Delaying Solid Foods May Not Prevent Allergy

March 22, 2004 -- New research challenges the widely held belief that delaying the introduction of solid foods helps reduce an infant's risk of developing asthma and allergies later in life. German investigators found no evidence that this is the case, calling into question expert guidelines recommending such delays in high-risk infants.

But a separate investigation from the U.K. appeared to contradict the German conclusion, finding that preterm infants did seem to benefit from later introduction of solid foods. Both studies are published in the latest issue of the journal Archives of Disease in Childhood.

"The advice of expert committees in the U.S. and Europe to delay the introduction of solid foods to reduce allergy risk is based on very little evidence," childhood allergy specialist Abbas Khakoo, FRCPCH, tells WebMD. "In my mind, the (German) study finding no benefit to such a practice is among the best research that has been done in this area. Given what we know right now, the expert recommendations cannot be justified."

Four percent to 6% of children have food allergies, and according to the American Academy of Pediatrics, the rate of food allergies in children has increased in the past decade. Chicken eggs, cow's milk, peanuts, fish, nuts, wheat, and soy are the most common.

The Studies

In the German study, 642 children were followed from birth to age 5 1/2. Researcher Anne Zutavern and colleagues found no evidence that delaying the introduction of solid foods helped protect the children against asthma, allergies, wheezing, or eczema.

On the contrary, the researchers found that introducing eggs later in life increased the risk of eczema and preschool wheezing, which is a common predictor of asthma.

The U.K. study included 257 infants born prematurely and studied for a year following their birth. Researchers showed that the introduction of four or more different solid foods prior to age 4 months was associated with a threefold increased risk of eczema.

Morgan tells WebMD that it is probably safe to introduce one or two solid foods that are not linked to allergies prior to age 4 months.

AAP Recommendations

In an editorial accompanying the two studies, Khakoo called for further research, noting that these and other conflicting studies do not allow a definitive statement on the impact of solid food introduction on allergies.

"It is surprising that expert committees like the ones in the United States and Europe have taken stands on this issue when there is so little evidence to support the link," Khakoo tells WebMD.

The American Academy of Pediatrics' recommends that infants at high risk for allergies, asthma, and eczema be exclusively breastfed for at least six months. Further delays are recommended for the introduction of foods typically associated with allergies. The guidelines call for delaying the introduction of cow's milk for one year; eggs until age 2; and tree nuts, peanuts, and fish until age 3.

AAP nutrition committee member Frank Greer, MD, agrees that there is little scientific evidence to support the recommendations. He tells WebMD that he is currently revising an AAP policy statement of infant formulas and allergies.

"The data just aren't there to make a strong statement on this issue," he says.

Khakoo says he supports a recent World Health Organization statement calling for the exclusive breastfeeding of babies until they are at least 6 months old, but he adds that, "from an allergy point of view, we can't really say right now if it is beneficial."