Should we lower IQ in exchange for better looking teeth?

Rich people in america filter their water. If you don't know this its because you are poor or nouveau riche

>is insignificant

If the content of sugar in foods has gone up shouldn't the number of cavities have also gone up?

...

what? world IQ has been increasing over time

Yes, the same way we should be improving our infrastructure by eating more mozzarella cheese.

I don't think you understand what insignificant means.

That line isn't as steep

Only if you don't count the population growth of africa.

That world IQ graph has no source and comes from a British tabloid site.