This is slightly non-sequitur but it seems as good a time as any to bring up relatively new research which seems not widely known to vets, let alone pet owners - namely that dogs in particular (also ferrets and I think cats) react very badly to another artificial sweetener, xylitol.
This substance is found in chewing gum and also baked products designed for diabetes sufferers.
I’m a bit hazy on the exact mode of action, but it seems that the body recognises that there is a sugary substance in the bloodstream and creates more insulin to try to get it taken up - the insulin reduces the levels of actual sugar (glucose) in the bloodstream but the xylitol remains, so the insulin spike never gets turned off. The result is a profound hypoglycaemia (low blood sugar) which can be life threatening. Pets which survive this phase can go on to get liver failure if the dose is high enough.
I realise this sounds like it has all the makings of a hoax, but if you trust Snopes you might want to check it out - and once convinced please let your friends know (on the basis that if you’re reading Straight Dope you’re probably the one they trust on this sort of thing).
“Cecil wrote: The NutraSweet company promptly rounded up experts to point out an obvious flaw: the incidence of brain tumors had begun to rise before the introduction of aspartame and has been leveling off since. Meanwhile use of the sweetener has increased sharply. You don’t need a Ph.D. to figure out that if there really were a connection the two rates would go up together.”
I don’t think this is necessarily true. In the two-hit hypothesis of cancer development, there is a defect in the host (say, a mutation) that would remain silent but for exposure to a second hit from the environment. For example, cigarette smoking causes cancer, but not all smokers get cancer. The ones that do may have had the first hit and their cigarette smoking introduced the carcinogens that comprise the second hit. So, if aspartame is the second hit, then an increase in the incidence of brain cancer followed by leveling off might simply reflect that the incidence of the first hit in the genome is limited to a certain percentage of the population.