February 10, l999
Minneapolis Neuropathy Association
Mr. Al Porte
P. O. Box 14901
Minneapolis, Mn 55414
Dear Mr. Porte:
I was asked to write to you about my concerns regarding the sweetener
aspartame, especially as regards neurological disorders. As you may
know, complaints against aspartame constitute 75% of all additive
related complaints relayed to the FDA department of consumer complaints.
Until recently, these were merely written off as anecdotal observations
of little scientific validity. But recent findings have shed some light
on this elusive compound and its deleterious effects of the human
.. Aspartame an L aspartyl L phenylalanine methyl ester, is composed of
two amino acids, aspartate and phenylalanine, linked by methanol.
Inside the gastrointestinal tract, especially in the stomach it is bro
ken down into its constitutent components . In some instances the
dipeptide is lysed within the cells of the gut. As a consequence the
methanol is rapidly absored and distributed throughout the tissues of
the body. Within the tissues substantial amounts of methanol’s two
metabolic breakdown products (formaldehyde and formic acid) have been
shown to accumulate in many tissues.”
These breakdown products, formaldehyde and formic acid, have been
shown in several important studies, to be extremely toxic to tissues in
very small doses. In fact, even small doses of formaldehyde are
considered to be carcinogenic. A recent study by Trocho, Pardo and co-
workers, have demonstrated that following aspartame ingestion,
significant amounts of formaldehyde accumulate in the tissues.
Formaldehyde is known to bind strongly to proteins and nucleic acids ,
forming adducts that are extremely difficult to eliminate through normal
In this study, they demonstrated that labeled methanol (as formaldehyde)
accumulated in high concentrations in the liver (50%) and in lower, but
substantial, concentrations in the kidney, adipose tissue, brain and
retina. Within the cell, they found large amounts located within the
DNA. It was interesting to note ethat these doses were lower than that
used in toxicity studies. Previous studies have shown that very high
doses of aspartame may not cause acute symptomatology. This study
indicates that the damage may necessitate longer periods of time to
manifest itself, and that the eventual effects can be quite deleterius.
The doses used were within those recommended by the FDA as ADI for
humans. This is especially of conern in children who may consume doses
of aspartame as high as 75 to 90mg/kg. It is also important to note
that in this study, the formaldehyde was accumulative as were its injury
to cellular proteins and DNA. In the real life situation, humans are
exposed to repeated doses of aspartame found in many foods, drinks,
medicines and chewing gum.
An earlier study by Shephard and co -workers, it was found that
aspartame is nitrosated within the gut and that this nitrosation of the
amine group is “quite cytotoxic” and represents a moderately strong
mutagen in the Ames test.
Another recent study, by Sorg, Willis and co-workers is also alarming.
In this study, it was found that prolonged exposure to low
concenetrations of formaldehyde could cause chemical sensitization to
cocaine, via a limbic mechanism. With increasing reports of multiple
chemical sensitivity syndrome, one must be concerned about chronic low
dose formaldehyde exposure via aspartame.”
In addition, a l997 study found that macrophages exposed to aspartame
produces a threefold rise in leukotriene (B4, C 4 and 15
hydroxyeicosatetraenoic acid) and arachidonic acid metabolites. This
would be detrimental to patients having autoimmune disorders such as
lupus, multiple sclerosis and rheumatoid arthritis. Clinically, there
is some evidence for worsening of two of the three conditions (MS and
Lupus) by aspartame use.
Finally, in the diabetic, great concern must be expressed about the
danger of toxin damage to already weakened peripheral nerves in the
diabetic situation. With the buildup of accumulated concentrations of
formaldehyde and formic acid in nervous tissue, long term damage and
drapid progression of diabetic peripheral neuropathy is almost a given.
We know that all of the components of aspartame are neurotoxic as well
as most of its breakdown products, such as diketopiperazine,
phenylethalamine, phenylalanine, aspartic acid, and methanol
(formaldehyde and formic acid) Aspartic acid is a known excitotoxin and
in the body is converted to glutamic acid, an even more poewrful
excitotoxin. Experimentally, the same widespread brain lesions produced
by MSG exposure can be produced by high dose aspartame exposure.
It is my opinion, and the opinion of many others, that aspartame is a
dangerous neurotoxin and its use should be discouraged generally, but
especially so in those harboring neurological diseases.
Russell L. Blaylock, M.D.
1. Shephard SE, Wakabayashi K and Nagao M. Mutagenic activity of
peptides and the artificial sweetener aspartame after nitrosation. Food
Chem Tox 31Z : 323-329, 1993.
2. Sorg BA, Willis JR , et al. Repeated low-dose formaldehyde
exposure produces cross-sensitization to cocaine; possible relevance to
chemical sensitivity in humans. Neuropsychopharmacol 18 :385, 394, l998
3. Trocho C, Pardo R, et al, Formaldehyde derived from dietary
aspartame binds to tissue components in vivo. Life Sciences 63:337-
4. Hardcastle JE, B ruch RT. Effect of L-aspartyl-L -phenylalanine
methyl ester on leukotriene biosynthesis in macrophage cells.
Prostagland Leukot Essen Fatty Acids 57: 331-333,1997.