shirts with armpit smell that does not want to leave even after several wash.

[CharonY]

On 10/14/2024 at 2:54 AM, exchemist said:

Early man (and woman) may have found the smell a turn-on. To this day, perfume preparations commonly include "musky" elements. (One of these is ambergris, which is basically shit from constipated whales....

I have not read the full paper, but based on a skim, I think the authors may have overstretched their claims. To be fair, most of it is in the discussions, which allows for some level of speculation, but this is (IMO) somewhat close to a wild guess.

The bacterial enzyme might be an adaption to the human metabolite as it might provide them with a selective advantage. But the analysis would not allow to make any statements regarding this process also being a selective advantage for humans. The authors speculate that the human precursor have no purpose and then speculate on how further processing might have a selective advantage. This is a rather broad extrapolation and would require a much deeper analysis of the metabolic processes leading on the humans side of things (i.e. the precursor). The production of them might not be the primary role of the involved enzymes, but rather a side aspect, that are exploited by bacteria, for example. 

[exchemist]

1 minute ago, zapatos said:

No one that I'm aware of.

OK so that shows the groin area does not produce body odour in the way the armpit does, right?

[zapatos]

Just now, exchemist said:

OK so that shows the groin area does not produce body odour in the way the armpit does, right?

No. It shows that YOU have not smelled it (hence the olfactory comment). A Google search and MY experience indicates it does. 

[exchemist]

3 minutes ago, CharonY said:

I have not read the full paper, but based on a skim, I think the authors may have overstretched their claims. To be fair, most of it is in the discussions, which allows for some level of speculation, but this is (IMO) somewhat close to a wild guess.

The bacterial enzyme might be an adaption to the human metabolite as it might provide them with a selective advantage. But the analysis would not allow to make any statements regarding this process also being a selective advantage for humans. The authors speculate that the human precursor have no purpose and then speculate on how further processing might have a selective advantage. This is a rather broad extrapolation and would require a much deeper analysis of the metabolic processes leading on the humans side of things (i.e. the precursor). The production of them might not be the primary role of the involved enzymes, but rather a side aspect, that are exploited by bacteria, for example. 

Sure, it is rather speculative. But the possible correlation of the appearance of the enzyme with the rise of the primates is an interesting finding.

[StringJunky]

2 minutes ago, exchemist said:

OK so that shows the groin area does not produce body odour in the way the armpit does, right?

We may not notice the groin smells because it is exposed to air, whereas the armpit is more enclosed and can contain the smell products to a more concentrated level, such that we notice it.

[exchemist]

11 minutes ago, zapatos said:

No. It shows that YOU have not smelled it (hence the olfactory comment). A Google search and MY experience indicates it does. 

Why then does nobody bother with deodorant for the groin?

[zapatos]

17 minutes ago, exchemist said:

Why then does nobody bother with deodorant for the groin?

I guess the same reason they don't put deodorant on their feet.

Why do people take a shower and wash their groin before going on a date?

Edited October 15 by zapatos

[TheVat]

1 hour ago, StringJunky said:

 

Eating a wide diversity of uncooked plant matter, each one having their own commensal species groups, are good probiotic sources as well AFAIK and probably the best way for its diversity. Kefir, which I use, along with veg and Greek yoghurt, has a few dozen species in it. It's probably the best fermented type of food for diversity in one product.

Kefir does seem to be about the best.  That and a high quality kombucha, and you've practically got a biome.  And for one golden moment, the thread was not discussing groin odours.  

 

2 minutes ago, TheVat said:

Greek yoghurt has low levels of lactose. Most of it is converted to lactic acid. Sensitivity will vary between individuals, I would imagine. Even then, there are women who apply it prophylactically. I knew one.

Wait...what?  

1 hour ago, zapatos said:

Why do people take a shower and wash their groin before going on a date?

They are optimists.

Edited October 15 by TheVat

[exchemist]

1 hour ago, zapatos said:

I guess the same reason they don't put deodorant on their feet.

Why do people take a shower and wash their groin before going on a date?

My point is there is a huge difference between a slight smell of sweat or traces of body fluids in the groin, for which washing is quite sufficient, and the powerful odour of unwashed and non-deodorised armpits. If you just wash your armpits, and don't use deodorant, they smell really rank after as little as 12 hours. Nobody's groin ever smells remotely like that.   

Edited October 15 by exchemist

[iNow]

4 hours ago, exchemist said:

Why then does nobody bother with deodorant for the groin?

Some do. Your premise is false

[zapatos]

2 hours ago, exchemist said:

If you just wash your armpits, and don't use deodorant, they smell really rank after as little as 12 hours.

Mine don't. In fact my pits never really smell bad with or without deodorant. I have no idea why.

2 hours ago, exchemist said:

Nobody's groin ever smells remotely like that.   

That's a pretty bold statement given your small sample size.

[CharonY]

2 hours ago, exchemist said:

Sure, it is rather speculative. But the possible correlation of the appearance of the enzyme with the rise of the primates is an interesting finding.

Yes, but one can turn the claim around. For example, mutations in the gene I mentioned earlier (ABCC11), reduces reduces the level of odorant precursors in human sweat. In some populations this variant accounts for over 90% of the population and it was speculated that reduction of body odor might have been under positive sexual selection.

3 minutes ago, zapatos said:

Mine don't. In fact my pits never really smell bad with or without deodorant. I have no idea why.

This might be an example of such

[exchemist]

10 hours ago, CharonY said:

Yes, but one can turn the claim around. For example, mutations in the gene I mentioned earlier (ABCC11), reduces reduces the level of odorant precursors in human sweat. In some populations this variant accounts for over 90% of the population and it was speculated that reduction of body odor might have been under positive sexual selection.

This might be an example of such

This is interesting. I found this article: https://www.ncbi.nlm.nih.gov/books/NBK127546/  according to which people with the A version of the gene do not produce odour precursors while those with the G type do. The A type is very highly prevalent in people of East Asian descent and in fact only 7% of them use deodorants. By contrast, those of European or African descent usually have the G type and so it is these societies where deodorant use has become the norm.   

[CharonY]

This is also one of the relatively few examples where we can link a single gene to a fairly clear phenotype (it also affects ear wax consistency). However, I want to reiterate that only because we know one if its associated phenotypes, it does not mean that the phenotype in itself is the trait under selection. While it is possible that body odor is under positive in some and negative in other populations, it is also possible that it is associated with some else that we are unaware of that is being selected, or it could be co-selected with a different allele that we are not considering and so on.