DENTISTS have been making the case for flossing for decades, to largely unreceptive audiences who nod politely and then put the little spool back in the drawer.
But the argument for actually using it just got considerably more compelling than avoiding cavities.
Does flossing really protect your heart?
Verdict:
TRUE, BUT...
Here is something most people do not know: the mouth is home to more than 700 species of bacteria.
Most of them are perfectly harmless.
But when plaque builds up in the gaps between teeth and along the gum line, the troublemakers move in.
The result is gum inflammation, and if left unchecked, something more serious called periodontitis, a gum infection that destroys the tissue and bone holding the teeth in place.
At that point, things start to get interesting in a way that has nothing to do with teeth.
Inflamed gums are essentially an open door.
Bacteria can slip directly into the bloodstream through damaged gum tissue, and once they are in circulation, they set off a chain reaction of inflammation throughout the body.
One of the main culprits is a bacterium called Porphyromonas gingivalis.
Research published in the journal Infection and Immunity found that this particular troublemaker alters the expression of genes that drive inflammation and atherosclerosis in the coronary arteries, the vessels that supply blood to the heart.
Atherosclerosis is the gradual buildup of fatty deposits inside artery walls.
It is also the underlying cause of most heart attacks and strokes.
In December 2025, the American Heart Association updated its scientific statement on the subject, confirming an independent association between gum disease and cardiovascular disease, linking periodontitis to increased risk of heart attack, stroke, atrial fibrillation, heart failure and peripheral artery disease.
That is quite a list for something that starts with not flossing.
A preliminary study presented at the American Stroke Association's International Stroke Conference in January 2025 found that people who flossed at least once a week had a lower risk of stroke caused by a blood clot and a lower risk of atrial fibrillation over a 25-year follow-up period.
Atrial fibrillation is the most common form of irregular heartbeat and can lead to stroke and heart failure.
The researchers themselves described the atrial fibrillation finding as a surprise.
A 2025 study published in Frontiers in Oral Health found that regular toothbrushing and flossing were protective against the development of heart failure.
A scoping review covering studies from 2012 to 2024, also published in Frontiers in Oral Health, found that regular oral hygiene practices, including flossing, significantly reduced the risk of cardiovascular events and mortality across multiple studies.
So where exactly does flossing come in?
A toothbrush does a decent job on the surfaces of teeth, but it simply cannot reach the gaps between them.
That is precisely where plaque accumulates and where gum disease tends to get its foothold.
Flossing is the main tool for disrupting that plaque before it hardens into tartar and sets off the inflammatory chain that eventually reaches the heart.
The BUT in the verdict matters, though, and it is worth being honest about.
The American Heart Association has been clear that while the association between gum disease and cardiovascular disease is well-supported, a direct cause-and-effect relationship has not been proven.
No study has established that flossing directly prevents heart disease, only that poor oral hygiene is consistently associated with worse cardiovascular outcomes.
Smoking, diabetes, stress and poor diet are risk factors shared by both gum disease and heart disease, and researchers acknowledge that fully untangling these overlapping variables is genuinely difficult.
What the evidence does confidently support is that flossing reduces gum disease, gum disease is independently associated with cardiovascular risk, and the biological mechanisms linking the two are becoming clearer all the time.
Flossing is not going to replace medication.
But for a habit that costs almost nothing and takes less than two minutes a day, the case for it has never been stronger.
Sources:
3. https://www.frontiersin.org/
4. https://www.frontiersin.org/
5. https://jada.ada.org/article/
6. https://pmc.ncbi.nlm.nih.gov/
7. http://www.myhealth.gov.my/en/
