Body odor

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Body odor or body odour (BO) is present in all animals and its intensity can be influenced by many factors (behavioral patterns, survival strategies). Body odor has a strong genetic basis, but can also be strongly influenced by various factors, such as sex, diet, health, and medication. [1] The body odor of human males plays an important role in human sexual attraction, as a powerful indicator of MHC/HLA heterozygosity. [2] [1] Significant evidence suggests that women are attracted to men whose body odor is different from theirs, indicating that they have immune genes that are different from their own, which may produce healthier offspring. [3]

Contents

Causes

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. [1] Humans have three types of sweat glands: eccrine sweat glands, apocrine sweat glands and sebaceous glands. Eccrine sweat glands are present from birth, while the latter two become activated during puberty. Among the different types of human skin glands, body odor is primarily the result of the apocrine sweat glands, which secrete the majority of chemical compounds that the skin flora metabolize into odorant substances. [1] This happens mostly in the axillary (armpit) region, although the gland can also be found in the areola, anogenital region, and around the navel. [4] In humans, the armpit regions seem more important than the genital region for body odor, which may be related to human bipedalism. The genital and armpit regions also contain springy hairs which help diffuse body odors. [5]

The main components of human axillary odor are unsaturated or hydroxylated branched fatty acids with E-3-methylhex-2-enoic acid (E-3M2H) and 3-hydroxy-3-methylhexanoic acid (HMHA), sulfanylalkanols and particularly 3-methyl-3-sulfanylhexan-1-ol (3M3SH), and the odoriferous steroids androstenone (5α-androst-16-en-3-one) and androstenol (5α-androst-16-en-3α-ol). [6] E-3M2H is bound and carried by two apocrine secretion odor-binding proteins, ASOB1 and ASOB2, to the skin surface. [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. Greater bacteria populations of Corynebacterium jeikeium are found more in the armpits of men, whereas greater population numbers of Staphylococcus haemolyticus are found in the armpits of women. This causes male armpits to give off a rancid/cheese-like smell, whereas female armpits give off a more fruity/onion-like smell. [8] Staphylococcus hominis is also known for producing thioalcohol compounds that contribute to odors. [9] These smaller molecules smell, and give body odor its characteristic aroma. [10] Propionic acid (propanoic acid) is present in many sweat samples. This acid is a breakdown product of some amino acids by propionibacteria, which thrive in the ducts of adolescent and adult sebaceous glands. Because propionic acid is chemically similar to acetic acid, with similar characteristics including odor, body odors may be identified as having a pungent, cheesy and vinegar-like smell although certain people might find it pleasant at lower concentrations. [11] Isovaleric acid (3-methyl butanoic acid) is the other source of body odor as a result of actions of the bacteria Staphylococcus epidermidis , [12] which is also present in several types of strong cheese.

Factors such as food, drink, gut microbiome, [13] and genetics can affect body odor. [5]

Function

Animals

In many animals, body odor plays an important survival function. Strong body odor can be a warning signal for predators to stay away (such as porcupine stink), or it can also be a signal that the prey animal is unpalatable. [14] For example, some animal species that feign death to survive (like opossums), in this state produce a strong body odor to deceive a predator that the prey animal has been dead for a long time and is already in the advanced stage of decomposing. Some animals with strong body odor are rarely attacked by most predators, although they can still be killed and eaten by birds of prey, which are tolerant of carrion odors.[ citation needed ]

Body odor is an important feature of animal physiology. It plays a different role in different animal species. For example, in some predator species that hunt by stalking (such as big and small cats), the absence of body odor is important, and they spend plenty of time and energy to keep their body free of odor. 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. In most animals, body odor intensifies in moments of stress and danger. [15]

Humans

In humans, body odor serves as a means of chemosensory signal communication between members of the species. These signals are called pheromones and they can be transmitted through a variety of mediums. The most common way that human pheromones are transmitted is through bodily fluids. Human pheromones are contained in sweat, semen, vaginal secretions, breast milk, and urine. [1] The signals carried in these fluids serve a range of functions from reproductive signaling to infant socialization. [16] Each person produces a unique spread of pheromones that can be identified by others. [2] This differentiation allows the formation of sexual attraction and kinship ties to occur. [2] [17]

Sebaceous and apocrine glands become active at puberty. This, as well as many apocrine glands being close to the sex organs, points to a role related to mating. [5] Sebaceous glands line the human skin while apocrine glands are located around body hairs. [1] Compared to other primates, humans have extensive axillary hair and have many odor producing sources, in particular many apocrine glands. [18] In humans, the apocrine glands have the ability to secrete pheromones. These steroid compounds are produced within the peroxisomes of the apocrine glands by enzymes such as mevalonate kinases. [19]

Sexual selection

Pheromones are a factor seen in the mating selection and reproduction in humans. In women, the sense of olfaction is strongest around the time of ovulation, significantly stronger than during other phases of the menstrual cycle and also stronger than the sense in males. [20] [21] Pheromones can be used to deliver information about the major histocompatibility complex (MHC). [2] The MHC in humans is referred to as the Human Leukocyte Antigen (HLA). [22] Each type has a unique scent profile that can be utilized during the mating selection process. When selecting mates, women tend to be attracted to those that have different HLA-types than their own. [2] [22] This is thought to increase the strength of the family unit and increase the chances of survival for potential offspring. [2]

