Body odour, also known as bromhidrosis, is the unpleasant smell that can occur when you sweat.
The sweat itself doesn’t smell. The unpleasant odour is produced by bacteria on the skin that break down the sweat into acids.
Sweating and body odor are facts of life for most people. Heavy perspiration and body odor can happen when you exercise, when you’re too warm, or when you’re nervous, anxious or under stress.
Your body has two main types of sweat glands, and they produce two very different types of sweat. Both types are odorless, but the type of sweat produced in your armpits and groin smells bad when it combines with bacteria found normally on your skin.
Unusual changes in sweating — either excessive perspiration (hyperhidrosis) or little or no perspiration (anhidrosis) — can be cause for concern. Likewise, changes in body odor may be a sign of a medical problem.
There are 3-4 million sweat glands on the human body. The two types of sweat gland are:
- eccrine glands – which are spread across the skin and regulate body temperature by cooling the skin with sweat when you get hot
- apocrine glands – which are mainly found in hairy areas of the body, such as the armpits and genital area; apocrine glands develop during puberty and release scented chemicals called pheromones
Sweat produced by the eccrine glands is usually odourless, although it can smell if bacteria start to break it down.
It can also take on an offensive odour if you consume certain food and drink, such as garlic, spices and alcohol, as well as some types of medication, such as antidepressants.
However, it’s the apocrine glands that are mainly responsible for body odour, because the sweat they produce contains high levels of protein, which bacteria find easy to break down.
People, who sweat excessively from their apocrine glands, or have a lot of bacteria on their skin, tend to have worse body odour.
Men are more likely to have body odour, because they tend to sweat more than women.
Sweat itself is virtually odorless to humans; it is the rapid multiplication of bacteria in the presence of sweat and what they do (break sweat down into acids) that eventually causes the unpleasant smell. The smell is perceived as unpleasant, many believe, because most of us have been brought up to dislike it. Body odor is most likely to occur in our feet, groin, armpits, genitals, pubic hair and other hair, belly button, anus, behind the ears, and to some (lesser) extent on the rest of our skin.
Body odor can have a nice and specific smell to the individual, and can be used – especially by dogs and other animals – to identify people. Each person’s unique body odor can be influenced by diet, gender, health, and medication.
TWO TYPES OF ACID ARE COMMONLY PRESENT WHEN THERE IS BODY ODOR:
- Propionic acid (propanoic acid) is commonly found in sweat – propionibacteria break amino acids down into propionic acid. Propionibacteria live in the ducts of the sebaceous glands of adult and adolescent humans. Some people may identify a vinegar-like smell with propionic acid, because it is similar to acetic acid, which gives vinegar its sour taste and pungent smell.
- Isovaleric acid (3-methyl butanoic acid) is another source of body odor as a result of actions of the bacteria Staphylococcus epidermidis, which are also present in several strong cheese types.
WHY DO PEOPLE GET SMELLY FEET (BROMODOSIS)?
Most of us wear shoes and socks, making it much more difficult for the sweat to evaporate, giving the bacteria more sweat to break down into smelly substances. Moist feet also raise the risk of fungi developing, which can also give off unpleasant smells.
HOW TO PREVENT BAD BODY ODOUR?
- Wash your body regularly, especially underarms, groin and feet. Dry your feet completely after you have washed them.
- Change and wash your clothes often.
- Let your shoes dry completely before wearing them again. If possible, wear different shoes on alternate days.
- Cotton socks might be better than synthetic socks, but the most important thing is to wash your feet daily, and change your socks daily if possible.
- If someone has told you that you have an unpleasant body odour, and you think that might be true, you could try an antibacterial soap when you wash your body. Most people do not need this.
DEODORANTS AND ANTI-PERSPIRANTS
Once you start going through puberty, it may be a good idea to start using underarm deodorants and anti-perspirants.
- Underarm deodorants make the sweat acidic which stops bacteria from growing. We still make the same amount of sweat, but there are fewer bacteria to make the smell.
- Anti-perspirants block the sweat ducts with aluminium salts, so that less sweat is produced. Less sweat equals fewer bacteria and less smell. They should only be used on underarms – you need to be able to sweat over the rest of your body to keep yourself healthy.
- There is no evidence that these products are linked to any health problems.
- Some deodorants are highly perfumed. Make sure that you are not replacing one smell with another one that other people will not enjoy either.
- Some people may be allergic to deodorant sprays and perfumes, so don’t spray them around other people in change rooms.
WHEN TO SEE YOUR DOCTOR?
Some medical conditions may change how much a person sweats, while others can alter how we sweat, subsequently changing the way we smell. For example, hyperthyroidism (an over-active thyroid gland) or the menopause can make people sweat much more, while liver disease, kidney disease, or diabetes can change the consistency of sweat so that the person smells differently.
You should see your doctor if:
- You start sweating at night
- You start sweating much more than you normally do, without any logical reason
- You have cold sweats
- Sweating disrupts your daily routine
- You body smells differently – if it is a fruity smell it could be due to diabetes, liver or kidney disease often makes the individual have a bleach-like smell.