Is aspartame (Nutrasweet® brand) safe?
read about one writer's personal experience with aspartame
by Sean Peterson
July 21, 2003 rev. March 20, 2006
I have always had a sweet-tooth, and enjoyed the taste and sensation of drinking soft drinks. Here is my experience in discovering the bad about aspartame sweetened soft drinks.
Since I am quite health-conscious, I wanted to avoid the significant amounts of caffeine and sugar I would ingest from several cans of regular soda each day. So, I selected soft drinks that were calorie and caffeine free, such as Diet 7UP®, Caffeine Free Diet Coke®, and diet root beer. Aspartame was the sweetener in each of the brands I chose. I found them to be very tasty.
Soon, I switched totally to these drinks, and did not drink anything else. I had become addicted. At that point, I drank two two-liter bottles of soda pop in three days.
I noticed feeling slightly odd. The feeling was slight and difficult to describe. For example, I would prepare to leave for a workout, but then just procrastinate and fiddle until it was too late. I felt a little listless. This went on for the few days that I was drinking the two liters per day of diet soda pop. The important point is that, very clearly to me, I did feel somehow different and worse than normal.
The slightly odd feeling went away a day or two after I stopped drinking the diet sodas. At the time I really did not think it was the diet sodas that made me feel odd. I thought it was something else, perhaps a mild cold or something I ate.
About a week after I began to feel better, I bought three more two-liter bottles, and once again began drinking about one bottle per day. Again the listless, procrastinating feeling came back. This time it was obvious that the aspartame sweetened soda was the cause of my symptoms.
I suppose some sort of bug or some other variable could explain why I felt badly in the first occurrence. But after two coincident occurrences of said symptoms with the drinking of the large quantities of diet soda, a pathogen was not the cause.
Also it is important to note that during this test period, I was in excellent health. I was practicing karate for about 1.5 hours per day, three days per week. In addition, three days per week, I was either strength training for two hours or doing intense aerobics for 30 to 45 minutes. I have no history of physical or mental disease or impairment.
my research--scientific articles
At the bottom of this page is a bibilography of abstracts of scientific articles on aspartame. I found these articles by searching PubMed. PubMed is an online service of the well-respected National Institutes of Health (NIH) and National Library of Medicine (NLM). It provides access to over 12 million biomedical citations from research-oriented, peer-reviewed, medical journals.
After reading these articles below and considering my own experience, you too may question aspartames safety. My conclusion from the articles is that aspartame is an excitotoxin, and in large quantities it overwhelms the bodys ability to block its damaging effects.
Note that the last two articles shown in the bibliography below by Bradstock and Yost, respectively, basically mirror the position of NutraSweet Company and the FDA, that there is no clear pattern of adverse symptoms from normal usage. Reading between the lines, this is obviously not a whole truth position, which you will see after reading the six articles that precede those last two.
You can read about why NutraSweet Co. believes their product is safe at http://www.nutrasweet.com. Naturally (excuse the irony), NutraSweet Co. will be biased in their opinion.
In 2000, Monsanto Corp. sold their NutraSweet Co. holding to an investment firm. Monsanto is a leader in the development of controversial, genetically modified organisms (GMOs), which the Europe Union has banned. They also manufacture toxic, carcinogenic pesticides and herbicides for use in agriculture, such as Roundup, which have been polluting our environment for decades. This company clearly has little respect for human and environmental safety.
By the way, monosodium glutamate (MSG) is also a controversial excitotoxin with similar biomechanism. Industry Websites arguing for its safety are at http://www.glutamate.org/ and http://www.msgfacts.com/. Do a search on the PubMed database of MSG and decide for yourself. The evidence is overwhelmingly negative. Websites that have strongly argued that MSG is harmful are found at http://www.truthinlabeling.org and by searching the Internet with Google.
You felt bad because you drank too much of it! Others would never drink as much as you did, so they are safe.
This statement is silly. It is like saying that exposure to a small amount of radioactive material will not hurt you. But at a certain level, you will not feel bad nor have any radiation poisoning symptoms for days, months or years. But eventually, you will see the effects. Similarly, aspartame has already been proven to be toxic.
Still unsure? Totally skeptical? Test yourself. Drink a liter per day of an aspartame sweetened product for three days. But if you fry your brain, please call Nutrasweet.
[ChampHealth.com editor's note: If you performed this test, tell us what happened in the ChampHealth.com forum.]
bibliography for aspartame toxicity
J Am Diet Assoc. 1994 Jan;94(1):71-7. Related Articles, Links
Dietary amino acids and brain function.
University of Pittsburgh School of Medicine, PA 15213.
