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                                             FDA and Monosodium Glutamate (MSG)
U.S. Food and Drug Administration]
 
Monosodium Glutamate (MSG)
 
August 31, 1995
 
     Monosodium glutamate (MSG) is used as a flavor enhancer in a
variety of foods prepared at home, in restaurants, and by food
processors. Its use has become controversial in the past 30 years
because of reports of adverse reactions in people who've eaten
foods that contain MSG. Research on the role of glutamate--a
group of chemicals that includes MSG--in the nervous system also
has raised questions about the chemical's safety.
 
     Studies have shown that the body uses glutamate, an amino
acid, as a nerve impulse transmitter in the brain and that there
are glutamate-responsive tissues in other parts of the body, as
well. Abnormal function of glutamate receptors has been linked
with certain neurological diseases, such as Alzheimer's disease
and Huntington's chorea. Injections of glutamate in laboratory
animals have resulted in damage to nerve cells in the brain.
Consumption of glutamate in food, however, does not cause this
effect. While people normally consume dietary glutamate in large
amounts and the body can make and metabolize glutamate
efficiently, the results of animal studies conducted in the 1980s
raised a significant question: Can MSG and possibly some other
glutamates harm the nervous system?
 
     A 1995 report from the Federation of American Societies for
Experimental Biology (FASEB), an independent body of scientists,
helps put these safety concerns into perspective and reaffirms
the Food and Drug Administration's belief that MSG and related
substances are safe food ingredients for most people when eaten
at customary levels.
 
     The FASEB report identifies two groups of people who may
develop a condition the report refers to as "MSG symptom
complex." One group is those who may be intolerant to MSG when
eaten in a large quantity. The second is a group of people with
severe, poorly controlled asthma. These people, in addition to
being prone to MSG symptom complex, may suffer temporary
worsening of asthmatic symptoms after consuming MSG. The MSG
dosage that produced reactions in these people ranged from 0.5
grams to 2.5 grams.
 
     Although FDA has not fully analyzed the FASEB report, the
agency believes that the report provides the basis to require
glutamate labeling. FDA will propose that foods containing
significant amounts of free glutamate (not bound in protein along
with other amino acids) declare glutamate on the label. This
would allow consumers to distinguish between foods with
insignificant free glutamate levels and those that might
contribute to a reaction.
 
What Is MSG?
 
     MSG is the sodium salt of the amino acid glutamic acid and a
form of glutamate. It is sold as a fine white crystal substance,
similar in appearance to salt or sugar. It does not have a
distinct taste of its own, and how it adds flavor to other foods
is not fully understood. Many scientists believe that MSG
stimulates glutamate receptors in the tongue to augment meat-like
flavors.
 
     Asians originally used a seaweed broth to obtain the flavor-
enhancing effects of MSG, but today MSG is made by a fermenting
process using starch, sugar beets, sugar cane, or molasses.
 
     Glutamate itself is in many living things: It is found
naturally in our bodies and in protein-containing foods, such as
cheese, milk, meat, peas, and mushrooms.
 
     Some glutamate is in foods in a "free" form. It is only in
this free form that glutamate can enhance a food's flavor. Part
of the flavor-enhancing effect of tomatoes, certain cheeses, and
fermented or hydrolyzed protein products (such as soy sauce) is
due to the presence of free glutamate.
 
     Hydrolyzed proteins, or protein hydrolysates, are acid-
treated or enzymatically treated proteins from certain foods.
They contain salts of free amino acids, such as glutamate, at
levels of 5 to 20 percent. Hydrolyzed proteins are used in the
same manner as MSG in many foods, such as canned vegetables,
soups, and processed meats.
 
Scientific Review
 
     In 1959, FDA classified MSG as a "generally recognized as
safe," or GRAS, substance, along with many other common food
ingredients, such as salt, vinegar, and baking powder. This
action stemmed from the 1958 Food Additives Amendment to the
Federal Food, Drug, and Cosmetic Act, which required premarket
approval for new food additives and led FDA to promulgate
regulations listing substances, such as MSG, which have a history
of safe use or are otherwise GRAS.
 
     Since 1970, FDA has sponsored extensive reviews on the
safety of MSG, other glutamates and hydrolyzed proteins, as part
of an ongoing review of safety data on GRAS substances used in
processed foods.
 
     One such review was by the FASEB Select Committee on GRAS
Substances. In 1980, the committee concluded that MSG was safe at
current levels of use but recommended additional evaluation to
determine MSG's safety at significantly higher levels of
consumption. Additional reports attempted to look at this.
 
     In 1986, FDA's Advisory Committee on Hypersensitivity to
Food Constituents concluded that MSG poses no threat to the
general public but that reactions of brief duration might occur
in some people.
 
     Other reports gave similar findings. A 1991 report by the
European Communities' (EC) Scientific Committee for Foods
reaffirmed MSG's safety and classified its "acceptable daily
intake" as "not specified," the most favorable designation for a
food ingredient. In addition, the EC Committee said, "Infants,
including prematures, have been shown to metabolize glutamate as
efficiently as adults and therefore do not display any special
susceptibility to elevated oral intakes of glutamate."
 
     A 1992 report from the Council on Scientific Affairs of the
American Medical Association stated that glutamate in any form
has not been shown to be a "significant health hazard."
 
     Also, the 1987 Joint Expert Committee on Food Additives of
the United Nations Food and Agriculture Organization and the
World Health Organization have placed MSG in the safest category
of food ingredients.
 
     Scientific knowledge about how the body metabolizes
glutamate developed rapidly during the 1980s. Studies showed that
glutamate in the body plays an important role in normal
functioning of the nervous system. Questions then arose on the
role glutamate in food plays in these functions and whether or
not glutamate in food contributes to certain neurological
diseases.
 
