Aspartame is one of the must trustable things we eat. Very few foods have been studied as much as it has. Both quality and quantity of studies.

This is part of how the medical regulation leaders in every country are the most insanely cautious, neurotic people on earth. They all recommend not to eat steaks rare. Everything is a carcinogen. When they have such a low tolerance for danger, it just means everyone learns not to listen to their advice.