印度研究人员综合多项实验数据后发现，在普通感冒初期补充锌能够减轻症状，缩短患病时间。
鉴于锌有毒性，不宜长期服用，而且过量服用副作用大，研究人员计划深入研究用于感冒治疗的适宜剂量和服用方法。
有助治疗
印度昌迪加尔医学教育研究所儿科医生米努·辛格带领研究小组回顾了涉及1360人的15项实验结果后发现，在出现感冒症状后一天内，服用含锌糖浆、药丸或含片能够减轻感冒症状，加速痊愈。
研究人员在网上医学电子杂志《科克伦图书馆》（The Cochrane Library）发表研究报告说，7天后，补充锌的感冒患者痊愈人数多于服用安慰剂者。此外，儿童服用含锌糖浆或含片5个月以上，感冒较少，缺课较少，服用抗生素较少。
不过，15项实验中研究对象服用锌的时间表和计量各不相同，研究人员无法得出统一结论。而且，与服用安慰剂者相比，服用锌的研究对象出现哮喘等副作用较多。
英国广播公司（BBC）2月16日援引辛格的话报道：“这一回顾增加了锌用于普通感冒治疗的证据。不过现阶段仍然难以给出一般建议，因为我们并不十分了解适宜剂量和服用方法或时间。”
可能原因
感冒是一种常见病。一年之中，成年人可能感冒三四次，而儿童最多可能感冒10余次。感冒病毒传播途径多，不仅可以通过咳嗽、喷嚏等方式直接传播，也可以通过触摸门把手等方式间接传播，预防难度大。普通感冒没有有效治疗方法。
研究人员认为，锌可以包裹普通感冒病毒，从而阻止病毒通过鼻黏膜进入人体，帮助预防和减少感染感冒病毒。
此外，实验结果显示，锌能够阻碍病毒复制。
还有专家认为，锌有助增强免疫系统，当身体遭病毒入侵时可能抑制某些不适反应，减轻病症。
有待深入
研究人员强调，锌具有毒性，不能长期服用，过量服用锌可能引起哮喘、呕吐、腹痛和腹泻。他们计划进一步研究用于感冒治疗的合适剂量。
《科克伦图书馆》主编戴维·托维说：“普通感冒治疗受人关注，这是一种给人带来某些希望的疗法。”
“尽管有许多非处方类感冒药，但能够消灭感冒症状或很大程度上减轻症状的药物并不多，”托维说，“不过，（锌的）最佳服用剂量、服用时间和方法仍然不清楚，有待进一步研究。”
英国加的夫大学普通感冒中心主任罗纳德·埃克尔斯质疑当前处方中锌用于治疗感冒的效用。他说，如果长期服用，锌的毒性是一个潜在风险。
Zinc for the common cold
Background
The common cold is one of the most widespread illnesses and is a leading cause of visits to the doctor and absenteeism from school and work. Trials conducted since 1984 investigating the role of zinc for the common cold symptoms have had mixed results. Inadequate treatment masking and reduced bioavailability of zinc from some formulations have been cited as influencing results.
Objectives
To assess the effect of zinc on common cold symptoms.
Search strategy
We searched CENTRAL (2010, Issue 2) which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to May week 3, 2010) and EMBASE (1974 to June 2010).
Selection criteria
Randomised, double-blind, placebo-controlled trials using zinc for at least five consecutive days to treat, or for at least five months to prevent the common cold.
Data collection and analysis
Two review authors independently extracted data and assessed trial quality.
Main results
We included 13 therapeutic trials (966 participants) and two preventive trials (394 participants). Intake of zinc is associated with a significant reduction in the duration (standardized mean difference (SMD) -0.97; 95% confidence interval (CI) -1.56 to -0.38) (P = 0.001), and severity of common cold symptoms (SMD -0.39; 95% CI -0.77 to -0.02) (P = 0.04). There was a significant difference between the zinc and control group for the proportion of participants symptomatic after seven days of treatment (OR 0.45; 95% CI 0.2 to 1.00) (P = 0.05). The incidence rate ratio (IRR) of developing a cold (IRR 0.64; 95% CI 0.47 to 0.88) (P = 0.006), school absence (P = 0.0003) and prescription of antibiotics (P < 0.00001) was lower in the zinc group. Overall adverse events (OR 1.59; 95% CI 0.97 to 2.58) (P = 0.06), bad taste (OR 2.64; 95% CI 1.91 to 3.64) (P < 0.00001) and nausea (OR 2.15; 95% CI 1.44 to 3.23) (P = 0.002) were higher in the zinc group.
Authors' conclusions
Zinc administered within 24 hours of onset of symptoms reduces the duration and severity of the common cold in healthy people. When supplemented for at least five months, it reduces cold incidence, school absenteeism and prescription of antibiotics in children. There is potential for zinc lozenges to produce side effects. In view of this and the differences in study populations, dosages, formulations and duration of treatment, it is difficult to make firm recommendations about the dose, formulation and duration that should be used.
