abstracted from the April 2005 issue of Pure Facts

As its patent for aspartame was running out, Monsanto developed a new, more potent version of its synthetic sweetener.

By adding 3-dimethylbutyl (a chemical the Environmental Protection Agency lists as hazardous) to aspartame, scientists at Monsanto drastically increased the sweetening power of the additive. The new version was named neotame. (The U.S. Food and Drug Administration approved it in 2002. It is also approved for use in Australia and New Zealand but has not yet been accepted in Europe.)

In addition to being far sweeter than aspartame, neotame is heat stable. This means that, unlike aspartame, it can be used in baked goods.

Dilemma for Feingold members

Depending on how it is used, neotame is from 7,000 to 13,000 times as sweet as sugar. It is 30 times sweeter than its cousin, aspartame, so only a tiny amount is needed. Since the FDA does not require labels to include ingredients that comprise less than one percent of the product, it's possible that neotame could be used in foods without having to be listed on the label. It might also be camouflaged under "natural flavors."

At this time, neotame is not available directly to consumers; instead, it is being used in several hundred different food products, often blended with other synthetic sweeteners.

(Note: Products that contain aspartame are required to include a caution for individuals who cannot tolerate the phenylalanine in it. Some manufacturers hide aspartame in foods, supplements, and medicines, by simply saying "contains phenylalanine.")

The story behind the "studies"

Critics say neotame is even more toxic than aspartame, and call for independent research (not studies funded by the manufacturer) to evaluate its effects. They allege that Monsanto's studies on humans lasted only one day! They accuse Monsanto of hiring a close business partner to conduct studies on the sweetener. The critics also say that it was discovered the researchers were hiding reaction-causing chemicals in the drinks given to control groups.

The non-profit group, Truth in Labeling, gained access to some of the neotame studies. They write, "At the time of our review of Monsanto's application, three human studies on the safety of neotame were presented. The studies had few subjects, all of whom were employees of the company. Some of the subjects reported headaches after ingesting neotame, but the researchers concluded that the headaches were not related to neotame ingestion. Not mentioned in the studies was the fact that migraine headache is, by far, the most commonly reported adverse reaction to aspartame in the files of the FDA."

H.J. Roberts, MD, who has studied the effects of aspartame for many years, writes: "The fundamental issue is that neotame, a synthetic variation of aspartame, requires extensive evaluation before the FDA should accept a superficial opinion about its purported safety based largely on limited short-term data involving potentially flawed protocols that were almost totally funded by corporate contracts."

We did a search of MedLine to find studies of adverse effects or side effects of Neotame. Only four studies appeared, two of which were not studies, and the other two of which were actually a single study done by NutraSweet company researchers.

  1. This is not a study, but a review of earlier literature. Weihrauch, in 2004, says that "It can be assumed that every citizen of Western countries uses artificial sweeteners, knowingly or not." He concludes, "Despite some rather unscientific assumptions, there is no evidence that aspartame is carcinogenic." but also notes that it is too early to know about the newer sweeteners (they are not tested before being sold to you - have you noticed that?) but "Case-control studies showed an elevated relative risk of 1.3 for heavy artificial sweetener use (no specific substances specified) of >1.7 g/day." Yet, he concludes that while the current mixing of sweeteners will make it difficult to know what any single one is doing to us, "according to the current literature, the possible risk of artificial sweeteners to induce cancer seems to be negligible."

    Translation: If we don't look, we won't know anything bad.

  2. Evaluation of certain food additives and contaminants. This is not a study at all, but a report by the World Health Organization, setting the acceptable daily intakes (ADIs) of the various additives including sweeteners.

  3. Finally, we see two studies - actually, they appear to be two articles on one study, printed in the same issue of the journal, Regulatory toxicology and pharmacology. Although they are the same researchers, the authors are listed as from the AAC Consulting Group in the first study, and from Regulatory Affairs, The NutraSweet Company, in the second.

    Their results apparently are that the rats don't like neotame very much, and would not eat it until they reduced the "dosage" drastically. Even so, they did not gain weight properly as they grew. How the doses that they tolerated compare with how much people actually may eat, is not mentioned in the abstract. The rats did not show any gross pathology when examined after being killed. It does not appear that they performed any neurological studies on these rats. Also, if the rats were refusing to eat the neotame, they could have given it to them by gavage (tube feeding), as they do in other studies when they really do want to know if the chemical will have any negative effect.

Where are the studies by unbiased, independent researchers? If they have been done, they do not appear to have been published. If you know of some, feel free to send them to us.

In a second MedLine search of "Neotame" alone, the same articles as above appeared, as well as a couple of reviews of literature apparently not published in MedLine, several articles describing the chemical stability, chemical structure, etc., a review of its discovery and development, and one on its effect on glucose levels in diabetics (unfortunately, there is no abstract of that one and the article is in Russian).

It is hard to escape the nagging feeling that the appropriate studies on safety, neurotoxicity, immunology, development, and safety during pregnancy, are just not there.