Unlocking Health Secrets: What Body Odour Reveals About Your Health

The Extraordinary Sense: How Body Odour Could Predict Your Health

Imagine a world where a simple sniff could reveal a serious illness years before symptoms even appear. It sounds like science fiction, but for some, it's a profound reality. Our bodies are constantly emitting a complex array of chemical signals through our skin and breath. While often dismissed, these subtle odours can serve as early warnings, hinting at impending health challenges. This fascinating field of olfactory diagnostics is revolutionizing how we understand and detect disease, fundamentally changingwhat body odour reveals about your health.

The Astonishing Case of Joy Milne: A Super-Smeller's Discovery

The journey into this realm often begins with an anecdote that initially strains credulity. Analytical chemist Perdita Barran was understandably skeptical when a colleague recounted the tale of Joy Milne, a Scottish woman who claimed she could smell Parkinson's disease. Barran, then at the University of Edinburgh, remembers thinking, "She's probably just smelling old people and recognising symptoms...".

Joy Milne, a retired nurse, first noticed a distinct, musky scent from her husband, Les, years before his Parkinson's diagnosis. It wasn't until she attended a support group in Perth, Scotland, that a revelation struck: every patient in the room carried the same musky aroma. This extraordinary observation led her to neuroscientist Tilo Kunath.

To test her unique ability, Kunath, Barran, and their team conducted an experiment. Joy was asked to identify which of 12 T-shirts had been worn by Parkinson's patients. She correctly identified all six, plus an additional shirt from someone who, less than a year later, received a Parkinson's diagnosis. This "pre-diagnosis" was, as Barran puts it, "amazing," echoing Joy's earlier experience with her husband. News of her astounding talent made international headlines in 2015.

Joy Milne possesses hereditary hyperosmia, an exceptionally heightened sense of smell – a true "super-smeller." Her case underscores the potential hidden in our personal biochemistry.

Beyond the Extraordinary: Common Scents of Sickness

While Joy's ability is rare, some diseases produce such potent, characteristic odours that even the average nose can detect them. For instance:

Infectious diseases also leave their unique scent signatures. Cholera orClostridioides difficile(a common cause of diarrhoea) can result in sweet-smelling stool. Tuberculosis can make a person's breath smell like stale beer and their skin akin to wet brown cardboard and brine.

However, many disease-related odour changes are far too subtle for human detection, pointing to the need for advanced diagnostic tools.

Canine Companions and Robotic Noses: The Future of Olfactory Diagnostics

Dogs, with a sense of smell up to 100,000 times more acute than ours, have proven invaluable. They've been successfully trained to sniff out lung, breast, ovarian, bladder, and prostate cancers, often with remarkable accuracy (one study showed a 99% success rate for prostate cancer in urine samples). Dogs can also detect early signs of Parkinson's, diabetes, epileptic seizures, and malaria, purely by scent.

Yet, training requires time and specific canine aptitudes. This has spurred scientists to develop technological solutions that can mimic, or even surpass, natural olfactory capabilities.

Andreas Mershin, a physicist and co-founder of RealNose.ai, is developing a robotic nose for disease diagnosis. "It drives me mad that people are dying and we are putting needles up people's butts in order to find out if they have prostate cancer, when the signal is already outside and detectable by dogs," he states, emphasizing the urgency and potential of this technology.

Unpacking the Odorants: How Scientists Are Pinpointing Disease Markers

Scientists like Perdita Barran are bringing laboratory precision to this field. Her team, now at the University of Manchester, uses gas chromatography-mass spectrometry to analyze sebum—the oily substance on human skin—from Parkinson's patients. This technique separates and weighs compounds, precisely identifying the molecules present.

From approximately 25,000 compounds on human skin, about 3,000 are regulated differently in Parkinson's patients. Barran's team has narrowed this down to around 30 consistently different compounds, primarily lipids and long-chain fatty acids. This aligns with existing research suggesting abnormal lipid metabolism is a hallmark of Parkinson's. "What we have found is that the ability of cells to transport long-chain fatty acids into the mitochondria is impaired," Barran explains. "We know, therefore, that there are more of these lipids circulating around the body, and some of those are excreted through skin, and that's what we measure."

This breakthrough is leading to the development of a simple skin swab test for early Parkinson's detection, potentially cutting years off the current diagnostic timeline. "What we want is to have a very quick, non-invasive test that will allow someone to be triaged effectively," says Barran.

The Science Behind the Scent: Volatile Organic Compounds (VOCs)

So, why do diseases alter our body odour? The answer lies in volatile organic compounds (VOCs). Our bodies constantly convert food and drink into energy through metabolic processes within our cells' mitochondria. These reactions produce metabolites, some of which are volatile, meaning they readily evaporate at room temperature and can be detected by smell.

As Bruce Kimball, a chemical ecologist at the Monell Chemical Senses Centre, explains, "If you are suffering from an infection, or a disease, or an injury, it's logical that there's going to be an effect on your metabolism." This metabolic shift directly changes the VOCs produced, effectively altering our body's unique odour fingerprint. Kimball notes that it's "very rare that we don't see an ability to discriminate between healthy and whatever condition we're looking at."

Brain Injuries and Mosquito Lures: Diverse Applications of Olfactory Diagnostics

The implications extend far and wide. Kimball's team is developing a test for brain injuries in children who play contact sports. Their research showed traumatic brain injuries in mice produce a distinct smell, and specific ketones appear in human urine hours after a concussion. These ketones are thought to be a byproduct of the brain attempting to repair itself or seeking alternative energy sources for recovery.

In another groundbreaking study, scientists discovered that children infected with malaria emit a "fruity and grassy" skin odour, making them particularly attractive to mosquitoes. Identifying the aldehydes (heptanal, octanal, nonanal) responsible for this unique scent could lead to new malaria tests or even lures to trap mosquitoes, protecting communities.

Engineering a 'Robotic Nose' for Cancer Detection

Back at RealNose.ai, Andreas Mershin and his team are focused on prostate cancer, a disease that claims one in 44 men. Their device incorporates lab-grown human olfactory receptors, fine-tuned to detect the myriad odorant molecules associated with the cancer. Machine learning then identifies patterns in these activations, much like the human brain processes complex smells. "We're looking for patterns in sensory activation which is closer to what you do as a mind, as a brain," Mershin explains.

The Human Element: Joy Milne's Enduring Legacy

Today, Joy Milne works alongside Barran's research team, contributing her invaluable insights to develop diagnostic tests. While her direct odour detection work is limited due to its emotional toll, her initial observation remains the bedrock of this pioneering research. "She's 75, so she's precious," Barran notes, highlighting the respect for Joy's unique gift.

The collaboration between scientists and extraordinary individuals like Joy Milne is a testament to the power of observation. "What I think is remarkable is how Joy and Les were medically trained people, so they knew that this observation was meaningful," says Barran. This story empowers everyone to pay attention to their health and the health of loved ones, recognizing that sometimes, the most profound insights are right under our noses.

The ability to detect diseases early through something as simple as a skin swab, inspired by a "super-smeller," promises a future of non-invasive, accessible diagnostics. This revolution in understandingwhat body odour reveals about your healthis not just about scientific advancement; it's about saving lives and improving wellbeing for generations to come.