Our Smell, Our Ability to Smell, and the Detection of Serious Diseases

Can smell technologies help shine a light on the onset of specific diseases? Of the 10 leading causes of death in the United States, 6 can be detected through smell.

Which raises the question, how can we use of smell to monitor health? Dogs can sniff for explosives and illegal drugs; they can also be trained to sniff liver disease, diabetes and various forms of cancer. This is unsurprising as the smells of our illnesses emanate through our breath and the pores of our skin. However, it is not only our body odors that hold the key to detecting illnesses but also our ability to smell and detect certain odors. A decreased ability to smell, for example, can predict the onset of Alzheimer and Parkinson’s years in advance.

Smells of Disease

Clinical trials are being conducted across European hospitals to use a breathalyzer to identify specific odor compounds for early detection of lung cancer, by far the most common form of cancer in both men and women worldwide. Doctors are monitoring asthma, the most common chronic airway disease in the world, by a handheld detection device that was recently approved by the FDA. And almost a decade ago, researchers identified and quantified the compounds involved in skin cancer odors — possibly removing the need for intrusive biopsies to diagnose skin cancer in the future. What is currently widely being used in hospitals is the use of breath odor tests to test for lactose and fructose intolerances and intestinal bacteria.

Although there have been encouraging developments in smell detection technologies, most correlations between body odors and diseases have yet to hit practical applications. As mentioned above, many diseases have associated body odors; the deadliest of cancers all have distinct smells that can be detected by dogs. However the human nose can also detect certain odor-associated diseases; to our noses, liver disease smells like bleach, kidney failure smells like ammonia or slightly fishy, diabetes smells like rotten apples and diabetic ketoacidosis (an acute and deadly complication of diabetes) smells sweet and fruity. From deadly lung cancer to diabetes, millions of people in the US alone remain undiagnosed. Yet these diseases have distinct smells that, if monitored correctly, could diagnose at early stages and prevent many unnecessary deaths.

Ability to Smell and What it Signifies

Not only our body odors but also what and how we can smell can indicate a condition.

That gut feeling indicating that something may be wrong may be an olfactory warning signal at play. In today’s world, we rarely notice smells, as most act as subtle warning signals that can even provoke a behavioral response.

However, in the case of autism, this behavioral change does not always take place. According to Prof. Noam Sobel at Weizmann Institute of Science, “People instinctively take in a deep breath when smelling a pleasant smell and limit their breathing when they encounter a foul smell”. However, in the case of a child on the autism spectrum, it takes them much longer to stop inhaling a malodor — the length of time being directly related to the severity of the child’s impairment. This test has not hit the clinic yet but the hope is that it will be able to help diagnose infants as it is a non-verbal test that only requires breathing.

The University of Pennsylvania Smell Test (UPSIT), the gold standard for smell tests, used by one million people and counting, has developed a test for use in clinics as well as an at-home method for $27 USD. This easy to use and reliable scratch and sniff test can predict the onset of neurodegenerative diseases such as Alzheimer’s and Parkinson’s, years before other symptoms are noticeable by determining smelling ability and odor identification. This works because many central nervous system disorders originate in and around the olfactory regions and are thus associated with olfactory dysfunction, so by monitoring olfactory dysfunction, we are able to detect early onset of these diseases and their severity.

However, according to Prof. Doty, creator of the test, a large percentage of people only realise they are losing their sense of smell once having taken the test. It is to no surprise, given that as it remains our most invisible, undervalued sense and not part of our routine general health screening — our eyes and ears are checked, yet our ability to smell, an indicator of serious conditions, remains unmonitored.

Electronic Nose for Health Monitoring

A researcher at the Monell Chemical Senses Center points out that the most appealing targets for sniff tests are diseases for which there is no existing blood test or method of early detection, like ovarian cancer, which tends to be diagnosed when the disease has already advanced considerably. Dogs can sniff for ovarian cancer with 100% accuracy, but imagine if consumer devices could also detect illnesses in far less invasive ways than traditional blood tests, biopsies and X-rays. What if these devices were seamlessly integrated into our daily rituals? Who really wants to (or would remember to) routinely take an at-home diabetes test? But maybe, if it’s part of a morning teeth brushing ritual, part of “softer” data collection related to our body like PH levels, maybe then it would be more likely to be tested for on a routine basis.

Where do we even stand in electronic nose technologies? Industrial applications of gas chromatography-mass spectrometry (GCMS) are nothing new and have been used for quality control in the food and beverage industries, environmental monitoring and military applications. These industrial machines, however, have limited application in a clinical setting due to their expense, difficulty of use, and the need for highly experienced persons to operate and interpret their results. Thanks to advances in sensors, AI and increasing knowledge on how olfaction works, smaller, handheld and easier to use devices have become available. Such methods hold great potential being non-invasive and inexpensive and thus allowing screening of high-risk populations, early detection and prediction of diseases reducing mortality rate as well as monitoring therapy efficacy.

The Cyranose® 320, was one of the first handheld devices, sold for $8000 USD, developed out of California Institute of Technology in 2000. Given its relatively low cost, it has been extensively used in over one hundred breath diagnosis studies since then, accelerating the research into the potential of odor detection for health.

Most recently, Na-Nose, developed specifically for medical use, is on its way to commercialization. Developed out of the labs of Prof. Hossam Haick at Technion-Israel Institute of Technology, Na-Nose can detect up to 17 different and unrelated diseases from multiple sclerosis to chicken pox and cancers.

Also of note is NeOse, by the French startup Arabelle Technologies, that is available for order from this June, appeared at CES this year with an electronic nose, that can identify up to 350 different smells in 15 seconds. Excitingly, they are also looking to one day make their core sensor available for third-party devices. This could lead to an increase in such a technology’s applications in consumer wearable technologies.

But some are already almost there as Raed Dweik M.D. at the Cleveland Clinic’s Respiratory Institute who is working on a sensor that can be attached to the iPhone to detect asthma, monitor the effects of medication, and give advance warning of asthma attacks.

As explored, both our body odors and our ability to smell can indicate the onset of diseases such as cancer and neurodegenerative diseases.

Furthermore, there have been technological advancements in electronic nose technology, which in the near future could become available to consumers, thus potentially making smell central to early stage diagnosis of diseases in clinics and households alike.

Now it’s a matter of creating the right user experience to manage, detect and account for the emotional discomfort when detecting possible diseases through wearables and in-home devices. Designers will play an integral role in the creating the user experience for consumers who could potentially be receiving devastating news from these technologies.

Cross collaboration between the fields of healthcare, technology and design with regards to smell technologies will enable us to shine a light and detect the onset of disease early enough to guard against it. Incorporating this into our daily lives is the next challenge. In an instantaneous society, the idea of planning for our future selves seems difficult — even too far-fetched — but if it comes to our health, maybe we will give it a try?

Our sense of smell, scent, tech and humanness. Find me on Instagram @futureofsmell.

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