What are the causes of bad breath (Halitosis)?

Bad breath is a common problem that can cause significant psychological distress and it’s the third most common reason that people seek dental care.

The most common cause of bad breath is poor dental hygiene. As bacteria break down particles of food, sulfur compounds are produced that cause odor.

There are a number of potential causes for bad breath which include:

  • Tobacco: tobacco products cause their own types of mouth odor. Additionally, they increase the chances of gum disease which can also cause bad breath.
  • Food: the breakdown of food particles stuck in the teeth can cause odors. Some foods such as onions and garlic can also cause bad breath. After they are digested, their breakdown products are carried in the blood to the lungs where they can affect the breath.
  • Dry mouth: saliva naturally cleans the mouth. If the mouth is naturally dry (for instance, in the morning) or is dry due to a specific disease (such as Xerostomia), odors can build up.
  • Dental hygiene: brushing and flossing ensure the removal of small particles of food that can build up and slowly break down, producing odor. A film of bacteria called plaque builds up if brushing is not regular. This plaque can irritate the gums and cause pockets of build-up between the teeth and gums called periodontitis. Dentures that are not cleaned regularly or properly can also harbor bacteria that cause halitosis.
  • Crash diets: fasting and low-carbohydrate eating programs can produce halitosis; this is due to the breakdown of fats producing chemicals called ketones. These ketones have a strong aroma.
  • Drugs: certain medications can reduce saliva and, therefore, increase odors. Other drugs can produce odors as they breakdown and release chemicals in the breath. Examples include nitrates used to treat angina, some chemotherapy chemicals and some tranquilizers, such as phenothiazines. Individuals who take vitamin supplements in large doses can also be prone to bad breath.
  • Mouth, nose and throat conditions: sometimes small, bacteria covered stones can form on the tonsils at the back of the throat and produce odor. Also, infections in the nose, throat or sinuses can cause halitosis.
  • Diseases: liver failure and other metabolic diseases can cause halitosis due to specific mixes of chemicals that they produce. Gastroesophageal reflux disease can cause bad breath due to the regular reflux of stomach acids.