Kate Johnson

March 03, 2013

SAN ANTONIO, Texas — Food-allergic children lag behind their peers on growth charts, particularly on the weight and body-mass index (BMI) scales, and especially if they have milk allergy, according to new research.

It's essentially a caloric issue. Dr. Brian Vickery

"It's essentially a caloric issue," senior investigator Brian Vickery, MD, told Medscape Medical News. "It's hard to draw a cause-and-effect conclusion, but I think we generally would believe that the effects on growth of the food-allergic population are due to the elimination of nutrient-dense food.... Milk, especially in young children, is a primary source of nutrition." Dr. Vickery is assistant professor of pediatrics at the University of North Carolina at Chapel Hill.

"I would encourage clinicians to consider the impact that food allergies may have on their patients' nutrition," lead investigator Caroline Hobbs, MD, also at the University of North Carolina, said during an interview.

"Routine nutritional assessment of children with food allergy, and dietary intervention as needed, may prevent growth delay in this population," said Dr. Hobbs. "Assessment and intervention may be most important in those with multiple food allergies and those with milk allergy."

The retrospective chart review presented here at the American Academy of Allergy, Asthma & Immunology (AAAAI) 2013 Annual Meeting included 245 food-allergic children.

Patients were aged-matched to healthy control participants (n = 4585) and to children with other disorders known to affect growth, such as celiac disease (n = 102) and cystic fibrosis (n = 106).

Growth percentiles calculated according to Centers for Disease Control and Prevention data showed that overall, children with food allergies have lower BMIs than healthy control participants, particularly in children older than 2 years (57.6th vs 68th percentile, P < .001).

This lower BMI is particularly evident in children with more than 2 allergies (49.7th percentile) but is also apparent in those with 1 or 2 allergies (57.8th percentile).

Children with more than 2 allergies also tend to do worse than those with fewer allergies in terms of weight (55.3rd vs 69.2nd percentile, P < .001) and height (62.2nd vs 74.8th percentile, P < .05).

And compared with other allergies, milk allergy appears to have the worst impact on weight (54.5th vs 70.6th percentile, P < .001) and BMI (48.9th vs 58.8th percentile, P < .05).

Milk-allergic patients younger than 2 years are particularly vulnerable compared with those with other food allergies in terms of both BMI (38.6th vs 56.3rd percentile, P < .05) and weight (45.9th vs 72.2nd percentile, P < .001).

Supplementation Diet

"After age 2, the effect of food allergy on the inhibition of growth is very similar to the effect of celiac disease," noted Dr. Vickery, stressing the importance of advising caregivers about the potential consequences of elimination diets.

"We feel that providers should ensure that nutritional assessment and/or supplementation is provided as needed and that subspecialty consult is arranged, especially for children at highest risk, as defined by those allergic to milk and/or multiple foods."

Asked by Medscape Medical News to comment on the findings, Marion Groetch, a senior dietician at the Jaffe Food Allergy Institute at Mount Sinai School of Medicine in New York City, said, "These findings are no surprise to those of us who work in the field of pediatric food allergy. Inadequate nutrient intake and poor growth has been a finding in other studies of children with cow's milk allergy or multiple food allergies," she said.

"The treatment for food allergy is elimination of the causative food, which can make providing a balanced, healthy diet challenging. There are substitutes available for cow's milk, wheat, and other common allergens, but many are inappropriate for young children. Enriched rice and almond milks, for example, are both low in fat and very low in protein. Young toddlers typically get a large percentage of their protein from dairy foods — milk, cheese, yogurt, etc — so if parents use these substitute products as they would milk products, children may not get the amount of protein they need for adequate growth."

Groetch added, "Toddlers have greater needs for dietary fats than adults to provide a concentrated source of energy as well as the 2 fatty acids that are essential in the human diet. It is difficult to meet energy needs when dietary fat intakes fall below recommended levels. When foods or entire food groups are eliminated, nutritionally dense alternative food sources should be substituted."

She emphasized that "simply teaching patients how to avoid the identified allergen is not enough. Medical nutrition therapy provided by a registered dietician involves a comprehensive assessment of nutritional status, identifying the nutrition problem or diagnosis, planning, and implementing a nutrition treatment plan and monitoring the patient's progress to ensure nutrition goals are met. The National Institute of Allergy and Infectious Diseases food allergy guidelines recommend nutrition counseling and close growth monitoring for all children with food allergy."

New Approach for Allergists

According to Stephen McGeady, MD, from Thomas Jefferson University in Philadelphia, Pennsylvania, "The implications of the findings are significant."

He explained, "If growth retardation is a widespread occurrence, it will have a major impact on what we do as allergists." However, Dr. McGeady told Medscape Medical News, he has not noticed this type of growth retardation very often in his own practice.

"It may be that I haven't looked closely enough, but our electronic medical record makes it very simple to monitor growth parameters over time, and we try to be vigilant about height and weight," he said. "We also have the advantage of a nutritionist at our hospital, and we have made so many referrals that she has a food-allergy-only clinic on Friday mornings."

Although Dr. McGeady says he believes it is essential to educate families about nutrition, "the problem is that I don't think most physicians are able to do that competently. I can only quote my own experience, but there was very little in the medical school curriculum about nutrition when I was in school (class of 1967). I suspect that most physicians have had a similar lack of curricular attention to nutrition, and I think that many allergists will jump at the chance to be educated at the next annual meeting."

Plans are underway to offer a half-day course on nutrition at next year's AAAAI meeting. "I think that a surprising number of physicians will be interested," he said.

"The very worst outcome that I ever saw from dietary restriction by an allergist was in a child that I cared for in the late 1970's," he said. "The child's diet had been so restricted that he developed Kwashiorkor due to inadequate protein intake. He was receiving adequate calories but insufficient protein, and he came to us with widespread edema. That syndrome usually occurs in developing countries, but here it was in a middle-class American child from the suburbs."

This study was funded by the University of North Carolina. The investigators, Ms. Groetch, and Dr. McGeady report no relevant financial relationships.

American Academy of Allergy, Asthma & Immunology (AAAAI) 2013 Annual Meeting. Abstract 361. Presented February 24, 2013.