Hello. Just wanted to add a few thoughts based on my understanding of this issue developed from discussions with researchers and reading the research. A few years ago I was asked to participate in a meta-analysis of the research, but the project never got off the ground -- everyone was too busy!
It wasn't until a few years ago that research in Italy showed that aspartame ingestion at relatively small amounts led to the accumulation of formaldehyde "adducts" (bound to protein) in the brain, liver, and other organs and tissues.
"These are indeed extremely high levels for adducts of formaldehyde, a
substance responsible for chronic deleterious effects that has also been
considered carcinogenic.
....
"It is concluded that aspartame consumption may constitute a hazard
because of its contribution to the formation of formaldehyde adducts."
(Life Sci, 63(5):337+, 1998)
Exposure to formaldehyde from aspartame ingestion can be calculated. However, this was the first study to look at formaldehyde accumulation.
About that same time, there were several other findings including 1) the fact that almost all studies independent of the manufacturer found problems with aspartame (including double-blind studies) while manufacturer-funded studies claimed safety; and 2) the claims that the manufacturer made for several years that the chemicals from aspartame were metabolized similarly to that of natural food products (e.g., tomatoes, fruits, meat, dairy, etc.) were disproven by their own research and by independent research.
Since that time, there have been independent human studies linking aspartame to fibromyalgia, memory loss, and one small study linking diet beverages to large brain tumors in certain population groups.
It is true that there are a couple of "urban legend" sites and some web sites created by the manufacturer or organizations funded by the manufacturer. However, the urban legend sites are put together by well-meaning persons who have no familiarity with the subject. In fact, one person (not me) made an attempt to discuss the science on the snopes.com message board, but the science of the issue was deemed to be off-topic (like this subject :-)).
The best place to get information on this any most related health subjects is from persons and organizations that are 1) completely independent of the manufacturer and the trade groups, and 2) familiar with the research (not just summaries/abstracts). Come to think of it, whever I want to buy an expensive product, I look for total independence and thorough knowledge of the subject. Of course, independence and familiarity doesn't necessarily mean that the information is accurate, but I do think there is a better chance of accuracy.
Here are a couple of sites I like:
http://www.additivesout.org.uk/
(click on aspartame link on left of page)
Government *scientists*
http://www.dorway.com/betty/fdainves.txt
http://www.dorway.com/gross.txt
http://www.dorway.com/bressler.txt
Scientific FAQs
http://www.holisticmed.com/aspartame/aspfaq.html
http://www.holisticmed.com/aspartame/abuse/
Statements by independent physicians
http://www.dorway.com/doctors.html
=============
Now I just need to find the right Pocket PC to help me in my work!
Cordially,
Twoggle