UW-Madison alumnus Graham Bernstein's lactose intolerance depressed him.
\I thought I could never eat dairy again,"" he said of his diagnosis at age 12. Bernstein diagnosed himself as lactose intolerant after noticing his discomfort after eating dairy. He never saw a doctor about his condition.
Not seeing a doctor is insufficient, said University Health Services director Scott Spear, as many people do not know how to treat allergies or identify them.
""We urge people who are thinking they have a food allergy to come and talk to a clinician,"" Speer said.
Bernstein said his depression stemmed from not realizing lactose pills could ease his symptoms and let him eat dairy again.
""Once I found out I could take these snazzy pills, everything was OK,"" Bernstein said.
Lactose intolerance is not an allergy to lactose. Lactose intolerant people lack the crucial digestive enzyme that breaks down lactose, Spear said. That's why taking pills with the enzyme eases the symptoms. The enzyme digests the lactose so it doesn't travel through the digestive tract, making the person uncomfortable.
An intolerance and an allergy are two different reactions to foods. Nearly 10 percent of the U.S. population is lactose intolerant. Only about 1 percent has a food allergy, according to the National Institutes of Health.
Food allergies are an immune system response, not intolerance of undigested food.
An allergen-the part of the food responsible for the allergy-starts a cascade of cell signaling, said Dr. Mark Moss, assistant professor of medicine and pediatrics at UW Medical School. The allergen protein binds to antibodies on specialized immune system cells called mast cells.
""The binding triggers mast cells to release histamine, which could mean sneezing, itchy eyes, itchy mouth or a cough,"" he said.
If the mast cells release large amounts of histamine, the symptoms are severe.
Blood vessels dilate, breathing constricts and the person could go into life-threatening anaphylactic shock, Moss said, which requires a trip to the emergency room and a shot of epinephrine.
But not all allergen exposures are alike.
""A sudden exposure makes the reaction much, much worse,"" Speer said. ""Cells store up the allergy reaction.""
That means if a person avoids the allergen, but then accidentally eats it, her cells have stored the chemicals that trigger the allergic reaction. More chemicals equals a stronger reaction.
Food allergies and environmental allergies act in the same way.
""It doesn't matter how you get into contact with the allergen-through the skin, gastrointestinal tract, or respiratory system,"" Speer said. ""Think of the intestine as a defense. It's your skin inside you. If people ate nickel [a common skin allergy], they could have the same reaction.""
Moss speculated that food allergies arose as people began to live more cleanly.
""One hundred or 200 hundred years ago, people would have been exposed to more parasites,"" he said.
""It's called the hygiene hypothesis. Dirtier living may be better because it challenges the body to respond to disease, parasites and bacteria,"" Moss said.
The antibodies that responded to a parasitic infection then triggered the food allergies we see today.
""If we don't have parasitic infections, the [antibodies] cause reactions to other things in the environment, like food,"" Moss said.
Moss said the incidence of food allergies has been increasing, especially in children. Many children outgrow their food allergies, but some allergies persist to adulthood. Peanuts are one example, and the allergy may be life-threatening.
""Peanuts are one of the most common causes of allergies in adults. Figuring out why is the million-dollar question,"" he said.
Moss and his colleagues at the UW-Madison Allergy and Immunology Clinic are currently testing how much peanut allergen an allergic person can eat before getting sick. Some participants take a placebo, others a small amount of the peanut allergen.
""This is done with a very tiny dose of the allergen-micrograms,"" Moss said. ""And it's done in a hospital with intense monitoring.""
The goal, Moss said, is to establish how much peanut allergen is too much.
By 2006, the FDA will require labeling of all major allergens-peanuts, tree nuts, eggs, milk, soy, fish, crustacean shellfish and wheat-present in food.
The trace amounts of peanut allergen in a peanut-free food manufactured in a plant that handles peanuts may not be enough to cause a reaction, Moss said. UW-Madison's research will establish an allergy threshold.
""Better labels and better information will hopefully allow more choices for people with food allergies,"" Moss said.
