Ask LH: Is Stevia Bad For Your Teeth?

Dear Lifehacker, I recently cut sugar from my diet and swapped to stevia-based sweeteners in a bid to lose weight. So far it’s working (2kg in one week!) However, one thing that isn’t clear to me is how stevia affects tooth decay. Is it safe to swish this stuff around in my mouth, or should I still be using a straw? Thanks, Sweet Tooth

Stevia picture from

Dear ST,

Tooth decay is caused by a microscopic menagerie of acidogenic bacteria (chiefly mutans streptococci and lactobacilli.) These bacterial nasties use fermentable sugars — sucrose, fructose and glucose — as an energy/food source by converting them into lactic acid. The presence of sugar on a tooth’s surface can therefore result in a breakdown of enamel and other hard tissues, which causes cavities to form.

The short answer to your question is no. Stevia and other artificial sweeteners are not fermentable sugars and more closely resemble proteins. Without sugar, any bacteria that’s present in the tooth or gums cannot produce the acid that harms teeth.

However, this doesn’t mean you should start rinsing your mouth out with Pepsi Next or Coke Life. As we have explained in the past, most stevia-based soft drinks still contain sugar — there’s just less than in the normal version.

Coke Life, for example, only cuts the sugar content by 35 per cent to retain its familiar taste profile. While this can be beneficial to weight loss, the pits and fissures in your teeth will still receive a coating of sticky sugar. Eew.

Some dentists have also raised cautions about stevia. While it’s not a suitable energy source for cavity-causing bacteria, we don’t actually know what the oral health affects are as no long-term scientific studies have been conducted.

You should also be mindful of processed stevia such as powder sachets. The extraction process may involve the use of harmful additives and chemicals that aren’t present in the unrefined plant. In short, you shouldn’t assume that any artificial sweetener is good for your teeth even if it’s sugar-free.

Your best bet to healthy teeth is to practice good oral hygiene. This includes brushing before breakfast, getting into the habit of flossing and avoiding late-night snacking. For more information on healthy brushing, check out our in-depth guide. (Oh, and congrats on the weight loss!)


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