A dentist has issued a warning to anyone who likes sugar-free drinks over their 'lesser-known' ingredients. 

High acid content in sugar-free drinks can cause irreversible tooth decay, according to Dr Deepak Aulak.

Most people might be aware that sugary drinks cause tooth decay, but many may not know of the risks of sugar-free beverages.

The dentist warns that the dangers of sugar-free drinks lie in their high acidity levels.

Dr Deepak Aulak says that while most people are aware that sugary drinks can cause tooth decay, the risks of sugar-free beverages are lesser known - and the danger lies in their high acidity levels. (Getty Images)Dr Deepak Aulak says that while most people are aware that sugary drinks can cause tooth decay, the risks of sugar-free beverages are lesser known - and the danger lies in their high acidity levels. (Getty Images) (Image: Getty Images)

For instance, many fizzy diet drinks often contain the likes of phosphoric, citric and tartaric acid.

“Both fizzy and non-fizzy sugar-free drinks can be surprisingly bad for your teeth," the founder of AI-powered dental app Toothfairy.

The dentist continued: “The lower the pH of a food or drink, the higher the risk of erosion - and many of these drinks contain multiple acids and have low pH values. 

“While sugar in regular drinks forms harmful acid in the mouth, sugar-free drinks often contain phosphoric acid, citric acid and tartaric acid, all of which can damage our teeth.

“These acids eat away at the protective outer layer of enamel on our teeth, and every sip you take, the acid weakens that protection, leaving the softer dentin underneath exposed and ripe for tooth decay.”

Do sugar-free drinks affect your teeth? The lesser-known ingredients


200 times sweeter than natural sugar, aspartame is an odourless, white powder.

It was first discovered in 1965 by an American chemist, James Schlatter.

Aspartame is so sweet that only a very small amount is needed to sweeten foods and beverages.

Is aspartame bad for you?

The dentist has advised that aspartame doesn’t cause tooth decay or cavities, but it can indirectly impact oral health by causing wider body issues.

Dr Deepak said: “Excessive consumption of artificial sweeteners like aspartame affects the gut’s natural processes as it isn’t easily digested, leading to bloating, diarrhoea and fatigue”.

Phosphoric acid

Used for metal cleaning and refining, Phosphoric acid is also used in fertilizer manufacturing.

It can also be found in disinfectants and detergents. 

Phosphoric acid can be added to soft drinks as an acidifying agent,

This is to give the drink a sharpness of flavour and help reduce the growth of bacteria. 

Is Phosphoric acid harmful to you?

Phosphoric acid is dangerous if you come into contact with it as a chemical substance. The toxic fumes can irritate skin, eyes, and the respiratory system. 

While the quantities used in fizzy drinks are relatively small - around 50 - 60mg in diet Coke for example, the acid can dissolve and soften the enamel surface of your teeth.

Citric acid

Citric acid gives fizzy drinks their fizz by reacting with the carbonate in bicarbonate of soda to form carbon dioxide gas forming the bubbles in your drink. 

Is Citric acid bad for you?

Dr Deepak said: “Studies have shown that citric acid actually causes far more erosion over the pH range than Phosphoric Acid. 

“It is highly erosive and binds to the teeth working on the enamel, with each acid attack lasting about 20 minutes after each sip, and this starts over again with every sip.”

What is the pH of Coca-Cola, Fanta and other fizzy drinks?

“The pH of a beverage gives a strong indication of their potential to damage your teeth ," according to Dr Deepak.

The scale ranges from 1 - 14, with 7 registering as neutral. 

The dental expert explained that tooth decay can occur when the pH level in the mouth begins to fall below 5.5. 

Sugar-free drinks with their pH of less than 4 are damaging to the teeth which can cause tooth enamel erosion.

“The scary thing is the damage is irreversible," the dentist warned.

The expert continued: "Tooth enamel isn’t like skin or the soft tissues in your mouth, which can grow back after minor damage. 

“When tooth enamel is gone, it doesn’t regenerate. You can spot signs of dental erosion with tooth sensitivity to hot and cold, and a yellowing or darkening of the teeth as the white enamel wears away.”

Researchers tested the acidity of both sugary and non-sugary sodas in a 2016 study. 

In their analysis, they found that almost every soda on the market has a pH below 4.

Which drinks are bad for your teeth?

Minimally erosive

  • Tap water  pH + 7.67
  • Milk pH 6.7


  • Red Bull Energy Drink 3.3
  • Sprite 3.24
  • Dr Pepper Diet 3.2
  • Sprite Lite 3.14
  • Coca Cola Diet 3.1
  • Diet Pepsi 3.02

Extremely erosive

  • Coca Cola Zero 2.96
  • Fanta Orange 2.82
  • Pepsi Max 2.74
  • Pepsi 2.39
  • Coca Cola Classic 2.37
  • Battery acid 1

Can you make your teeth healthier?

Dr Deepak has shared some important tips for how you can improve the health of your teeth.

Choose teeth-friendly alternatives

While cutting out all sugar and sugar-free drinks might feel like a bridge too far, there is certainly room for compromise, and viewing them as an occasional treat.

Dr Deepak said: “ Try dramatically reducing these particular drinks to one or two a week. Replace sugar-free drinks with teeth-friendly alternatives like water (natural or sparkling), unsweetened tea, milk and diluted juice, which have little or no sugar in them."

Timing is everything

If you really can’t resist a sugar-free drink, it’s far better to have it with a meal, rather than drinking it slowly all day, meaning each sip can continue to erode your enamel. Using a straw is also recommended. 

Dr Deepak said: “There are simple ways you can protect your teeth such as drinking through a straw, which reduces the acids’ contact with your teeth."

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Rinse your mouth

Another useful tip is to rinse your mouth post drink, to help wash away the acids.

Dr Deepak said: “Water or milk are a good choice to rinse out with, or you can also try a nibble of cheese. 

“Calcium-rich food and drink can help neutralise acids in your mouth.  Sugar-free gum is another option after a drink, because it stimulates saliva, which is helpful in rebalancing the pH in your mouth. 

“Adults only get one set of teeth, so taking these precautions, and being mindful of your oral hygiene, should help keep you on track for a healthy set of teeth for the long term.”