Bad breath, medically known as halitosis, affects millions of people worldwide. While the causes can be varied—from poor oral hygiene to gastrointestinal diseases—bacterial imbalances in the mouth play a central role. This is where probiotics come in. Not only are they important for the gut, they can also specifically support the oral microbiome and help effectively combat bad breath.
How does bad breath arise and what role do bacteria play?
Bad breath is primarily caused by volatile sulfur compounds (VSCs), which are produced by anaerobic bacteria in the mouth. These bacteria break down proteins from food residue, saliva, or dead cells, releasing foul-smelling substances such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide. The surface of the tongue, in particular, provides ideal conditions for these bacteria.
A healthy oral microbiome contains both "good" and "bad" microorganisms. However, when this balance is disrupted—for example, due to inadequate oral hygiene, antibiotics, or certain diseases—odor-causing bacteria gain the upper hand.
Probiotics as natural support against bad breath
Probiotics are live microorganisms that, when administered in sufficient quantities, have beneficial effects on the host. While probiotics are often associated with digestive health, research is increasingly showing that they can also be effective locally in the oral cavity.
Probiotic bacteria can balance the oral microbiome by:
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displace pathogenic germs (competitive inhibition),
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produce antibacterial substances (e.g. bacteriocins),
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stimulate the immune system in the mouth and
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Reduce inflammation.
Through these mechanisms, they can specifically combat the main causes of bad breath.
Streptococcus salivarius: The star among oral probiotics
A particularly promising probiotic against bad breath is Streptococcus salivarius , a natural inhabitant of the human oral flora. Healthy people typically have high concentrations of this bacterium, while people with frequent bad breath often have lower levels.
The two strains Streptococcus salivarius K12 and M18 are particularly interesting:
Streptococcus salivarius K12
The K12 strain is particularly well-studied. It produces specific antimicrobial peptides (bacteriocins) called salivaricin A2 and salivaricin B, which can specifically suppress pathogenic bacteria responsible for bad breath—including various species of Fusobacterium and Porphyromonas.
Studies have shown that regular use of S. salivarius K12 (e.g., in lozenge form) can significantly reduce the amount of odor-causing bacteria on the tongue and sustainably improve bad breath. Additionally, it has been observed that K12 can also prevent sore throats by protecting against certain throat infections.
Streptococcus salivarius M18
While K12 primarily targets the control of bad breath and sore throat, M18 offers additional benefits for oral health. M18 not only produces bacteriocins, but also enzymes such as dextranase and urease. These enzymes help reduce plaque accumulation and stabilize the pH in the mouth, which in turn reduces the formation of cavities and gum disease.
Indirectly, this also helps prevent bad breath, as plaque and gingivitis can be major sources of bad odors.
Other probiotics with potential
In addition to Streptococcus salivarius, there is evidence that other probiotic strains may also play a role in combating bad breath:
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Lactobacillus reuteri : Studies suggest that this strain positively influences the oral microbiome and reduces inflammation in the gum area.
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Lactobacillus rhamnosus : Also associated with better oral health and less plaque.
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Weissella cibaria : Produces hydrogen peroxide, which acts against anaerobic bacteria that cause bad breath.
These strains are usually used as a supplement or in combination with other probiotics to achieve a more comprehensive effect.
Application and tips
If you want to use probiotics to combat bad breath, consider the following:
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Formulation : Lozenges, mouthwashes or oral sprays work best because they are released directly into the mouth.
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Regularity : Probiotics must be used regularly, ideally daily for several weeks.
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Accompanying measures : Good oral hygiene (brushing teeth, cleaning the tongue, flossing) remains essential. Adequate fluid intake is also important to stimulate saliva production.
Conclusion
Probiotics, particularly Streptococcus salivarius K12 and M18 , offer promising natural support for bad breath. By restoring a healthy oral microbiome and specifically eliminating odor-causing germs, breath can become noticeably fresher. Therefore, anyone suffering from recurring bad breath and suspecting the cause is in the mouth should consider trying specially formulated probiotics – ideally in consultation with a dentist or specialist.