Studies have suggested that people might be using odor cues associated with the immune system to select mates. 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. When the study was expanded to include lesbian women, the results were consistent with previous findings – meaning that lesbian women were not as responsive to male-identified odors, while responding to female odors in a similar way as heterosexual males. [23] According to the researchers, this research suggests a possible role for human pheromones in the biological basis of sexual orientation. [24]

Furthermore, recent advances in technology, such as the use of electronic noses, have expanded our understanding of how odor influences sexual selection. A study from Airlangga University demonstrated that electronic noses could classify human gender with high accuracy by analyzing sweat odors, showing that sweat contains distinct chemical components that differ between genders. This discovery not only enhances our understanding of the role of scent in human interactions but also opens up potential applications in fields like biometric identification and personalized product development. The ability of electronic noses to detect and classify these subtle chemical signals could eventually lead to new insights into the role of odor in sexual selection and attraction, reinforcing the idea that human scent plays a crucial role in reproductive success and mate selection. [25]

Kinship communication

Humans can olfactorily detect blood-related kin. [17] Mothers can identify by body odor their biological children, but not their stepchildren. 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. [26] Babies can recognize their mothers by smell while mothers, fathers, and other relatives can identify a baby by smell. [5] This connection between genetically similar family members is due to the habituation of familial pheromones. In the case of babies and mothers, this chemosensory information is primarily contained within breastmilk and the mother's sweat. When compared to that of strangers, babies are observed to have stronger neural connections with their mothers. [27] This strengthened neurological connection allows for the biological development and socialization of the infant by their mother. Using these connections, the mother transmits olfactory signals to the infant which are then perceived and integrated. [27]

In terms of biological functioning, olfactory signaling allows for functional breastfeeding to occur. In cases of effective latching, breastfed infants are able to locate their mother's nipples for feeding using the sensory information enclosed in their mother's body odor. [28] While no specific human breast pheromones have been identified, studies compare the communication to that of the rabbit mammary pheromone 2MB2. [29] [30] The perception and integration of these signals is an evolutionary response that allows newborns to locate their source of nutrition. Signaling contains a level of precision that allows babies to differentiate their mother's breasts from that of other women. Once the baby recognizes the familiar olfactory signal, the behavioral response of latching follows. Over time the infant becomes habituated to their mother's breast pheromones which increases latch efficiency. [28]

Beyond a biological function, a mother's body odor plays a role in developing a baby's social capabilities. The ability of an infant to evaluate the properties of human faces stems from the olfactory cues given from their mother. [16] Frequent exposure to the pheromones exuded by their mother allows the connection between vision and smell to form in infants. [27] 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. [16]

Environmental threats

The connection between olfactory and visual cues has also been observed outside of familial relationships. Evolutionarily, body odor has been used to communicate messages about potentially dangerous stimuli in the environment. [1] Body odor produced during particularly stressful situations can produce a cascade of reactions in the brain. Once the olfactory system is activated by a threatening stimuli, heightened activity in the amygdala and occipital cortex is triggered. [31] [1] This chain reaction serves to help assess the nature of the threat and increase chance of survival.

Humans have few olfactory receptor cells compared to dogs and few functional olfactory receptor genes compared to rats. 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. However, it has been argued that humans may have larger brain areas associated with olfactory perception compared to other species. [18]

Genes affecting body odor

World map of the distribution of the A allele of the single nucleotide polymorphism rs17822931 in the ABCC11 gene. The proportion of A alleles in each population is represented by the white area in each circle. World map ABCC11 A Allele.svg
World map of the distribution of the A allele of the single nucleotide polymorphism rs17822931 in the ABCC11 gene. The proportion of A alleles in each population is represented by the white area in each circle.

MHC

Body odor is influenced by major histocompatibility complex (MHC) molecules. These are genetically determined and play an important role in immunity of the organism. The vomeronasal organ contains cells sensitive to MHC molecules in a genotype-specific way.[ 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. Married couples are more different regarding MHC genes than would be expected by chance. This behavior pattern promotes variability of the immune system of individuals in the population, thus making the population more robust against new diseases. Another reason may be to prevent inbreeding. [5]

ABCC11

The ABCC11 gene determines axillary body odor and the type of earwax. [6] [32] [33] [34] The loss of a functional ABCC11 gene is caused by a 538G>A single-nucleotide polymorphism, resulting in a loss of body odor in people who are specifically homozygous for it. [34] [35] Firstly, it affects apocrine sweat glands by reducing secretion of odorous molecules and its precursors. [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] Secondly, it is also associated with a strongly reduced/atrophic size of apocrine sweat glands and a decreased protein (such as ASOB2) concentration in axillary sweat. [6]

The non-functional ABCC11 allele is predominant among East Asians (80–95%), but very low among European and African populations (0–3%). [6] Most of the world's population has the gene that codes for the wet-type earwax and average body odor; however, East Asians are more likely to inherit the allele associated with the dry-type earwax and a reduction in body odor. [6] [32] [34] The reduction in body odor may be due to adaptation to colder climates by their ancient Northeast Asian ancestors. [32]

