Bad breath, also called halitosis, can be so telling that doctors may even be able to use it to identify diabetes. Recently, researchers have found that infrared breath analyzers can be effective in identifying prediabetes or early-stage diabetes.

Your breath has an interesting ability to provide clues to your overall health. A sweet, fruity odor can be a sign of ketoacidosis, an acute complication of diabetes. An odor of ammonia is associated with kidney disease. Similarly, a very foul, fruity odor may be a sign of anorexia nervosa. Other diseases, such as asthma, cystic fibrosis, lung cancer, and liver disease, also can cause distinct odors on the breath.

Diabetes-related halitosis has two main causes: periodontal disease and high levels of ketones in the blood.

Periodontal diseases

Periodontal diseases, also called gum diseases, include gingivitis, mild periodontitis, and advanced periodontitis. In these inflammatory diseases, bacteria attack the tissues and bone that support your teeth. Inflammation can affect metabolism and increase your blood sugar, which worsens diabetes.

While diabetes can lead to periodontal diseases, these diseases can also create further problems for people with diabetes. According to a report in IOSR Journal of Dental and Medical Sciences, an estimated one in three people with diabetes will also experience periodontal diseases. Heart disease and stroke, which can be complications of diabetes, are also linked to periodontal disease.

Diabetes can damage blood vessels, which can reduce blood flow throughout your body, including your gums. If your gums and teeth aren’t receiving a proper supply of blood, they may become weak and more prone to infection. Diabetes may also raise glucose levels in your mouth, promoting bacteria growth, infection, and bad breath. When your blood sugars are high, it becomes hard for the body to fight infection, which makes it harder for the gums to heal.

If someone with diabetes gets a periodontal disease, it may be more severe and take longer to heal than in a person without diabetes.

Bad breath is a common sign of periodontal disease. Other signs include:

red or tender gums

bleeding gums

sensitive teeth

receding gums

Ketones

When your body can’t make insulin, your cells don’t receive the glucose they need for fuel. To compensate, your body switches to plan B: burning fat. Burning fat instead of sugar produces ketones, which build up in your blood and urine. Ketones can also be produced when you’re fasting or if you’re on a high-protein, low-carbohydrate diet, although not to the same level as they are in diabetic ketoacidosis.

High ketone levels often cause bad breath. One of the ketones, acetone (a chemical found in nail polish), can cause your breath to smell like nail polish.

When ketones rise to unsafe levels, you’re at risk of a dangerous condition called diabetic ketoacidosis (DKA). Symptoms of DKA include:

a sweet and fruity odor on your breath

more frequent urination than normal

abdominal pain, nausea, or vomiting

high blood glucose levels

shortness of breath or difficulty breathing

confusion

DKA is a dangerous condition, mostly limited to people with type 1 diabetes whose blood sugars are uncontrolled. If you have these symptoms, seek medical help immediately.