Does an apple a day keep the dentist away?

The saying goes that “an apple a day keeps the doctor away”. But can apples keep dentists away too? Back in the day a lot of people believed they could. The belief was that an apple is good for your teeth, especially after a meal. This could be because apples are so crunchy and chewy, so they cause your mouth to produce a lot of saliva. After all, saliva washes away food particles and kills undesirable bacteria. It also creates an alkaline environment which means it makes it harder for acid-loving plaque to grow.

Some people have even dubbed the apple “nature’s toothbrush”. According to Indian dental surgeon Dr Kinjal Shah, apples “act as natural cleanser for your teeth. They are crunchy in texture and require a lot of chewing, which in turn helps to clean the surface of the teeth.” Dr Shah even believes that the annoying fibres that get stuck between your teeth act as a natural floss.

However, most studies find apples don’t improve dental health, and some even find apples can damage teeth. After all, a medium-sized apple contains roughly 20g of sugar, which is two thirds of the amount in a can of coke. What makes things worse is that the sugar content in apples has risen by up to 50% over the last decade, because apple breeders have created new types of apple with more sugar to give a sweeter taste.

What’s more, although apples do clean our teeth a little, they don’t remove plaque between the teeth and near the gums, which are the most important sites.

But perhaps the worst thing about apples is their high acid content. Acid erodes our enamel, which never grows back. Once it’s gone, it’s gone. Acid also creates the perfect environment for plaque to grow. According to an experiment in 1977 by Geddes et al., the acidity of apples cancels out any benefit from saliva produced from chewing.

A study by Professor David Bartlett published in 2011 in the Journal of Dentistry found that apple eaters were 3.7 times more likely to have damage to their dentine (the tooth’s main support) than people who never ate apples. And even worse were people who drank fruit juice (such as apple juice), because they were four times more likely to have dentine damage.

So given that apples aren’t that great for our teeth, how can we still enjoy them while limiting their damage? Professor Bartlett concludes that it’s best to eat apples quickly, because this reduces the time acids are present in the mouth. He also advises eating apples as part of a meal rather than as a snack, to limit the number of times your teeth are under attack by acid throughout the day. But if you do snack, try something like peanuts or cheese, because these contain little acid and are therefore harmless to your teeth. Finally, it’s better to eat apples rather than drinking them as a juice, because this way your teeth benefit from saliva produced.

So an apple a day won’t keep the dentist away. Perhaps the saying should instead be ‘brush twice a day to keep the dentist away’. We’ll leave apples to the doctors.

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