Today I Learned

Eh, it's probably good enough for this. Go for it.

Can I just rub some Asian people on me?

The pro tip that we had to give out in college for the newcomers to the ballroom team every semester to mitigate body odor (edit: done in exactly this order):

1. Shower with soap.
2. Apply deodorant with antiperspirant.
3. Put on clean clothes.

You would be surprised how many people in college don't understand the nuances of these points. Or other basically accepted hygiene practices of the area. For example, cologne or perfume is not "deodorant". Also, most things are not clean after you wear them (esp if you sweat), and dont become clean again until they are laundered. You may also notice we had to specify "with soap" for a shower.

The bit about antiperspirant is not strictly necessary, but nobody wants to put their hand near or accidentally in a sweaty pit.

In a genetic sense, it is a dysfunction of the gene that causes this. It's neat because we can actually trace the history of human migrations by looking at the distribution of this particular allele (version of a gene). We have analysed DNA from ancient remains of early Europeans and found that the A allele is absent. It appears like this version of the gene first emerged in an ancient East Asian population.

This gene also determines whether you have dry or sticky ear wax. It's a neat gene because it's uncommon for physical human traits to be controlled by one gene — most human characteristics are controlled by multiple genes (polygenic traits); ginger hair is another example of a monogenic trait. ABCC11 is neat because it affects multiple traits: sweat smell and earwax dryness.

It might also be implicated in breast cancer risk (I can't tell whether that's in an increased risk or decreased risk), but we don't really understand yet how that would work. From skimming the research, I would say we generally don't understand how this gene works at all. We do know some stuff about it and how/why it works, but we're still a decent way off of actually understanding its implications.

The condition is caused by a loss-of-function mutation. It's a statement about a protein, not about the whole person.

Edit: ChatGPT explains it better than I can.

The ABCC11 gene encodes an apical efflux pump that helps transport fatty compounds, or lipids, from cells into sweat. When the gene is non-functional, these lipids can't cross the membrane barrier to reach the armpit. This prevents bacteria from accessing and metabolizing the organic compounds in sweat, which in turn reduces the production of odorant substances.

This is a good point.

Yes. It is. The article specifically calls out east asia.

A lot of that is diet and, of course, hygiene. Having 10% less BO doesn't do anything for you if you're not showering, or eating garlic gloves whole.

Yah, wow, some Indians need to have some intervention done. I know plenty of Indians that are perfectly fine, and then there's a subset that smell like me after a 2 week solo backpacking trip.

I can’t smell myself at all, but then again, people are usually habituated to their own scents.

Olfactory fatigue

IME no one is immune to gym odors. There are still many fats and proteins secreted by non-apocrine glands that are digestible by bacteria, so to eliminate body odor entirely we would probably need to evolve strong antimicrobial secretions or something.

Sweat rinses much of this bacteria-food off of us, but since we started wearing clothes it just transports the bulk of it to what we’re wearing (now stinky gym clothes).

That’s why showering before a workout is so effective for controlling gym odors: most of the bacteria and its food ends up in the drain rather than your clothes. Showering after is then mostly to rinse off salt.

Anyway I imagine the times you’ve smelled people after the gym were simply the times they skipped that pre-workout shower.

Onions, yes. Spices and cheese? What?

I’ve noticed after a workout a balls scent, but I’ve never thought of onions, spices and cheese.

It reminds me of how there is a gene that determines whether eating asparagus makes your pee stink, and there's a different gene that determines whether you can smell it. I had a friend who didn't have the stinky pee gene, but her boyfriend did, and she complained of the smell when she used the bathroom after him occasionally. He had the stinky pee gene, but not the gene to be able to smell the stink.

This came up in a random conversation with my friend, before she knew about the genes thing. I was so excited that I got to tell her about a cool science thing that I couldn't speak for a few moments.

I somehow got this . I never wear deodorant and don't get any BO even after a crazy sweaty day .