Body odour is one of those embarrassing conditions that most people go out of their way to mask. But they’re not always successful — anyone who’s found themselves face-to-pit with a smelly straphanger on the subway can attest to that.
But sometimes, the type of odour or a change in odour can reveal an underlying health condition.
Before you rush to analyze the kind of scent emanating from your body, keep in mind that body odour is completely natural and is the result of bacteria on the body breaking down protein into certain acids.
WATCH BELOW: Woman who sweats blood a medical mystery: doctors
“Body odour becomes stronger over time as more bacteria and sweat build up on the skin, and they interact with each other,” Dr. Joshua Zeichner, director of cosmetic and clinical research in dermatology at Mount Sinai Hospital in New York City, said to Allure. “This is not harmful, as healthy bacteria live symbiotically on our bodies.”
When should you be concerned about your smell
There are some rare conditions that can lead to excessive body odour and that can be hard to control. Trimethylaminuria, also known as fish odour syndrome, is a disorder that causes the sufferer’s urine, breath and sweat to smell like fish due to the body’s inability to metabolize trimethylamine, a gut compound. It’s a very rare condition and it’s unknown exactly how many people suffer from it, however, anecdotal evidence suggests it can be managed by avoiding consumption of fish, showering and changing clothing frequently, with antibiotics to control gut bacteria and with activated charcoal.
Some chronic conditions can also cause an unpleasant smell. Liver disease, diabetes and kidney issues are often accompanied by strong-smelling breath or body odour, and while the scents usually follow a diagnosis of these conditions, in some rare cases, doctors may use them as a guide to zeroing in on the disease.
In the case of liver disease, sufferers can experience excessive sweating and a foul-smelling odour that’s been likened to rotten eggs; diabetic ketoacidosis, which is the result of a blood-sugar spike, causes both fruity-smelling breath and a pungent body odour; and excessive sweat and odour can occur in people with kidney failure due to their overactive parathyroid gland.
Some people may find that they smell perfectly normal after a long run, but the minute their stress levels spike — whether it’s at work or at the dinner table with their in-laws — it can start to take on a pungent odour.
As it turns out, that’s because the sweat that’s secreted during exercise or when you’re in a hot environment comes from the eccrine glands, which are all over your body and work to release sweat to help cool you down. Your armpit, however, houses apocrine glands that kick into high gear when stress mounts.
Unlike the sweat that comes out of the eccrine glands, which is mostly water, the apocrine glands release a higher concentration of fat, lipids, and proteins resulting in a much stronger odour.
“When you’re feeling anxiety, the sympathetic system causes your hands, feet, and underarms to perspire,” Dr. Ramsey Markus, associate professor of dermatology at Baylor College of Medicine in Houston, said to Refinery29. “That’s priming you for action under the fight-or-flight response.”
You might be able to smell a person’s mood
Although it’s still a nascent field, some studies have been conducted on how moods like happiness, fear and disgust can actually be communicated through body odour. The message is carried through what’s called chemical signals or “chemosignals.”
In a study published in the journal Psychological Science, researchers from Utrecht University in the Netherlands found that the sweat secreted by test subjects when exposed to fear-inducing or disgust-inducing movies was able to elicit the same emotional responses in neutral subjects who smelled their sweat.
“If you were able to analyze the chemical composition, the biochemical signature of the odour, the types of things you could do with that are quite unlimited,” lead researcher Gün Semin said to The Globe & Mail. “Imagine that I give you a soap or a perfume that has the same biochemical composition as a happy sweat — I would be a rich man, probably.”