What? Milk is bad for your teeth?
Haven’t we been brought up to believe that it is GOOD for our teeth?
Yes, we have, and not without some justification. We are told that milk is good for our teeth as it contains Calcium, and as our teeth are made of hydroxyapatite (calcium phosphate). That part is certainly true, but milk also contains something that is very bad for our teeth – lactose. You don’t need to know much chemistry to see that lactose is a precursor to lactic acid, the chemical most responsible for tooth decay.
Here’s what happens.
When you drink milk, it coats your teeth with both glycoproteins and lactose. If you brush your teeth regularly, it’s brushed away, and all is well.
But if you don’t, plaque builds up quickly, and there is nothing that makes plaque better than milk. The lactose in the plaque than experiences microbial degradation, and is converted to lactic acid. Lactic acid is quite a strong acid and then dissolves the calcium phosphate of which your teeth is composed.
Lactic acid also is the product of the breakdown of sugar (sucrose) in other drinks, and the main reason why sugary drinks are bad for your teeth