Determination of minimum and non-provoking doses of soy protein in soy allergic individuals

The purposes of this study are to determine a lowest observed adverse effect
level (LOAEL) and to establish a no observed adverse effect level (NOAEL) for
soy protein when consumed by soy-allergic individuals. This information is
beneficial in that it assists the clinician and the individual in assessing
clinical reaction risk and in implementing suitable avoidance diets.
Soy-allergic individuals will also benefit because the food processing
industry and government agencies that regulate it will improve their practices
as a result of knowledge gained regarding the minimal eliciting dose for soy
protein. For example, the food industry uses shared equipment for
soy-containing and soy-free products. The level of care needed for sanitation
of shared food processing equipment to assure its safe use is uncertain. As a
result, many foods are labeled with precautionary statements such as *may
contain soy*. The establishment of a LOAEL and a NOAEL will provide guidance
to regulators and the food industry in the establishment of circumstances where
residual levels of soy protein from shared processing equipment warrant the use
of precautionary labeling. Soy-allergic individuals will benefit from these
food industry and government regulatory agency actions because they should
result in the availability of a wider variety of safe food choices.

Primary Objective: To determine minimum and non-provoking doses of soy protein
(in mg) for soy allergic individuals
Secondary Objective(s): To determine the relevant allergens of soy in soy
allergy and to determine the relation between allergen recognition pattern and
severity of the allergy.

The study design will be cross-sectional. Subjects will be identified by a
blood draw and a skin prick test. Twenty-nine soybean allergic individuals will
be selected as subjects and challenged with a double blind placebo controlled
food challenge based on well established international guidelines. In the UMCU
10 subjects will be included.

Not applicable

Benefits: The direct benefit to the subject is to know what amount of soy flour
is an allergy risk for him or her. Results from all o f the subjects will be
used to help determine regulatory and industry labeling policies for food
products produced in facilities that also manufacture foods containing soy
flour.
Risks: Skin prick testing is considered a relatively safe procedure and is
performed daily in allergy clinics. The most common side effect is the
development of an itchy spot (like a mosquito bite) in the area of skin where a
positive reaction occurs. The itchiness resolves after a few minutes and the
skin lesion should resolve within an hour or two.
The drawing of blood from subjects is also an everyday procedure but
side effects may occur. The most common side effect is a small discoloration or
bruise that may remain at the site for several days.
The reactions that can occur with food challenges are often mild or
moderate. We note that there are risks associated with food challenges, but
these risks are reasonable since challenges are performed under the guidance of
an experienced practitioner in a properly equipped setting and the soy dosages
will be increased gradually. Nursing and physician staff will be present
during the oral food challenge. In the event that the subject has a reaction
during the oral food challenge, emergency supplies and medications will be
available and be administered according to the level and severity of reaction.
The precise risk of anaphylaxis from the food challenge is unknown but is very
low.