Anecdotal Evidence
 
     Many of these safety assessments were prompted by
unconfirmed reports of MSG-related adverse reactions. Between
1980 and 1994, the Adverse Reaction Monitoring System in FDA's
Center for Food Safety and Applied Nutrition received 622 reports
of complaints about MSG. Headache was the most frequently
reported symptom. No severe reactions were documented, but some
reports indicated that people with asthma got worse after they
consumed MSG. In some of those cases, the asthma didn't get worse
until many hours later.
 
     Also, several books and a TV news show have reported
widespread and sometimes life-threatening adverse reactions to
MSG, claiming that even small amounts of manufactured glutamates
may cause adverse reactions.
 
     A problem with these unconfirmed reports is that it is
difficult to link the reactions specifically to MSG. Most are
cases in which people have had reactions after, but not
necessarily because of, eating certain foods containing MSG.
 
     While such reports are helpful in raising issues of concern,
they do not provide the kind of information necessary to describe
who is most likely to be affected, under what conditions they'll
be affected, and with what amounts of MSG. They are not
controlled studies done in a scientifically credible manner.
 
1995 FASEB Report
 
     Prompted by continuing public interest and a flurry of
glutamate-related studies in the late 1980s, FDA contracted with
FASEB in 1992 to review the available scientific data. The agency
asked FASEB to address 18 questions dealing with:
 
*    the possible role of MSG in eliciting MSG symptom complex
 
*   the possible role of dietary glutamates in forming brain
lesions and damaging nerve cells in humans
 
*   underlying conditions that may predispose a person to
adverse effects from MSG
 
*    the amount consumed and other factors that may affect a
person's response to MSG
 
*   the quality of scientific data and previous safety reviews.
 
     FASEB held a two-day meeting and convened an expert panel
that thoroughly reviewed all the available scientific literature
on this issue.
 
     FASEB completed the final report, over 350 pages long, and
delivered it to FDA on July 31, 1995. While not a new study, the
report offers a new safety assessment based on the most
comprehensive existing evaluation to date of glutamate safety.
 
     Among the report's key findings:
 
*    An unknown percentage of the population may react to MSG and
develop MSG symptom complex, a condition characterized by one or
more of the following symptoms:
 
     *    burning sensation in the back of the neck, forearms and
chest
 
     *    numbness in the back of the neck, radiating to the arms
and back
 
     *    tingling, warmth and weakness in the face, temples,
upper back, neck and arms
 
     *    facial pressure or tightness
 
     *    chest pain
 
     *    headache
 
     *    nausea
 
     *    rapid heartbeat
 
     *    bronchospasm (difficulty breathing) in MSG-intolerant
people with asthma
 
     *    drowsiness
 
     *    weakness.
 
*  In otherwise healthy MSG-intolerant people, the MSG symptom
complex tends to occur within one hour after eating 3 grams or
more of MSG on an empty stomach or without other food. A typical
serving of glutamate-treated food contains less than 0.5 grams of
MSG. A reaction is most likely if the MSG is eaten in a large
quantity or in a liquid, such as a clear soup.
 
*    Severe, poorly controlled asthma may be a predisposing
medical condition for MSG symptom complex.
 
*    No evidence exists to suggest that dietary MSG or glutamate
contributes to Alzheimer's disease, Huntington's chorea,
amyotrophic lateral sclerosis, AIDS dementia complex, or any
other long-term or chronic diseases.
 
*    No evidence exists to suggest that dietary MSG causes brain
lesions or damages nerve cells in humans.
 
*    The level of vitamin B6 in a person's body plays a role in
glutamate metabolism, and the possible impact of marginal B6
intake should be considered in future research.
 
*    There is no scientific evidence that the levels of glutamate
in hydrolyzed proteins causes adverse effects or that other
manufactured glutamate has effects different from glutamate
normally found in foods.
 
Ingredient Listing
 
     Under current FDA regulations, when MSG is added to a food,
it must be identified as "monosodium glutamate" in the label's
ingredient list. Each ingredient used to make a food must be
declared by its name in this list.
 
     While technically MSG is only one of several forms of free
glutamate used in foods, consumers frequently use the term MSG to
mean all free glutamate. For this reason, FDA considers foods
whose labels say "No MSG" or "No Added MSG" to be misleading if
the food contains ingredients that are sources of free
glutamates, such as hydrolyzed protein.
 
     In 1993, FDA proposed adding the phrase "(contains
glutamate)" to the common or usual names of certain protein
hydrolysates that contain substantial amounts of glutamate. For
example, if the proposal were adopted, hydrolyzed soy protein
would have to be declared on food labels as "hydrolyzed soy
protein (contains glutamate)." However, if FDA issues a new
proposal, it would probably supersede this 1993 one.
 
     In 1994, FDA received a citizen's petition requesting
changes in labeling requirements for foods that contain MSG or
related substances. The petition asks for mandatory listing of
MSG as an ingredient on labels of manufactured and processed
foods that contain manufactured free glutamic acid. It further
asks that the amount of free glutamic acid or MSG in such
products be stated on the label, along with a warning that MSG
may be harmful to certain groups of people. FDA has not yet taken
action on the petition.
 
     Copies of the 1995 FASEB report are available for $50
each by writing to FASEB at 9650 Rockville Pike, Bethesda, MD
20814.
 
[References: Federal Register, Dec. 4, 1992 (FR 57467) and
Federal Register, Jan. 6, 1993 (FR 2950); FDA Consumer, December
1993, "Food Allergies: When Eating is Risky."]
 
BG 95-16