However, research has observed that this allele is not solely responsible for ethnic differences in scent. A 2016 study analyzed differences across ethnicities in volatile organic compounds (VOCs), across racial groups and found that while they largely did not differ significantly qualitatively, they did differ quantitatively. Of the observed differences, they were found to vary with ethnic origin, but not entirely with ABCC11 genotype. [36]

One large study failed to find any significant differences across ethnicity in residual compounds on the skin, including those located in sweat. [37] 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. [38] [36] [39]

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. [34]

Age-Related Differences

As seen in non-human animals such as mice, black-tailed deer, rabbits, otters, and owl monkeys, body odor contains age-related signals that these animals can detect and process. Similarly, humans have been seen to distinguish age-related information from body odor, particularly relating to odors of those of old age. In a study determining if there is a difference between the body odor of individuals of various ages, three groups were studied: those aged 20-30, aged 45-55, and aged 75-95, corresponding to young age, middle-aged, and old age, respectively. This study determined that individuals could distinguish between odors of various ages and group odors of old age, suggesting that there are certain chemical differences in age resulting in “age-dependent odor characteristics”. [40]

Another study evaluated the components of body odor in participants aged 26 through 75 using headspace gas chromatography and mass spectroscopy. This study demonstrated that in individuals 40 years or older, 2-Nonenal, an unsaturated aldehyde producing a greasy and grassy odor, was detected in increasing concentrations of those individuals. 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. [41]

Body Odor and Disease

In mammals, body odor can also be used as a symptom of disease. One's body odor is completely unique to themselves, similar to a fingerprint, and can change due to sexual life, genetics, age and diet. Body odor, however, can be used as an indication for disease. For example, typically, human urine contains 95% water, [42] however, for a person with an abnormal amount of blood sugar, their urine becomes more concentrated with glucose. [43] Therefore, if a person's body odor or urine smells unusually fruity or sweet, that can be a sign of diabetes. Additionally, an ammonia smell that occurs in one's body, urine, or breath could also be an indicator of kidney disease. Typically, the liver converts ammonia to urea because ammonia has a high level of toxicity. The kidneys are responsible for removing waste, such as urea, out from the body. However, if the kidneys are not functioning properly, this urea is kept as ammonia, causing the urine and even one's breath to smell like ammonia. [44] In conclusion, body odor could be used as a helpful indicator of disease, especially when it suddenly deviates from normal.


Frequencies of ABCC11 allele c.538 (One nonsynonymous SNP 538G > A) [45] [46]
Ethnic groupsTribes or inhabitantsAAGAGG
Korean Daegu city inhabitants100%0%0%
Chinese Northern and southern Han Chinese80.8%19.2%0%
Mongolian Khalkha tribe75.9%21.7%2.4%
Japanese Nagasaki people69%27.8%3.2%
Thai Central Thai in Bangkok63.3%20.4%16.3%
Vietnamese People from multiple regions53.6%39.2%7.2%
Dravidian Inhabitants of southern India54.0%17%29%
Native American 30%40%30%
Filipino Palawan22.9%47.9%29.2%
Kazakh 20%36.743.3%
Russian 4.5%40.2%55.3%
White Americans From CEPH families without the French and Venezuelans1.2%19.5%79.3%
African From various sub-Saharan nations0%8.3%91.7%
African Americans 0%0%100%
Amino-acid conjugates of key human body odorants in sweat samples of panelists with different genotypes, determined by liquid chromatography-mass spectrometry [47]
Genotype
ABCC11		SexEthnic populationAgeNet weight
sweat (g)/2 pads		HMHA–Gln
(μmol/2 pads)		3M2H–Gln
(μmol/2 pads)		Cys–Gly conjugate

of 3M3SH (μmol/2 pads)

AAFChinese272.05ND'NDND
AAFFilipino332.02NDNDND
AAFKorean351.11NDNDND
GAFFilipino311.471.230.17Detectable, < 0.03 μmol
GAFThai250.900.890.14Detectable, < 0.03 μmol
GAFGerman251.640.540.10Detectable, < 0.03 μmol
GGFFilipino451.740.770.13Detectable, < 0.03 μmol
GGFGerman280.711.300.190.041
GGFGerman331.231.120.160.038

* ND indicates that no detectable peak is found on the [M+H]+ ion trace of the selected analyte at the correct retention time.
* HMHA: 3-hydroxy-3-methyl-hexanoic acid; 3M2H: (E)-3-methyl-2-hexenoic acid; 3M3SH: 3-methyl-3-sulfanylhexan-1-ol.

Alterations

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. [48] 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". [49]

Industry

As many as 90% of Americans and 92% of teenagers use antiperspirants or deodorants. [50] [51] In 2014, the global market for deodorants was estimated at US$13 billion with a compound annual growth rate of 5.62% between 2015 and 2020. [52]

Medical conditions

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). [33] This can be particularly strong when it happens in the axillary region (underarms). In this case, the condition may be referred to as axillary osmidrosis. [33] The condition can also be known medically as apocrine bromhidrosis, ozochrotia, fetid sweat, body smell, or malodorous sweating. [53] [54]

Treatment

If body odor is affecting a person’s quality of life, then seeing a primary care physician may be helpful. A doctor could recommend prescription antiperspirants containing aluminum-chloride. [55] This chemical agent helps temporarily block sweat pores which reduces the amount a person will sweat. Deodorant is another remedy for body odor. It specifically targets odor but will not reduce sweat. Deodorants are usually alcohol-based which fights off bacteria. [56] Most deodorants contain perfumes which also help with masking odor. If someone is experiencing severe body odor, a doctor may recommend a surgical procedure called endoscopic thoracic sympathectomy. [57] This surgery will cut nerves that control sweating. This surgery poses the risk of harming other nerves in the body.

