When Alice Dogruyol’s boyfriend told her that she had bad breath, she was mortified. So she began brushing her teeth obsessively, chugging water and carrying breath sprays wherever she went – but nothing would get rid of the heavy odour that left a sour taste in her mouth and shattered her confidence.
‘I’d never experienced anything like it before,’ says Alice, 49, a publicist from London. ‘My boyfriend said my breath smelled like nail varnish remover, which was very strange but I could actually taste it in my mouth.’
It took a year – and a host of other unpleasant symptoms, including recurrent fungal infections and rapid weight loss – for Alice to realise her problem wasn’t caused by poor oral hygiene. Instead, it was a life-threatening complication of type 1 diabetes.
The condition, called diabetic ketoacidosis, happens when high blood sugar and a lack of insulin cause the body to rapidly burn fat for energy, producing chemicals known as ketones. These have a distinctive acetone, or pear-drop, smell and are emitted through the breath and sweat.
Without urgent treatment, diabetic ketoacidosis can ultimately lead to unconsciousness, coma and even death.
Just before Christmas in 2020, after several attempts to resolve Alice’s growing list of symptoms, a nurse suggested she be tested for type 1 diabetes. This led to her diagnosis in January 2021 and the start of insulin treatment, after which the bad breath disappeared.
Confusingly, Alice had previously been diagnosed with type 2 diabetes in 2019 – a misdiagnosis that delayed her access to the correct treatment.
The difference is crucial. People with type 1 diabetes can no longer make the hormone insulin, so they need daily injections to survive.
When Alice Dogruyol’s boyfriend told her that she had bad breath, she was mortified. So she began brushing her teeth obsessively, chugging water and carrying breath sprays everywhere
After a year and a host of other unpleasant symptoms Alice realised her problem wasn’t caused by poor oral hygiene. Instead, it was a life-threatening complication of type 1 diabetes
People with type 2 diabetes still make insulin, but their bodies struggle to use it properly, meaning many can initially control the condition with diet, exercise and medication.
A study by researchers at the University of Exeter found that 38 per cent of adults with type 1 diabetes diagnosed after the age of 30 were initially treated as having type 2 diabetes and were not given the insulin they needed.
‘By the time I was diagnosed, my symptoms were outrageous,’ says Alice. ‘I remember feeling like I was dying. Doctors said I was a week away from a coma.’
Alice’s experience highlights a little-known fact: changes in the way a person smells – whether on the breath, skin, sweat or urine – can sometimes be one of the earliest signs that something is wrong.
Dr Dean Eggitt, a GP at The Oakwood Surgery in Doncaster, explains: ‘When people have diseases, the chemical composition of the body changes.
‘These chemicals – which have their own unique smells – are naturally excreted through sweating, breathing and going to the toilet.’
He is keen to stress that bad breath is not always a sign of a serious disease, as hygiene habits, strongly flavoured foods, dental issues and common infections such as tonsillitis are usually the culprits. He says: ‘It’s all about context. I wouldn’t necessarily say that a 40-year-old who smells a bit funny has an underlying disease, but if they are generally unwell and their new smell comes alongside new symptoms, it should be a red flag.’
Another condition often associated with a characteristically strong smell is advanced liver failure, or cirrhosis. The distinct, musty, sweet or sulphur-like body odour occurs when the liver loses its ability to properly filter toxins from the bloodstream. This causes sulphur-containing compounds to build up in the blood and be exhaled through the lungs.
‘I would describe the smell as like an old granny’s house, where it’s a little bit stale and mouldy,’ says Dr Eggitt. This is usually combined with other symptoms, such as jaundice, confusion or abdominal swelling.
Similarly, chronic kidney disease, which affects about one in ten adults in the UK, can cause an unpleasant ammonia-like smell known as uraemic breath. This happens when failing kidneys struggle to filter toxins, causing a dangerous build-up of waste in the bloodstream and saliva.
While a potent smell on a person’s breath is often very noticeable, some conditions alter their smell in ways that are too subtle for most people to detect.
In 2015, retired nurse Joy Milne, who has a rare condition called hyperosmia which gives her a heightened sense of smell, made headlines after proving she could smell Parkinson’s disease.
She had first noticed a distinct, musty odour on her husband 12 years before he was diagnosed with the condition, and later correctly identified Parkinson’s from sufferers’ T-shirts, inspiring a new skin swab test that detects the distinct chemical biomarkers.
‘All of these smells come from chemicals that continuously release gases,’ explains Dr Eggitt. ‘The body will give off these compounds depending on what is happening to it.’
Using this, researchers are developing what is known as an ‘electronic nose’ to capture and analyse these specific chemicals in a clinical setting in the hope of detecting diseases such as cancer.
Professor Victoria Tzortziou Brown, of the Royal College of GPs, says: ‘Changes in a person’s body odour or breath can provide a clinical clue that something isn’t quite right – but they are very unlikely to be used in isolation to diagnose a health condition.
‘Smell is just one small part of a much wider clinical assessment. Diagnosis is based on a patient’s symptoms, medical history, examination findings and, where appropriate, investigations and tests.’
Alice’s advice is simple: ‘Instead of masking the bad smell, I wish I had taken it seriously because it was a very strong warning sign that I was unwell. Had I known the change in my breath was a sign of how unwell I was, I might have pushed for a diagnosis sooner.’
