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How a Public Relations Campaign Deceives the Public
About Formaldehyde Poisoning From Aspartame
October 15, 2000
I have recently been sent some information about aspartame and formaldehyde that looks
like it might be part of one last public relations campaign to claim the chemical is 'safe'.
The formaldehyde exposure number cited in the text is off by a factor of over 400,000
and would not be taken seriously by knowledgable scientists. The scientific literature
cited has clearly not been read by the author. However, since a few consumers might
inadvertently take the text seriously, I have chosen to point out some of the more
obvious problems with the text.
> A simple MEDLINE search reveals that the levels of
> formaldehyde they are talking about (30 micrograms after the
> ingestion of 200 mg/kg/day of aspartame for 11 days) are
> well within 'safe' levels, even though 200 mg/kg is equal to
> about 60 Diet Cokes per day(!).
The truth is that there is no MEDLINE summary showing an exposure to or an accumulation
of 30 micrograms (ug) of formaldehyde in humans after ingestion of 200 mg/kg/day of aspartame. This figure appears
to be either fabricated or caused by some serious math errors. The actual figure can be calculated
quite easily and is approximately 61.3 milligrams (mg) for ingestion of one liter of
The actual measured amount of aspartame in one liter of diet soda is approximately 600 mg. [Ref. 1].
If a 60 kg (132 lbs) woman ingested one liter of diet soda, she would
be ingesting 10 mg/kg of aspartame:
600 mg aspartame / 60 kg body weight = 10 mg/kg
Aspartame breaks down into 10.9% methanol by weight [Ref. 2]. So that the amount of methanol obtained
from 600 mg of aspartame is:
600 mg aspartame * 10.9% = 65.4 mg of methanol
Methanol converts to formaldehyde in the body. [Note: Methanol from fruit and alcoholic
beverages does not convert to formaldehyde because of protective factors/chemicals in the
Methanol [CH(3)OH] has a molecular weight of approximately 32.0. Formaldehyde
[HCHO] has a molecular weight of approximately 30.0. Therefore, 65.4 mg of methanol
65.4 mg methanol * ( 30.0 / 32.0 ) = 61.3 mg of formaldehyde.
If we had used a dose mentioned by the author in the industry public relations (PR)
article of 200 mg/kg instead of an easily-obtainable dose of 10 mg/kg, the formaldehyde
exposure would be 20 times greater or 1,226 mg of formaldehyde. If we used the length
of exposure mentioned in this PR article of 11 days, the exposure to formaldehyde would
be a further 11 times greater or 1,226 * 11 = 13,486 mg of formaldehyde.
The author of the PR article was off by a factor of:
(13,486 mg * 1,000 micrograms/mg) / 30 micrograms = 449,533 !
Some scientists might argue that only 70 - 75% of the methanol from aspartame is
absorbed and of that amount, approximately 90% is converted into formaldehyde
during the metabolic process [Ref. 3]. Even if true, it is clear that the
exposure to formaldehyde is somewhere from 283,000 to 449,533 times
what was mentioned in the PR piece. Using these figures, the exposure to
formaldehyde from a 600 mg dose of aspartame would be:
61.3 mg * 72.5% * 90% = 40 mg of formaldehyde
Rather than discussing an unobtainable daily dose of 200 mg/kg, it is preferable to
discuss a very easily obtainable dose of 10 mg/kg of aspartame. Actually, a large
number of people have reported to this author ingesting far in excess of this amount on a
daily basis. Even the industry's own research shows that higher dosages are easily-obtainable
by consumers [Ref. 4].
An exposure to a daily dose of 40.0 mg to 61.3 mg of formaldehyde is clearly enough to cause gradual
damage (without even considering aspartame's excitotoxin that would likely worsen the damage as
The daily dose of airborne formaldehyde exposure that was shown to cause irreversible
genetic damage [Ref. 5] was:
2.25 ppm formaldehyde (average) ~= 3.375 mg/m3
The genetic damage from formaldehyde exposure at approximately 33.75 mg/day was seen
after many years of exposure. The longer the exposure, the more genetic damage.
3.375 mg/m3 * 10 m3/workday = 33.75 mg/day (for a
It is important to
keep in mind that the health effects of methanol are different in humans as compared to
rodents and non-human primates [Ref. 6], so experiments of the health effects
of aspartame in rodents and non-human primates might not apply readily to health effects in
humans. Methanol is many times more toxic to humans than to rodents.
Exposure to formaldehyde at levels much lower than the 33.75 mg per day (that causes
irreversible genetic damage) has been shown
to cause musculoskeletal problems, cardiovascular symptoms, gastrointestinal problems,
and a wide range of other chronic toxicity symptoms. Formaldehyde exposure, especially
in the presence of co-exposure to an excitotoxin from aspartame appears to cause gradual
neurological damage and immunological system changes. Please see discussions at both:
http://www.holisticmed.com/aspartame/methanol.faq for details and scientific references
related methanol and formaldehyde toxicity.
The study by Trocho et al. [Ref. 7] showed that exposure to a single dose of 20 mg/kg of
aspartame (or a chronic dose of 200 mg/kg) led to the accumulation of formaldehyde in the body.
