Body Odor, part 1
Oh, body odor. For many (perhaps most!) of us, the thought of body odor and how we smell to those around us is a constant concern that drives a few of our daily habits. In general western life, we shower even when we’re not literally dirty. We apply deodorant and perfumes and scented lotions with the intent to mask or change our smell for ourselves or others. We wash clothes in scented detergent, adding scented dryer sheets. We even fall for marketing ploys about refreshing our genitalia with fragrant products!
Is all of this inherently bad or wrong? Of course not, except maybe the products designed for our genitalia, but that’s for another article. Scent is an important factor in our lives and relationships, with cultures or subcultures defining the parameters of what is accepted and attractive. However, we may be targeting the wrong source with our products. If sweat and dirt don’t cause us to smell bad… then what does?
The smelly source
“Remarkably, body odour is linked to the presence of a few species of commensal microbes. Herein we discover a bacterial enzyme, limited to odour-forming staphylococci that are able to cleave odourless precursors of thioalcohols, the most pungent components of body odour.” (Rudden, Herman, Rose, 2020)
Our sweat is odorless. The personalized stench comes from specific bacteria present in our underarm and genital areas, mostly Staphylococcus, Cutibacterium, and Corynebacterium. These bacteria process sweat secretions from our apocrine glands and then release chemical byproducts, with thioalcohols being considered the most pungent. Three strains of staphylococcus (S. hominis, S. lugdunensis, and S. haemolyticus) were identified as having the strongest link to releasing thioalcohols and therefore causing bad odor. You may have heard of “staph” or “staph infections” but those arise only in extreme situations. We have staph species on us at all times.
So what does this mean for me?
If you’re concerned about body odor, you are on the right track by reading about your skin microbiome. You have a general understanding that not all bacteria are bad or dangerous, and that some are even very helpful! The general takeaway is that our sweat itself does not stink, and body odor does not have to smell bad. It is not a done-deal.
Many groups of people do not present unpleasant body odor, because they have not interrupted the natural cycle of bacteria and sweat as we have with our many products and over-cleanliness. Body Odor Part 2 will explore the types of skin bacteria that reduce or eliminate body odor, the habits that can help those bacteria thrive, and I will reveal a shocking secret about my own skin!
TLDR: Sweat is odorless, so our unpleasant body odor is caused by a few specific types of bacteria that break down our sweat. Stinky body odor is not a human necessity, in fact both clinical and anthropological studies have shown that groups of people who do not habitually use antiperspirants, deodorants, and daily soap on their bodies have no body odor at all. This is due to a better balance of bacteria types than those who use daily hygiene products.
BO Fun Fact: A study found that women identified male non-meat eaters as more attractive than males who ate red meat. Their scents were perceived by the women as significantly more attractive, more pleasant, and less intense. The experiment was even reversed, and the males switched their diets for a period of time. The no-red-meat dieters were preferred again!
Sources and helpful info:
Callewaert, C., Hutapea, P., Van de Wiele, T., Boon, N. (2014). Deodorants and antiperspirants affect the axillary bacterial community. Archives of dermatological research, 306(8), 701–710. https://doi.org/10.1007/s00403-014-1487-1
Collen, A. (2015). 10% Human: How your body’s microbes hold the key to health and happiness. HarperCollins.
Hara T, Matsui H, Shimizu H. (2014, November 12). Suppression of microbial metabolic pathways inhibits the generation of the human body odor component diacetyl by staphylococcus spp.. PLoS ONE 9(11). https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0111833
Havlicek, J. & Lenochova, P. (2006, October). The effect of meat consumption on body odor attractiveness, Chemical Senses, 3(8), 747–752. https://doi.org/10.1093/chemse/bjl017
Lam, T.H., Verzotto, D., Brahma, P. et al. (2018). Understanding the microbial basis of body odor in pre-pubescent children and teenagers. Microbiome 6, 213. https://doi.org/10.1186/s40168-018-0588-z
Rudden, M., Herman, R., Rose, M. (2020). The molecular basis of thioalcohol production in human body odour. Sci Rep 10. https://doi.org/10.1038/s41598-020-68860-z
