Diabetes and Bad Breath: Why It Happens and What You Can Do

Text Size:
Diabetes and Bad Breath: Why It Happens and What You Can Do

No one likes having bad breath, although it happens to everyone at one time or another. Socially, it can be embarrassing and anxiety provoking (especially if you’re on a job interview or a date!), but it can also be annoying and downright concerning if the cause is an underlying health condition. How is bad breath linked to diabetes? And what can you do to stop it?

What is bad breath?

The medical term for bad breath is halitosis (Latin for “bad breath”), and it’s more common than you may think. The Cleveland Clinic’s website states that “1 out of 4 people around the globe” are affected by this, and research indicates that about 32% of the population is afflicted.

Halitosis that doesn’t go away is called chronic halitosis, and it can be a warning that something else is going on besides overdoing the garlic or not regularly brushing your teeth.

To get cutting-edge diabetes news, strategies for blood glucose management, nutrition tips, healthy recipes, and more delivered straight to your inbox, sign up for our free newsletters!

What causes bad breath?

There are many possible causes of bad breath; some are more common than others.

Poor oral hygiene

This is one of the most common causes of halitosis. Failing to properly brush and floss your teeth, not properly cleaning dentures, and not getting regular dental cleanings leads to a film of bacteria that coat your teeth and tongue. This can lead to a foul odor, and eventually cause periodontitis, or gum disease. Periodontal disease affects the tissues and bones that support your teeth. In addition, periodontal disease may cause inflammation and infection, and for people who have diabetes, this spells double trouble, as it can lead to high blood sugar levels. High blood sugars, in turn, provide food for the bacteria in your mouth, which can cause plaque buildup. If you aren’t getting your routine dental cleanings, plaque can cause tooth decay and gum disease, both of which can cause bad breath.

Dry mouth

Also called xerostomia, dry mouth means that you don’t have enough saliva in your mouth. Saliva is a good thing, since it helps to keep your mouth clean by removing food and other particles that can cause odor. You might notice that your mouth is dry when you wake up in the morning and others might notice your pungent “morning breath.” Causes of dry mouth include medications, smoking, cancer treatment, Sjogren’s syndrome, and diabetes.


Smoking cigars or cigarettes, as well as using oral tobacco products, can lead to unpleasant smelling breath all on their own, but they can also cause gum disease, which only worsens the situation. Vaping can also cause bad breath: a study published in the journal iScience showed that e-cigarettes increased bacteria levels in the mouth, which not only caused bad breath but raised the risk of infection, cavities, and oral cancer.


Not surprisingly, various foods can cause stinky breath. Typical culprits include onions, garlic, fish, and spicy foods. When you eat these foods, bacteria in the mouth feed on them, but after you digest them, they enter the bloodstream, are carried to your lungs, and then cause bad breath. Coffee and alcohol are other culprits that can lead to halitosis.

Medical conditions

Acid reflux (also called gastroesophageal reflux, or GERD, for short), diabetes, kidney disease, liver disease, pneumonia, cystic fibrosis, and some types of cancer can cause bad breath. Post-nasal drip, tonsil stones, and any infection of the nose, throat, or mouth can, too.

Certain diets

You might have bad breath if you follow a very-low-carb diet or a keto diet. That’s because these diets cause the formation of ketones, which can impart a fruity or acetone smell to your breath.

Why are people with diabetes more likely to have bad breath than people without diabetes?

Two of the main causes of bad breath in people with diabetes are diabetic ketoacidosis (DKA) and periodontal disease.


DKA happens when there isn’t enough insulin in the body. Since insulin is needed to move glucose from the blood into cells for energy, the body shifts to using fat for fuel. This leads to the production of ketones which give a fruity or nail polish (acetone) smell to the breath. DKA is more common in those with type 1 diabetes, but it can happen in those with type 2 diabetes, as well. DKA is a very serious medical condition that needs immediate treatment.

Periodontal disease

Periodontal disease, as mentioned above, happens more often in people with diabetes due to constant high blood sugars. In fact, one study showed that periodontal disease showed that the prevalence in people with diabetes in the U.S. was 58%. These high blood sugars promote bacterial growth, as well as inflammation and infection, and cause bad breath. Periodontal disease is another serious condition that requires prompt attention to help avoid tooth loss.

Other factors that put people with diabetes at risk for having bad breath include:

  • Having kidney disease.
  • Having dry mouth.
  • Taking certain medications, such as some antidepressants, antihistamines, or diuretics.
  • Following a very-low-carb or keto diet to help with blood sugar management.

How can you banish bad breath?

While occasional bad breath from, say, drinking coffee or eating a lot of garlic isn’t generally cause for concern, constant foul-smelling breath is worrisome. Here’s what you can do:

  • Let your health care provider know. You may have an underlying medical condition that needs further evaluation and treatment.
  • Focus on good oral hygiene, which means brushing your teeth at least twice daily and flossing once a day. If you wear dentures, make sure they fit properly and clean them well every night. Invest in a metal tongue scraper to help remove bacterial film that can coat your tongue.
  • See your dentist or dental hygienist at least twice a year for cleanings. Let them know if you have any teeth that are bothering you. Also, ask about special antibacterial toothpaste and antiseptic mouthwash.
  • Stop smoking and using tobacco of any kind.
  • Keep your mouth moist. Drinking water regularly, chewing sugar-free gum, and using over-the-counter products to help treat dry mouth, such as sprays, gels, and toothpastes, can help. Using a humidifier can be helpful, too, especially when you are sleeping.
  • Rethink your diet. Go easy with pungent foods like garlic, onions, and spicy foods. Consider adding these foods into your eating plan: plain yogurt, green tea, raw vegetables, and herbs such as parsley, basil, and fennel.
  • Remember that high blood sugars can set off events that can cause bad breath. These include periodontal disease and DKA. Talk with your provider or diabetes educator about how you can adjust your diabetes treatment plan to bring and keep your blood sugars down.

Want to learn more about keeping your mouth healthy with diabetes? Read “Diabetes and Dental Care,” “Four Ways to Improve Your Oral Health,” and “Practice Good Oral Health for Diabetes.”

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES on social media

A Registered Dietitian and Certified Diabetes Educator at Good Measures, LLC, where she is a CDE manager for a virtual diabetes program. Campbell is the author of Staying Healthy with Diabetes: Nutrition & Meal Planning, a co-author of 16 Myths of a Diabetic Diet, and has written for  publications including Diabetes Self-Management, Diabetes Spectrum, Clinical Diabetes, the Diabetes Research & Wellness Foundation’s newsletter, DiabeticConnect.com, and CDiabetes.com

Save Your Favorites

Save This Article