The night-time habit that could reduce your risk of dementia by nearly half

In the UK, there are estimated to be 982,000 people living with dementia – and one in three people will develop the condition in their lifetime.

Eating a balanced diet, getting enough exercise and quitting smoking can all lower your risk of developing the neurological disease, and scientists have also found a link between a simple two-minute bedtime habit and a major reduction in your risk.

In a recent episode of the podcast The Diary of a CEO, guest and epidemiologist Dr Tim Spector shed light on the little-known association between flossing your teeth and better brain health, telling host Stephen Bartlett: “Studies show that, if you are flossing, you can reduce your risk of dementia by nearly half, which is quite impressive.”

Discussing the benefits of using cheap and readily available supermarket floss to remove the bacteria sitting on your gum line, the gut health scientist added: “This is really new science that shows just how important getting the right bugs in the right places and avoiding the ones in the wrong place really is.”

How are flossing and dementia linked?

For years, we’ve been told that flossing can help to remove trapped food particles between teeth where traditional brushing cannot reach.

Over time, this brings down inflammation in the gums that, if left unchecked, can lead to periodontal disease – an infection of the tissues that hold your teeth in place.

But scientists reckon that it’s not just tooth loss that we should be worried about, as studies have linked the oral bacteria that cause gum disease with the development of Alzheimer’s – the progressive brain disorder that affects memory and learning.

Spector explained to listeners: “If you’re eating and leaving stuff in and around your gums, that gets inflamed, [which] creates an environment where nasty microbes that love inflammation live.

“And, for reasons we don’t know, they seem to pass from your mouth into your brain and trigger inflammation in the brain that increases your risk of dementia.”

Plenty of research papers have already uncovered links between poor oral health and a higher risk of neurodegenerative diseases, with one 2025 study suggesting the risk of Alzheimer’s was more than double in those struggling with issues like gum disease and tooth loss.

In the same way we care for our gut health to reduce our risk of serious diseases like cancer and heart disease, Spector believes it’s now just as important to pay attention to the bacteria in our mouths, taking steps like flossing to remove the inflammatory microbes that live on our teeth, tongue and gums.

Is it ever too late to start flossing?

In the UK, only a minority of people floss regularly, with studies showing just 30% of adults use dental floss.

“It is definitely never too late to start,” reckons dentist Dr Nayan Patel from Harley Street Dental Studio. “Just like it’s never too late to visit the dentist.”

No matter how long you’ve delayed flossing, or the condition of your teeth, Patel assures that focusing on improving your oral health can make a significant difference and even slow the progression of gum disease in some cases.

“Flossing can sometimes be tricky if you have crowded teeth or have accumulated tartar build-up inbetween the teeth, but your dentist and hygienist can educate you on this if you are struggling,” he adds.

How often should I floss?

Whether you’re coming home from a night out or you’re physically exhausted from a busy week, flossing is one of those habits that it’s easy to skip when you’re desperate to crawl into bed – but Patel says consistency is vital.

“It should really be done once daily as a minimum, either before or after brushing,” he says. If you’re already struggling with sore or painful gums, some dentists recommend increasing your flossing efforts to twice daily (both morning and night) to help bring the existing inflammation down.

“The biggest concern patients complain of when they start a flossing habit is bleeding,” says Patel, who assures this is usually nothing to worry about. “Often, the bleeding comes from the inflammation itself, not because you’re flossing wrong.”

In fact, Patel says this inflammation tends to occur due to a lack of flossing, and that you’ll usually notice the bleeding reduces as the inflammation settles.

What’s the best type of floss to use?

While any efforts to floss your teeth are going to spell good news for your oral health, Patel reckons there’s one style that has a slight edge over the other.

“Interdental brushes [tiny tooth-sized cleaners you can wedge between the gaps in your teeth] are slightly better than classic string floss, as they’re physically bigger, so they clean and contact more surface area,” he notes.

“That said, some patients with overlapping teeth prefer to switch to string floss for certain areas of the mouth, as this can get in between tight spots better.”

If you’re concerned about your teeth or gums, he recommends booking an appointment with a dentist, who can check for signs of decay and gum disease and suggest the right treatment plan to stabilise your oral health.