John smells. Every time you walk past his desk your nostrils are assaulted by the heady stench of body odour (BO). You’re not sure if John has noticed that he smells but you’re afraid some of his fellow students have and there is a danger that they will start ribbing him about it. You feel that you need to talk to him about the issue, but how do you even begin to have such a sensitive conversation?

You don’t want to make matters worse and give him a complex about it. What would really help is if you understood what was occurring in his body at the moment so that you could educate him about the biological mechanisms underpinning BO and how he should best go about tackling the problem.

So, how and when is BO created and what’s the best way of sensitively broaching this highly personal issue with a child?

First things first: we all sweat to a greater or lesser extent. Sweating is actually healthy for us in some situations. For instance, when you go for a run, sweating helps your body to cool down. We also all smell to a greater or lesser extent, and the vast majority of adults will use some form of underarm roll-on or spray on a daily basis to help keep on top of the situation.

While smaller children may also sweat, BO usually begins around puberty, according to Chris Callewaert, senior post-doctoral researcher at Ghent University’s FWO Center for Microbial Ecology and Technology.

“With puberty, the body is going through hormonal changes,” explains Callewaert. “As well as more sebaceous sweat [the oily sweat all mammals excrete to lubricate their skin and hair] being produced, it also leads towards the activation of the apocrine sweat glands.

“They are only present in the armpits, nipples, anogenital area, ear canal and eyebrows. Most of the apocrine sweat glands are actually present in the armpits. The apocrine sweat glands produce a milky, fatty sweat solution, contrary to the eccrine sweat glands, which produce mostly water and salts.”

The armpit doctor will see you now

Callewaert, who has set up a science communication platform called Doctor Armpit (drarmpit.com) to share research in “armpit microbiology” in relation to BO, adds that, with the change in sweat-gland production as someone enters puberty, the skin microbiome also changes towards more lipophilic bacteria.

“The transformation of lipids, amino acids and typical apocrine secretions by these microbiota can result in malodour generation,” he says.

“Because of the high load of bacteria in the armpit, as well as many apocrine sweat glands, an odour can emanate. Sterile sweat does not smell; it’s the biotransformation of the fatty acids from the apocrine sweat glands by the bacteria that produces smaller and volatile molecules, and causes a body odour.”

Essentially, sweat alone doesn’t cause body odour, the breakdown of sweat by bacteria does. Earlier this year, researchers at the University of York, working with scientists from consumer goods giant Unilever, started looking into what exactly within that process causes the bad BO smell. The layman’s answer is a unique enzyme found only in the bacteria that lives in your armpit.

Michelle Rudden, a research associate in molecular microbiology in the department of biology at the University of York, worked on the project and she says that although the research provided some interesting answers, there are still a number of unanswered questions that require further exploration.

“The only thing that we know for sure is that the molecules are secreted from our sweat glands and it’s the bacteria that live in your underarm that can then uptick them and break them down to produce the body odour,” says Rudden.

“So, obviously, there are questions around ‘do some people produce more smelly bacteria or not?’, and ‘do we always produce the same amount?’, which are great questions but we don’t really know the answer.

“I’d suggest that it is quite dynamic. You generally will have a relatively stable population of bacteria that typically live in your underarm and you can have fluctuations.”

Breaking the taboo

Unfortunately, some children - like John - suffer from more malodorous BO than others but, at the moment, even experts like Rudden don’t really know why this occurs.

“They could just be producing more of the molecule or the compound that’s then available for the bacteria to break down or they can be producing different metabolites that are quite smelly,” she says.

Regardless of the severity of the problem, if you feel it’s got to the stage where you need to mention it to a child, then you have to tread carefully, says Callewaert.

Not all students will have been taught about proper hygiene at home and, depending on their living situation, not all will have easy access to clean clothes or a bathroom they can use whenever they want.

“It is a taboo condition, so it is sensitive and needs to be broached in a delicate way,” he says. “[But] the best way is directly informing someone about the condition. Better that than to hear it behind their backs.”

While Kate Mason, chartered clinical psychologist at Roots Psychology Group, agrees that caution is needed when broaching such a sensitive subject, she thinks a better approach would be to speak to the child’s parents first. “I would say that teachers, perhaps, are not best placed to address the pupil individually,” she says.

“But maybe talk sensitively to the parents initially, who may know how best to approach the issue with their child.

“I think for a teacher to approach a pupil themselves might be more embarrassing for the pupil. They may feel they have done something wrong or have been singled out, which may even elicit shame in the child.”

However, she warns that if teachers take this approach, there is a danger that parents may be protective of their child owing to the sensitivity of the subject matter. They may well feel that it isn’t a teacher’s place to advise them about a personal issue of this nature “which may cause issues in the parent-teacher relationship”.

As a result, Levy thinks the best plan of attack may actually be to “address the whole class in an educational way, still remaining sensitive but giving over the information of what body odour is, normalising it and offering advice on what they can do about it as a whole group, therefore not singling anyone out”.

In terms of what the children themselves can do to tackle a BO problem once it’s been identified to them, beyond properly cleaning their armpits on a regular basis, there are essentially two options available: antiperspirants and deodorants.

“Deodorants usually target the bacteria to try to inhibit them and antiperspirants will try to block your sweat pores,” says Rudden.

Both options work, and some people have a personal preference as to which they use and also which delivery mechanism - roll-on or spray - works best for them.

The good news is that, as a result of the work undertaken by the University of York researchers and Unilever, we may have moved a step closer to seeing a new generation of products available that are even more effective at tackling the age-old issue of BO.

“We have partnered up with Unilever and they’re working on trying to develop technologies that can specifically target body odour now that we know what causes it,” says Rudden. They are working on developing more targeted solutions “because we don’t want to a) be blocking up your sweat pores and b) we don’t want to eradicate your normal healthy microbiome because your bacteria are supposed to live there”, she says.

“So now that we’ve identified this enzyme, the theory might be to develop small molecules that only inhibit the enzyme but don’t really affect the bacteria.”

Armed with this knowledge about what causes BO - and about the wide range of different products on the market to help tackle it - hopefully teachers can give students like John the tools to eradicate their lingering BO issue once and for all.

Simon Creasey is a freelance journalist

This article originally appeared in the 14 May 2021 issue under the headline “Tes focus on...Body odour”