Prevention

There are a number of ways to prevent body odor. These suggestions may help with those suffering from body odor. Bathing daily with antibacterial soap helps reduce the amount of bacteria found on the skin. [58] This is especially important after doing any type of physical activity. Shaving armpit hair allows for sweat to evaporate more quickly so it won’t produce an odor. Applying deodorant or antiperspirant after showering which helps kill bacteria and prevent someone from sweating is helpful. Wearing fresh and clean clothes is also very important especially if you sweat a lot.


Trimethylaminuria (TMAU), also known as fish odor syndrome or fish malodor syndrome, is a rare metabolic disorder where trimethylamine is released in the person's sweat, urine, and breath, giving off a strong fishy odor or strong body odor. [59]

See also

Related Research Articles

<span class="mw-page-title-main">Perspiration</span> Fluid secreted from sudoriferous glands

Perspiration, also known as sweat, is the fluid secreted by sweat glands in the skin of mammals.

<span class="mw-page-title-main">Pheromone</span> Secreted or excreted chemical factor that triggers a social response in members of the same species

A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavior of the receiving individuals. There are alarm pheromones, food trail pheromones, sex pheromones, and many others that affect behavior or physiology. Pheromones are used by many organisms, from basic unicellular prokaryotes to complex multicellular eukaryotes. Their use among insects has been particularly well documented. In addition, some vertebrates, plants and ciliates communicate by using pheromones. The ecological functions and evolution of pheromones are a major topic of research in the field of chemical ecology.

A deodorant is a substance applied to the body to prevent or mask body odor caused by bacterial breakdown of perspiration, for example in the armpits, groin, or feet. A subclass of deodorants, called antiperspirants, prevents sweating itself, typically by blocking sweat glands. Antiperspirants are used on a wider range of body parts, at any place where sweat would be inconvenient or unsafe, since unwanted sweating can interfere with comfort, vision, and grip. Other types of deodorant allow sweating but prevent bacterial action on sweat, since human sweat only has a noticeable smell when it is decomposed by bacteria.

<span class="mw-page-title-main">Sebaceous gland</span> Gland to lubricate the hair and skin

A sebaceous gland or oil gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest number on the face and scalp, but also on all parts of the skin except the palms of the hands and soles of the feet. In the eyelids, meibomian glands, also called tarsal glands, are a type of sebaceous gland that secrete a special type of sebum into tears. Surrounding the female nipples, areolar glands are specialized sebaceous glands for lubricating the nipples. Fordyce spots are benign, visible, sebaceous glands found usually on the lips, gums and inner cheeks, and genitals.

<span class="mw-page-title-main">Axilla</span> Area of the human body beneath the joint between arm and torso

The axilla is the area on the human body directly under the shoulder joint. It includes the axillary space, an anatomical space within the shoulder girdle between the arm and the thoracic cage, bounded superiorly by the imaginary plane between the superior borders of the first rib, clavicle and scapula, medially by the serratus anterior muscle and thoracolumbar fascia, anteriorly by the pectoral muscles and posteriorly by the subscapularis, teres major and latissimus dorsi muscle.

Underarm hair, also known as axillary hair or armpit hair, is the hair in the underarm area (axilla).

<span class="mw-page-title-main">Sweat gland</span> Small sweat-producing tubular skin structures

Sweat glands, also known as sudoriferous or sudoriparous glands, from Latin sudor 'sweat', are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial surface by way of a duct. There are two main types of sweat glands that differ in their structure, function, secretory product, mechanism of excretion, anatomic distribution, and distribution across species:

<span class="mw-page-title-main">Scent gland</span> Exocrine glands found in most mammals

Scent gland are exocrine glands found in most mammals. They produce semi-viscous secretions which contain pheromones and other semiochemical compounds. These odor-messengers indicate information such as status, territorial marking, mood, and sexual behaviour. The odor may be subliminal—not consciously detectable. Though it is not their primary function, the salivary glands may also function as scent glands in some animals.

Dogs, as with all mammals, have natural odors. Natural dog odor can be unpleasant to dog owners, especially when dogs are kept inside the home, as some people are not used to being exposed to the natural odor of a non-human species living in proximity to them. Dogs may also develop unnatural odors as a result of skin disease or other disorders or may become contaminated with odors from other sources in their environment.

