There is not one credible piece of evidence to back up any of these claims. Aspartame is an artificial sweetener sold as Nutrasweet, Equal, or other brand names and is commonly added to soft drinks and many other food products that are processed without high heat.
Heat breaks down Aspartame.
This is true, but the amount of methanol in a can of diet soda is considerably less than in a glass of orange or tomato juice and MUCH less than in a shot of liquor or a glass of wine. All the published studies on the adverse effects of Aspartame indicate that, at worst, some people might experience headaches from it but controlled studies have not verified this. Despite many self-diagnosed problems claimed to be caused by Aspartame, none have been verified by medical experts. The Internet posting of unsubstantiated claims is just one example of people wanting to find a cause for conditions which have unknown etiologies. Now when nutrition news gets confusing, there IS a place to go to get the real story.