When people hear the word “microbiome,” they often think of intestinal bacteria. (As well they should. For fascinating insight into some unexpected ways the intestinal microbiome affects our health, you may wish to listen to our one-hour interview with Dr. David Perlmutter, author of Brain Maker.)
We now know that there are more bacterial cells than human cells in any individual person. What most people don’t consider, however, is the microbiome of the skin. We are teeming with microbes adapted to their own particular niches.
The Microbiome of the Armpit:
One place, in particular, has a rich microbiome, and that is the armpit. This part of the body hosts a lot of bacteria, and the ecology of the bacterial communities in the armpit varies greatly between individuals.
Researchers in North Carolina conducted a study that compared bacterial communities between people who use underarm products such as antiperspirants and deodorants and those who do not. There were striking differences.
Differences in Armpit Ecology:
Not only were there many more bacteria in product-free armpits, the mix of species was quite different. Stopping the use of deodorants or antiperspirants resulted in an increase of bacteria that could be cultured. The dominant species still differed from those in armpits not accustomed to hygiene products.
Unfortunately, the authors are unable to say whether these changes have an impact on human health overall. Perhaps future studies will shed light on the impact of antiperspirants and deodorants over the long term.