I have gout & take medicine for that daily. Since I've started taking the gout medicine, (about three years now), I've noticed that my body retains caffine (in particular) and aspertame (maybe) for much longer than before I began taking the medicine.
If I have ANYTHING with caffine at lunch or after, I'll be awake all night! Aspartame sodas (even without caffine) at supper seem to affect me the same way (?!). I'm slowly doing away with all caffine and aspartame in my diet. Will it improve my health? I can't say, but it WILL let me sleep better.
Just my two cents.