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- In reviewing the available literature on aspartame toxicity
I have developed several concerns. First, is the results of the GD Searle
study itself in 1977 which indicated a significant increase in brain tumor
induction in the aspartame fed animals. This appeared to be secondary to
a breakdown product, DKP. Follow up studies with DKP were seriously flawed,
as demonstrated by the Bressler report. It should also be noted that other
tumors appeared in the NutraSweet group including breast tumors, pancreatic
tumors, testicular tumors, ovarian tumors and other tissues. Aspartame
has been reported in association with a cutaneous panniculitis as well
in human cases.
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- The recent study using radiolabeled aspartame that indicated
attachment of the formaldehyde breakdown product to DNA and that the formaldehyde
was cumulative with each dose should cause all of us concern. This is especially
so in relation to oncogene activation and in disorders associated with
elevated rates of DNA damage, such as lupus and the neurodegenerative disorders.
I have found no studies relating to possible elevation of free radicals
with aspartame exposure, but this certainly deserves review.
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- Shephard, et al found that aspartame was nitrosated in
the GI tract and that in this form was significantly mutagenic. Such nitrosation,
according to their findings, could also occur in endothelial cells and
stimulated macrophages. This would raise concern not only of carcinogenic
potential but also the stimulation of free radical generation in blood
vessels associated with atherosclerosis. Related to this finding is another
report by Hardcastle and Bruch, in which they found that macrophages treated
with aspartame produced an excess of leukotrienes and other arachidonic
acid metabolites. Yamada, et al found that aspartic acid inhibited melatonin
secretion from the pineal gland. It has been shown that aspartame consumption
does increase aspartic acid blood levels, especially when consumed with
MSG.
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- Another concern is the formation of stereoisomer when
aspartame is heated. Jeffry Bada has shown that when aspartame is heated
there is a significant conversion of the L-phenylalanine and aspartate
to the D- form. In addition, he found 6 to 10 decomposition products, some
of which are known to have deleterious neurological effects. Elevated levels
of D-aspartate have been described in several of the neurodegenerative
diseases.
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- The effect of aspartame feeding on blood phenylalanine
is of concern to the pregnant mother and those with newborns as well, since
phenylalanine has been associated with abnormal neural connectivity in
the immature brain. It has been established that PKU carriers develop phenylalanine
blood levels double that of normals. Further, it has been shown that the
placenta concentrates phenylalanine on the fetal side of the circulation.
Matalon, et al demonstrated that in the human a loading dose of 34mg/kg
increased phenylalanine levels greater than 6mg/dl in 14% of normals and
35% of PKU carriers. Of even more concern 5% of normals and 12% of carriers
had blood Phe levels exceeding 10mg/dl. The National Collaborative Study
for Maternal PKU has recommended that during pregnancy blood Phe should
not exceed 6mg/dl. This means that 14% of the general public could exceed
this level when consuming high intakes of aspartame and that 5% of normal
people could exceed 10mg/dl. One in fifty persons carries a heterozygous
gene for PKU. Up to 35% of such unfortunate individuals, and their babies,
would be at risk without knowing it. Especially, since the babies brain
levels would even exceed that of the mother.
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- With the complexity of the central nervous system it
would be irresponsible for the FDA to allow the widespread selling of aspartame
without further independent study of the neurophysiological, neurobehavioral
and neurochemical effects of high intakes of this drug at all ages using
chronic studies. I think it is foolish to ignore the complaints of millions
of individuals reporting difficulties with this substance.
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- Dr. Russell L. Blaylock, MD
Neurosurgeon
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