<span class="mw-page-title-main">Apocrine sweat gland</span> One of several types of glands, in humans and other animals, that secrete sweat

An apocrine sweat gland is composed of a coiled secretory portion located at the junction of the dermis and subcutaneous fat, from which a straight portion inserts and secretes into the infundibular portion of the hair follicle. In humans, apocrine sweat glands are found only in certain locations of the body: the axillae (armpits), areola and nipples of the breast, ear canal, eyelids, wings of the nostril, perineal region, and some parts of the external genitalia. Modified apocrine glands include the ciliary glands in the eyelids; the ceruminous glands, which produce ear wax; and the mammary glands, which produce milk. They are distinct from eccrine sweat glands, which cover the whole body.

Fox–Fordyce disease (FFD) is a chronic blockage of the sweat gland ducts with a secondary, non-bacterial inflammatory response to the secretions and cellular debris in the cysts. The inflammation is often accompanied by intense itching. In general, the disease often causes skin to darken near the affected area and raised bumps or papules to appear. In addition, hair follicles can become damaged which cause hair loss. Hidradenitis is very similar, but tends to have a secondary bacterial infection so that pus-draining sinuses are formed. It is a very devastating skin disease that does not have universally curative treatments.

<span class="mw-page-title-main">ABCC11</span> Mammalian protein found in Homo sapiens

ATP-binding cassette transporter sub-family C member 11, also MRP8, is a membrane transporter that exports certain molecules from inside a cell. It is a protein that in humans is encoded by gene ABCC11.

<span class="mw-page-title-main">Odor</span> Volatile chemical compounds perceived by the sense of smell

An odor or odour is a smell or a scent caused by one or more volatilized chemical compounds generally found in low concentrations that humans and many animals can perceive via their olfactory system. While smell can refer to pleasant and unpleasant odors, the terms scent, aroma, and fragrance are usually reserved for pleasant-smelling odors and are frequently used in the food and cosmetic industry to describe floral scents or to refer to perfumes.

<i>trans</i>-3-Methyl-2-hexenoic acid Chemical compound

trans-3-Methyl-2-hexenoic acid (TMHA) is an unsaturated short-chain fatty acid that occurs in sweat secreted by the axillary (underarm) apocrine glands of Caucasians and some Asians.

Odour is sensory stimulation of the olfactory membrane of the nose by a group of molecules. Certain body odours are connected to human sexual attraction. Humans can make use of body odour subconsciously to identify whether a potential mate will pass on favourable traits to their offspring. Body odour may provide significant cues about the genetic quality, health and reproductive success of a potential mate.

<span class="mw-page-title-main">Androstadienol</span> Chemical compound

Androstadienol, or androsta-5,16-dien-3β-ol, is a 16-androstene class endogenous steroid, pheromone, and chemical intermediate to several other pheromones that is found in the sweat of both men and women.

No study has led to the isolation of true human sex pheromones, although various researchers have investigated the possibility of their existence.

<span class="mw-page-title-main">Scent rubbing</span> Behaviour where a mammal rubs its body against an object in their environment

Scent rubbing is a behavior where a mammal rubs its body against an object in their environment, sometimes in ones covered with strongly odored substances. It is typically shown in carnivores, although many mammals exhibit this behavior. Lowering shoulders, collapsing the forelegs, pushing forward and rubbing the chin, temples, neck, or back is how this act is performed. A variety of different odors can elicit this behavior including feces, vomit, fresh or decaying meat, insecticide, urine, repellent, ashes, human food and so on. Scent rubbing can be produced by an animal smelling novel odors, which include manufactured smells such as perfume or motor oil and carnivore smells including feces and food smells.

The biochemistry of body odor pertains to the chemical compounds in the body responsible for body odor and their kinetics.

<span class="mw-page-title-main">Olfactic communication</span> Social interaction through smell

Olfactic communication is a channel of nonverbal communication referring to the various ways people and animals communicate and engage in social interaction through their sense of smell. Our human olfactory sense is one of the most phylogenetically primitive and emotionally intimate of the five senses; the sensation of smell is thought to be the most matured and developed human sense.

