We often think of oral hygiene as something that only affects our teeth and gums. Brush, floss, rinse — end of story, right? But what if the state of your mouth is actually influencing your gut health? Well, the bacteria in your mouth don’t just stay there. They can travel down to your digestive system, affecting everything from digestion to immunity, and contribute to serious gut disorders.
“There is a saying that the face is the index of mind, the same way the oral cavity reflects the condition of general health,” says Dr V Venkatesh, BSc (Hons), BDS, MDS, senior consultant and clinical director and specialist in oral and maxillofacial surgery at Apollo Hospitals.
The mouth, like the gut, is home to a mix of good and bad bacteria. When this balance is disturbed, trouble begins. “Good bacteria help maintain oral health, while bad bacteria cause dental caries and gum infections (gingivitis and periodontitis). These infections can spread to the gut, leading to IBD (inflammatory bowel disease) and other gastric-related diseases,” he explains.
Dr Hemanth Kumar, senior consultant dental surgeon at Renova Hospitals, further breaks down how oral bacteria make their way to the gut. “Despite the environmental segregation of the mouth and gut, over half of microbial species are commonly found in both. Oral bacteria like veillonella species modulate host immunity, with ectopic colonisation in a healthy gut aiding immune development. These bacteria reach the digestive system through hematogenous and enteral routes,” he says.
Once there, harmful bacteria can disrupt the gut’s microbial balance, weakening immune defences. He points out, “Pathogenic oral bacteria can translocate to the gut, disrupting microbial balance and weakening immune defences, particularly in those with chronic periodontitis. Porphyromonas gingivalis has been linked to reduced microbial diversity, depleting beneficial bacteria like akkermansia and clostridiaceae, compromising gut barrier integrity and increasing vulnerability to pathogens.”
It’s not just gum disease that affects gut health — the relationship works both ways. An unhealthy gut can contribute to gum disease, as conditions like IBD often manifest in the mouth. Severe chronic lesions linked to IBD commonly appear on the buccal Mucosa and gingiva. Other warning signs include persistent bad breath, mouth sores, enamel erosion, and a burning sensation. Halitosis that isn’t related to poor oral hygiene may also indicate underlying issues like gastroesophageal reflux disease (GERD) or stomach ulcers.
There are specific toothpastes, mouthwashes, or oral probiotics that help maintain a healthy balance of good bacteria. Probiotics like lactobacillus and bifidobacterium in mouthwashes may help balance the oral microbiome, potentially reducing plaque, bleeding, and pathogenic bacteria, though their overall effectiveness remains unclear. Propolis, a bee-derived resin, has antimicrobial properties that may combat oral pathogens. While promising, further research is needed to confirm their role in oral health.
So, what’s the best way to protect both your mouth and gut? Diet plays a major role. Dr Venkatesh is firm about one thing — “Processed and fast foods are major contributors to oral and gut-related issues, while freshly cooked food remains the best choice.” On the other hand, Dr Kumar highlights, “Refined sugars and carbs increase the risk of periodontal disease, while fibre, whole grains, PUFAs (polyunsaturated fatty acids), antioxidants, prebiotics, and probiotics support oral and gut health. Vegetarian diets may lower the periodontitis risk, whereas vegan diets (low calcium, vitamin B12, lower salivary pH) can lead to dental erosion.”
Oral hygiene also matters. “Optimal oral hygiene is essential not just for oral health but also to prevent harmful bacteria from reaching the gut. Regular brushing, flossing, and alcohol-free mouthwash help maintain balance, while a diet rich in fruits, vegetables, and probiotics supports both oral and gut microbiomes. Staying hydrated and regular dental check-ups further safeguard overall well-being,” says Dr Kumar.
At the end of the day, your gut health isn’t just about what you eat — it’s also about how well you take care of your mouth. A little extra effort with your oral hygiene routine could go a long way in keeping your digestive system happy too.
