Body odor
[3] In humans, the formation of body odors is caused by factors such as diet, sex, health, and medication, but the major contribution comes from bacterial activity on skin gland secretions.
The genital and armpit regions also contain springy hairs which help diffuse body odors.
[7] Body odor is influenced by the actions of the skin flora, including members of Corynebacterium, which manufacture enzymes called lipases that break down the lipids in sweat to create smaller molecules like butyric acid.
For other predators, such as those that hunt by visually locating prey and running for long distances after it (such as dogs and wolves), the absence of body odor is not critical.
[15] In humans, body odor serves as a means of chemosensory signal communication between members of the species.
[1] Compared to other primates, humans have extensive axillary hair and have many odor producing sources, in particular many apocrine glands.
Using a brain-imaging technique, Swedish researchers have shown that homosexual and heterosexual males' brains respond in different ways to two odors that may be involved in sexual arousal, and that homosexual men respond in the same way as heterosexual women, though it could not be determined whether this was cause or effect.
Preadolescent children can olfactorily detect their full siblings, but not half-siblings or step-siblings, and this might explain incest avoidance and the Westermarck effect.
[27] Beyond a biological function, a mother's body odor plays a role in developing a baby's social capabilities.
[26] This type of connection is only found between mothers and babies and over time it socializes the ability to recognize the features that distinguish human faces from inanimate objects.
This is in part due to a reduction of the size of the snout in order to achieve depth perception as well as other changes related to bipedalism.
[citation needed] Experiments on animals and volunteers have shown that potential sexual partners tend to be perceived more attractive if their MHC composition is substantially different.
[6] The lack of ABCC11 function results in a decrease of the odorant compounds 3M2H, HMHA, and 3M3SH via a strongly reduced secretion of the precursor amino-acid conjugates 3M2H–Gln, HMHA–Gln, and Cys–Gly–(S) 3M3SH; and a decrease of the odoriferous steroids androstenone and androstenol, possibly due to the reduced secretion of dehydroepiandrosterone sulfate (DHEAS) and dehydroepiandrosterone (DHEA), possibly bacterial substrates for odoriferous steroids; research has found no difference, however, in testosterone secretion in apocrine sweat between ABCC11 mutants and non-mutants.
[6][31][33] The reduction in body odor may be due to adaptation to colder climates by their ancient Northeast Asian ancestors.
[35] One large study failed to find any significant differences across ethnicity in residual compounds on the skin, including those located in sweat.
[36] If there were observed ethnic variants in skin odor, one would find sources to be much more likely in diet, hygiene, microbiome, and other environmental factors.
[37][35][38] Research has indicated a strong association between people with axillary osmidrosis and the ABCC11-genotypes GG or GA at the SNP site (rs17822931) in comparison to the genotype AA.
[39] Another study evaluated the components of body odor in participants aged 26 through 75 using headspace gas chromatography and mass spectroscopy.
The detection of increasing amounts of 2-Nonenal in individuals 40 years or older suggested that 2-Nonenal contributes to the deteriorating body odor seen with aging.
One's body odor is completely unique to themselves, similar to a fingerprint, and can change due to sexual life, genetics, age and diet.
[42] Therefore, if a person's body odor or urine smells unusually fruity or sweet, that can be a sign of diabetes.
of 3M3SH (μmol/2 pads) * ND indicates that no detectable peak is found on the [M+H]+ ion trace of the selected analyte at the correct retention time.
Body odor may be reduced or prevented or even aggravated by using deodorants, antiperspirants, disinfectants, underarm liners, triclosan, special soaps or foams with antiseptic plant extracts such as ribwort and liquorice, chlorophyllin ointments and sprays topically, and chlorophyllin supplements internally.
Although body odor is commonly associated with hygiene practices, its presentation can be affected by changes in diet as well as the other factors.
[47] Skin spectrophotometry analysis found that males who consumed more fruits and vegetables were significantly associated with more pleasant smelling sweat, which was described as "floral, fruity, sweet and medicinal qualities".
[51] Osmidrosis or bromhidrosis is defined by a foul odor due to a water-rich environment that supports bacteria, which is caused by an abnormal increase in perspiration (hyperhidrosis).
[52][53] If body odor is affecting a person’s quality of life, then seeing a primary care physician may be helpful.
If someone is experiencing severe body odor, a doctor may recommend a surgical procedure called endoscopic thoracic sympathectomy.
[58] Alicja Janosz, the winner of Polish Idol season 1, is said to have a strong, but attractive, body odor.
She met her husband while competing on World Idol when the odor caused him to instantly fall in love.