References

  1. 1 2 3 4 5 6 7 8 Lundström JN, Olsson MJ (2010). "Functional Neuronal Processing of Human Body Odors". Vitamins & Hormones. 83: 1–23. doi:10.1016/S0083-6729(10)83001-8. ISBN   978-0-12-381516-3. PMC   3593650 . PMID   20831940.
  2. 1 2 3 4 5 6 Grammer K, Fink B, Neave N (February 2005). "Human pheromones and sexual attraction". European Journal of Obstetrics, Gynecology, and Reproductive Biology. 118 (2): 135–142. doi:10.1016/j.ejogrb.2004.08.010. PMID   15653193.
  3. ↑ Everts S (July 21, 2021). "What Your Body Odor Says About You". Time. In one study about smell and romance, straight women preferred the body odor of straight men whose immune systems were different enough that any offspring would have healthy immune systems. For most of human history, infectious disease has been our greatest threat. In modern times we may seek life-partners that satisfy a multitude of needs, but more fundamentally, if you could produce babies with immune systems able to fight a potpourri of pathogens, then your progeny—and your genes—stand a better chance at survival.
  4. ↑ Turkington C, Dover JS (2007). The encyclopedia of skin and skin disorders (3rd ed.). New York: Facts on File. pp.  363. ISBN   978-0-8160-6403-8.
  5. 1 2 3 4 5 Wedekind C (2007). "Body Odours and Body Odour Preferences in Humans". Oxford Handbook of Evolutionary Psychology. pp. 315–320. doi:10.1093/oxfordhb/9780198568308.013.0022. ISBN   978-0-19-174365-8.
  6. 1 2 3 4 5 6 7 Martin A, Saathoff M, Kuhn F, Max H, Terstegen L, Natsch A (February 2010). "A functional ABCC11 allele is essential in the biochemical formation of human axillary odor". The Journal of Investigative Dermatology. 130 (2): 529–540. doi: 10.1038/jid.2009.254 . PMID   19710689.
  7. ↑ Zeng C, Spielman AI, Vowels BR, Leyden JJ, Biemann K, Preti G (June 1996). "A human axillary odorant is carried by apolipoprotein D". Proceedings of the National Academy of Sciences of the United States of America. 93 (13): 6626–6630. Bibcode:1996PNAS...93.6626Z. doi: 10.1073/pnas.93.13.6626 . PMC   39076 . PMID   8692868.
  8. ↑ Kort R (September 2017). De microbemens: Het belang van het onzichtbare leven[The microbes: The importance of the invisible life.] (in Dutch). Amsterdam: Athenaeum, Polak & Van Gennep. ISBN   978-90-253-0692-2.
  9. ↑ "Bacterial genetic pathway involved in body odor production discovered" (Press release). Society for General Microbiology. March 30, 2015.
  10. ↑ Buckman R (2003). Human Wildlife: The Life That Lives On Us. Baltimore, Md.: The Johns Hopkins University Press. pp. 93–94. ISBN   978-0-8018-7407-9.
  11. ↑ Charles M, Martin B, Ginies C, Etievant P, Coste G, Guichard E (2000). "Potent aroma compounds of two red wine vinegars". Journal of Agricultural and Food Chemistry. 48 (1): 70–77. doi:10.1021/jf9905424. PMID   10637054.
  12. ↑ Ara K, Hama M, Akiba S, Koike K, Okisaka K, Hagura T, et al. (April 2006). "Foot odor due to microbial metabolism and its control". Canadian Journal of Microbiology. 52 (4): 357–364. CiteSeerX   10.1.1.1013.4047 . doi:10.1139/w05-130. PMID   16699586.
  13. ↑ Gabashvili IS (2020). "Cutaneous Bacteria in the Gut Microbiome as Biomarkers of Systemic Malodor and People Are Allergic to Me (PATM) Conditions: Insights from a Virtually Conducted Clinical Trial". JMIR Dermatology. 3: e10508. doi: 10.2196/10508 . S2CID   226280399.
  14. ↑ Ruxton GD, Allen WL, Sherratt TN, Speed MP (2018). Avoiding Attack: The Evolutionary Ecology of Crypsis, Aposematism, and Mimicry. Oxford University Press. ISBN   978-0-19-186849-8.[ page needed ]
  15. ↑ Takahashi LK (March 11, 2014). "Olfactory systems and neural circuits that modulate predator odor fear". Frontiers in Behavioral Neuroscience. 8: 72. doi: 10.3389/fnbeh.2014.00072 . PMC   3949219 . PMID   24653685.
  16. 1 2 3 Damon F, Mezrai N, Magnier L, Leleu A, Durand K, Schaal B (October 5, 2021). "Olfaction in the Multisensory Processing of Faces: A Narrative Review of the Influence of Human Body Odors". Frontiers in Psychology. 12: 750944. doi: 10.3389/fpsyg.2021.750944 . PMC   8523678 . PMID   34675855.
  17. 1 2 Porter RH, Cernoch JM, Balogh RD (March 1985). "Odor signatures and kin recognition". Physiology & Behavior. 34 (3): 445–448. doi:10.1016/0031-9384(85)90210-0. PMID   4011726. S2CID   42316168.
  18. 1 2 Roberts SC, Havlicek J (2011). "Evolutionary psychology and perfume design". Applied Evolutionary Psychology. pp. 330–348. doi:10.1093/acprof:oso/9780199586073.003.0020. ISBN   978-0-19-958607-3.
