WHEN Dr. Mel Rosenberg, professor of microbiology and co-founder of the International Society for Breath Odour Research, declared that bad breath is mostly caused by bacteria build-up on the back of the tongue where postnasal drip collects, many dentists were surprised for various reasons. However, I believe we were all shocked to learn that the ultimate non-invasive medical test indicates that a number of health problems can actually be diagnosed by analysing a patient’s breath alone.

For centuries, doctors noticed that patients with liver and kidney disorders had distinctive smells on their breath. In fact, Hippocrates, who is known as the Father of Medicine, wrote a treatise on breath aroma and disease around 400BC. Today, scientists are identifying thousands of chemical compounds that create those telltale odours. For example, nitrous oxide levels rise in the breath of someone suffering from asthma, and there is elevated hydrogen in those with irritable bowel syndrome. And the list goes on.
Anything you can have a blood test for, there is potentially a breath test for, as long as there is a volatile compound. Tools called mass spectrometers can detect them in quantities as minute as parts-per-trillion, the equivalent of finding a single table tennis ball in a thousand football fields filled with table tennis balls.
Presently, researchers are working on developing breath analyser tests that can diagnose and monitor liver, kidney, asthma, diabetes, tuberculosis and gastrointestinal infections, and even the rejection of transplanted organs.
So, your breath odour is not only important to dentists; the clues that come out of your mouth can even be more specific than blood tests. For instance, there are recent reports from Colorado and Israel that prove that breath analysis could distinguish between benign (harmless) and malignant (lethal) pulmonary nodules in a group of 72 patients with an 88 per cent accuracy; the test could also assess the specific type and stage of lung cancers.
You see, every individual has a unique breath signature – like a fingerprint – that contains not only oxygen, nitrogen and carbon dioxide, but also volatile organic compounds (like garlic or alcohol, if we consume them). In addition, there are those chemicals from inside and outside the body that evaporate at room temperature, and are the source of most breath odours. For example, there are microscopic droplets of proteins, antibodies and DNA (genetic material which contain a wealth of health information). Incidentally, exhaled breath also contains a host of ‘confounders’ inhaled from the ambient air. These include smoke, molecules of pollution, paint, medications, etc. These can all affect the breath signature.
Breath tests are painless, faster to return results, and potentially less expensive than blood tests. Also, they are easy to repeat as often as needed. However, many of these breath tests are still in the research stage, and need to be standardised and validated in large clinical trials before they will be ready for use in doctors’ offices. Meanwhile, scientists are still cataloguing the thousands of different molecules in exhaled breath, and determining what concentrations are normal, and what indicate health problems.
Notwithstanding the relative simplicity with which this innovative medical device can improve our lives, it comes with enormous implications. There are hundreds of companies that manufacture the reagents (chemicals that are used in the laboratories to analyse blood, urine, faeces, etc.) which give us the results for our usual diagnostic lab tests. What will be the future of these? Obviously, the majority will become immediately redundant.
And what will happen to the thousands of factories, equipment and the millions of persons who work in that industry? Conventional lab tests may eventually become obsolete.  Clearly, the thousands of medical and allied training institutions will be obligated to modify their curricula to accommodate this revolutionary method. One would be naïve to believe that all this could happen without a stubborn resistance.
But despite all considerations, it seems that sceientists are clearly aiming for the Star Trek Tricorder concept, where you would breathe into a device, and a sign would pop up saying what health problems you have. Recently, a research update was published about a portable paediatric asthma monitor. The cell-phone-like gadget has a tube that children could breathe into during the day; it would analyse the level of nitric oxide in their breath, an indicator of inflammation, and transmit the data to their doctors to aid in fine-tuning their medication. So, it may not be too long before there is intense competition between us dentists and the physicians to have access to your mouths.