Dentist Explains Why You Should Never Brush Your Teeth After Breakfast in Viral Video

UK-based dentist Anna Peterson recently took to TikTok with a piece of advice: always brush your teeth before eating breakfast. The clip quickly went viral, but viewers were deeply split over the warning.

"Did you know you shouldn't brush your teeth after breakfast? Always before," says Peterson in the clip, found here.

She explains: "There's two reasons for this. When you eat breakfast, your mouth becomes acidic. So what you're doing when you brush your teeth after breakfast is brushing the acid into the tooth, and this wears away the enamel."

"And," she continues, "brushing before breakfast protects your teeth from anything you're going to eat."

While the advice might seem a bit odd, Peterson's claims do have a scientific basis. According to Healthline, in an article reviewed by Jennifer Archibald, DDS, "while you sleep, plaque-causing bacteria in your mouth multiply."

"That's part of why you may wake up with a 'mossy' taste in your mouth and 'morning breath,'" they added. "Washing those bacteria right out with a fluoride toothpaste rids your teeth of plaque and bacteria. It also coats your enamel with a protective barrier against acid in your food."

Meanwhile, the Mayo Clinic recommended that "if you've eaten an acidic food or drink, avoid brushing your teeth right away." It might sound counterintuitive, but "these acids weaken tooth enamel, and brushing too soon can remove enamel."

Adding to the case for brushing pre-breakfast is the fact that many breakfast foods are, indeed, acidic. Several fruits, including citrus, berries, pineapples, and grapes all sit low on the pH scale. Coffee, grains (including oats, a breakfast favorite), and cheese also make the cut. If you're eating breakfast, chances are at least some of it will be acidic.

Commenters, however, had mixed reactions to the clip, which quickly amassed over 844,000 views at the time of writing, along with hundreds of comments.

Wrote one viewer: "I've always told people this but seemed like I was still the only one."

"I do this all the time and tell my students this when we are learning about ... health and nutrition in PE," echoed another.

That being said, some viewers disagreed with Peterson's warning. "Not all dentists agree on this," wrote one viewer. "Some dentists say it's fine as long as you leave 30 mins after eating [or] drinking."

Others dismissed the advice "rubbish" and "ridiculous."

Several other viewers seemed to reject the claim purely on the basis that brushing one's teeth before breakfast would lead to "minty cereal" and bad-tasting orange juice.

Newsweek has reached out to Anna Peterson for further comment but did not receive a response in time for publication.

Toothbrushes in a windowsill, 2019. A recent viral TikTok claims that brushing your teeth after eating breakfast is worse than doing it before. MICHELE SPATARI/AFP/Getty Images