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Study Finds Drinkers Have Different Mouth Bacteria Than Nondrinkers

Research links drinking alcohol with disease-causing bacteria in the oral microbiome
Some bacteria in our mouths are beneficial, while others can do us harm.
Photo by: istockphotos
Some bacteria in our mouths are beneficial, while others can do us harm.

Lexi Williams
Posted: June 18, 2018

When it comes to having a healthy smile, most wine drinkers are concerned with what wine does to their teeth. But a recent study on alcohol and oral health has focused attention down to a microscopic level.

The study by New York University (NYU) researchers, published April 24 in the online journal Microbiome, looked at how drinking habits can influence the oral microbiome (the abundance and types of bacteria that inhabit your mouth). The researchers employed data on 1,044 U.S. adults between the ages of 55 to 87, who are participating in two ongoing national cancer trials.

Of the participants, 614 were moderate drinkers, 160 were heavy drinkers and 270 were nondrinkers. The study used the American Dietary Guidelines definition for moderate drinkers: women who had up to one drink per day, and men who had up to two drinks per day. Women and men who had more than one and two drinks per day, respectively, were considered heavy drinkers in this study.

Participants provided mouthwash samples, along with information about their alcohol consumption from the past year (from around the time that their oral wash sample was collected), including frequency of consumption, serving sizes and types of alcohol consumed. The researchers analyzed lab tests results to determine the type and quantity of oral bacteria in each. They then graphed out the results to determine which bacteria appeared to be more or less frequent among heavy, moderate and non-drinkers.

Compared to nondrinkers, both men and women who have one or more drink per day had more harmful bacteria in their samples, including Bacteroidales, Actinomyces and Neisseria species; they appeared to possess fewer Lactobacillales, which are commonly used in probiotic food supplements to prevent sickness. Some of the so-called "bad" bacteria found at higher levels in drinkers' mouths have previously been linked to gum disease, heart disease and some cancers.

Possible explanations for these microbiome imbalances, according to an NYU statement on the study, include alcohol's high acidity, which might make the oral environment hostile for certain bacteria, or the byproducts that come from the body's breakdown of alcohol, such as acetaldehydes.

However, this isn't to say that a daily glass of wine will ruin your gums or lead to a heart attack or cancer. First of all, there were not enough wine-, beer-, or spirits-only drinkers to determine whether type of alcohol plays a role in the mouth's bacteria balance. Previous studies have shown that both wine and winemaking components have the potential to inhibit the growth of harmful bacteria in the mouth.

This study could be used as a jumping-off point for future research. The research team's next steps are to determine the mechanisms by which alcohol affects the oral microbiome. This, in turn, could help scientists develop ways to rebalance the bacteria levels in the mouths of drinkers and minimize health risks for wine lovers.

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