Bowl of yogurt with fruit

A breakfast of yogurt and fruit (Photo by Vicky Ng on Unsplash)

LONDON — Looking to get rid of bad breath? A new study finds eating yogurt and other fermented foods could be the answer. Researchers in China say probiotic bacteria in foods like yogurt, sourdough bread, and miso soup can help dispel the embarrassing problem.

Specifically, Lactobacillus salivarius, Lactobacillus reuteri, Streptococcus salivarius, and Weissella cibaria may help freshen the breath, according to results of a pooled data analysis, where participants consumed these bacteria in the form of supplements.

Halitosis, better known as bad breath, is primarily the result of volatile sulphuric compounds. Scientists say the compounds come from mouth bacteria resulting from bacterial mixing and food debris tied to poor dental hygiene. Typical options for fighting halitosis include mouthwashes, chewing gum, teeth scaling, and tongue scraping.

However, scientists note that there is emerging evidence pointing to probiotic bacteria as a simpler alternative. To find out how long any such effects might last, the researchers reviewed databases for relevant clinical trials published up until February 2021.

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Out of an initial 238 records, the team focused on seven studies, involving a total of 278 people. The number of participants in each study was small, ranging from 23 to 68, with an age range between 19 and 70 years-old. The studies lasted anywhere from two to 12 weeks.

The team defined bad breath severity according to the levels of volatile sulphuric compounds detected in the mouth or each person’s OLP score, which measures breath odor at various distances from the mouth.

Tongue coating scores (three studies) and the plaque index (three studies) were also included in the analysis because an unclean tongue and the build-up of tartar between the teeth are often major causes of bad breath.

The pooled data analysis, published in BMJ Open, shows that OLP scores fell significantly in those taking probiotics compared with those in the control groups, irrespective of the length of the monitoring period.

Researchers observed a similar result for the levels of volatile sulphuric compounds detected, although these varied “substantially” in the individual studies. The observed effects were also relatively short-lived — up to four weeks, after which there was no noticeable difference. However, there were no significant differences in tongue coating scores or plaque index between those consuming probiotics and those who didn’t.

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Study authors believe probiotics “may inhibit the decomposition of amino acids and proteins by anaerobic bacteria in the mouth, so curbing the production of smelly by-products.”

However, the researchers caution that these findings come from studies with small sample sizes, with some of the data providing incomplete results.

“This systematic review and meta-analysis indicates that probiotics (eg, Lactobacillus salivarius, Lactobacillus reuteri, Streptococcus salivarius and Weissella cibaria) may ease halitosis by reducing the [volatile sulphuric compound] concentration levels in the short term, but there is no significant effect on the major causes of halitosis, such as plaque and tongue coating,” the study authors conclude in a media release.

“More high-quality randomized clinical trials are required in the future to verify the results and to provide evidence for the efficacy of probiotics in the management of halitosis.”

South West News Service writer Stephen Beech contributed to this report.

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