Consuming alcohol may increase bacteria linked to disease

A study published in the journal Microbiome suggests that men and women who had one or more alcoholic drinks per day may have an overabundance of oral bacteria linked to gum disease, some cancers, and heart disease.

Consuming alcohol may increase bacteria linked to disease

While previous studies have examined alcohol consumption and its broad links to disease and some changes in the microbiome, the researchers say the new study is the first to directly compare drinking levels and their effects on all oral bacteria. The study involved 1,044, mostly white participants between the ages of 55 and 87. All came from two ongoing, national cancer trials, and all were healthy when they enrolled in either study and provided mouthwash samples of their oral microbiome, along with detailed information about their alcohol consumption. Laboratory testing was then used to genetically sort and quantify the oral bacteria among the 270 nondrinkers, 614 moderate drinkers, and 160 heavy drinkers. Results were plotted on graphs to determine which bacteria in drinkers stood out—and grew more or less—than in nondrinkers.

The researchers found that drinkers had more of the potentially harmful Bacteroidales, Actinomyces, and Neisseriaspecies, and fewer Lactobacillales bacteria commonly used in probiotic food supplements meant to prevent sickness.

“Our study offers clear evidence that drinking is bad for maintaining a healthy balance of microbes in the mouth and could help explain why drinking, like smoking, leads to bacterial changes already tied to cancer and chronic disease,” said study senior investigator and epidemiologist Jiyoung Ahn, associate professor at New York University’s Langone Health.

According to Ahn, possible explanations for drinking-related microbiome imbalances could be that acids in alcoholic beverages make the oral environment hostile for certain bacteria to grow. Another reason could be the buildup of harmful byproducts from alcohol’s breakdown, including chemicals called acetaldehydes, which along with the harmful toxins in the mouth from tobacco smoke, are produced by certain bacteria, such as Neisseria.

The researchers’ next steps are to work out the biological mechanisms behind alcohol’s effects on the oral microbiome.