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pregnant woman holding eggs

How does diet during pregnancy impact allergies in offspring?

pregnant woman holding eggs

A small percentage of women said they consumed fewer allergens during pregnancy to stave off food allergies in their newborns, according to preliminary research Karen Robbins, M.D., presented during the American College of Asthma Allergy and Immunology 2018 Annual Scientific Meeting.

Pregnant women routinely swear off alcohol and tobacco to boost their chances of having a healthy baby. What about common food allergens like nuts and milk?

There are scant data that describe how often pregnant women deliberately stop eating a specific food item in order to prevent future food allergies in their newborns. As a first step toward addressing this data gap, a research team led by Karen Robbins, M.D., an allergist at Children’s National Health System, pored through a longitudinal study conducted by the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention.

About 4,900 pregnant women completed the Infant Feeding Practices Study II prenatal questionnaire from May 2005 to June 2007. The study tracked 2,000 pregnant women from the third trimester of pregnancy and their infants through the first year of life. A small percentage of women said they had consumed fewer allergens during pregnancy to stave off food allergies in their newborns, according to a poster Dr. Robbins presented during the American College of Asthma Allergy and Immunology 2018 Annual Scientific Meeting. While their numbers were small, most of these women reported giving up major allergens like nuts, milk or eggs during pregnancy, including:

  • 144 (2.9 percent) reported restricting their diet in some way to prevent future food allergies in their offspring
  • 84 women (1.7 percent) ate fewer nuts
  • 15 women (.3 percent) ate fewer eggs and
  • 2 women (.04 percent) ate/drank consumed less dairy/milk.

“At the time the survey was conducted, few pregnant women in this large data set said they gave up certain foods with the express aim of avoiding a food allergy in their babies,” Dr. Robbins says. “However, mothers who had an older child with a food allergy or who had food allergies themselves had significantly higher odds of trying this food avoidance strategy.”

Despite the diet changes, infants born to these expectant mothers were twice as likely to experience problems with food at age 4 months – though not at age 9 months or 12 months. And these infants were no more likely to be diagnosed with a food allergy.

According to the FDA, millions of Americans suffer a food allergy each year. Reactions can range from mild to life-threatening and can begin soon after eating a problematic food item or an ingredient from that food. Among the most common allergenic foods are milk, eggs, fish, shellfish, tree nuts, peanuts, wheat and soybeans.

“We really need to know more about how often targeted food avoidance occurs among U.S. pregnant women who have a family history of food allergies,” Dr. Robbins adds. “We hope to learn what factors into these women’s decision-making as well as why many of them settled on food avoidance as a potential strategy to try to prevent food allergy in their infants.”

American College of Asthma Allergy and Immunology 2018 Annual Scientific Meeting presentation

  • “Prenatal food allergen avoidance practices for food allergy prevention.”

Karen Robbins M.D., lead author; Ashley Ramos Ph.D., co-author; Marni Jacobs, Ph.D., co-author; Kate Balas BS, co-author; and Linda Herbert, Ph.D., director of Children’s Division of Allergy and Immunology’s psychosocial clinical program, and senior author.

Adora Lin

Funding will help uncover immune system differences that trigger food allergies

Adora Lin

“When it comes to food allergies, we really don’t know how they develop. We don’t know how to best differentiate between a child who can safely eat a potential allergen, like peanuts, compared with a child who cannot safely eat peanuts.” says Adora A. Lin, M.D., Ph.D.

Adora A. Lin, M.D., Ph.D., an attending physician in Children’s department of Allergy and Immunology, was awarded $240,000 to improve understanding of how children’s immune systems tolerate or react to certain food allergens – sometimes triggering a cascade of side effects that can be fatal.

The three-year American Academy of Allergy, Asthma & Immunology (AAAAI) Foundation award will underwrite Dr. Lin’s ongoing research into the regulation of the antibody Immunoglobulin E (IgE), which plays a pivotal role in these allergic responses.

“Our immune system maintains a delicate balance, working just enough to ward off potential invaders and pathogens, but not so much that it triggers problems of its own making,” Dr. Lin says. “When it comes to food allergies, we really don’t know how they develop. We don’t know how to best differentiate between a child who can safely eat a potential allergen, like peanuts, compared with a child who cannot safely eat peanuts.”

Food allergies have become a growing problem and affect about 1 in 13 U.S. children, or about two per classroom. Food items such as eggs, milk, peanuts, tree nuts, soy and wheat trigger allergic reactions that can include itching, swelling, hives and difficulty breathing. As children’s immune systems react to exposure to such allergens, their B-cells produce IgE antibodies.

Apart from avoiding these foods and carrying rescue medications, which must be used immediately after accidental exposure, there is no way to treat food allergies effectively. That makes it essential to better understand how the immune system works in order to innovate new and better food allergy treatments and diagnostics.

Dr. Lin’s work involves isolating immune cells from blood samples, culturing them and stimulating an immune response to known food allergy triggers. B-cells make IgE, but additional clarity is needed about what turns on the “make IgE” signal as well as which signals indicate it’s time to stop making IgE. Ultimately, the aim is to identify biomarkers that are akin to the “check engine” light that illuminates to warn of a potential problem long before a car stalls in traffic.

“I’m very excited about this funding,” Dr. Lin adds. “Our field has done an exceptional job with clinical work to help children with food allergies. This award recognizes the importance of the mechanistic side of the equation. I’m excited to help make that contribution to the research.”

As it stands now, blood tests are sensitive to food-related IgE, but are not specific. Only 30 to 55 percent of children who have IgE to common food allergens have an allergic reaction after eating the food, which means that 45 to 70 percent are merely sensitized and could tolerate eating the food. Current tests cannot distinguish between sensitized and allergic children.

“Our hope is to identify biomarkers that would serve as the ‘check engine’ light that tell us in advance which child’s immune system will react strongly to that food. Right now, there is no way to tell. This project will help uncover those differences,” she says.

Dr. Lin was one of three recipients of the AAAAI Foundation’s faculty development award, which was presented during a March 3, 2018, award ceremony held during the organization’s business meeting.