Why do certain foods cause bad breath (halitosis)?

Jonathan B. Levine, DMD
Many different foods encourage bad breath. Some are obvious; others may influence you to change your usual menu selections.
  • High-protein foods:  Bacteria love glomming onto proteins, so high-protein foods contribute generously to halitosis. Top contenders are fish, red meat and beans.
  • Coffee: Caffeinated or not, coffee contains high levels of acid, and bacteria love acid as much as they love protein. Acid, however, also causes bacteria to reproduce more rapidly, resulting in a bitter taste in the mouth.
  • Onions and garlic: Both are packed with odorous molecules that are actually sulfur compounds themselves.
  •   Sugar: Sugar fuels bacteria to reproduce and create even more volatile sulfur compounds. Sugar can attract other bacteria and produce glycan strands with it, which result in thick layers of plaque on tooth enamel and around the gums. This leads to decay and gingivitis, which translates into worse breath.
  • Acidic foods and drinks: Along with aiding bacteria reproduction, acids are also great at creating sour, bitter and/or metallic tastes in the mouth.
  • Dairy products: Lactose intolerance causes more than stomach discomfort. It means the inability to breakdown the lactose protein that's in dairy foods. This results in a buildup of amino acids, which easily convert into volatile sulfur compounds thanks to the anaerobic bacteria in the tongue.
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What you eat affects the air you exhale. Once the food is absorbed into the bloodstream, it is transferred to the lungs, where it is expelled. Brushing, flossing and mouthwash will only mask the odor temporarily. Odors continue until the body eliminates the food.
When you eat, food is broken down into small particles called molecules, which are absorbed into the bloodstream and transferred to the lungs. Each time you exhale (breathe out), the smells of foods with strong odors such as onions and garlic, are released until you fully eliminate them from your body.

Continue Learning about Bad Breath (Halitosis)

Bad Breath (Halitosis)

The easy cases of bad breath can be fixed by brushing and flossing. Drink lots of water. Use mouthwash and remember to brush your tongue too. But there are other things that can cause bad breath. Smoking is an obvious culprit. Foo...

ods like garlic and onions can cause bad breath long after you brush them out of your mouth. Dry mouth can cause bad breath, drinking plenty of water helps, as does chewing gum. Some illnesses and medicines may also cause bad breath, and plaque or tartar on teeth and gum disease may also contribute.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.