: Most of the concerns about aspartame have come from the fact that it is
: made from the combination of phenylalinine and aspartic acid, the latter of
: which can be made highly epileptogenic (e.g., as in NMDA, methylated
: aspatic acid). Thus the hypothesis that aspartame would lead to seizures
: was borne since it was supposedly to be converted to NMDA or a similar
: compound in some unknown reaction in the brain.
Where did you get this!? This has nothing to do with why it is believed
aspartame lowers the seizure threshhold. There is no hypothesis by
independent researchers that aspartic acid is converted to NMDA. Sheesh!
Ingesting aspartame (dissolved in liquid) spikes the plasma phenylalanine
to very high levels (See Metabolism, 36(5): 507-512 for example) because
it is absorbed so quickly. Aspartame contains no other Large Neutral
Amino Acids (LNAAs), therefore the plasma phenylalanine/LNAA ratio also
gets spiked to very high levels (and even to higher levels if ingested
with sugary products) (See Metabolism 31(9): 937 for example).
The high phenylalanine/LNAA ratio can affect the uptake of phenylalanine
(and possibly tyrosine) into the brain. This can not only change brain
chemistry over time, but have severe health reprecussions in some people
including lowering the seizure threshhold, affecting serotonin production,
causing behavioral and mood changes, etc.
Seizures linked to aspartame ingestion are one of the most common reports
to the FDA. When the CDC looked at seizures linked to aspartame they
attempted to dismiss all that might have had *any* other possible cause.
However, there were a number that they were unable to dismmiss. Due to
the type of work they perform and the large amount of diet beverages that
they sometimes ingest, pilots seem to be more susceptible to
aspartame-induced seizures and vertigo than the general population. Both
the Air Force's and Navy's official publications recently warned pilots
about aspartame. Other piloting magazines have published similar warnings
including the National Business Aircraft Association Digest (1993),
Aviation Medical Bulletin (1988), The Aviation Consumer (1988), Canadian
General Aviation News (1990), Pacific Flyer (1988, 1995), General Aviation
News (1989), Aviation Safety Digest (1989), Plane & Pilot (1990), CAA
General Aviation Safety Information Leaflet (1989), International Council
of Air Shows (1995), and a paper warning about aspartame was presented at
the 57th Annual Meeting of the Aerospace Medical Association (1986). Of
course seizures from aspartame are not limited to pilots.
The only *independent* study on aspartame and seizures (that I am aware
of) showed that aspartame ingestion (short-term) exacerbated EEG
spike-wave discharges in children with generalized absences epilepsy
(Neurology 1992; 42:1000-1003). The NutraSweet studies conducted to try
and disprove this independent finding were very poorly designed. I would
be happy to discuss these flaws.
: There were extensive
: safety studies of this sweetener prior to its use, and the FDA indeed
: was extremely scrutinous of this chemical because they had failed so
: miserably on examination of prior artificial sweeteners (the first ones,
: introduced in the 50s caused many many cancer deaths; reports about
: saccharin use unrealistic doses because of the panic over earlier
: sweeteners). It was found that this sweetener was entirely safe on a
: variety of scales.
You have got to be kidding! :-) The pre-approval studies of aspartame
are almost universally recognized as some of the worst in the history of the
FDA approval process. I have enclosed a short section of the history of
aspartame just so you get a sense of a) how bad it really was, and b) how
badly those reviews you are reading distort history.
As for cancer, all indenpendent groups were against the approval of
aspartame because at least one animal experiments showed a significant
increase in brain tumors (12 in test animals, 0 in controls). Several
independent FDA Investigators testified against approval because of the
brain cancer issue, the Public Board of Inquiry voted unanimously against
approval because of the brain cancer issue. (The board included the
president of the American Association of Neuropathologists.) Even the
FDA Commissioner's own appointed scientific review team was against
approval because the brain cancer figures were so worrisome. At least
one researcher has called for detailed epidemiological studies on this
issue because brain cancer incidence has increase significantly since the
mid-1980s (even when taking into account diagnostic techniques and immune
system disorders). (See Journal of Advancement in Medicine, 4(4): 231-241).
On another cancer-related issue, G.D. Searle did admit that one
pre-approval experiment showed a significant increase in uterine polyps.
: Moreover, the post-marketing reviews which Mark
: claims support the view that aspartame causes serious concerns actually
: do not. Indeed, Aspartame is commonly used as the example of how
: post-marketing review of anecdotal clinical reports can actually show how
: untrue they are.
They do not show serious concerns for the simple reason that you are not
reading the report itself. It seems that you are reading "information"
based on a CDC report conducted in 1985. The summary of the report was
not written by the authors of the report and waters it down
considerably. Then, the FDA took the watered-down summary and twisted it
to remove any negative comments about aspartame that were left. Finally,
reviews by NutraSweet will put their own spin on the FDA report to make
their product sound even "safer."