A few weeks ago I stumbled upon a two-sentence blurb in a pediatric newsletter summarizing the results of a study comparing the chemical profile of infant body odor with that of postpubertal adolescents. The investigators found that, not surprisingly, the smell of the chemical constituents wafting from babies was more appealing than that emanating from sweaty teenagers. I quickly moved on to the next blurb hoping to find something I hadn’t already experienced or figured out on my own.
But, as I navigated through the rest of my day filled with pickleball, bicycling, and the smell of home-cooked food, something about that study of body odor nagged at me. Who had funded that voyage into the obvious? Were my tax dollars involved? Had I been duped by some alleged nonprofit that had promised my donation would save lives or at least ameliorate suffering? Finally, as the sun dipped below the horizon, my curiosity got the best of me and I searched out the original study. Within minutes I fell down a rabbit hole into the cavernous world of odor science.
Dr. William G. Wilkoff
Having had zero experience in this niche field, I was amazed at the lengths to which these German odor investigators had gone to analyze the chemicals on and around their subjects. Just trying to ensure that materials and microclimates in the experimental environment were scent-free was a heroic effort. There was “Mono-trap sampling of volatiles, followed by thermodesorption-comprehensive gas chromatography, and time of flight-mass spectrometry analysis.” There were graphs and charts galore. This is serious science, folks. However, they still use the abbreviation “BO” freely, just as I learned to do in junior high. And, in some situations, the investigators relied on the observation of a panel of trained human sniffers to assess the detection threshold and the degree of pleasantness.
Ultimately, the authors’ conclusion was “sexual maturation coincides with changes in body odor chemical composition. Whether those changes explain differences in parental olfactory perception needs to be determined in future studies.” Again, no surprises here.
Exhausted by my venture into the realm of odor science, I finally found the answer to my burning question. The study was supported by the German Research Foundation and the European Union. Phew! Not on my nickel.
Lest you think that I believe any investigation into the potential role of smell in our health and well-being is pure bunk, let me make it clear that I think the role of odor detection is one of the least well-studied and potentially most valuable areas of medical research. Having had one family tell me that their black lab had twice successfully “diagnosed” their pre-verbal child’s ear infection (which I confirmed with an otoscope and the tympanic membrane was intact) I have been keenly interested in the role of animal-assisted diagnosis.
If you also have wondered whether you could write off your pedigreed Portuguese Water Dog as an office expense, I would direct you to an article titled “Canine olfactory detection and its relevance to medical detection.” The authors note that there is some evidence of dogs successfully alerting physicians to Parkinson’s disease, some cancers, malaria, and COVID-19, among others. However, they caution that the reliability is, in most cases, not of a quality that would be helpful on a larger scale.
I can understand the reasons for their caution. However, from my own personal experience, I am completely confident that I can diagnose strep throat by smell, sometimes simply on opening the examination room door. My false-positive rate over 40 years of practice is zero. Of course I still test and, not surprisingly, my false-negative rate is nothing to brag about. However, if a dog can produce even close to my zero false negative with a given disease, that information is valuable and suggests that we should be pointing the odor investigators and their tool box of skills in that direction. I’m pretty sure we don’t need them to dig much deeper into why babies smell better than teenagers.
Dr. Wilkoff practiced primary care pediatrics in Brunswick, Maine, for nearly 40 years. He has authored several books on behavioral pediatrics, including “How to Say No to Your Toddler.” Other than a Littman stethoscope he accepted as a first-year medical student in 1966, Dr. Wilkoff reports having nothing to disclose. Email him at pdnews@mdedge.com.