How Much Peanut is Too Much?
By Michael Goldman,
Peanuts are one of the most common foods to cause allergic reactions
in both children and adults and are the most common cause of fatal
food allergic reactions. In peanut allergic individuals, accidental
ingestion of peanut products can produce any or all of the following
symptoms: hives, itching or swelling of the mouth and throat, tightening
of the throat, sneezing, chest tightness, cough, shortness of breath,
stomach upset, vomiting, drop in blood pressure, loss of consciousness,
and even death.
Once the diagnosis of
peanut allergy has been made (by a history of a reaction and/or
confirmed by allergy testing), the mainstay of treatment is avoidance.
If an accidental ingestion occurs, experts recommend rapid treatment
with early use of epinephrine to prevent drastic outcomes. Each
peanut allergic individual should have an action plan developed
with his/her physician in case of accidental peanut ingestion.
The question many parents,
caregivers and peanut allergic individuals themselves want to know
is "how much peanut is too much?" The short answer is that any amount
is too much. Microscopic quantities of peanuts may be enough to
produce a reaction in some individuals. It is important to read
all ingredients and to avoid obvious sources of peanut protein such
as peanut butter and peanut flour. It is equally important to avoid
"hidden" sources of peanuts as in baked goods, candies and certain
ethnic foods (Thai, Vietnamese, Chinese and Mexican) that tend to
use peanuts, peanut butter or peanut flour as ingredients in many
dishes. Do not forget about cross-contamination of other foods with
peanut protein. The jelly jar that is used with a knife containing
peanut butter may contain enough peanut to produce a reaction.
Two recent studies published
last year in the Journal of Allergy and Clinical Immunology underscore
how small quantities of peanut protein can produce a reaction. In
the first, twelve adult peanut allergic individuals were given capsules
with increasing amounts of peanuts. One patient reacted to 16 mg
of defatted peanut, which is equivalent to 1/27 of a peanut. The
other eleven patients reacted to between 100 and 4000mg of defatted
peanut (1/4 to 9 peanuts). However, since the peanuts were in capsules,
they bypassed contact with the mouth and throat and so probably
did not simulate the typical peanut ingestion.
The second study was a closer approximation of "real life" ingestion.
Fourteen peanut allergic individuals were given increased amounts
of peanut protein in the form of peanut flour mixed in rice pudding.
Three patients reported mild symptoms (warm feeling in the throat,
lip tingling) at 0.1 to 0.25 mg of peanut protein. By my calculations,
this is approximately equivalent to eating 1/2000th to 1/800th of
a peanut. Five other patients had similar symptoms after ingesting
1 to 10 mg doses of peanut protein (1/200th to 1/20th of a peanut).
One patient had lip swelling, hives, vomiting and wheezing after
ingesting a total of 9 mg of peanut protein (~1/20th of a peanut).
Five patients had no reactions after eating 90 mg of peanut protein
(one-half of a peanut), the maximum dose in this study, suggesting
that higher doses would be required to induce their symptoms.
What conclusions can
we make from these two studies? First, minute quantities of peanut
can produce symptoms. Second, the higher the dose ingested the more
likely a reaction. Finally smaller quantities ingested by a single
individual may produce milder symptoms while larger quantities are
more likely to produce severe symptoms. However, these "larger quantities"
can still be a fraction of a single peanut. I never recommend taking
a "test bite" of a cake or candy for that one small bite may have
Careful avoidance of
all potential sources of peanut protein is essential to prevent
a reaction. However, accidents are likely to occur. In a study of
32 peanut allergic individuals at the National Jewish Center for
Respiratory Diseases, three-fourths had accidentally eaten peanuts
in the previous five years, with one-half in the preceding year.
It is vitally important that all peanut allergic patients have an
action plan in place to deal quickly with such an accidental ingestion.
Most (if not all) peanut allergic patients should have epinephrine
(EPIPEN, EPIPEN-Jr., Anakit) readily available to treat these potentially
life threatening reactions. For peanut allergic children, caregivers
(parents, grandparents, teachers, school nurses and babysitters,
etc.) need to be aware of the seriousness of the condition and instructed
what to do if an accidental ingestion occurs. It is my firm belief
that all fatal reactions to food allergies can be prevented with
careful avoidance and rapid use of epinephrine for accidental ingestion.
You should discuss your specific action plan with your physician.
Goldman is an Instructor of Medicine at Johns Hopkins University
in the Division of Allergy and Clinical Immunology and Clinical
Assistant Professor of Allergy/Immunology at the University of Maryland.
He is the Medical Advisor for the Maryland Food Allergy and Asthma
Network, an AAFA-MD Educational Support Group. Dr. Goldman is also
in private allergy practice in Columbia and Baltimore and is the
father of a four-year-old son with severe peanut and fish allergies.)
original article was printed by the Asthma & Allergy Foundation
of America, Maryland Chapter in their April/May 98 Newsletter.
Used by permission.
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