How does diet affect body odor?


Breathtaking -- for some people.
Breathtaking -- for some people.
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Who doesn't love a good, perfectly cooked steak? OK, vegetarians don't. And cows probably don't, either.

There are benefits and drawbacks to a diet that includes red meat and a seemingly endless debate over eating it. Red meat is packed with iron and protein, important sources of nutrients and essential to tissue and muscle fiber. On the other hand, a recent landmark study of 500,000 Americans found that the people who eat the most red meat are more likely to die (especially from cancer and heart disease) than the people who eat the least [source: Brody].

The study results are probably far from surprising for some; other smaller and less refined studies have yielded similar results for decades. This hasn't stopped American's love for red meat, though; rates of meat consumption have doubled in the country since the 1960s.

But there's another study out there that might give red meat eaters pause. In 2006, an anthropological study carried out by researchers in the Czech Republic found that meat eaters smell worse than their vegetarian counterparts.

The researchers collected samples of the natural body odors emitted by male meat and non-meat eaters over a two-week period. After they had their stores of used underarm pads assembled, the researchers presented them to a group of 30 women who smelled and rated the attractiveness of the odor on each pad. When the results were tallied, the non-meat eaters' odors were "judged as significantly more attractive, more pleasant and less intense" [source: Havlicek, et al].

Why should this be? The old adage you are what you eat makes sense, but the idea that what you smell like depends on what you eat is slightly less self-evident. How can a certain type of food or diet affect your body odor? To find out, first we'll look at the science of sweating.

The Science of Sweating

Sweating can be caused by physical exertion, heat or emotional response. If it's excreted from apocrine glands, it can lead to body odor.
Sweating can be caused by physical exertion, heat or emotional response. If it's excreted from apocrine glands, it can lead to body odor.
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You've got two types of sweat glands across your skin (a third type, the sebaceous gland is similar in structure and function, but produces sebum, not sweat). They serve as a part of the integumentary system, which is also composed of your hair, fingernails and skin. The sweat glands serve on another system as well, the excretory system. The first type of sweat gland that develops is the eccrine gland. It's found all over your skin, but most abundantly on the palms of your hands, the soles of your feet, your underarms (axillae) and your forehead.

Eccrine sweat glands are activated when the hypothalamus senses the body's internal temperature is rising. Sweat composed mainly of water and salts is released and the body cools down. Since eccrine gland sweat is mostly water and salt, it doesn't tend to produce a scent, so it's not responsible for humans' natural body odor. That honor lies with the apocrine gland.

The apocrine glands don't develop until puberty, and since they are the glands responsible for body odor, this is the reason that kids don't typically begin to use deodorant or antiperspirant until the onset of puberty.

Apocrine glands are found most abundantly in the axillae, around the genitals and breasts and around the belly button. These glands are responsible for excreting waste, mostly proteins and lipids (fats). This type of sweat doesn't smell inherently, it's when it reaches the skin that an odor is produced. There is native flora (microorganisms like bacteria and fungi found in colonies) on healthy human skin, and these florae set about eating your apocrine sweat when it's excreted onto your skin's surface. As they feed on your sweat, the microorganisms produce the familiar scent of body odor as a byproduct of metabolism.

We've already seen that eating red meat can produce malodorous results. But what are some other foods you might want to avoid if you care to smell nice and pretty?

Is there a non-stinky diet?

Curry is a pungent food, but whether it causes pungent people remains unproven scientifically.
Curry is a pungent food, but whether it causes pungent people remains unproven scientifically.
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There is some disagreement over what causes body odor in some proponents of natural lifestyles. In these quarters, it is the impurities and toxins the body releases through sweat that stink us up, not the bacteria eating the secretions in said sweat [source: Adams]. Others have gotten more specific, citing ama (undigested food; part of the ayurvedic tradition) as the culprit behind body odor. Under the purview of ayurveda, ama finds its way into the bloodstream, acting as a toxin in the body before it's excreted through the sweat glands [source: McIntyre]. The last page covered the topic from the vantage point of accepted medical science. However, it's about here that medicine's research into the topic ends; there is a dearth of studies on exactly what foods might cause the most pungent body odor.

While science has bowed out at this point, there is some room for conventional wisdom. If native florae on the skin like to chow down on fats and proteins and, as a result, produce malodorous byproducts like androstenes (steroid compounds) and isovaleric acid, then cutting down on foods heavy in these nutrients should reduce body odor. It's kind of like odor reduction through bacterial starvation. This could explain why the meat-eating participants in the Czech experiment had a less preferable body odor than their vegetarian counterparts. It's important to point out, however, that the experiment provided a correlation between meat and the perception of body odor, not a causal link.

Other foods that are perennially cited as worth avoiding to reduce body odor have their own strong scents. Curries, onions and garlic all fall into this category. The reasoning is that the enzymes that give these foods their strong smell may escape full digestion and be excreted intact from the eater's pores, creating body odor. This remains unproven through scientific inquiry, however.

Food can also lead to body odor in a more roundabout way. Spicy food tends to make its eater sweat from both the apocrine and eccrine glands. More sweat can equal more body odor; hence, cutting spicy foods from your diet can lead to a reduction in body odor [source: Mayo Clinic].

Ultimately, if you subscribe to Western science, simply bathing regularly and using antiperspirant or deodorant is the best way to reduce body odor. If it persists, seeing a physician might be a good next step.

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Sources

  • Adams, Mike. "Body odor can be eliminated through a change in diet." Natural News. Feb. 8, 2005.http://www.naturalnews.com/004417.html
  • Baker, Donald J., M.D. and Heymann, Warren R., M.D. "Eccrine and apocrine glands." American Academy of Dermatology.http://www.aad.org/education/students/glands.htm
  • Brody, Jane E. "Paying a price for loving red meat." New York Times. April 27, 2009. http://www.nytimes.com/2009/04/28/health/28brod.html
  • Dermaxime. "Sweat glands." Accessed Sept. 17, 2009. http://www.dermaxime.com/skin-sweat-glands.htm
  • Elsner, Peter. "Antimicrobials and the skin; physiological and pathological flora."
  • Efficiency of Biofunctional Textiles. 2006. http://www.online.karger.com/ProdukteDB/Katalogteile/isbn3_8055/_81/_21/Biofunctional_Textiles_02.pdf
  • Havlicek, J and Lenochova, P. "The effect of meat consumption on body odor attractiveness." Chemical Senses. October 2006. http://www.ncbi.nlm.nih.gov/pubmed/16891352
  • McIntyre, Anne. "Herbal treatment of children: Western and Ayurvedic perspectives." Elsevier Health Sciences. 2005.
  • The Mayo Clinic. "Sweating and body odor; lifestyle and home remedies." Dec. 9, 2008. http://www.mayoclinic.com/health/sweating-and-body-odor/DS00305/DSECTION=lifestyle-and-home-remedies