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Subject: Testimony before Congress by FDA toxicologist, M. Jacqueline Verrett, Ph.D. on Aspartame - November 3, l987 (The studies that approved aspartame - says safety questions remain unanswered). Cc: [email protected]

From l957-l977 I was employed as a Biochemist/Toxicologist in what is now designated the Center for Food Safety and Applied Nutrition of the Food and Drug Administration.

During this time my duties were twofold: 1) evaluation of experimental data submitted to FDA in support of the safety of a wide variety of chemicals and processes (such as irradiation) intended for food additivem use directly and indirectly, as well as data pertaining to various contaminants such as mycotoxins, pesticides, and also some drugs; 2) a variety of research pertinent to FDA's mission, and for the most part devoted to the overall toxicity and more specifically to teratogenic (birth-deforming) capabilities of several hundred substances that may be broadly classified as food additives, both direct and indirect, or as food contaminants.

In the early l970's, I examined the animal studies submitted by G. D. Searle and Co. on aspartame prior to the initial approval by FDA in l974. While I cannot recall any specific examples, it was my overall impression that these studies raised numerous questions in a number of areas that needed to be resolved before approval of aspartame for any food additive use.

In l977 I served as a member of an FDA team (from the Bureau of Foods which was charged with examining three studies (the rat DKP long term study, and aspartame teratology studies in mice and rats) to determine if they were authentic'. We were instructed to incorporate the findings of the FDA task force investigation of Searle (Bressler Report) and to determine whether alterations and adjustments to the data engendered by inclusion and consideration of these discrepancies resulted in significantly different results from those presented in the original Searle submission. This authentication was hence intended to verify that the submitted data had not been altered, that it reflected the actual outcome of the study, and that it did not change substantially, particularly in a statistical sense, the various parameters from which the conclusion of safety had been derived. Our analysis of the data in this manner revealed that, in these three studies no substantial change resulted, although in numerous instances a definitive answer could not be arrived at because of basic inadequacies and improper procedures used in the execution of these studies.

I wish to emphasize at this point that we were specifically instructed not to be concerned with, or comment upon, the overall validity of the study' this was to be done in a subsequent review carried out at the Bureau level. It is apparent that that review, on a point by point basis, discarded or ignored the problems and deficiencies outlined in this Team report, and concluded that, even in toto, these problems were insufficient to render the study invalid. It also appears that the serious departures from acceptable toxicological protocols that were noted in the reevaluation of these studies were also discounted.

At this point it might be helpful to mention some of the deficiencies and improper procedures encountered: no protocol was written under the study was well underway; animals were not permanently tagged to avoid mixups; changes were introduced in some laboratory methods during the study with inadequate documentation; there was sporadic monitoring and/or inadequate reporting of food consumption and animal weights; tumors were removed and the animals returned to the study; animals were recorded as dead, but subsequent records, after varying periods of time indicated the same animal was still alive (almost certain evidence of mixups); many animal tissues were autolyzed (decomposed) before any postmortem examinations were performed; and finally, of extreme importance, in the DKP study there was evidence, including pictures, that the diets were not homogeneous and that the animals could discriminate between feed and the included DKP. Almost any single one of these aberrations would suffice to negate a study designed to assess the safety of a food additive, and most certainly a combination of many such improper practices would, since the results are bound to be compromised.

It is unthinkable that any reputable toxicologist, giving a completely objective evaluation of data resulting from such a study, could conclude anything other than that the study was uninterpretable and worthless, and should be repeated. This is especially important for an additive such as aspartame, which is equally vital since DKP is a major breakdown product of aspartame in liquid media. Not only is aspartame being used in the absence of basic toxicity information, but there is also no data to assess the toxicity of the interactions of DKP with the excess phenylalanine generated, with any other metabolite of aspartame, and its interactions with other additives, drugs, or other chemicals which may be present simultaneously in persons exposed to high levels of DKP in presweetened liquids such as diet drinks.

While I have not been involved in aspartame safety matters since the team effort described previously, a brief examination of studies completed and currently underway seems to indicate that the subject studies have not been repeated, so the safety questions remain unanswered. It would appear that the safety of aspartame (and its breakdown products) has still not been satisfactorily determined, since many of the flaws cited in the studies referred to here were also present in other studies submitted by Searle. Dr. M. Jacqueline Verrett.

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