Di tutte le innumerevoli persone affette da sgradevole odore corporeo nel corso della storia, è difficile trovare un caso più estremo di quello dell'imperatore romano Galerio, che regnò dal 305 al 311.
Galerio era un monarca crudele che perseguitava i primi cristiani, e alcuni credevano che la punizione divina fosse stata inflitta su di lui sotto forma di una misteriosa malattia. Quell'afflizione fece marcire la sua carne e il suo intestino si riempì di vermi, così che trasudava "un fetore così pestifero, che nessun uomo poteva sopportarlo", come lo descrisse lo storico religioso John Foxe .
Alla fine, l'odore odoroso (e odoroso) dell'imperatore con riluttanza alleviò le sue persecuzioni, ma era troppo tardi. Morì subito dopo aver emesso il suo editto di tolleranza [fonte: Encyclopedia Britannica ]. Oggi, alcuni pensano che Galerio soffrisse di una condizione chiamata cancrena di Fournier, aggravata dal suo apparente diabete. Entrambi potrebbero aver contribuito al suo estremo odore corporeo, piuttosto che alla scarsa igiene personale.
L'odore corporeo generalmente inizia con la sudorazione, in particolare sotto le ascelle e l'inguine, che fornisce nutrimento ai batteri che a loro volta rilasciano prodotti di scarto dall'odore sgradevole. Nella maggior parte dei casi, il bagno regolare e l'uso di un deodorante o antitraspirante possono controllare il problema.
Ma a volte, ci sono altre cause dell'odore corporeo, come malattie, dieta e l'uso di determinati farmaci, che non hanno nulla a che fare con la sudorazione. Eccone 10.
- Carne rossa
- La mente
La trimetilaminuria è una rara malattia genetica in cui il corpo non è in grado di scomporre il composto chimico trimetilammina . Quest'ultimo è prodotto dai batteri nell'intestino durante la digestione delle proteine di uova, fegato, legumi come soia e piselli, alcune varietà di pesce e altri alimenti. Normalmente, un enzima scompone la trimetilammina, che ha un odore che è stato paragonato a pesce o uova in decomposizione, spazzatura o urina [fonte National Library of Medicine ].
Ma le persone con trimetilaminuria , a causa di una mutazione nel gene FM03, o non hanno la capacità di produrre l'enzima o ne producono troppo poco. In alcuni casi, anche le persone con il gene normale possono sviluppare un odore simile, a causa di un eccesso di proteine alimentari o di malattie epatiche o renali [fonte: National Library of Medicine ]. Il risultato è che i pazienti emanano un forte odore di pesce. Non esiste una cura per la trimetilaminuria, ma le persone potrebbero essere in grado di frenare l'odore evitando i prodotti elencati in precedenza e assumendo determinati integratori e antibiotici [fonte: NIH ].
Quello strano aroma che noti quando vai a trovare la tua prozia non proviene solo dalla naftalina o dai vecchi libri ammuffiti. I ricercatori del Monell Chemical Senses Center nel 2012 hanno scoperto che le persone anziane hanno effettivamente un odore caratteristico, che credono sia causato dai cambiamenti nelle ghiandole della pelle e dalle loro secrezioni quando invecchiamo.
L'odore di una persona anziana può essere una sorta di segnale chimico sviluppato durante l'evoluzione umana, che ci consente di distinguere tra individui più giovani e più forti in età riproduttiva e individui più anziani e meno sani che potrebbero essere partner meno desiderabili.
Tra i lati positivi , i tester dell'olfatto volontari hanno valutato l'odore degli uomini anziani come meno pungente e sgradevole dell'odore corporeo degli uomini di mezza età [fonte: Sifferlin ].
Stranamente, i contraccettivi orali possono alterare l'aroma delle donne che li assumono. Questo secondo uno studio sugli animali pubblicato nel 2010 sulla rivista scientifica, Proceedings of the Royal Society B. I ricercatori del Duke Lemur Center hanno studiato l'effetto del medrossiprogesterone acetato , solitamente noto con il suo marchio Depo-Provera, su 12 anelli di femmine adulte- lemuri dalla coda e ha scoperto che il contraccettivo alterava la composizione chimica delle secrezioni dalle aree genitali dei lemuri, rendendo il loro profumo meno attraente per i lemuri maschi [fonte: Bates ].
Does the same hold true for humans? People are known to send and receive olfactory cues about hormonal status, and the Duke researchers said more study would need to be done to see whether humans can detect whether someone is on birth control through scent.
Meanwhile a 2008 study showed that being on birth control pills can affect a woman's taste in men. Women were asked to smell T-shirts worn by men and pick the ones they were most attracted to. They overwhelmingly picked ones for men whose immune systems were different from theirs. From an evolutionary point of view, this is a good thing as it ensures a more diverse gene pool. However, when the women were on the birth control pill, they tended to pick men with similar immune systems. Could that mean that they might end up with the wrong man? [source: Nalls]
If you've ever eaten a spicy meal and then gone to the gym later in the day for a hard, sweaty workout, you may have noticed that other exercisers gave you a wide berth. It's not just because of your breath. Foods containing curry, garlic and various other spices are metabolized by your body to produce stinky chemicals such as sulfur , which ooze out of your pores to create a pungent body odor.
Some food ingredients such as capsaicin, the hot pepper used in Buffalo-style chicken wings , make matters worse by stimulating the nerve receptors in your mouth and tricking your nervous system into thinking that your body is outside in 90 degree F (32 degree C) heat, so that you start sweating more than usual [sources: Watson, Kosecki and Gelman]. So if you're going to indulge in a peppery, curry dish, you might want to go for a walk in the woods by yourself rather than hit the gym.