  19. ↑ Rothardt G, Beier K (August 2001). "Peroxisomes in the apocrine sweat glands of the human axilla and their putative role in pheromone production". Cellular and Molecular Life Sciences. 58 (9): 1344–1349. doi:10.1007/PL00000946. PMC   11337405 . PMID   11577991. S2CID   28790000.
  20. ↑ Lundström & Olsson 2010 :"In addition, the impact that biological factors have on our percept of body odors has recently been indirectly demonstrated by several experiments. Our percept of body odors is dependent on the sexual orientations of both the donor and the perceiver (Martins et al., 2005), and heterosexual women's percept of men's body odor varies over their menstrual cycle (Roberts et al., 2004)."
  21. ↑ Navarrete-Palacios E, Hudson R, Reyes-Guerrero G, Guevara-Guzmán R (July 2003). "Lower olfactory threshold during the ovulatory phase of the menstrual cycle". Biological Psychology. 63 (3): 269–279. doi: 10.1016/s0301-0511(03)00076-0 . PMID   12853171. S2CID   46065468.
  22. 1 2 Kromer J, Hummel T, Pietrowski D, Giani AS, Sauter J, Ehninger G, et al. (August 2016). "Influence of HLA on human partnership and sexual satisfaction". Scientific Reports. 6: 32550. Bibcode:2016NatSR...632550K. doi:10.1038/srep32550. PMC   5006172 . PMID   27578547.
  23. ↑ Berglund H, Lindström P, Savic I (May 2006). "Brain response to putative pheromones in lesbian women". Proceedings of the National Academy of Sciences of the United States of America. 103 (21): 8269–8274. Bibcode:2006PNAS..103.8269B. doi: 10.1073/pnas.0600331103 . PMC   1570103 . PMID   16705035.
  24. ↑ Wade N (May 9, 2005). "Gay Men Are Found to Have Different Scent of Attraction". The New York Times.
  25. ↑ Sabilla IA, Cahyaningtyas ZA, Sarno R, Al Fauzi A, Wijaya DR, Gunawan R (2021). "Classification of Human Gender from Sweat Odor using Electronic Nose with Machine Learning Methods". 2021 IEEE Asia Pacific Conference on Wireless and Mobile (APWiMob). pp. 109–115. doi:10.1109/APWiMob51111.2021.9435205. ISBN   978-1-7281-9475-2.
  26. ↑ Weisfeld GE, Czilli T, Phillips KA, Gall JA, Lichtman CM (July 2003). "Possible olfaction-based mechanisms in human kin recognition and inbreeding avoidance". Journal of Experimental Child Psychology. 85 (3): 279–295. doi:10.1016/s0022-0965(03)00061-4. PMID   12810039.
  27. 1 2 3 Endevelt-Shapira Y, Djalovski A, Dumas G, Feldman R (December 2021). "Maternal chemosignals enhance infant-adult brain-to-brain synchrony". Science Advances. 7 (50): eabg6867. Bibcode:2021SciA....7.6867E. doi:10.1126/sciadv.abg6867. PMC   8664266 . PMID   34890230.
  28. 1 2 Varendi H, Porter RH, Winberg J (October 1994). "Does the newborn baby find the nipple by smell?". Lancet. 344 (8928): 989–990. doi:10.1016/S0140-6736(94)91645-4. PMID   7934434. S2CID   35029502.
  29. ↑ Schaal B (2014), Mucignat-Caretta C (ed.), "Pheromones for Newborns", Neurobiology of Chemical Communication, Frontiers in Neuroscience, Boca Raton (FL): CRC Press/Taylor & Francis, ISBN   978-1-4665-5341-5, PMID   24830031 , retrieved November 27, 2022
  30. ↑ "Pheromone From Mother's Milk May Rapidly Promote Learning In Newborn Mammals". ScienceDaily. Retrieved November 27, 2022.
  31. ↑ Mujica-Parodi LR, Strey HH, Frederick B, Savoy R, Cox D, Botanov Y, et al. (July 2009). "Chemosensory cues to conspecific emotional stress activate amygdala in humans". PLOS ONE. 4 (7): e6415. Bibcode:2009PLoSO...4.6415M. doi: 10.1371/journal.pone.0006415 . PMC   2713432 . PMID   19641623.
  32. 1 2 3 Yoshiura K, Kinoshita A, Ishida T, Ninokata A, Ishikawa T, Kaname T, et al. (March 2006). "A SNP in the ABCC11 gene is the determinant of human earwax type". Nature Genetics. 38 (3): 324–330. doi:10.1038/ng1733. PMID   16444273. S2CID   3201966.
  33. 1 2 3 Kanlayavattanakul M, Lourith N (August 2011). "Body malodours and their topical treatment agents". International Journal of Cosmetic Science. 33 (4): 298–311. doi: 10.1111/j.1468-2494.2011.00649.x . PMID   21401651.
  34. 1 2 3 4 Nakano M, Miwa N, Hirano A, Yoshiura K, Niikawa N (August 2009). "A strong association of axillary osmidrosis with the wet earwax type determined by genotyping of the ABCC11 gene". BMC Genetics. 10 (1): 42. doi: 10.1186/1471-2156-10-42 . PMC   2731057 . PMID   19650936.
  35. ↑ Preti G, Leyden JJ (February 2010). "Genetic influences on human body odor: from genes to the axillae". The Journal of Investigative Dermatology. 130 (2): 344–346. doi: 10.1038/jid.2009.396 . PMID   20081888.
  36. 1 2 Prokop-Prigge KA, Greene K, Varallo L, Wysocki CJ, Preti G (January 2016). "The Effect of Ethnicity on Human Axillary Odorant Production". Journal of Chemical Ecology. 42 (1): 33–39. Bibcode:2016JCEco..42...33P. doi:10.1007/s10886-015-0657-8. PMC   4724538 . PMID   26634572.
