Zinc can prevent the symptoms of common colds and flu-like illnesses and shorten the course of the disease

A new rapid systematic review and meta-analysis of randomized controlled trials showed that zinc can prevent symptoms and shorten the duration of community-acquired acute viral respiratory infections (such as the common cold and flu-like illness)

The review published today in the British Medical Journal Open Edition (https://bmjopen.

International research teams from Western Sydney University, University of Sydney, Southern Cross University, McMaster University and National University of Natural Medicine found:

• When zinc is used for prevention, the risk of common cold symptoms is reduced by 28%, and the risk of flu-like illness is reduced by 68%

  
  

• When zinc was used for treatment, it was found that the duration of symptoms before and after the peak of the disease was shortened by about 2 days, reducing the severity of symptoms on the third day, but the overall symptom severity was not significantly reduced

  
  

• Although the increased risk of non-serious adverse events may limit the tolerability of certain drugs (such as nausea or oral and nasal irritation), the risk of serious adverse events (such as oral zinc deficiency, copper and zinc nasal sprays and loss of gels) The sense of smell) is very low

  
  

The lead author of the study, associate professor Jennifer Hunter, PhD of Integrative Medicine at the NICM Health Institute of Western Sydney University, said that these findings build on previous systematic reviews and add important new ideas to the role of zinc.

"It is generally believed that the role of zinc in preventing and treating infections is only for people who are zinc-deficient; our findings really challenge this concept," said Associate Professor Hunter

"Two large trials in China found that extremely low-dose zinc nasal sprays reduced the risk of clinical disease

However, Associate Professor Hunter said that not all research results are in favor of zinc

"Our systematic review included studies for the first time in which participants were deliberately infected with human rhinovirus, which is a common cause of upper respiratory tract infection

"These human rhinovirus tests are small in scale, which makes the results of the study unreliable

The researchers also emphasized the diversity of zinc formulations and dosages and the challenges faced by their mechanism of action in their findings

"Clinicians and consumers need to be aware that there are still considerable uncertainties in the clinical efficacy of different zinc formulations, dosages and routes of administration," said Associate Professor Hunter

"There is not enough research to show whether zinc nasal sprays, nasal gels, lozenges, and oral zinc are better or worse than other products

Despite these uncertainties, Associate Professor Hunter said that zinc products are widely available, reasonably priced, and generally safe, including short-term use of high-dose zinc ingots and capsules used in many trials

"When people have a cold, they want to know two things: first, how long will the cold last, and second, how uncomfortable will I be?" We found that zinc may reduce the duration of the disease.

The results of the review are also consistent with the call for more immunonutrition research, especially in people at higher risk of SARS-CoV-2
.
The researchers commented from the review results and preliminary SARS-CoV-2 studies that zinc alone may be effective, which is reasonable
.

Associate Professor Hunter said: "We have now delved into the pandemic and quickly learned that many effective therapies for other viral infections are not necessarily effective for COVID-19.
We cannot assume that these results are applicable to COVID-19
.
"