A recent paper in the Journal of Allergy and Clinical Immunology suggests that introducing allergenic food to babies may help to prevent food allergies from developing. The WSJ article below states that while more research is needed, observational studies show that kids with early exposure have lower allergy rates. If true, parents who shield thier children from 'germs' or certain types of foods, may actually be doing thier children a diservice.
Food Allergy Advice for Kids: Don't Delay Peanuts, Eggs
WSJ On-Line YOUR HEALTH Updated March 4, 2013, 8:00 p.m by Sumathi Reddy
Parents trying to navigate the confusing world of children's food allergies now have more specific advice to consider. Highly allergenic foods such as peanut butter, fish and eggs can be introduced to babies between 4 and 6 months and may even play a role in preventing food allergies from developing.
These recommendations regarding children and food allergies—a rising phenomenon that researchers don't fully understand—come from the American Academy of Allergy, Asthma & Immunology in a January article in the Journal of Allergy & Clinical Immunology: In Practice. The AAAAI's Adverse Reactions to Foods Committee outlined how and when to introduce highly allergenic foods, which include wheat, soy, milk, tree nuts, and shellfish.
The recommendations are a U-turn from 2000, when the American Academy of Pediatrics issued guidelines that children should put off having milk until age 1, eggs until 2 and peanuts, shellfish, tree nuts and fish until 3. In 2008, the AAP revised its guidelines, citing little evidence that such delays prevent the development of food allergies, but it didn't say when and how to introduce such foods.
Food allergies affect an estimated 5% of children under the age of 5 in the U.S., according to the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health. The prevalence of a food allergy for children under 18 increased by 18% from 1997 to 2007.
"There's been more studies that find that if you introduce them early it may actually prevent food allergy," said David Fleischer, co-author of the article and a pediatric allergist at National Jewish Health in Denver. "We need to get the message out now to pediatricians, primary-care physicians and specialists that these allergenic foods can be introduced early."
Dr. Fleischer said more study results are needed to conclusively determine whether early introduction will in fact lead to lower food-allergy rates and whether they should be recommended as a practice.
The first trials to split children into groups, with some eating highly allergenic foods early on and others delaying, are continuing in the United Kingdom and Australia with some preliminary results expected to be out next year. This type of trial with children is rare and the results are highly anticipated.
One theory to explain why early introduction is important holds that if babies aren't exposed early enough to certain foods, their immune systems will treat them as foreign substances and attack them, resulting in an allergy.
"The body has to be trained in the first year of life," says Katie Allen, a professor and allergist at the Murdoch Childrens Research Institute at Royal Children's Hospital in Australia. (The institute was founded in part by the late Dame Elisabeth Murdoch, mother of Rupert Murdoch, who is chairman of News Corp., which owns The Wall Street Journal.) "We think there's a critical window, probably around 4 to 6 months, when the child first starts to eat solids," she says.
Another possible explanation from some experts for the increase in allergies: As westernized countries have become more hygienic, children don't have the same exposure to germs, which affects the development of the immune system.
Dr. Allen believes there may be a link between food allergies and vitamin D. In a study out this week in the Journal of Allergy and Clinical Immunology, researchers took blood samples from more than 5,000 babies and found that those with low vitamin D levels were three times more likely to have a food allergy.
Food-allergy reactions range from hives and eczema to asthma, vomiting and anaphylaxis, a life-threatening reaction in which the body's major systems quickly shut down. A 2011 prevalence study in the journal Pediatrics found that 39% of children with food allergies have a history of severe reactions.
The new recommendations include introducing highly allergenic foods after typical first foods have been eaten and tolerated, such as rice cereal, fruits and vegetables. They suggest children be fed the foods at home and in gradually increasing amounts. The AAAAI recommendations cited about half-a-dozen studies in making its new guidelines.
One observational study compared Jewish children in the United Kingdom with those in Israel, where the peanut-allergy rate is low. The 2008 study of more than 5,000 children in each country in the Journal of Allergy Clinical Immunology found the rate of peanut allergies among the U.K. children was 10 times that of those in Israel. Gideon Lack, a professor of paediatric allergy at King's College London, said the researchers followed up with surveys given to the parents of about 100 infants hundred in each country. They found that popular snacks with peanuts were given to Israeli babies often before they were 6 months of age, whereas the majority of babies in the United Kingdom didn't taste peanut products until after the age of 1.
Dr. Lack is in the midst of the much-anticipated, randomized controlled trial in the U.K., which is following 640 children with a high risk of allergy—determined by eczema—from infancy to the age of 5. Half of the children are consuming at least 24 grams of peanuts three times a week, while the others have none. About two-thirds of the children are now 5 and receiving peanut-allergy testing. Preliminary results are expected next year.
Some experts are critical of the observational studies cited in the recommendations. "The evidence that has come up is of great interest but it's all either anecdotal or epidemiological and not the intervention studies that are going on right now that will lead to answers in the next three years," said Robert Wood, director of Pediatric Allergy and Immunology at Johns Hopkins University School of Medicine.
Dr. Wood said he tells parent they don't need to feel pressured to do an early introduction. "You can do whatever you want because we're not sure what makes a difference," he said.
When food allergies first started becoming more common in the 1990s, the prevailing thought among experts was that delaying introduction of such foods would reduce the prevalence of food allergies.
"As these guidelines were implemented we've seen a paradoxical increase in foods allergies in young children, especially with peanut allergies," said Anna Nowak-Wegrzyn, associate professor of pediatrics at the Icahn School of Medicine at Mount Sinai Hospital.
The new recommendations from the AAAAI committee say an allergist should be consulted in cases when an infant has eczema that is difficult to control, or an existing food allergy. For children who have a sibling with a peanut allergy—and have a 7% greater risk of a peanut allergy—parents may request an evaluation but the risks of introducing peanut at home in infancy are low, the recommendations noted.
Debby Beerman, a Chicago-area mom, has two boys, ages 4 and 3, with a number of allergies.
"It scares me to think that you would give the food to a child at such a young age when they can't really express that they're not feeling well or they're in distress or something's not right," said Ms. Beerman, a member of the Food Allergy & Anaphylaxis Network, an advocacy group. "But if the data was there to support it, I think we would all do anything we could to try and avoid this.
Primary Prevention of Allergic Disease Through Nutritional Interventions
With the rising prevalence of atopic disease, primary prevention may play a role in reducing its burden, especially in high-risk infants. With this in mind, the Adverse Reactions to Foods Committee of the American Academy of Allergy, Asthma & Immunology was charged with the task of developing recommendations for primary care physicians and specialists about the primary prevention of allergic disease through nutritional interventions according to current available literature and expert opinion. Recommendations that are supported by data are as follows. Avoidance diets during
pregnancy and lactation are not recommended at this time, but more research is necessary for peanut. Exclusive breast-feeding for at least 4 and up to 6 months is endorsed. For high-risk infants who cannot be exclusively breast-fed, hydrolyzed formula appears to offer advantages to prevent allergic disease and cow’s milk allergy. Complementary foods can be introduced between 4 and 6 months of age. Because no formal recommendations have been previously provided about how and when to introduce the main allergenic foods (cow’s milk, egg, soy, wheat, peanut, tree nuts, fish, shellfish), these are now provided, and reasons to consider allergy consultation for development of a personalized plan for food introduction are also presented. _ 2012 American Academy of Allergy, Asthma & Immunology ( J Allergy Clin Immunol: In Practice 2013;1:29-36)