Imagine a crowded gym locker room. You walk in, and it immediately overwhelms your sense of smell. It’s one smell that you can identify immediately. Everyone knows you’re smelling body odor, affectionally known as BO.
As a country, we spend a significant amount of money managing BO. We’ve had deodorant for more than 50 years — can you imagine what it was like before that? Think about sitting in the crowded Globe Theater watching a play in Shakespeare’s time — talk about a 4D experience. Today in the United States, about 90 percent of 18- to 29-year-olds and 78 percent of those 60 and older use deodorant every day.
How much do we spend every year to cover up this socially offensive smell? Americans spend about $60 per month on personal care products and household goods. The estimated revenue for 2020 for deodorant sales in the United States is $4.7 billion. Degree, Dove, Old Spice and Secret are the leading brands and account for about one-third of the deodorant market.
Did you ever wonder where that offensive smell comes from? It turns out it’s not us. The offender belongs to our skin microbiome. Often when we speak about the human microbiome, we’re referring to the microbes that inhabit the human intestinal tract.
Each area of the body, however, has its own distinct microbe population, including the skin. The members of the microbiome can change depending on the area of the body. Exposed skin on the arms and legs has its own unique microbiome, while warm moist areas have different microbe populations.
The chemical basis for that BO smell comes from a bacterium called Staphylococcus hominis, which is part of the human underarm microbiome. This bacterium can convert a chemical from our sweat glands into a pungent substance called a thioalcohol — 3M3SH. A particular protein in the bacterium makes the conversion to create the chemical. In one way, we’re our own worst enemies in that our noses are extremely efficient at detecting thioalcohols.
The scientists searched in the bacterium’s DNA and found the gene that creates the protein. To be sure they had the right one, they used genetic techniques to transfer the gene into a different type of bacterium called Staphylococcus aureus. And guess what — that recombinant bacteria was now capable of producing BO. The gene for the conversion protein came from an ancient species of Staphylococcus about 60 million years ago.
This research gives our scientists a target to focus on to eliminate BO. The strategy would likely be to selectively remove S. hominis from the underarm microbiome. Removing the bacterium would mean no converting enzyme and no smell.
We don’t know, however, the potential impact of removing this bacterium from the microbe population. Bacteria are successful in the world because of their ability to adapt to changing situations, and it remains to be seen how they could adapt to our sinister plans to put the deodorant companies out of business.