Doctors see more food allergies, few remedies

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Doctors see more food allergies, few remedies
Physicians don't understand why food allergies are becoming more prevalent, though they have plenty of theories
By Jeremy Olson St. Paul Pioneer Press
"Don't eat that" remains the best advice doctors can give to people suffering from food allergies.
There are no therapies - no shots, no pills - specifically marketed to treat food allergies, which appear to be on the rise in the United States. By one estimate, the rate has doubled in 20 years.
While doctors are exploring new remedies, unique ethical, business and safety barriers hinder their research, especially when children are involved. They also don't understand why food allergies are becoming more prevalent, though they have plenty of theories.
Take peanut allergies, which are among the most potent and deadly food allergies. Maybe children develop allergies by eating too many peanut products as infants, or through breast milk. Maybe roasted peanuts explain America's problem, because countries that fry or boil nuts have lower rates. Maybe the increase in peanut allergies reflects the increase in all allergies - from pollen to pets to peanuts.
'Hygiene' theory
All of the explanations have flaws, said Dr. Scott Sicherer of the Jaffe Food Allergy Institute in New York's Mount Sinai School of Medicine. He supports the "hygiene" theory that Americans live such clean, antibiotic lives that their immune systems are finding something else to attack - the proteins in certain foods.
The immune system gets "misdirected," Sicherer said. "It is not getting the practice that it needs to."
The compelling evidence is the lower allergy rate in undeveloped countries, where people's immune systems are busy fighting off bacteria, viruses, water contaminants and other pollutants.
If true, the hygiene theory presents a public health dilemma. America isn't going to revert to dirty conditions to prevent allergies. And yet, food allergies present dangers, including anaphylactic shock, that kill as many as 150 to 200 people each year.
Roughly 4 million Americans have true food allergies, which involve the immune system's reaction to food proteins. Allergies are distinct from milder cases of food intolerance, which are often temporary.
More awareness
One positive result, physicians said, is the growing public awareness. Most people have probably been on an airplane, in a classroom or at a public gathering where special precautions were taken to protect people with food allergies.
Even without a wonder drug, Sicherer said, doctors provide meaningful care by teaching patients to avoid certain foods and hidden ingredients.
"Education," he said, "is a treatment, in my book."
Researchers are testing experimental drugs for food allergies, but the cruel twist is they must expose people to the allergens in order to know whether the drugs work.
Degrees of reaction
A national study based in Denver was marred by the death of a child who mistakenly received an experimental treatment, which contained peanut extract, instead of a traditional allergy injection without the extract. The idea was to desensitize people with peanut allergies by exposing them to the extract in a rapid series of doses.
"The difficulty with food allergies is these people have fairly violent degrees of reactivity," said Dr. John Yunginger, whose team at the Mayo Clinic in Rochester, Minn., helped investigate the child's death and verified the error.
A 2003 study showed promise with a drug that muted the immune system's attack against proteins contained in peanut products. Two drug manufacturers had conflicting plans for the drug, though, which ended up being federally approved and marketed for treatment of asthma. The larger market for asthma weighed heavily in that decision.
An attempt to resume research with the drug, Xolair, was halted earlier this month when two patients in the study suffered worse-than-expected reactions to peanut protein. They had been exposed to the protein at the start of the study to gauge the severity of their allergies.
The National Institute of Allergy and Infectious Diseases created its first group of food allergy experts last year and backed it with a five-year research grant.
First on the experts' agenda is "immunotherapy," which would involve exposing children to potential food allergens so they develop tolerance to them.
"The reality is we know exactly how to do that in mice and no idea how to do that in people," said Dr. Robert Wood, director of the pediatric allergy clinic at Johns Hopkins Medical Institutions in Baltimore.
The ethical and physical risks of clinical research, especially research involving children, have prevented discoveries in mice from being repeated in humans.
Another idea is the use of "probiotics," which are strains of bacteria. Exposure to these strains would theoretically occupy the immune system and discourage it from attacking food proteins.
Dietary restrictions
Physicians also have attacked the problem through dietary restrictions, such as encouraging parents to withhold problem foods such as milk, eggs and peanuts until their children are older. However, the latest research suggests this makes no difference.
The solution might not be specific to food. Asthma, airborne allergies and eczema are also becoming more common. How the immune system misbehaves appears to be a key to all of these disorders. A solution for one, Wood said, may present answers for others.