If untreated, various types of cancer can cause the development of necrotic lesions — that is, dead, rotting tissue — that give off a powerful odor. For instance, a man who suffered from an undiagnosed cancer in his penis developed such a powerful stink that his office colleagues refused to work with him – which was the only reason he sought medical help. His doctor hypothesized that some substance was being drawn from the necrotic lesion and released through the sweat glands [source: Liddell].
Another patient with psychosis had such a bad body odor that her psychiatrist could smell her even before she got to his office. "It turned out that this poor lady had advanced breast cancer , with a lesion that was eating through the breast and oozing foul-smelling necrotic gunk," the doctor wrote. "She was too psychotic to know what was happening." But after the psychiatrist got her to have cancer surgery and put her on antipsychotic medication, both the odor and her mental confusion subsided [source: Cohen].
Sometimes, diabetes can be a cause of body odor. When untreated, this disease can cause a condition called diabetic ketoacidosis. Without enough insulin to regulate the metabolism, the body starts to break down fat for fuel. This causes a sickeningly sweet aroma comparable to decomposing apples . It's most obvious on a person's breath, but it's also given off by the body as well [source: Liddell].
That's why when a patient seeks treatment for body odor, physicians may order blood or urine tests to determine if there is an underlying medical condition such as diabetes [source: Mayo Clinic].
4: Typhoid Fever
Do you smell baking? According to a 1976 medical journal article, patients afflicted with typhoid fever "emit a smell comparable to freshly baked brown bread " [source: Liddell]. That may actually sound kind of pleasant, but rest assured that typhoid fever is anything but.
Patients with this disease usually develop a sustained fever as high as 103 to 104 degrees F (39 to 40 degrees C), and suffer stomach pains and headaches, as well as weakness. In some cases, they also experience a rash of flat, rose-colored spots. About 21.5 million people die from typhoid fever each year, mostly in developing countries. It's spread by eating food or drinking water handled by someone who already has the disease and is shedding the Salmonella Typhi bacteria [source: CDC].
As we've mentioned before, infectious diseases often cause changes in body odor . But immunizations , interestingly, can have similar effects. In an animal study published in 2014 in the journal Physiology and Behavior, researchers from the Monell Chemical Senses Center and the U.S. Department of Agriculture demonstrated that immunization can trigger a distinct change in scent. Scientists believe that humans and other animals may give off "immune-activated odors" as a way of signaling to other members of their species that they have become infected with diseases. (This could also explain why certain diseases have specific odors).
Researchers found a pathway between immune activation and changes in body odor compounds, and believe that eventually, it may be possible for doctors to use odor to "eavesdrop" upon the immune system and make noninvasive diagnoses [source: ScienceDaily].
2: Red Meat
If you're thinking about trying a caveman-style "paleo " diet, in which you would eat a whole lot of meat and sharply cut your carbohydrates, you may want to consider the effect on your aroma. In a study published in the journal Chemical Senses in 2006, 17 male subjects ate a diet containing red meat for two weeks and sweated into pads, which a panel of women volunteers then sniffed to evaluate the aroma. The subjects then switched to a diet without red meat for a similar period, and were subjected to a second smell test for comparison.
The researchers reported that "the odor of donors when on the non-meat diet was judged as significantly more attractive, more pleasant, and less intense." Which implies that red meat consumption has an adverse impact upon one's scent [source: Havlicek and Lenochova].
1: The Mind
While your nose picks up the chemicals that create aromas, it's your brain that actually tells you what you smell. That's one reason that patients who suffer from Alzheimer's disease and other neurological disorders sometimes experience a loss of their olfactory abilities [source: Doty].
What's even more surprising, though, is that mental illness can make you believe that you smell terrible, even if you don't. Olfactory Reference Syndrome is a psychiatric disorder characterized by a false belief that you have a bad body odor. Eighty-five percent of people with the disease report that they actually can smell their own imaginary stink [source: Phillips and Menard].
Lots More Information
Author's Note: 10 Sources of Body Odor That Aren't Just Sweat
You may have heard this one already, but if not, there's the famous story about Samuel Johnson, the 18th-century British poet and essayist. On a summer day in London, he paused to sit down on a park bench because he was perspiring so heavily. A young woman next to him complained that he smelled. "No Madam," he replied. "You smell. I stink."
- How Body Odor Works
- What does a change in body odor mean?
- How do antiperspirants keep you from sweating?
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- Medscape. "Bromhidrosis." Medscape.com. (May 10, 2014) http://emedicine.medscape.com/article/1072342-overview
- Newitz, Annalee. "Birth control pills make females smell "wrong" to males." Io9.com. July 29, 2010. (May 10, 2014) http://io9.com/5599793/birth-control-pills-make-females-smell-wrong-to-males
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- Science Daily. "Body odor changes following vaccination." April 2, 2014. (May 10, 2014) http://www.sciencedaily.com/releases/2014/04/140402211946.htm
- Science News. "Lemurs on Contraceptives Don't Smell Right." July 28 2010. (May 14, 2014). http://www.americanscientist.org/science/pub/lemurs-on-contraceptives-dont-smell-right
- Sifferlin, Alexandra. "'Old-Person Smell' Really Exists, Scientists Say." Healthland.time.com. May 31, 2012. (May 10, 2014) http://healthland.time.com/2012/05/31/old-person-smell-really-exists-scientists-say/
- Watson, Stephanie. "Can What You Eat Make You Sweat?" WebMD. (May 10, 2014) http://www.webmd.com/skin-problems-and-treatments/features/what-you-eat