The accumulation of formaldehyde was seen throughout the body, in the organs
(liver, kidneys, brain) and tissues.
http://www.presidiotex.com/barcelona/SUMMARY/summary.html.) The level of
formaldehyde accumulation was calculated by Trocho et al. to be from 5% of the
total methanol levels of aspartame given. For every 600 mg of aspartame (a 10 mg/kg
dose in a 60 kg woman), the amount of formaldehyde estimated to accumulate is:
61.3 mg of formaldehyde * 5% = 3.065 mg of formaldehyde
The research on formaldehyde toxicity and damage is based upon exposure only. If
formaldehyde from aspartame accumulates in organs and tissues
as the Trocho et al. experiment appears to demonstrate, then it is like a ticking time bomb
for those who ingest aspartame (even if they have not yet experienced symptoms).
> Well, this published MEDLINE study states that the safe level
> of formaldehyde consumption for humans is 3 mg/kg/day. So
> someone who weighs 70kg (154 pounds) can safely
> consume 70 x 3 = 210 milligrams of formaldehyde per day.
This is a complete misrepresentation of the formaldehyde research.
Formaldehyde is not readily abosrbed from foods [Ref. 8]. But the methanol
in aspartame is readily and quickly absorbed and then converted into
formaldehyde once in the body [Ref. 9, Ref. 10]. (Methanol in fruits has protective
factors/chemicals to prevent conversion into formaldehyde.)
"Ingestion represents a minor route of [formaldehyde] exposure
because the dilution factor and the binding to the macromolecules
present in food reduce substantially the [formaldehyde]
concentration that enters into contact with the gastrointestinal
mucosa" (Restani 1991) [Ref. 8]
Therefore, any comparison to formaldehyde in foods, is useless. A closer
comparison (but still not ideal) is a comparison to the inhalation toxicity
of formaldehyde since formaldehyde is easily introduced into the bloodstream
through inhalation or from methanol derived from aspartame ingestion. The
toxicity differences between inhalation of formaldehyde and formaldehyde derived from
aspartame appear to relate to:
- Aspartame also breaks down into an excitotoxin that would be expected to increase
the toxicity of the formaldehyde and its metabolite, formic acid. Please see discussions at both:
- Inhalation exposure to formaldehyde likely leads to a greater exposure of
formaldehyde to organs other than the liver. But the Trocho et al study makes
it clear that at least some of the formaldehyde derived from aspartame is
distributed to other organs and tissues.
To conclude, the 30 microgram figure was obviously off by a factor of over
400,000. The amount of formaldehyde exposure is more than what
has been seen to cause chronic toxicity in independent formaldehyde exposure
research. When one considers 1) the total formaldehyde exposure, 2) the long
term exposure to and accumulation of formaldehyde, 3) the excitotoxin obtained
from aspartame that would likely increase the toxicity of the formaldehyde, 4) the
permanent damage that can result from chronic formaldehyde poisoning, 5) the huge
numbers of people reporting serious health problems from long-term aspartame use
6) the fact that independent controlled human studies nearly always find
problems with aspartame (even though the experiments are quite short), it is
a good idea to avoid any aspartame ingestion.
Tsang, Wing-Sum, et al., 1985. "Determination of Aspartame
and Its Breakdown Products in Soft Drinks by Reverse-
Phase Chromatography with UV Detection," Journal
Agriculture and Food Chemistry, Vol. 33, No. 4, page 734-738.
Aspartame is composed of: C(14) O(5) N(2) H(18) [See Journal of AOAC International,
Volume 76, No. 2, 1993: "Determination of Aspartame and Its Major Decomposition
Products in Foods."]
The molecular weights are:
C : 12 * 14 = 168
The total molecular weight of methanol is approximately 32.0 as described above. Therefore,
aspartame breaks down into:
O : 16 * 5 = 80
N : 14 * 2 = 28
H : 1 * 18 = 18
Total = 294
(32.0 / 294) * 100 = 10.9% methanol
Kavet, Robert, Kathleen M. Nauss, 1990. "The Toxicity of
Inhaled Methanol Vapors," Critical Reviews in Toxicology,
Volume 21, Issue 1, page 21-50.
Porikos, Katherine P., Theodore B. Van Italie, 1984.
"Efficacy of Low-Calorie Sweeteners in Reducing Food
Intake: Studies with Aspartame" IN Stegink, L., Filer L.,
1984. "Aspartame: Physiology and Biochemistry," Marcel
Dekker, Inc., N.Y., page 273-286.
Shaham, J., Y. Bomstein, A. Meltzer, Z. Kaufman, E. Palma, J. Ribak, 1996.
"DNA--protein Crosslinks, a Biomarker of Exposure to Formaldehyde--in
vitro and in vivo Studies," Carcinogenesis, Volume 17, No. 1, page
Roe, O., 1982. "Species Differences in Mehtanol Poisoning," CRC Critical
Reviews In Toxicology, October 1982, page 275-286.
Trocho, C., et al., 1998. "Formaldehyde Derived From Dietary Aspartame
Binds to Tissue Components in vivo," Life Sciences, Vol. 63, No. 5, pp.
Restani, Patrizia, Corrado Galli, 1991. "Oral Toxicity of Formaldehyde and
Its Derivatives," Critical Reviews in Toxicology, Volume 21, Issue 5,
Haggard, H., L. Greenberg, 1939. "Studies in the absorption, distribution and
elimination of alcohol IV. The elimination of methyl alcohol," Journal of Pharmacology
and Experimental Therap., Volume 66, pages 479-496.
Stegink, Lewis, 1984. "Aspartame Metabolism in Humans: Acute Dosing Studies,"
IN Stegink, L., Filer L., 1984. "Aspartame: Physiology and Biochemistry," Marcel
Dekker, Inc., N.Y., page 509-553.