When teen-ager Allison Pansius was 10 months old, she had her first and last taste of peanut
butter. Almost at once, she turned gray, stopped breathing and passed out.
Allison, now 13 years old, is one of the two to three percent of Americans with a potentially life-threatening
food allergy. She knows she must scrupulously avoid peanuts, as well as any product, such as chocolate,
that comes from machinery that also handled nuts.
To protect Allison, her school adopted a "no-nut" policy, and she flies only on airplanes that do not
serve nuts for snacks. Such arrangements are critical for someone like Allison, says Suzanne Teuber, UC
Davis associate professor of internal medicine in the Division of Rheumatology, Allergy and Clinical Immunology.
She adds that Allison's blood level of immunoglobulin E (IgE) toward peanuts an indicator of allergy
severity is "off the charts." Severely allergic people, she says, have had a reaction just from having
multiple bags of peanuts popped open around them and then by breathing in peanut dust.
Teuber's research interests include characterizing allergens and identifying those that cross-react among
nuts. For instance, someone who is allergic to walnuts will usually react with pecans as well, and may
react to multiple other nuts due to cross-reactive similar proteins. Such cross-reactions are typically
due to similar proteins in the different plants.
Her ultimate goal is to help people like Allison know exactly what they need to avoid, and possibly
find ways to reduce allergic reactions through injections of modified allergen components, an area of
research that is showing some promise.
The immune system is also the focus of research by Judy Van de Water, UC Davis associate professor in
the Division of Rheumatology, Allergy and Clinical Immunology. The relationship between diet and the immune
system has become such a large field that nutritional immunology is now a science of its own.
"The immune system is our first line of defense," Van de Water says. "When we cut ourselves or become infected with a virus or bacteria, the immune cells are the first responders."
Van de Water, who is also the core director of the molecular and cell biology core for the National Institute
of Environmental Health Sciences Center for Children's Environmental Health, has documented an increased
production of virus-fighting cytokines in people who eat live-culture yogurt and shown that certain Chinese
botanicals improve the immune response.
Some health problems, such as rheumatoid arthritis, result from the immune system working overtime, and
as a result, calming it is beneficial. She has found that flavanols, found in cocoa, chocolate, green
tea, grapes, apples and red wine, reduce the production of several signaling molecules associated with
immune function and inflammation. This may help explain the benefit these foods for cardiovascular disease,
a problem increasingly linked to excess inflammation.
Van de Water also participates in studies from the Center for Alternative Medicine evaluating claims
made in the media about certain products. "We are at the point where we can analyze immune markers in
a systematic, controlled manner," she says. "Nutritional immunology allows us a glimpse at the link between
our ability to fight disease and the foods we eat."
Both Teuber and Van de Water also are investigating the possibility that autism may be, in part, due
to an allergic response in children with autism or in their mothers. Considerable interest was generated
in this theory when other investigators noted that some children with autism had specific antibodies against
certain foods, such as components of wheat. However, this kind of finding must be approached with caution,
according to Teuber. It is actually normal for people to generate antibodies against certain foods without
apparent clinical manifestations. Carefully controlled trials by Teuber and Van de Water, and a careful
review of published evidence, has led them both to conclude that there is not yet any compelling evidence
that autism has a food allergy component.