Your mouth hosts hundreds of types of bacteria. While some are protective, others can cause inflammation and disease. When harmful bacteria build up, they don’t just attack your gums — they can move beyond the mouth and trigger problems in other parts of the body.

Hormonal changes throughout life — from menstruation to menopause — can influence how bacteria behave in the mouth. Imbalances can lead to gum disease, which may also play a role in bone loss, cardiovascular health, and systemic inflammation.

During pregnancy, oral bacteria can enter the bloodstream and affect the placenta. Studies link these bacteria to preterm birth, low birth weight, and pregnancy complications. Supporting saliva and gum health is an important step for expectant mothers and mothers to be.

As teenagers go through hormonal changes, their saliva balance and oral bacteria can shift. This can increase the risk of gum inflammation, cavities, and even systemic inflammation — making early oral care habits especially important for lifelong health.

Certain oral bacteria have been discovered in clogged arteries. They contribute to inflammation and plaque buildup, raising the risk of heart disease, heart attacks, and strokes.

Bacteria that cause gum disease have been found in the brains of people with Alzheimer’s disease. Scientists believe these microbes may fuel brain inflammation, which is linked to memory loss and cognitive decline.

Some mouth bacteria — like Fusobacterium nucleatum — have been found in colon cancer tumors. Research shows that oral bacteria may influence cancer development and even tumor growth in other parts of the body.