University of North Carolina researchers compared data on the weight and body mass index of 245 food-allergic children between the ages of 1 and 11 years old against data on other children of the same age range. Data were also compared between the children with allergies and children with cystic fibrosis or celiac disease, two conditions which are also known to inhibit growth.

It was discovered that after 2 years of age, children with any food allergy had lower weight and BMI than those without allergies, regardless of whether they had celiac disease or cystic fibrosis. Researchers also discovered that having a milk allergy in particular meant even less weight gain, as did having multiple food allergies.

“The impact of food allergies was particularly pronounced when it involves cow’s milk or when it requires the elimination of more than two foods,” Dr. Brian Vickery, the study’s lead author, told a news conference. “Milk allergic children aged less than 2 were particularly vulnerable to growth restriction, with weight and BMI significantly lower than in those children with other types of food allergies,” he said.

Vickery said physicians need to do nutritional assessment with children in either of the two groups, and consider whether supplements are required. He also recommended nutrition counseling for those dealing with children with milk allergy or multiple food allergies.

“We feel that health providers should counsel patients and caregivers about the growth-related risks of the elimination diets that are used to treat food allergy, and ensure that families are excluding only the foods that are medically required,” he said.

See more news from the AAAAI 2013 conference here.

A study published in the July issue of Clinical Pediatrics found that in cities, almost 9.8 percent of young people have food allergies, while only 6.2 percent of rural kids had this condition. Shellfish allergies were three times as common in city kids and peanut allergies were double the farm incidence.

Using data from a survey of 38,465 young people from infancy to age 18, “we have found for the first time that higher population density corresponds with a greater likelihood of food allergies in children,” says lead author Dr. Ruchi Gupta, an assistant professor of pediatrics at Northwestern University’s Feinberg School of Medicine and a physician at the Ann & Robert H. Lurie Children’s Hospital of Chicago. Previously, similar demographic trends have been found for the incidence of environmental allergies and asthma.

The study, funded by the Food Allergy Initiative (FAI), effectively “maps” the occurrence of food allergy across the United States. The states with the highest rates of food allergy (greater than 9.5 percent) were Florida, Georgia, Nevada, New Jersey, Delaware, Maryland and Alaska. Gupta is also the author of a 2011 study that found 8 percent of children across the United States have food allergies.

In an interview with Allergic Living, Gupta notes intriguing trends that need more investigation. For instance, in her Q&A with editor Gwen Smith, she says she is fascinated to find a greater tendency to have food allergy in southern states – which she agrees is contrary to studies that find vitamin D in areas with stronger sun exposure may protect against allergies. She also sees proximity to water as a variable that deserves more scrutiny.

Next page: Q&A on Food Allergy’s Traits