Editor’s Note: Foodfacts.com takes no position on the use of aspartame, but we think that strong opinions expressed on our blog recently about aspartame justifies another look into this issue.
While questions about saccharin may persist, the safety of another artificial sweetener, aspartame, is clear cut, say FDA officials. FDA calls aspartame, sold under some famous trade names, one of the most thoroughly tested and studied food additives the agency has ever approved. The agency says the more than 100 toxicological and clinical studies it has reviewed confirm that aspartame is safe for the general population.
This message would not necessarily be apparent to consumers surfing the Internet, especially those who use Web-based search engines to find information about sugar substitutes or artificial sweeteners. Websites with screaming headlines and well-written text attempt to link aspartame consumption to systemic lupus, multiple sclerosis, vision problems, headaches, fatigue, and even Alzheimer’s disease. One report distributed nationally over e-mail systems claims that aspartame-sweetened soft drinks delivered to military personnel during the Persian Gulf War may have prompted Gulf War syndrome.
No way, says FDA, along with many other health organizations such as the American Medical Association. David Hattan, Ph.D., acting director of FDA’s division of health effects evaluation, says there is no “credible evidence,” to support, for example, a link between aspartame and multiple sclerosis or systemic lupus. Some Internet reports claim that patients suffering from both conditions went into remission after discontinuing aspartame use. “Both of these disorders are subject to spontaneous remissions and exacerbation,” says Hattan. “So it is entirely possible that when patients stopped using aspartame they might also coincidentally have had remission of their symptoms.”
It is true, says Hattan, that aspartame ingestion results in the production of methanol, formaldehyde and formate — substances that could be considered toxic at high doses. But the levels formed are modest, and substances such as methanol are found in higher amounts in common food products such as citrus juices and tomatoes.
Other circulating reports claim that two amino acids in aspartame — phenylalanine and aspartic acid — can cause neurotoxic effects such as brain damage. “This is true in certain individuals and in high enough doses,” says Hattan. He explains that a very small group of people who have the rare hereditary disease phenylketonuria have to watch their intake from other sources as well. Women with certain genetic traits (e.g., phenylketonurics) may metabolize the amino acid, phenylalanine, poorly and thus accumulate far higher than normal blood levels of phenylalanine. During pregnancy, high maternal levels of blood phenylalanine can be transferred to the fetus and produce serious adverse effects on brain development. While the protein eaten by these pregnant women contributes most of the resulting elevation of phenylalanine, they should also be aware of the presence of phenylalanine in beverages and foods that contain aspartame. FDA requires all products containing aspartame to be labeled for phenylalanine so consumers will be aware of the substance’s presence and can avoid or restrict it.
Aspartic acid also has the potential to cause brain damage at very high doses. But under normal intake levels, the brain’s mechanism for controlling aspartic acid levels ensures no adverse effects. It is unlikely that any consumer would eat or drink enough aspartame to cause brain damage: FDA figures show that most aspartame users only consume about 4 to 7 percent of the acceptable daily intake the agency has set for the sweetener.
Still other reports attempt to link aspartame to seizures and birth defects. Regarding seizures, Hattan cites animal and human studies showing that the sweetener neither causes nor enhances the susceptibility of seizures. Aspartame also has been evaluated for its potential to cause reproductive effects or birth defects. Again, researchers found no evidence, even in test animals fed the sweetener at doses much higher than those to which humans would be exposed.
Approved in 1981, aspartame is 180 times sweeter than sugar. It is used in products such as beverages, breakfast cereals, desserts, and chewing gum, and also as a tabletop sweetener. In 1996, a study raised the issue that aspartame consumption may be related to an increase in brain tumors following FDA’s approval of the sweetener in 1981. But analysis of the National Cancer Institute’s database on cancer incidence showed that cases of brain cancers began increasing in 1973 — well before aspartame was approved — and continued to increase through 1985. In recent years, brain tumor frequency has actually decreased slightly. NCI currently is studying aspartame and other dietary factors as part of a larger study of adult brain cancer.