Two groups of amino acids--the aromatic and the acidic amino acids--are reputed to influence brain function when their ingestion in food changes the levels of these amino acids in the brain. The aromatic amino acids (tryptophan, tyrosine, phenylalanine) are the biosynthetic precursors for the neurotransmitters serotonin, dopamine, and norepinephrine. Single meals, depending on their protein content, can rapidly influence uptake of aromatic amino acid into the brain and, as a result, directly modify their conversion to neurotransmitters. Such alterations in the production of transmitters can directly modify their release from neurons and, thus, influence brain function. The acidic amino acids glutamate and aspartate are themselves brain neurotransmitters. However, they do not have ready access to the brain from the circulation or the diet. As a result, the ingestion of proteins, which are naturally rich in aspartate and glutamate, has no effect on the level of acidic amino acid in the brain (or, thus, on brain function by this mechanism). Nevertheless, the food additives monosodium glutamate and aspartame (which contains aspartate) have been reputed to raise the level of acidic amino acid in the brain (when ingested in enormous amounts), to modify brain function, and even to cause neuronal damage. Despite such claims, a substantial body of published evidence clearly indicates that the brain is not affected by ingestion of aspartame and is affected by glutamate only when the amino acid is administered alone in extremely large doses. Therefore, when consumed in the diet neither compound presents a risk to normal brain function.
PMID: 7903674 [PubMed - indexed for MEDLINE]
Neurotoxicology. 1994 Fall;15(3):535-44. Related Articles, Links
Excitotoxins in foods.
Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110.
Evidence is reviewed pertaining to excitatory neurotoxins (excitotoxins) encountered in human food supply. The most frequently encountered food excitotoxin is glutamate (Glu) which is commercially added to many foods despite evidence that it can freely penetrate certain brain regions and rapidly destroy neurons by hyperactivating the NMDA subtype of Glu receptor. Hypersensitivity of NMDA receptors during development makes the immature nervous system especially sensitive to Glu excitotoxicity. On the other hand, elderly consumers are particularly sensitive to domoic acid, a powerful excitotoxic Glu analog that activates both NMDA and non-NMDA receptors. A high content of domoic acid in shell fish caused a recent food poisoning incident that killed some elderly victims and caused brain damage and memory impairment in others. Neurolathyrism is a crippling neurodegenerative condition associated with ingestion of a legume that naturally contains BOAA, an excitotoxic Glu analog that hyperactivates non-NMDA receptors. Thus, the human food supply is a source of excitotoxins that can damage the brain by one type of mechanism to which immature consumers are hypervulnerable, or by other mechanisms to which adult and elderly consumers are peculiarly sensitive.
PMID: 7854587 [PubMed - indexed for MEDLINE]
Biol Psychiatry. 1993 Jul 1-15;34(1-2):13-7. Related Articles, Links
Adverse reactions to aspartame: double-blind challenge in patients from a vulnerable population.
Walton RG, Hudak R, Green-Waite RJ.
Department of Psychiatry, Northeastern Ohio Universities College of Medicine, Youngstown.
This study was designed to ascertain whether individuals with mood disorders are particularly vulnerable to adverse effects of aspartame. Although the protocol required the recruitment of 40 patients with unipolar depression and a similar number of individuals without a psychiatric history, the project was halted by the Institutional Review Board after a total of 13 individuals had completed the study because of the severity of reactions within the group of patients with a history of depression. In a crossover design, subjects received aspartame 30 mg/kg/day or placebo for 7 days. Despite the small n, there was a significant difference between aspartame and placebo in number and severity of symptoms for patients with a history of depression, whereas for individuals without such a history there was not. We conclude that individuals with mood disorders are particularly sensitive to this artificial sweetener and its use in this population should be discouraged.
PMID: 8373935 [PubMed - indexed for MEDLINE]
Toxicology. 1988 Jun;50(1):1-26. Related Articles, Links
Aspartame: review of recent experimental and observational data.
Janssen PJ, van der Heijden CA.
National Institute of Public Health and Environmental Hygiene, Bilthoven, The Netherlands.
In this report the neurotoxicity of aspartame and its constituent amino acids aspartic acid and phenylalanine is reviewed. The adverse reactions ascribed to the consumption of aspartame-containing products, as reported in the U.S.A., are discussed and placed in perspective with the results of recent behavioural studies in humans and animals. The issue of common intake levels associated with proposed uses of aspartame is addressed. In brief, the following conclusions can be drawn: When aspartame is consumed at levels within the ADI-limit of 40 mg/kg body wt, there is no significant risk for an aspartate-induced neurotoxic effect in the brain. When aspartame is consumed at levels within the ADI-limit by normal subjects or persons heterozygous for phenylketonuria (PKU) the resultant plasma phenylalanine concentrations are practically always within the normal postprandial range; elevation to plasma concentrations commonly associated with adverse effects has not been observed. Persons suffering from phenylketonuria (PKU-homozygotes) on a phenylalanine-restricted diet should avoid consumption of aspartame. PKU-homozygotes on the (less strict) phenylalanine-liberalized diet should be made aware of the phenylalanine content of aspartame. In the available behavioural studies in humans with acute dosing, no adverse effects were observed. Long-term studies on behaviour and cognitive function in (sensitive) humans are lacking. Analyses of adverse reaction reports made by consumers in the U.S.A. have not yielded a specific constellation of symptoms clearly related to aspartame that would suggest a widespread public health hazard associated with aspartame use. Focussed clinical studies are now being carried out in the U.S.A.; the results should provide additional evidence concerning the interpretation of the reports on adverse reactions ascribed to aspartame. In the regulation of admitted uses for aspartame the possibility of intake levels exceeding the ADI-limit in some groups of consumers should be a point of attention.
