What is the link between periodontitis and non-alcoholic fatty liver disease?

Periodontitis is a chronic inflammatory gum disease. Non-alcoholic fatty liver disease (NAFLD) is a buildup of fat in the liver not caused by alcohol. Researchers have wondered if the inflammation and bacteria from periodontitis could affect the liver. The answer is not yet clear. Some studies suggest a link, but a large analysis of many studies did not find a strong connection.

What the research says

A 2023 meta-analysis of seven studies with nearly 193,000 people found no overall association between periodontitis and NAFLD (odds ratio 1.04, 95% CI 0.97-1.12) ¹¹. This means the risk of NAFLD was not significantly higher in people with periodontitis. However, the results varied across studies, and two cohort studies did show a small increased risk ¹¹.

On the other hand, a 2022 review described the 'oral-gut-liver axis,' where oral bacteria from periodontitis can travel to the liver and cause inflammation ⁹. Another review identified periodontitis and specific oral bacteria, like Fusobacterium nucleatum, as independent risk factors for NAFLD progression and even liver cancer ⁶. These reviews suggest possible mechanisms, such as bacteria entering the bloodstream and triggering liver inflammation ⁶⁹.

A broader review of oral-systemic links also noted that periodontitis may contribute to metabolic diseases through chronic inflammation and immune changes ³. However, the evidence is not strong enough to prove that periodontitis causes NAFLD. The large meta-analysis did not find a clear link, so more research is needed ¹¹.

What to ask your doctor

• Could my gum health affect my liver condition?
• Should I be screened for periodontitis if I have NAFLD?
• Would treating my gum disease help improve my liver health?
• Are there any specific oral hygiene steps I should take to reduce inflammation?