Symptom Survey-24 (WURSS-24) consists of 24 questions rated on a 0.7 Likert scale. Symptoms rated for physical severity include headache, body ache, and fever and the other symptoms rated in WURSS-21.
§
4-point scale: 0 = none; 1 = mild; 2 = moderate; and 3 = severe.
‖
Symptoms include sneezing, nasal drainage, nasal congestion, headache, sore throat, scratchy throat, cough, hoarseness, muscle ache, and fever.
¶
Additional symptom: myalgia.