Brush Your Teeth and Prevent Cancer: The Surprising Link Between Oral Hygiene and Overall Health

You don’t need a perfect Hollywood smile to stay healthy—but keeping your mouth clean may be more important than you think. Developing research suggests a convincing relationship between oral care and cancer prevention.

Importance of Oral Health

Oral health isn’t just about avoiding tooth decay and bad breath. Your mouth acts as an entry point to your entire body and provides a breeding ground for bacteria. Poor oral hygiene can lead to gum disease and long-term inflammation, which may allow harmful bacteria to enter the bloodstream. Once in circulation, these bacteria can contribute to the development of serious health conditions, including cancer.

Oral Microbiome: The Body’s Second-Largest Ecosystem

• Over 700 species of bacteria live in your mouth.

• Disruptions to this microbial balance (from poor hygiene, smoking, etc.) can lead to oral diseases and systemic inflammation.

• Dysbiosis in the oral microbiome is associated with heart disease, Alzheimer’s, and various cancers.

HPV and Oral Health: A Dangerous Link

Human papillomavirus (HPV), a common sexually transmitted infection linked to oropharyngeal cancers, has also been associated with poor oral hygiene.

A study from the University of Texas Health Science Center found poor oral health to be an independent risk factor for oral HPV infection. Thanh Cong Bui of the university shares that the good news is this risk factor is modifiable. By maintaining good oral hygiene, one can prevent HPV infection and subsequent HPV-related cancers.

Pathophysiological Basis of the Association

Scientists are uncovering potential biological links between poor oral hygiene and cancer, focusing on the following mechanisms:

• Widespread inflammation: Chronic gum inflammation extending beyond the oral cavity influences overall health and cancer susceptibility.

• Bacterial migration: Oral bacteria enter the bloodstream, releasing carcinogenic by-products.

• Immune response: Recurring oral infections might cause an overactive immune response that inadvertently promotes cancer.

Dr. Rutika Mehta, Gastrointestinal Oncology Program, commented, “Fusobacterium nucleatum secretes inflammatory proteins that can lead to precancerous lesions and, eventually, cancer.”

Oral Health and Colorectal Cancer Risk

Research by Harvard University and Massachusetts General Hospital found that periodontal disease and tooth loss are linked to a higher risk of developing precursors to colorectal cancer. ⁽¹⁾

• Individuals with periodontal disease had a 17% higher risk of developing adenomas or serrated polyps.

• Those who lost four or more teeth had a 20% higher risk of developing serrated polyps.

The Global Evidence

Japan Study (JACSIS, 2022)

A large-scale study involving over 32,000 participants found:

• Those who brushed their teeth only 1–5 times per week had a 4–7x higher risk of cancer.

• Poor oral health increased HPV infection risk by 56%.

• Gum disease and dental problems raised the HPV risk by 51%.

The research concluded that socioeconomic factors were not significantly linked to cancer risk; oral hygiene was the key variable.

Cancer Types Potentially Linked to Poor Oral Health

Emerging evidence connects oral hygiene to several cancer types:

• Oral and throat cancers (linked to HPV and inflammation)

• Colorectal cancer (linked to Fusobacterium nucleatum)

• Esophageal and stomach cancers (linked to gum disease)

• Liver and pancreatic cancers (linked to oral pathogens)

• Breast and lung cancers (linked to systemic inflammation)

According to the Harvard Cohort Study, people with a history of gum disease were 43% more likely to develop esophageal cancer and 52% more likely to develop stomach cancer.

Oral Care During Cancer Treatment

Cancer treatments, which include chemotherapy and radiation, can cause dry mouth, ulcers, and infections. Better oral hygiene helps patients reduce discomfort and complications associated with treatment.

Daily Habits That Matter

Oral hygiene is a modifiable risk factor. Small daily habits (2) can have long-term protective effects:

• Brush twice a day with fluoride toothpaste.

• Floss or use a water flosser.

• Rinse with antibacterial mouthwash.

• Visit your dentist regularly.

Lifestyle Tips for Better Oral and Overall Health:

• Avoid tobacco.

• Limit alcohol.

• Eat a balanced diet rich in fruits and vegetables.

• Stay hydrated.

Warning Signs Your Oral Health May Need Attention

• Bleeding gums

• Persistent bad breath

• Tooth sensitivity

• Receding gums

These may indicate gum disease or infection and should be evaluated by a dental professional.

MedBound Times connected with Dr. Arungiri Karunanithi, and he shared his insights on this matter:

Better Oral Hygiene, Better You

Poor oral hygiene may do more than damage your smile—it may increase your risk of serious illnesses, including cancer. The good news? It’s largely preventable. Through consistent oral care and healthy lifestyle choices, you can protect both your mouth and your overall health.

References:

1. Harvard T.H. Chan School of Public Health. "Oral Hygiene Can Reduce Risk of Some Cancers." Harvard T.H. Chan School of Public Health News, 2025. Accessed April 2, 2025. https://hsph.harvard.edu/news/oral-hygiene-can-reduce-risk-of-some-cancers/.

2. Wang, X., Y. Li, J. Chen, and L. Zhang. "Association Between Oral Hygiene and Cancer Risk: A Systematic Review and Meta-Analysis." Journal of Oral Health Research 18, no. 2 (2025): 123–135. https://doi.org/10.1101/PMC11039440.

By Dr. Anjaly KTK

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