CAN FOOD ALLERGIES BE PREVENTED?

Studies Show Introducing Risky Foods in Infancy Lowers Incidence

It’s estimated that approximately 4% of adults and teens, and about 5% of children under the age of 5 suffer from food allergies. And according to the Centers for Disease Control and Prevention, food allergies increased dramatically between 1997 and 2007.

Food allergies can vary in severity from mild, self-limiting reactions to severe, life-threatening ones. While eight foods—milk, eggs, peanuts, tree nuts, fish, crustacean shellfish, wheat, and soy—account for 90% of food allergic reactions in the United States, more than 160 foods have been documented to cause reactions.

Researchers and physicians haven’t been able to determine the exact etiology of food allergies and the reasons for the increase in allergic diseases. A variety of hypotheses have emerged, including the impact of changes in the environment or food system, vitamin D deficiencies, and the fact we’re no longer plagued by parasites and pathogens as our ancestors were due to better sanitation. To complicate matters, there appears to be a genetic component, since those with one or more first-degree relatives with allergic diseases are considered at higher risk. Children who have severe allergic disease, including asthma or atopic dermatitis, also are considered high risk.

Important efforts are under way to determine how to reverse food allergies by developing tolerance in sufferers. This research gets much attention, but other studies are focusing on allergy prevention. Evidence shows that children born to mothers who don’t avoid potential allergic foods are less likely to develop food allergies. This article reviews some of the research along with the latest recommendations to help reduce the risk.

Maternal Diet

Good nutrition starts before birth, as babies receive all their nutrition from their mother’s diet while in the womb. What she eats has an incredible effect on health in the short- and long-term, from folic acid’s role in preventing neural tube defects to potentially reducing risk factors for obesity later in life. Ensur­ing that expectant mothers make good choices nutritionally is essential to helping ensure a healthy next generation.

Recommendations for maternal diets have been varied and represent an interesting mix of superstition and science. Over the years, medical professionals have vacillated between recommending pregnant women avoid potential allergens to suggesting they set no limits on what they eat as a means to prevent food allergies. As we consider evidence-based practice, it’s helpful to know what the research and latest recommendations say.

Results of a 2011 study in Finland revealed that in a popu­lation of women predisposed to type 1 diabetes, increased consumption of cow’s milk during pregnancy was associated with a lower incidence of cow’s milk allergy in their offspring. A 2012 study of more than 60,000 Danish women showed that increased consumption of peanuts and tree nuts was associ­ated with a decrease in asthma and allergic disease in their children.4 Researchers in this latter study suggest that pea­nuts and tree nuts shouldn’t be avoided during pregnancy and may actually confer protection.

The National Institute of Allergy and Infectious Diseases (NIAID)-sponsored 2010 guidelines for managing food allergy state that restricting the maternal diet isn’t recommended as a strategy to reduce the development of food allergies in children. These guidelines are a collection of recommenda­tions for clinicians on how to manage food allergies, and they represent the collective agreement and review of literature regarding all areas of clinical food allergy management.

Infant and Early Child Feeding

Breast-feeding is known to be the best way to nourish new­born children because breast milk contains all necessary nutri­ents in appropriate quantities and confers immune protection via the transfer of antibodies. It’s also known that allergenic proteins may be secreted in breast milk; however, limited stud­ies haven’t proven they cause clinical food allergy. Allergenic proteins in breast milk have been linked to higher sensitization to food, but sensitization isn’t the same as being food allergic—one can be sensitized without having clinical food allergy. While breast-feeding has many benefits and should be encouraged, the NIAID-sponsored guidelines state there’s no strong evidence that breast-feeding will prevent allergic disease.

Past recommendations from the AAP and other organiza­tions have suggested exclusive breast-feeding for the first 12 months as an optimal way to feed infants and avoid potential allergens as a means to reduce food allergies. However, in 2008, the AAP changed its guidelines to say there’s no reason to restrict the introduction of potential allergens to infants when solid foods are introduced. Moreover, in a 2011 article in Pediatrics expressing the application of the NIAID guidelines, complimentary feeding at 4 to 6 months of age is recommended along with breast-feeding without the recommendation to restrict potential allergens. For children who aren’t breast-fed, there’s some evidence that partially hydrolyzed infant formula may protect those at high risk against the develop­ment of food allergy but not soy formula.

