Previous studies in mice by the Ohio State University had shown that zinc-deficiency could lead to excessive inflammation. The mineral has many complex roles in the body and as a result it is still not fully understood how exactly it helps to fight off an infection.

A study by the journal Cell Reports indicated through human and animal studies that a protein which crops up in many body processes called NF-kB contributed to this effect. It manages to lure zinc into the immune cells that are fastest to respond to fighting infection. Next, the zinc slows down the further activity in that pathway which in turn slows down the immune response and ultimately limits the level of inflammation.

Dr Daren Knoell who led the study added: “The immune system has to work under very strict balance, and this is a classic example of where more is not always better. We want a robust inflammatory response, which is part of our natural programming to defend us against a bug.”

This is not the first time zinc has been suggested to help with medical problems. Back in 2005, US researchers found that zinc supplements reduced illness in children with HIV. The chances of Diarrhoea and pneumonia were reduced safely and without any risk of making the HIV infection worse. They viewed this as a cheap and effective way on reducing the number of children dying from HIV-1 infection in poorer areas.

Zinc is thought to be the most important mineral supplement by many nutritionists because it is commonly deficient in the diet. Foods that are rich in zinc include fish, meat, cheese, some nuts and seeds as well as brown rice.

More research was carried out in 2011 on whether taking zinc can lessen the severity of a common cold. The mineral was digested in the form of either syrup, tablets or lozenges. That research also indicated that by aiding the immune system, zinc may decrease the unpleasant reactions the body has when there is a virus present.

There has been no conclusion on the recommended dosage and it has been suggested that further study is needed. The main problem is that researchers are still uncertain whether zinc should be used long term and excessively due to concerns over its toxicity.

Such breath analysis could reduce the time taken to diagnose lung infections from weeks down to minutes according to the study, published in the Journal of Breath Research.

Currently, bacterial infections are identified by collecting samples from the infected area and using these to grow more of the bacteria in a lab. These bacteria can then be identified through tests and subjected to different antibiotics to determine an effective treatment.

Unfortunately this is a relatively slow process, which can take weeks to produce a result. The longer it takes to identify the bacteria, the more time the infection has to grow and spread in the patient.

Breath analysis offers a faster, cheaper, non-invasive way to diagnose bacterial infections. The method has already been used in other research to diagnose asthma and lung cancer, with Richard Hubbard, professor of respiratory epidemiology at Nottingham City Hospital labelling breath analysis an”emerging field” which is “likely to take off across the board.”

In this new study, the scientists at the University of Vermont infected mice with two strains of bacteria that often cause lung infections – Pseudomonas aeruginosa and Staphylococcus aureus. They then waited 24 hours before sampling the mice’s breath and analysing the samples for volatile organic compounds (VOCs) normally produced by the bacterium.

A “statistically significant” difference was found in the levels of VOCs in the breath samples from infected mice, compared to those that were uninfected. It was also possible for the researchers to distinguish between two species of bacteria and two different strains of the same P. aeruginosa bacterium.

But the study’s co-author, Jane Hill, said there was still some way to go before “breath-prints” could become a standard diagnostic tool for lung infections, and that they were “collaborating with colleagues to sample patients in order to demonstrate the strengths, as well as limitations, of breath analysis more comprehensively.”

Professor Hubbard, a spokesman for the British Lung Foundation, said breath analysis was already being used to diagnose children with asthma and could potentially be useful for children with cystic fibrosis as well. The technique has also been used to identify conditions such as diabetes, rejection of transplanted organ, gastritis and fructose malabsorption.