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A new study suggests that four probiotics found in fermented foods can help reduce the sulphuric compounds that cause bad breath. Design by MNT; Photography by Carmen Palma/Stocksy & Ivona Zivulj/Stocksy
  • One of the main sources of halitosis, otherwise known as bad breath, is the buildup of volatile sulphuric compounds in the mouth produced by anaerobic bacteria that feed on food left behind.
  • A new meta-analysis found that the ingestion of four probiotics can reduce the compounds that cause bad breath, at least in the short term.
  • The four beneficial probiotics are Lactobacillus salivarius, Lactobacillus reuteri, Streptococcus salivarius, and Weissella cibaria, all of which may benefit gut health. They are found in fermented foods.

There are many possible causes of persistent bad breath, or halitosis, with poor dental hygiene as a main contributing factor.

A recent meta-analysis suggests that certain probiotics can address one of the main causes of bad breath. The findings show that probiotics help eliminate the buildup of foul-smelling volatile sulphuric compounds, or VSCs, in oral biofilms.

The authors of the analysis report that Lactobacillus salivarius, Lactobacillus reuteri, Streptococcus salivarius, and Weissella cibaria, which are found in fermented foods,reduce volatile sulphuric compounds for up to 4 weeks compared to control groups.

The results of the study were recently published in BMJ Open.

To conduct the meta-analysis, the researchers examined the results of seven randomized controlled trials (RTCs) involving 278 participants.

The number of participants in each study varied from 23 to 68, and individuals’ ages ranged from 19 to 70.

Each study was analyzed to measure halitosis subjectively and objectively for up to 12 weeks.

The researchers detected halitosis levels from participants who had closed their mouths for 1 minute before exhaling into the evaluator’s nose from 10 centimeters away. Their subjective impressions produced organoleptic scores (OLPs), which are based on senses like smell and taste.

Next, volatile sulphuric compounds, or VSCs, were objectively measured using a halimeter, an instrument that detects and measures the presence of gases.

VSCs are produced by anaerobic bacteria interacting with food remaining in the mouth due to insufficient dental hygiene.

Michelle Routhenstein, MS, RD, CDE, CDN, a cardiology dietitian at EntirelyNourished.com, explained to Medical News Today:

“Specific bacteria can live in the mouth and break down food, leading to the production and release of volatile sulphuric compounds that contribute to bad breath. The bacteria that are most associated with halitosis are gram-negative bacteria.”

The new study identified four beneficial probiotics containing gram-positive bacteria.

Such bacteria alter “the oral microbiota to reduce the buildup of these volatile sulphuric compounds,” Routhenstein explained.

The authors of the present study cite a growing body of evidence that probiotics can crowd out the bacteria responsible for decomposing amino acids and proteins.

The findings show a significant decrease in halitosis according to both measurement methods they used.

Compared to control groups, OLP scores decreased by 58%, while VSC scores dropped by 26%.

According to the VSC scores, however, the positive effect of the probiotics did not last beyond 4 weeks. But the improvement in OLP scores remained beyond 4 weeks.

The analysis also found that probiotics do not address the other two major sources of halitosis, plaque buildup, and tongue-coating. However, one of the studies showed some beneficial effects on plaque buildup at 12 weeks.

As a meta-study, the authors note weaknesses in the original research that need to be considered as limitations in their meta-analysis.

There were significant differences between the studies regarding methodology, data reported, and risk of bias in their assessments.

People may try various means of reducing bad breath, including teeth-scaling, tongue-scraping, and mouthwash.

Others may try to improve their breath with gum chewing, which may not be the most effective option in the long term.

“When you chew, you set your body up to trigger stomach acid and digestive enzymes. When there is no food coming in, you set yourself up for GERD [or] acid reflux and more dental problems,” Lyn-Genet Recitas, nutrition expert and bestselling author of “The Plan” and “The Metabolism Plan,” told MNT.

“Oral health, or lack thereof, has been linked to many diseases: rheumatoid arthritis, diabetes, respiratory illness, and even heart disease.”

The authors of the present study suggest that probiotics may improve oral hygiene by fighting bad breath.

Probiotics are living organisms, beneficial bacteria and yeasts that occur naturally in the human body. They may be consumed as supplements or in foods.

While both methods may deliver benefits, a 2016 meta-analysis found that consuming probiotics found in food sources may be the optimal way to obtain them.

To benefit from the probiotics Lactobacillus salivarius, Lactobacillus reuteri, and Streptococcus salivarius, Routhenstein recommended fermented foods such as yogurt, kefir, kimchi, and pickled beetroot.

“Having a variety of probiotic-rich foods can benefit not only the oral microbiota but also the gut microbiome, which is an important component to overall health and heart health, specifically,” Routhenstein said.

Recitas added that miso and real sauerkraut, fermented cheeses, and sourdough bread are other great food sources of probiotics, noting that the Weissella cibariais bacteria found in these foods allow them to ferment.