PMID: 3291200 [PubMed - indexed for MEDLINE]
Environ Health Perspect. 1987 Nov;75:53-7. Related Articles, Links
Possible neurologic effects of aspartame, a widely used food additive.
Maher TJ, Wurtman RJ.
Department of Pharmacology, Massachusetts College of Pharmacy, Boston 02115.
The artificial sweetener aspartame (L-aspartyl-L-phenylalanyl-methyl ester), is consumed, primarily in beverages, by a very large number of Americans, causing significant elevations in plasma and, probably, brain phenylalanine levels. Anecdotal reports suggest that some people suffer neurologic or behavioral reactions in association with aspartame consumption. Since phenylalanine can be neurotoxic and can affect the synthesis of inhibitory monoamine neurotransmitters, the phenylalanine in aspartame could conceiveably mediate neurologic effects. If mice are given aspartame in doses that elevate plasma phenylalanine levels more than those of tyrosine (which probably occurs after any aspartame dose in humans), the frequency of seizures following the administration of an epileptogenic drug, pentylenetetrazole, is enhanced. This effect is simulated by equimolar phenylalanine and blocked by concurrent administration of valine, which blocks phenylalanines entry into the brain. Aspartame also potentiates the induction of seizures by inhaled fluorothyl or by electroconvulsive shock. Perhaps regulations concerning the sale of food additives should be modified to require the reporting of adverse reactions and the continuing conduct of mandated safety research.
PMID: 3319565 [PubMed - indexed for MEDLINE]
Neurobehav Toxicol Teratol. 1984 Nov-Dec;6(6):455-62. Related Articles, Links
Excitotoxic food additives--relevance of animal studies to human safety.
Evidence is reviewed supporting the view that excitotoxic food additives pose a significant hazard to the developing nervous system of young children. The following points are stressed: (1) although blood-brain barriers protect most central neurons from excitotoxins, certain brain regions lack such protection (a characteristic common to all vertebrate species); (2) regardless of species, it requires only a transient increase in blood excitotoxin levels for neurons in unprotected brain regions to be silently destroyed; (3) humans may be at particularly high risk for this kind of brain damage, since ingestion of a given amount of excitotoxin causes much higher blood excitotoxin levels in humans than in other species; (4) in addition to the heightened risk on a species basis, risk may be further increased for certain consumer sub-populations due to youth, disease or genetic factors; (5) despite these reasons for maintaining a wide margin of safety in the use of excitotoxins in foods, no safety margin is currently being observed, i.e., a comparative evaluation of animal (extensive) and human (limited) data supports the conclusion that excitotoxins, as used in foods today, may produce blood elevations high enough to cause damage to the nervous system of young children, damage which is not detectable at the time of occurrence but which may give rise to subtle disturbances in neuroendocrine function in adolescence and/or adulthood.
PMID: 6152304 [PubMed - indexed for MEDLINE]
Am J Clin Nutr. 1986 Mar;43(3):464-9. Related Articles, Links
Evaluation of reactions to food additives: the aspartame experience.
Bradstock MK, Serdula MK, Marks JS, Barnard RJ, Crane NT, Remington PL, Trowbridge FL.
Despite the widespread use of chemical food additives, few criteria exist to evaluate consumer reports of adverse reactions. We analyzed 231 consumer complaints associated with the food additive aspartame. We developed a methodologic approach to evaluate all complaints by adapting general criteria used to investigate adverse reactions to medications. Complaints were ranked according to the effects of cessation and rechallenge. Using this method, we found no clear symptom complex that suggests a widespread public health hazard associated with aspartame use; however, we identified some case reports in which the symptoms may be attributable to aspartame in commonly-consumed amounts. The systematic application of pre-defined review criteria, such as those described here, to monitor consumer complaints related to food additives will help identify products that warrant more focused clinical studies.
PMID: 3953484 [PubMed - indexed for MEDLINE]
Am Fam Physician. 1989 Feb;39(2):201-6. Related Articles, Links
Clinical safety of aspartame.
University of Arizona College of Medicine, Tucson.
Aspartame is a synthetic sweetener commonly used in soft drinks and many foods. Even with high doses, the metabolites of this sweetener do not accumulate in toxic amounts. To date, no definite symptom complex has been connected with aspartame, and it is considered safe for use in all populations, including diabetics, phenylketonuric heterozygotes and pregnant women.
PMID: 2644789 [PubMed - indexed for MEDLINE]