Is someone able to tell me about the chemistry of bone?

Question

I've been reading about the ocean segment of the carbon cycle... particularly about how the burning of fossil fuels and resulting CO2 on ocean water acidity affects the ocean's effectiveness as a carbon sink. Carbon dioxide, carbonic acid, bicarbonate, and carbonate ions interact with limestone and calcium carbonate in the ocean -- particularly dissolving calcium carbonate shells of mollusks... especially the planktonic ones.

It brings to mind soft-drinks and increased risk of bone fractures... I wonder if they are linked in some way. Anybody have some information? I haven't been able to find related info on the web. Thanks!

Answer 1

I think that the idea that soft drinks lead to increased risk of bone fractures is an urban legend, because the pH inside your body is kept within very tight limits, however much soft drinks you consume. If I'm wrong, I greatly appreciate a reference on this.

However, you are right to be concerned about the effect of carbon dioxide on the pH of the oceans. There have been a number of recent papers about this in journals such as Science. What happens is that it is more difficult for the plankton to make their shells, because calcium carbonate is a salt of a weak acid and calcium hydrogencarbonate is soluble.

CaCO3(s) + H+(aq) + H2O <==> Ca2+(aq) + HCO3-

Bone does dissolve in acid, because it is made with a calcium phosphate, and phosphoric acid is a weak acid. However, as I said, I'm not convinced that this is what happens when people, especially older people, get more brittle bones.

Answer 2

I learned in chemistry last week...if coke can clean off a car battery....what do you think it can do to your body???? The bone is particular carbon-based...as all living things are. However, some people don't realize how acidic coke is. It is possible that it can weaken bone structure.