The Surprising Habit That Could Be Bad for Gut Health

Alcohol is a common ingredient in mouthwashes because of its antibacterial properties. Alcohol-based mouthwashes may reduce bacteria and plaque buildup that contribute to cavities, gum disease and poor oral health. But if an alcohol-based mouthwash is part of your daily habits, you may want to reconsider it. 

Alcohol-based mouthwashes are designed to kill oral pathogens, but they may impact beneficial bacteria as well. As research on the human oral and gut microbiome continues to evolve, so does our understanding of alcohol-based mouthwashes’ role in oral and overall health. Here we’ll explain why using alcohol-based mouthwash is the surprising habit that could be bad for gut health—and share alternatives for supporting a healthy gut. 

The mouth is home to diverse communities of bacteria that are essential for supporting health. Alcohol kills both “good” and “bad” bacteria. Many mouthwashes have alcohol concentrations of 5% to 27%. These alcohol-based mouthwashes can disrupt the oral microbiome, potentially increasing bacteria like Fusobacterium nucleatum and Streptococcus anginosus that are linked to gum disease and certain types of cancers, explains registered dietitian Angela Konegni, M.S., RD, CSR.

In fact, some alcohol-based mouthwashes have been shown to selectively eliminate beneficial bacteria while allowing harmful bacteria to thrive; if swallowed or introduced into the gut, these harmful bacteria can disrupt gut microbiota balance and promote inflammation, Konegni explains.  

Research shows increases in F. nucleatum and S. anginosus bacteria with daily use of alcohol-based mouthwash for three months. These bacteria are associated with microbiome imbalances. 

F. nucleatum attaches to other microorganisms in the mouth to create dental plaque, contributing to gum disease. According to some research, there may be a link between a specific subtype of F. nucleatum and colorectal cancer. This subtype, called F. nucleatum animals 2 (Fna C2), is resistant to acid, enabling it to move through the digestive tract and reach the intestines. Fna C2 increases the number of precancerous growths in the large intestine. Also, it produces compounds that create an environment ripe for tumor growth.

S. anginosus influences bacterial composition, affecting cancer and heart disease risk. S. anginosus contributes to chronic stomach-lining inflammation (gastritis), potentially leading to precancerous stomach lesions. Research has also observed an association between increased levels of S. anginosus and coronary atherosclerosis and systemic inflammation.

Besides their potential to disrupt the microbiome, alcohol-based mouthwashes may also influence the risk of head and neck cancers. When you consume alcohol, the body converts it to the compound acetaldehyde, which is categorized as a carcinogen. Some of the alcohol you consume is broken down in the liver, and some is metabolized in the mouth. 

Although some evidence suggests that the carcinogenic effects of alcohol may also apply to alcohol-based mouthwashes, not all research agrees. More research is needed to better understand the long-term effects of these types of mouthwashes on human health. 

How Oral Health Impacts Overall Health

Maintaining good oral health helps reduce the risk of cavities and gum disease and benefits overall health. Research shows a link between poor oral health and an increased risk of chronic conditions like cognitive decline, heart disease and diabetes. 

Our understanding of how oral health influences gut and overall health is evolving. Interactions between the oral microbiome and your immune system may significantly affect overall health. Certain oral bacteria have been shown to trigger an immune response implicated in autoimmune conditions like rheumatoid arthritis.

Maintaining good oral health remains a cornerstone of microbiome and overall health. Oral and gut microbiomes may be connected instead of being two separate microbial communities.

Good oral health, such as strong teeth and the absence of gum disease, allows you to consume a greater variety of foods—like the chewier, tougher, more fibrous foods like vegetables and whole grains that are associated with health benefits, including maintaining healthy blood sugar and cholesterol levels. 

Flossing and brushing your teeth after meals and getting regular dental checkups support oral and overall health. Konegni recommends practicing good oral hygiene to prevent the overgrowth of harmful bacteria and reduce inflammation associated with gum disease, which can trigger systemic inflammation.

Are There Alternatives to Alcohol-Based Mouthwashes?

Natural mouthwashes include salt washes, baking soda rinses and plant extracts. Research on the effectiveness of these natural mouthwashes has been inconclusive. Still, these alternatives may help manage plaque and provide antimicrobial properties. 

Saltwater and baking soda rinses may reduce oral bacteria. Ayurvedic medicine recommends oil pulling—swishing coconut oil around your mouth for 10 to 20 minutes— to help reduce oral bacteria. Still, randomized controlled trials found no effects on bacterial populations. Charcoal may enhance enamel whitening but does not appear to influence bacteria growth. 

Alcohol-free, probiotic mouth rinses are an emerging alternative that can introduce beneficial bacteria, which may help maintain a balanced oral microbiome, says Konegni. Probiotic mouthwashes claim to contain living microbes, which may reduce cavities and gum disease and promote the growth of beneficial bacteria. Still, probiotic mouthwashes are new, and more research is needed.

Other Tips for Supporting a Healthy Gut

The good news about the gut microbiome is that it’s adaptable. You can support a healthy gut with dietary and lifestyle modifications.

• Increase your fiber intake: Fiber is essential for gut health—it acts as food for “good” bacteria in the gut, supporting a healthy microbiome. Additionally, fiber moves through the digestive tract undigested, acting like a broom to sweep particles out of the body via feces. 
• Incorporate more fermented foods: Fermented foods like yogurt, kefir, kimchi, sauerkraut, kombucha, tempeh and miso contain probiotics, compounds that support a healthy gut and confer other health benefits. Incorporate fermented foods into your diet to boost microbiome diversity and help reduce inflammation. 
• Exercise regularly: Participating in exercise improves gut microbial diversity, favoring healthy microbial species over more pathogenic ones. Exercise influences immune responses that may positively alter the gut microbiome as well. The current Physical Activity Guidelines for Americans recommends at least 150 minutes of moderate-intensity aerobic exercise and two muscle-strengthening activities weekly.    
• Limit alcohol: Alcohol can change gut microbiota composition unfavorably, reducing beneficial and increasing harmful bacteria and leading to inflammation. Animal research indicates chronic and short-term alcohol consumption similarly alter gut microbiota, but the effects can be reversed with acute alcohol consumption.
• Quit smoking: People who smoke may have less microbial diversity and could be at a greater risk of gut dysbiosis. Quitting smoking is linked to positive changes in the gut microbiome, including the potential growth of beneficial bacteria and improved overall gut health. Talk to your health care team about resources that can help. 

The Bottom Line

Alcohol-based mouthwashes are effective at killing bacteria that contribute to cavities and gum disease—but they also may destroy beneficial bacteria, disrupt the oral microbiome and negatively affect gut health. Emerging research suggests that frequent use of alcohol-based mouthwashes can increase harmful bacteria linked to systemic inflammation and certain cancers. While more studies are needed to understand these risks fully, alcohol-free or probiotic alternatives might be a safer option for supporting oral and overall health. 

Maintaining good oral hygiene through brushing, flossing and regular dental visits is essential for a balanced microbiome and overall well-being.  Lifestyle modifications that focus on reducing alcohol and smoking and boosting fiber, fermented foods and exercise can support gut health.