Alcohol damages microbiome in the mouth

By Dr. Ananya Mandal, MDApr 25 2018

A new study has shown that alcohol alters and damages the natural bacterial environment in the mouth. The study titled, “Drinking alcohol is associated with variation in the human oral microbiome in a large study of American adults,” published this week (24th April 2018) in the journal Microbiome explored the effects of alcohol on these bacterial compositions within the mouth.

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The bacteria present over the mucosal surfaces of the body that help in a variety of functions including maintaining normal immunity are part of the microbiome. Some of these bacteria are good for the body while some strains of these bacteria may raise the risk of oral disease including gum ailments and even cancer. The study noted that some strains of these bacteria that are associated with a raised risk of oral and other cancers, heart disease and gum infections are increased in persons who consume alcohol. This has been shown earlier among animals, this is the first time that similar findings have been demonstrated among humans, write the researchers.

Senior investigator Jiyoung Ahn, epidemiologist at the New York University School of Medicine, explained that this was one of the risk factors associated with alcohol consumption. Heavy drinking is not a good option and this is another reason why, she said. The study looked at a total of 1044 adults. Of these 270 did not drink alcohol while 614 drank moderately and 160 drank heavily. Moderate drinking was defined as one drink per day for women, and one or two drinks per day for men while heavy drinking was defined as more than a drink per day for women, and more than two drinks per day for men. Each of the participants were asked to swish their mouths with mouthwash and then hand over the sample they had spit out for genetic analysis including 16S rRNA genes and microbial analysis. Details of their health and lifestyles were also assessed alongside using questionnaires.

The samples were analysed in the labs and the researchers noted that there was a difference in the microbiomes of the mouths of the drinkers and non-drinkers. Drinkers for example had higher levels of certain bacteria compared to non-drinkers. Some of these included those of species, Actinomyces, Leptotrichia, Cardiobacterium, and Neisseria. These strains have been known to raise the risk of head and neck cancers as well as a cancers of the food pipe or esophagus and pancreas. Ahn explained that heavy drinkers showed more pronounced presence of these bacteria. The bacteria interacted with the alcohol as it was broken down by the body and this led to preferential growth of certain strains of the bacteria. The strains of healthy bacteria Lactobacillales were however much reduced.

She added of course, that more studies were necessary to understand the phenomenon. Further studies to look at how different types of alcohol could affect the microbiome of the mouth are underway she said. This study looked at differences between liquor, beer, or wine on the microbiome she said.