Good teeth enable us to eat and enjoy a wide variety of nutritional food. But what we eat also affects our teeth.
Tooth decay
Tooth decay is one of the most serious effects of diet on teeth.
Each time we consume food and drinks that contain sugars, our teeth are attacked by dietary acids produced by the bacteria present in our mouth.
Drink | Added sugar content |
---|---|
Water | none |
Flavoured water | 2.5 tsp ![]() |
Plain milk | none |
Carton flavoured milk (1 cup/250 ml) | 3 tsp ![]() |
Carton fruit juice (1 cup/250 ml) | 7 tsp ![]() |
Energy drink (1 cup/250 ml can) | 7 tsp ![]() |
Sports drink (600 ml bottle) | 10 tsp ![]() |
Fizzy drink (1 can/355 ml) | 10 tsp ![]() |
Dental erosion
Dental erosion is the loss of the surface of the tooth caused by acids in food and drinks. Acidic food and drinks (with a pH lower than 5.5) cause the enamel in teeth to dissolve.

Drink | Acid content |
---|---|
Water | 7 (pH neutral) |
Plain milk | 6.8 |
Apple juice | 3.3 |
Grapefruit juice | 3.2 |
Orange juice | 3.7 |
Fizzy drinks | 2.4–3.2 |
Wine | 3.7 |
Sports drinks | 2.8–3.4 |
A tooth friendly diet
To keep your teeth healthy, you should:
- reduce how much and how often you have sugary food and drinks (especially if it’s added sugar)
- have a diet that is high in fruits, vegetables, wholegrain starchy food and food that is low in sugars and fat
- choose healthy food for snacks instead of sweet food and drinks (the more time your teeth are in contact with sugars and acids, the more likely the teeth are to decay or erode)
- have a glass of water after eating.
Reproduced with the permission of the New Zealand Dental Association, based on the ‘Keeping Your Teeth for a Lifetime ... Easy As’ resource.
pH scale reproduced from the publication Healthy Smiles – Oral Health & Fluoride Varnish Information for Health Professionals, with permission from the Department of Health, Northern Territory Government, Australia.