Order Code RS20218
June 3, 1999
CRS Report for Congress
Received through the CRS Web
Donna V. Porter
Specialist in Life Sciences
Domestic Social Policy Division
Recent information broadcast on the internet, suggesting that there are health
hazards associated with use of the artificial sweetener, aspartame, has precipitated
constituent mail to congressional offices. Since it was first approved for use as a food
additive in 1981, aspartame has been linked by its critics to a number of health problems.
However, federal officials report that, after more than a decade of monitoring, there is
no clinical evidence that this artificial sweetener poses a hazard to the average consumer.
Individuals with phenylketonuria (PKU), a genetic metabolic disorder, should avoid
aspartame because it contains phenylalanine which they can not metabolize. The Food
and Drug Administration (FDA) has approved aspartame for use in all food and
beverages, following one of the most rigorous testing programs and regulatory reviews
in food additive history. Food labels are required to identify the presence of aspartame
both on the ingredient label and the warning statement for individuals with PKU. Bills
were introduced in the 98th and 99th Congresses to address maximum concentrations,
labeling, and consumer education issues, but no final action was taken. In 1987, the
Senate Committee on Labor and Human Resources (since renamed Health, Education,
Labor and Pensions (HELP)) held the most recent aspartame hearing. This report
provides background information and will not be updated.
Aspartame and Health Problems
Since aspartame was first approved for use as a food additive, there have been
concerns raised about the health problems associated with this artificial sweetener. Its
critics linked aspartame use with Alzheimer’s disease, various birth defects, brain tumors,
diabetes, Gulf War syndrome, lupus, multiple sclerosis and seizures. However, these
assertions have not been borne out by clinical studies following accepted scientific
To date, the only condition for which aspartame use has been recognized as a
potential health problem is phenylketonuria (PKU). PKU occurs in individuals with a
genetic metabolic disorder in which the amino acid phenylalanine is not metabolized.
Aspartame is composed of two amino acids, aspartic acid and phenylalanine. If
Congressional Research Service ˜ The Library of Congress
phenylalanine builds up in the body, it can cause brain damage. Prenatal diagnosis is now
possible in the majority of PKU families and their newborns are tested within 48 hours of
birth. Individuals with this condition generally follow a fairly strict dietary regimen to
minimize their intake of this amino acid, while otherwise maintaining a balanced diet.
Phenylketonurics generally are advised by their health professionals on how to avoid food
sources of phenylalanine, including aspartame.
Recent information broadcast on the internet has suggested that aspartame is
converted to formaldehyde, then to formic acid, which in turn causes metabolic acidosis.
As it is metabolized, aspartame is split into its respective parts, aspartic acid, phenylalanine
and methanol. The internet report suggests that methanol toxicity results. However, there
is no evidence in the scientific literature to support this contention. In the extensive
literature on studies of aspartame metabolism, methanol blood levels were unchanged by
normal consumption of this additive. Other commonly consumed foods (for example,
tomato juice) result in significantly higher levels of methanol in the body, without any
The Food and Drug Administration (FDA) first approved aspartame for use as a food
additive in 1981. Since 1996 it has been approved for use in all foods and beverages.1
The sweetener has been approved by more than 90 countries. As a sweetener, it is 200
times sweeter than sugar, enhances fruit flavors, saves calories and does not contribute to
Prior to its approval, aspartame underwent one of the most extensive testing
programs and regulatory reviews in food additive history. Tests were conducted in
animals and humans, including normal adults and children, lactating women, and
individuals with diabetes, obesity and special genetic problems. Aspartame was tested in
amounts significantly higher than individuals could normally consume in their diets. This
sweetener continues to be studied by scientists as is done for many other ingredients in the
food supply. FDA also continues to monitor and evaluate all new research on this
compound and other food ingredients.
There is no scientific evidence that aspartame is linked to adverse reactions in
humans, with the exception of PKU as noted above. Since 1981 FDA has investigated all
reported complaints and has reported a gradual decrease in reports of adverse reactions
to aspartame received since the 1985 peak. Individuals who have concerns about possible
adverse reactions from the consumption of aspartame are advised to contact their
By regulation, if aspartame is present in a food product, it must be listed on the
ingredient label of the product in which it is used. The following warning statement,
Phenylketonurics: Contains Phenylalanine, is also required to appear on the product
to advise consumers who have this genetic defect. This warning statement recognizes the
potential health problem to phenylketonurics from the use of aspartame. Early in its use,
Department of Health and Human Services (HHS). Food and Drug Administration. FDA
Statement on Aspartame. FDA Talk Paper. T96-75. November 18, 1996.
the company used the trademark symbol for aspartame on the front panel of product
packages containing the sweetener. This trademark was not required by any regulation
and seems to have been largely phased out.
It is relatively easy for consumers to avoid aspartame. First, if a product is not
marked as “diet or sugar-free,” it probably does not contain any artificial sweetener.
Regardless of whether a product is marked as “diet or sugar-free,” the ingredient listing
can be checked to determine whether aspartame is present, because all food products are
required to provide a complete list of all ingredients. There are other approved artificial
sweeteners that may be used alone or in combination with aspartame to sweeten a product.
The product can also be checked for the presence of the company trademark for aspartame
on the label or the warning statement for phenylketonurics, if consumers wish to avoid this
In the 98th Congress, H.R. 4112 was introduced by Congressman Gejdenson to
require the Secretary of the Department of Health and Human Services (HHS) to establish
a maximum concentration level for aspartame as a food additive. It was referred to the
House Committee on Energy and Commerce’s Subcommittee on Health and the
Environment, but no further action was taken.
In the 99th Congress, Senator Metzenbaum introduced S. 1557 which would have
provided for public information concerning the use of products containing aspartame and
the conduct of studies to determine the health effects of using this sweetener in food
products. Entitled the Aspartame Safety Act of 1985, this measure was referred to the
Committee on Labor and Human Resources, but no further action was taken. Earlier in
the session, Senator Metzenbaum also sponsored an amendment that would have required
a soft drink containing aspartame to be labeled with a statement of the total number of
milligrams of the sweetener contained in the drink. The amendment was defeated in the
Senate in a recorded vote. Since then no other bills have been introduced on aspartame.
The most recent hearing on aspartame identified was held on November 3, 1987 by
the Senate Committee on Labor and Human Resources, chaired by Senator Metzenbaum.
The hearing, entitled “Nutrasweet” — Health and Safety Concerns, included testimony
from consumers who believed that they had experienced severe reactions to aspartame,
and a physician who reported having observed reactions in his patients. In addition,
several scientists on both sides of the controversy and the FDA commissioner, a consumer
attorney concerned about food safety in general, and the president of Nutrasweet
(aspartame manufacturer) also testified.
No additional attention to this food additive has been identified since the 99th
Congress. The outcome of the 1987 hearing seemed to be that the ongoing clinical studies
and post-marketing surveillance reported at that time were sufficient to address the
concerns that had been raised, with the understanding that FDA would continue to monitor
whether there was evidence of any pattern of adverse effects from the use of aspartame.