Interestingly, cases of food allergies can be low in countries that don’t restrict foods in the diet of infants when solid foods are introduced. In a study of genetically similar populations in Israel and the United Kingdom, the rate of peanut allergy was 10 times lower in the Israeli children who ate a peanut snack before 9 months of age than those in the United Kingdom where parents restricted peanuts as per healthcare provider recom­mendations. The authors noted that in the United Kingdom and the United States, where potential allergens often were restricted, food allergies have continued to rise in spite of recommendations to restrict the introduction of these foods.

In a recent Australian study, it was determined that children who were introduced to boiled or scrambled (but not baked) eggs at 4 to 6 months of age had a much lower incidence of egg allergy than those who received eggs after 10 months of age, regardless of other risk factors. Studies such as Learning Early About Peanut Allergy in the United Kingdom are under way to explore how the timing of introducing potential aller­gens may impact the development of food allergies. Results from these studies should be available sometime next year.

Practice Pearls

Meanwhile, it’s important to recognize that the world of food allergies is dynamic, and additional knowledge is con­tinually emerging. Practitioners—particularly those working with pregnant women, infants, and children—need to keep abreast of the research and any changes in guidelines.

Although the guidelines from the AAP have been published and publicized, many practitioners continue to use old recom­mendations focusing on food restriction. In a recent study of Canadian physicians and dietitians, the authors stated that prac­titioners could benefit from increased awareness, especially among pediatricians, with regard to these recommendations.

The following key recommendations can help dispel myths and provide the best course of action for clients and patients regarding maternal and infant diet and food allergies:

•  Evidence doesn’t support the recommendation to restrict potential allergens in the diet of pregnant women or during lactation. Instead, efforts should be made to ensure a health­ful and well-balanced diet, including appropriate vitamin and mineral supplementation.

•  Solid foods should be introduced between 4 and 6 months of age, not excluding potential allergens. It’s prudent to recommend watching for reactions, especially in any high-risk infant.

• For those infants at high risk and not breast-feeding, a partially hydrolyzed formula may reduce the risk of food allergies. Soy formula isn’t recommended as a strategy for reducing cow’s milk allergy.

All Fitness ___ CAN FOOD ALLERGIES BE PREVENTED?

— Sherry Coleman Collins, MS, RD, LD, has worked in clinical pediatrics and school foodservice, where she gained hands-on experience working with students, families, and staff to manage food allergies. She’s currently the senior manager of marketing and communications for the National Peanut Board.

References

1. Boyce JA, Assa’ad A, Burks AW, et al. Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel. J Allergy Clin Immunol. 2010;126(6):1105-1118.

2. Food allergies: what you need to know. US Food and Drug Administration website. http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm079311.htm. May 14, 2012. Accessed January 1, 2013.

3. Tuokkola J, Luukkainen P, Tapanainen H, et al. Mater­nal cow’s milk consumption during pregnancy is inversely associated with the risk of cow’s milk allergy (CMA) in the offspring in a prospective birth cohort study. Clin Transl Allergy. 2011;1(Suppl 1):P114.

4. Maslova E, Granstrom C, Hansen S, et al. Peanut and tree nut consumption during pregnancy and allergic disease in children—should mothers decrease their intake? Longitudinal evidence from the Danish National Birth Cohort. J Allergy Clin Immunol. 2012;130(3):724-732.

5. Mofidi S. Nutritional management of pediatric food hypersensitivity. Pediatrics. 2003;111(Suppl 3):1645-1653.

6. Burks AW, Jones SM, Boyce JA, et al. NIAID-sponsored 2010 guidelines for managing food allergy: applications in the pediatric population. Pediatrics. 2011;128(5):955-965.

7. Du Toit G, Katz Y, Sasieni P, et al. Early consumption of peanuts in infancy is associated with a low prevalence of peanut allergy. J Allergy Clin Immunol. 2008;122(5):984-991.

8. Koplin JJ, Osborne NJ, Wake M, et al. Can early introduc­tion of egg prevent egg allergy in infants? A population-based study. J Allergy Clin Immunol. 2010;126(4):807-813.

9. Background on the LEAP study. Immune Tolerance Network website. http://www.leapstudy.co.uk/LEAP.html. Accessed January 2, 2013.

10. Leo S, Dean J, Chan ES. What are the beliefs of pediatri­cians and dietitians regarding complementary food introduction to prevent allergy? Allergy Asthma Clin Immunol. 2012;8:3.