Professor Stefan Zimmer is head of the Dental Clinic at the University of Witten/Herdecke. © private
Mr. Zimmer, what are probiotic bacteria anyway?
These are live bacteria that are part of any healthy oral flora. Their job is to push back the anaerobic bacteria that indicate unhealthy oral flora and cause bad breath.
In what form are there probiotics against bad breath?
They are usually offered as a dietary supplement in the form of lozenges or chewing gum, but also as a mouthwash solution.
Which probiotic bacteria are used?
They are called, for example, Lactobacillus salivarius, reuteri and acidophilus, Streptococcus salivarius and Weissella cibaria. The latter bacterium has been shown to inhibit the formation of volatile sulfur compounds that cause bad breath.
Details on the current probiotics study
For their meta-analysis, published in the journal BMJ Open, the authors searched medical databases for studies addressing the effect of probiotics on bad breath. Of more than 200 studies, seven met the requirements for a high-quality study design. Result of the analysis: Probiotics reduce the noticeable bad breath. The volatile sulfur compounds decrease for a short period of four weeks.
How exactly is bad breath caused?
Around 80 percent of bad breath originates in the oral cavity and only around 20 percent in the nose, throat or gastrointestinal tract. There is the “normal” bad breath in the morning, which is caused by the low level of salivation at night and the resulting increased nocturnal metabolic activity of bacteria. Garlic, onions, smoking or alcohol can of course also cause bad breath.
Bad breath has other causes. It is formed in the oral cavity mainly by anaerobic bacteria that break down sulphur-containing amino acids. In the process, so-called volatile sulfur compounds are formed, which smell unpleasant. The bacteria are mainly found in the back third of the tongue. But they can also collect in the spaces between the teeth and gum pockets.
What should those affected do if they have bad breath?
A good start is a professional teeth cleaning. The odor-causing bacteria are removed from all niches. Sometimes periodontitis treatment is also required. At home, good oral hygiene is important, with regular cleaning of the spaces between the teeth and the back of the tongue. The deposits can be scraped off with a tongue cleaner combined with an antimicrobial toothpaste. An antibacterial mouthwash solution can complement this cleaning.
If possible causes in the oral cavity have been eliminated and the bad breath is still there, an internist should be consulted to look for causes outside the mouth.
Do you recommend taking probiotics for bad breath?
The study situation is not yet so convincing that I would like to recommend it as the sole therapy. In addition, probiotics do not reduce the amount of bacteria in the oral cavity. I see them mainly as a means to stabilize a healthy environment in the mouth. After professional teeth cleaning and good oral hygiene, I recommend using them for four weeks on a trial basis.
Do probiotic foods like yoghurt also help against bad breath?
I cannot recommend an increased consumption of yoghurt. Yoghurt contains the bacteria Lactobacillus bulgaricus and Streptococcus thermophilus. They are related to those in probiotics. There is also a lab study showing that one of the yogurt bacteria inhibits the formation of volatile sulfur compounds in an anaerobic bacterium. However, I am not aware of any clinical studies that conclusively prove an effect against bad breath.