Any parent with preschoolers or school-age children knows that food allergies are on the rise. What’s going on?
As I noted in a review last year in Alternative & Complementary Therapies, atopic disorders, including food allergies, are widely considered to be rising in prevalence at epidemic rates. Support for this statement comes from multinational sources, including the International Study of Asthma and Allergies in Childhood (ISAAC), which surveyed rates of atopic disease in nearly 200,000 children aged 6-7 years in 37 countries and in over 300,000 children aged 13-14 years in 56 countries. Food allergies specifically have rapidly risen in prevalence, with reactions to peanuts reported in greater than one in a hundred children.
A mom in my practice, Gina, recently sent me a story from The New York Times, profiling Robyn O’Brien, a Colorado mom driven by her children’s food allergies to raise awareness about this disturbing trend. Ms. O’Brien is importantly shifting the focus to our nation’s food quality, encouraging families to avoid processed foods with additives and preservatives. Gina writes: “As a mom with a 2 year old daughter who has a significant peanut allergy, after having read this article I have to admit I’d been thinking the same thing Robyn O’Brien thought. Recently I was at the supermarket buying a cake mix and I was reading the ingredients to make sure it didn’t contain peanut traces. There were so many ingredients on the box that to me seemed so superfluous; I went home to make a cake from scratch.”
This common sense health-promoting approach has been touted for years as a “whole foods” diet, supported by author Michael Pollan (The Omnivore’s Dilemma) in his new book, “In Defense of Food.” His advice? “Eat food. Not too much. Mostly plants.” Well that’s pretty simple. It makes sense to me that one of the reasons of children are developing more allergies at younger ages would have to do with immune dysregulation from things that aren’t food and shouldn’t be in food. While there is a paucity of well-designed trials on the subject, perhaps MSG and other food additives are exacerbating reactions to food antigens like peanuts, and creating more severe reactions and reactions at younger ages. Authors of an article published in Pediatrics in December, 2007 concluded, “In the past decade, the ages of first peanut exposure and reaction have declined among peanut-allergic children.”
There is conflicting advice about what age is safest to introduce the most allergenic foods, including peanuts, tree nuts, eggs, cow’s milk, soy, shellfish and wheat. The American Academy of Pediatrics updated 2008 statement, “Effects of Early Nutritional Interventions on the Development of Atopic Disease in Infants and Children,” includes the following recommendations.
1. At the present time, there is lack of evidence that maternal dietary restrictions during pregnancy play a significant role in the prevention of atopic disease in infants. Similarly, antigen avoidance during lactation does not prevent atopic disease, with the possible exception of atopic eczema, although more data are needed to substantiate this conclusion.
2. For infants at high risk of developing atopic disease, there is evidence that exclusive breastfeeding for at least 4 months compared with feeding intact cow milk protein formula decreases the cumulative incidence of atopic dermatitis and cow milk allergy in the first 2 years of life.
3. There is evidence that exclusive breastfeeding for at least 3 months protects against wheezing in early life. However, in infants at risk of developing atopic disease, the current evidence that exclusive breastfeeding protects against allergic asthma occurring beyond 6 years of age is not convincing.
4. In studies of infants at high risk of developing atopic disease who are not breastfed exclusively for 4 to 6 months or are formula fed, there is modest evidence that atopic dermatitis may be delayed or prevented by the use of extensively or partially hydrolyzed formulas, compared with cow milk formula, in early childhood. Comparative studies of the various hydrolyzed formulas have also indicated that not all formulas have the same protective benefit. Extensively hydrolyzed formulas may be more effective than partially hydrolyzed in the prevention of atopic disease. In addition, more research is needed to determine whether these benefits extend into late childhood and adolescence. The higher cost of the hydrolyzed formulas must be considered in any decision-making process for their use. To date, the use of amino acid–based formulas for atopy prevention has not been studied.
5. There is no convincing evidence for the use of soy-based infant formula for the purpose of allergy prevention.
6. Although solid foods should not be introduced before 4 to 6 months of age, there is no current convincing evidence that delaying their introduction beyond this period has a significant protective effect on the development of atopic disease regardless of whether infants are fed cow milk protein formula or human milk. This includes delaying the introduction of foods that are considered to be highly allergic, such as fish, eggs, and foods containing peanut protein.
7. For infants after 4 to 6 months of age, there are insufficient data to support a protective effect of any dietary intervention for the development of atopic disease.
8. Additional studies are needed to document the long-term effect of dietary interventions in infancy to prevent atopic disease, especially in children older than 4 years and in adults.
9. This document describes means to prevent or delay atopic diseases through dietary changes. For a child who has developed an atopic disease that may be precipitated or exacerbated by ingested proteins (via human milk, infant formula, or specific complementary foods), treatment may require specific identification and restriction of causal food proteins. This topic was not reviewed in this document.
Essentially, no one knows the best time to introduce highly allergenic foods. It still makes sense to me, especially for children with strong atopic family histories or early evidence of atopic disease, to avoid peanut/tree nut exposure until 3 years old. I do advise pregnant moms and those breastfeeding to avoid highly allergenic foods if they have a strong family history for atopy and food allergies. The role of other CAM therapies to reduce expression of allergic symptoms, like prebiotics and probiotics, is still unclear. While there are published trials suggesting these approaches may reduce the risk of allergic disorders, relevant Cochrane Database Systematic Reviews cite insufficient evidence and call for more research to be done.