by Amy Spangler
December 14, 2009

The incidence of food allergy is aptly described as an epidemic. Current data show that food allergy affects 8 percent of children under age three, 6–8 percent of school age children, and nearly 4 percent of adults. While there is little doubt that human milk plays a key role in providing optimal nutrition during the first months of life and beyond, the role of exclusive breastfeeding in the prevention of allergic disease (especially in children at greater risk for allergic disease) remains unclear.

Among the most promising approaches for reducing the incidence of food allergy is to tweak the immune system by introducing solid foods at an earlier age. This theory was recently tested by a group of Finnish researchers in an analysis of data gathered for the Diabetes Prediction and Prevention (DIPP) nutrition study. They found that late introduction of solid foods may increase a child’s risk for developing food allergies.

Research
A total of 994 children participated in the analysis. The diet of each child was assessed at 3, 6, and 12 months of age. Solid foods common in the Finnish diet that were included in the dietary assessment were potatoes, fruits and berries, carrots, cabbage, oats, wheat, rye, meat, fish, and eggs.

IgE levels were measured when the children were 5 years of age. IgE is an antibody produced in response to exposure to specific allergens such as food, dust, or pollen. Allergic individuals can have up to 10 times the normal level of IgE in their blood. It’s important to note that clinical symptoms and food tolerance were not measured. Other than elevated IgE levels, there were no other signs of food allergy.

Since all of the children who participated in the Finnish study carry a specific gene type that increases their risk for developing type 1 diabetes, these children may differ from children in the general population in terms of their response to solid foods. Theoretically, children who are at greater risk for an autoimmune disease such as type 1 diabetes might also be at greater risk for other immune dysfunctions such as allergic disease.

Results
IgE levels indicated that 17 percent of the children were sensitive to foods and 23 percent to dust or pollen. Food sensitivity was associated with delayed introduction of potatoes for 4 months, oats for 5 months, rye for 7 months, wheat for 6 months, meat for 5.2 months, fish for 8.2 months, and eggs for 10.5 months.

Recommendations
Before breastfeeding began to regain its position as the normal way to feed a baby, cow’s milk was among the more common food allergies. Cow’s milk allergy also serves as a predictor for allergic disease. One out of every three children who are allergic to cow’s milk will go on to develop another food allergy and four out of five will develop inhalant allergies later in childhood. Despite these statistics, the Finnish researchers reported no association between exclusive breastfeeding, total length of breastfeeding, or age at introduction of cow’s milk (on average two months) and allergic sensitization at five years.

The American Academy of Pediatrics (AAP) in its 2007 clinical report readily acknowledges that there is no evidence to support delaying the introduction of solid foods beyond 4–6 months. This includes foods known to cause allergies in young children such as eggs, fish, or peanut butter.

“If a child is going to be allergic to peanuts or eggs, it doesn’t seem to matter [after 4 to 6 months] when you introduce these foods,” says AAP clinical report co-author Frank Greer, MD.

Don’t blame it on the food. Blame it on the genes.