That was the findings of a full risk assessment report published by the EFSA yesterday.
Nutrasweet (or aspartame) is an artificial sweetener used to sweeten soft drinks such as diet coke. There are many claims on the internet regarding its effects on health (click here to read the story on Wikipedia) but studies by both the FSA and EFSA state that it is safe at the levels currently used in food and drink.
The study concluded that the current Acceptable Daily Intake (ADI) of aspartame, 40mg/kg bw/day is safe for the general population. This is not applicable to people with sensitively to phenylalanine.
The breakdown products of aspartame, methanol and the amino acids aspartic acid and phenylalanine, can be toxic when at high concentrations but not at levels consumed and are in fact found at similar concentrations in other food and drink items.