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10 Eye-Opening Facts About Body Odor

Body odor is more than just a smell.

Dealing with body odor is a concession we make to live in society. As we all know, its smell is unmistakable. Maybe you passed someone on the street and were taken aback. Maybe you got a whiff of folks engaged in manual labor. Maybe you’re pumping up at the gym. It’s everywhere.

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Source: dandamanwasch/123RF

The weird thing about the smell of sweat is that it’s both revolting and enticing—depending on the circumstances. Body odor appeals to our animal instincts.

Here are 10 interesting facts about body odor.

  1. Production. Apocrine glands make an odorless mixture of lipids and amino acids, as well as pheromones, which is metabolized by bacteria to make stinky sweat. Apocrine glands make far less sweat than eccrine glands, which are the body’s other variety of sweat gland. Sweat from eccrine glands is odorless. On a related note, eccrine sweat glands are activated sympathetically by the cholinergic system; whereas, apocrine glands are activated parasympathetically by the adrenergic system.
  2. Location. The armpits have the highest density of apocrine sweat glands and largest apocrine glands in the body. Apocrine sweat glands are not active until puberty. In addition to the armpits, these glands are also located in the scalp, the anogenital region, the eyelids, the ear canal, and the mammary glands. Fewer apocrine glands are found on the face and belly. Men have larger apocrine sweat glands in the armpits than do women, which is why men typically smell worse.
  3. Function. Human body odor may help with mate choice in two ways: 1) inbreeding avoidance and 2) assessing the health status of a potential mate. With regard to inbreeding avoidance, the smell of a person’s sweat could convey a person's complement of immune system genes (ie, human leukocyte antigens). As for health status, sweat’s smell changes with disease and infection.
  4. Diet. Differences in diet are reflected in the smell of sweat. Research indicates that women prefer the smell of men who eat a diet rich in eggs, cheese, soy, fruit, and vegetables compared with a red-meat diet.
  5. Attraction. The smell of sweat is more important in attractiveness judgments made by women than those made by men. On a related, women have a better sense of smell than do men.
  6. Cell decapitation. When producing sweat, the cells in apocrine glands are lost in part to the sweat. In other words, sweat contains cellular content, too.
  7. Yellowness. Skin yellowness predicts sweat attractiveness among female judges in research studies. Skin yellowness is hypothesized to be a reflection of a diet rich in fruits and veggies or, in other words, a healthy diet. This yellowness is derived from the carotenoids in fruits and vegetables. (The only animal product that contains carotenoids is eggs.)
  8. Disgust. Scientists have developed a “Body Odor Disgust Scale” (BODS). The BODS likely reflects perceived vulnerability to disease. Remember that sweat changes smell based on pathogen exposure, which decreases the smell’s attractiveness to women.
  9. Different flavors. Different people harbor different bacteria in their armpits and other crevices. These different types of bacteria result in different smells, such as sour, meaty, oniony, or rotten egg.
  10. Deodorants. Deodorants work in various ways: They kill bacteria, cover odors with perfumes, and decrease sweat production.

References

Harbour P, Song DH. The Skin and Subcutaneous Tissue. In: Brunicardi F, Andersen DK, Billiar TR, Dunn DL, Kao LS, Hunter JG, Matthews JB, Pollock RE. eds. Schwartz's Principles of Surgery, 11e New York, NY: McGraw-Hill; 2019.

Liuzza MT, et al. Body Odor Trait Disgust Sensitivity Predicts Perception of Sweat Biosamples. Chemical Senses. 2017; 42: 479–486.

Zouboulis CC, Tsatsou F. Chapter 85. Disorders of the Apocrine Sweat Glands. In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K. eds. Fitzpatrick's Dermatology in General Medicine, 8e New York, NY: McGraw-Hill; 2012.

Zuniga, A, et al. Diet quality and the attractiveness of male body odor. Evolution and Human Behavior. 2017; 38: 136–143.

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