  37. ↑ Shetage SS, Traynor MJ, Brown MB, Raji M, Graham-Kalio D, Chilcott RP (February 2014). "Effect of ethnicity, gender and age on the amount and composition of residual skin surface components derived from sebum, sweat and epidermal lipids". Skin Research and Technology. 20 (1): 97–107. doi:10.1111/srt.12091. PMC   4285158 . PMID   23865719.
  38. ↑ Tullett W (July 2, 2016). "Grease and Sweat: Race and Smell in Eighteenth-Century English Culture". Cultural and Social History. 13 (3): 307–322. doi: 10.1080/14780038.2016.1202008 . S2CID   147837009.
  39. ↑ Li M, Budding AE, van der Lugt-Degen M, Du-Thumm L, Vandeven M, Fan A (August 2019). "The influence of age, gender and race/ethnicity on the composition of the human axillary microbiome". International Journal of Cosmetic Science. 41 (4): 371–377. doi:10.1111/ics.12549. PMID   31190339. S2CID   189816630.
  40. ↑ Mitro S, Gordon AR, Olsson MJ, Lundström JN (May 30, 2012). "The Smell of Age: Perception and Discrimination of Body Odors of Different Ages". PLOS ONE. 7 (5): e38110. Bibcode:2012PLoSO...738110M. doi: 10.1371/journal.pone.0038110 . PMC   3364187 . PMID   22666457.
  41. ↑ Haze S, Gozu Y, Nakamura S, Kohno Y, Sawano K, Ohta H, et al. (December 8, 2015). "2-Nonenal Newly Found in Human Body Odor Tends to Increase with Aging". Journal of Investigative Dermatology. 116 (4): 520–524. doi: 10.1046/j.0022-202x.2001.01287.x . PMID   11286617.
  42. ↑ Sarigul N (2019). "A New Artificial Urine Protocol to Better Imitate Human Urine". Scientific Reports. 9 (1): 20159. Bibcode:2019NatSR...920159S. doi:10.1038/s41598-019-56693-4. PMC   6934465 . PMID   31882896.
  43. ↑ Siyang S (2012). "Diabetes diagnosis by direct measurement from urine odor using electronic nose". The 5th 2012 Biomedical Engineering International Conference. IEEE. pp. 1–4. doi:10.1109/BMEiCon.2012.6465441. ISBN   978-1-4673-4892-8 – via IEEE conference publication.
  44. ↑ Chan MJ (2020). "Breath Ammonia Is a Useful Biomarker Predicting Kidney Function in Chronic Kidney Disease Patients". Biomedicines. 8 (11): 468. doi: 10.3390/biomedicines8110468 . PMC   7692127 . PMID   33142890.
  45. ↑ Ishikawa T, Toyoda Y, Yoshiura K, Niikawa N (2012). "Pharmacogenetics of human ABC transporter ABCC11: new insights into apocrine gland growth and metabolite secretion". Frontiers in Genetics. 3: 306. doi: 10.3389/fgene.2012.00306 . PMC   3539816 . PMID   23316210.
  46. ↑ Miura K, Yoshiura Ki, Miura S, Shimada T, Yamasaki K, Yoshida A, et al. (June 2007). "A strong association between human earwax-type and apocrine colostrum secretion from the mammary gland". Human Genetics. 121 (5): 631–633. doi:10.1007/s00439-007-0356-9. ISSN   0340-6717. PMID   17394018. S2CID   575882.
  47. ↑ Martin A, Saathoff M, Kuhn F, Max H, Terstegen L, Natsch A (February 2010). "A functional ABCC11 allele is essential in the biochemical formation of human axillary odor". The Journal of Investigative Dermatology. 130 (2): 529–540. doi: 10.1038/jid.2009.254 . PMID   19710689. S2CID   36754463.
  48. ↑ "Learn How to Fight Body Odor". MD Health Network. Archived from the original on March 24, 2010. Retrieved July 5, 2007.
  49. ↑ Zuniga A, Stevenson RJ, Mahmut MK, Stephen ID (January 2017). "Diet quality and the attractiveness of male body odor". Evolution and Human Behavior. 38 (1): 136–143. Bibcode:2017EHumB..38..136Z. doi:10.1016/j.evolhumbehav.2016.08.002. ISSN   1090-5138.
  50. ↑ Pomeroy R (August 10, 2014). "Antiperspirants Alter Your Armpit Bacteria and Could Actually Make You Smell Worse". RealClearScience.
  51. ↑ Considine A (January 17, 2013). "Genetically, Some of Us Never Have Body Odor, But We Still Think We're Smelly". Vice.
  52. ↑ "Global Deodorants Market is Expected to Reach USD 17.55 Billion by 2020". gosreports.com. Archived from the original on October 28, 2016. Retrieved July 29, 2016.
  53. ↑ William J, Berger T, Elston D (2005). Andrews' Diseases of the Skin: Clinical Dermatology (10th ed.). Saunders. p. 779. ISBN   978-0-7216-2921-6.
  54. ↑ Freedberg IM, Eisen AZ, Austen KF, Goldsmith LA, Katz SI (2003). Fitzpatrick's Dermatology in General Medicine (6th ed.). McGraw-Hill. p. 707. ISBN   978-0-07-138076-8.
  55. ↑ Felman A (November 29, 2017). "What to know about body odor". Medical News Today.
  56. ↑ "Sweating and body odor". Mayo Clinic.
  57. ↑ "Endoscopic thoracic sympathectomy". Medlineplus medical encyclopedia.
  58. ↑ Brennan D. "Tips for Reducing Body Odor". WebMD.
  59. ↑ "Body Odor: Causes, Prevention, Treatments". Medical News Today. Retrieved March 4, 2017.
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