You’ve heard of genomics, proteomics and metabolomics. Next up is volatilomics, the study of Volatile Organic Compounds. Science is rife with acronyms – in some dark room a linguistic post-grad (LPG) is surely tapping out a vaporous thesis (VT) on acrynomics – and scientists refer to volatile organic compounds as VOC’s.
When most people think of VOCs they think of benzene or formaldehyde, toxins given off by paint, particle board and foam insulation, which can accumulate in our homes and create health problems. Not all VOC’s are toxic, however. We make VOC’s in our own bodies which are released into the air around us, producing an exometabolic profile in our immediate environment.
The VOC metabolic profile of an organism is referred to as its ‘volatilome’, and it can tell us volumes about its diet and its health, as well as the lotion it rubs on its skin.
You can change your volatilome with foods, and asparagus and coffee are the two best-known examples of this.
If you eat asparagus for dinner you will smell it when you pee next morning; a mix of methanethiol, S-methylthioacrylate, S-methyl-3-(methylthio)thiopropionate and related compounds (1, 2). These are metabolites of asparagusic acid, a sulphur compound used by asparagus plants to fight off nematode infections (3).
If you started the day with coffee, your next sample will smell like coffee because it will contain the coffee flavour compound 5-hydroxymethyl-2-furoic acid (4, 5). More sensitive noses may detect 4-hydroxy-2,5-dimethyl-3 (2H) furanone glucaronide after eating strawberries (6), and 1′-hydroxyestragole, 1′-hydroxyestragole glucuronide and p-allylphenol glucuronide after consuming fennel (7).
Other VOC’s are signposts for illness. Unsurprisingly, the urine of patients with maple syrup urine disease smells like maple syrup (8, 9). The urine of tyrosinemia patients smells rancid (9) the urine of individuals with trimethylaminuria has a fishy odor (9, 10), and uncontrolled diabetics produce urine with a sweet or fruity smell. Parkinsonian patients smell woody and musky (11). But our senses only go so far. Humans are not very good at smelling out disease.
You can most easily turn up the gain by switching from a human to a canine nose. Dr Dogg can diagnose bladder cancer (12, 13), and prostate cancer (14, 15) from urine samples, with high levels of accuracy. He can also diagnose colorectal cancer from stool samples (16) and lung cancer from breath samples (17).
In this last case Snoop’s accuracy was initially found to be lower (17), but when animal experts (as opposed to medics) examined the set-up, they found the dogs’ under-performance was due to inappropriate sampling techniques. Integrating correct sampling methods into the dogs’ training improved their hit rate significantly (18).
This makes dogs valuable diagnosticians, but there’s more …
Using VOC’s given off by skin, man’s best friend can diagnose skin cancers and distinguish between benign pigmented moles, basal cell cancer and melanoma (19). Dogs can even sniff out cancers deeper under the skin such as breast cancer (20), and their chemo-detective skills work on biopsy samples too (21).
Pet scans are still holding their own (22, 23), but not everybody likes a mutt and far more money can be made selling using lab equipment to scan and identify VOC’s. And to be fair, these systems have their strengths. They enable very high throughput screening, and they don’t need to be taken for walks.
e-Noses are currently being picked to study interstitial lung disease (24), cancers of the lung (25, 26), breast (27-29), prostate (30), kidney (31) and bladder (32), Alzheimer’s (33, 34), Parkinsonism (11, 35), and a wide range of infections (36).
Some think these approaches are sufficiently specific to be used as a stand-alone diagnostic (36, 37), others say we are not there yet (23); so in future we may see sniffer dogs and analytical technology integrated into bimodal bionic screening systems (ie 13, 38, 39). In the meantime, if your dog starts looking at you sideways, you may want to invite your neighbor’s dachshund in for a second opinion. Especially if you are one of those paranoid people who agonise over Covid.
It appears that many PCR tests for Covid have been deliberately manipulated to give false positive results, by using up to 40 replication cycles when most specialists agree that the cut-off should be between 30 to 35 cycles (40). The higher the number of cycles, the greater the risk of false positives. Go figure.
Dogs are harder to ‘adjust’ upwards in this way and are extremely good at detecting Covid in breath, saliva and sweat (41-45). In today’s heavily politicised situation I would rather put my faith in a dog than some pharma-paid dogsbody who might be financially motivated to bump case numbers up (46). I am referring here to administrators and political figures, not doctors.
A dog can screen up to 250 people an hour (47) and dog teams have been used successfully for airport screening with near 100% accuracy (48); making vaccine passports, as pushed by noted libertarian and former Stasi afficionada Frau Merkel, somewhat redundant. Angela’s murky background and manipulative nature is revealed in ‘The First Life of Angela M’ (49), which remained in Der Speigel’s bestseller list for 18 weeks yet for some reason does not exist on ebay or Amazon.
Other respiratory tract infections produce VOC’s too. eNose technology is being developed in this area (50) and may find an application in early screening for TB (51), which would be a boon in developing nations and, increasingly, our prison system (52).
The latest chapter in volatilomics is nutrivolatilomics.
I mentioned asparagus and coffee above, but this developing science uses e-Noses to monitor VOC’s produced in the body in minuscule amounts by a more extensive range of foods. This can be used for dietary monitoring. The first batch of test systems could tell, for example, if you had recently consumed cheese, milk or soy products (53-55).
This will be invaluable next time you meet a virtue-signalling Starbuck Millenial who claims they only eat plant foods. Take a small blood or urine sample when they are not looking, put it through a combination of dynamic headspace vacuum transfer In Trap extraction and gas chromatography coupled with mass spectrometry, and you will know within hours if they were telling the truth – or lying.
There is a slightly more substantial side to nutrivolatilomics.
As public health has gone so far downhill after the nutrition transition (56), scientists all over the world are conducting clinical trials of different dietary interventions in the hope of finding the combination to this global health lock.
They ask their trial subjects what they eat, they use food diaries, and they try to cross-reference dietary patterns with health outcomes.
Unfortunately, as Dr Gregory House explained, everybody – not just Millenials – lies. People are also forgetful, biased, skewed and hopelessly subjective, which is why lab rats are so much better than humans except for the minor detail that they are not human. Nutrivolatilomics provides a way of recording what people really eat, so that scientists can jump to more informed conclusions. The latest generation of e-Noses can measure the consumption not only of soy and dairy but also of fish, eggs, fruits, carotenoid-rich vegetables, tea … and the list is growing (57).
Most of this research, IMHO, soaks up time and resources that could be used to better effect elsewhere.
The modern diet kills us with a pathogenic combination of chronic inflammation, Type B malnutrition, dysbiosis and excess glycemic load. Neutralize these with the usual pharmaco-nutritional tools and you revert to pre-transitional health, cutting the risk of degenerative disease by up to 90% (58, 59).
The same principles, by the way, apply to your dog.
Next week: Food to die for from – and why we have to get back to the garden.
Image credit: Shutterstock
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