Aspartame, an artificial sweetener that is used as a substitute for sugar in many foods and beverages, is considered by some scientists to be a neurotoxin, a substance that is detrimental to the nervous system. This allegation remains controversial.
Aspartame was introduced as an artificial sweetener by the Monsanto Company in the 1970s. For much of the intervening time, individuals and special interest groups have maintained that aspartame damages the nervous system. Given the number and popularity of the items that are sweetened using aspartame (i.e., yogurts, soft drinks), the special interest groups assert that the general population is at risk for neurological damage caused by the ingestion of aspartame.
Alleged harmful effects of aspartame ingestion include seizures and a change in the level of dopamine, a brain neurotransmitter. Symptoms associated with lupus, multiple sclerosis, and Alzheimer's disease have been claimed to result from an excess intake of aspartame. As well, aspartame consumption is claimed to increase the difficulty of diet-dependent diabetics in regulating their blood glucose level.
One peer-reviewed scientific study has documented an improvement in fibromyalgia symptoms (pain in the muscles, ligaments, and tendons) following the elimination of monosodium glutamate and aspartame from the diet. The influence of aspartame alone, however, was not assessed. Studies conducted prior to the marketing of aspartame and following its introduction have failed to demonstrate these claimed negative effects. The U.S. Food and Drug Administration (FDA) maintains that aspartame is not a health threat to the general population, although individuals who are sensitive to the compound can develop headaches and feel fatigued. Currently, there is no evidence directly linking aspartame with diseases such as lupus, multiple sclerosis, and Alzheimer's.
As the association of aspartame with neurological disorders is not proven, statistics relating to how often and how many individuals suffer ill effects from aspartame are unavailable. If the claim of a general population effect is true, and that the effect is cumulative (builds up over time), then aspartame would affect older people more than younger people. There has been no evidence or suggestion of any gender, race, or cultural predilection to negative effects from aspartame.
If, however, only certain people are predisposed to be more sensitive to the presence of aspartame, then the demographics would include this subpopulation. The characteristics of such a group have not been defined.
Causes and symptoms
At elevated temperatures of about 90° Fahrenheit, a component of aspartame can convert to formaldehyde. High concentrations of formaldehyde can kill cells and tissues. Furthermore, formaldehyde can, in turn, be converted to formic acid, which can cause metabolic acidosis. Whether these changes are detrimental to the nervous system is not known.
One research paper published in 2001 reported one patient in whom aspartame exacerbated an ongoing migraine attack. Whether this occurrence is more widespread among the general public is unknown.
Currently, any symptoms that are directly attributable to aspartame excess have not been conclusively identified. The suspected symptoms such as fibromyalgia and changes in dopamine levels are associated with other maladies including lupus, multiple sclerosis, or Alzheimer's disease. Factors that may trigger migraine headache vary among individuals, and physicians may suggest that those suffering from migraine lower their consumption of aspartame.
Symptoms may disappear when the use of aspartame is discontinued.
Aspartame poisoning is a contentious issue. Scientific peer-reviewed papers have reported on research performed at companies that have a vested interest in sales of aspartame. While the quality of the scientific data contained in these studies may be sound, other scientists criticize that the evidence presented is difficult to evaluate in light of possible conflicting interests. By the same token, the claims made by special interest groups concerning the dangers of aspartame should be viewed cautiously, as little or no data is presented to support their claims.
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Butchko, H. H., et al. "Aspartame: Review of Safety." Regulatory Toxicology and Pharmacology (April 2002): S1–93.
Newman, L. C., and R. B. Lipton. "Migraine MLT-down: An Unusual Presentation of Migraine in Patients with
Smith, J. D., C. M. Terpening, S. O. Schmidt, and J. G. Gums. "Relief of Fibromyalgia Symptoms following Discontinuation of Dietary Excitotoxins." Annals of Pharmacotherapy (June 2001): 702–706.
"Aspartame Information Page." National Institute of Neurological Disorders and Stroke. January 21, 2004 (May 17, 2004). <http://www.ninds.nih.gov/health_and_medical/disorders/aspartame.htm>.
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Brian Douglas Hoyle, PhD