Several years ago, the American Academy of Pediatrics recommended that parents delay introducing commonly allergenic foods into infants' diets. But new guidelines have reversed that recommendation, said Jamie Kabourek, resource manager with the Food Allergy Research and Resource Program at UNL.
Studies showed no evidence that delaying the introduction of certain foods lowered the risk of developing food allergies. In fact, studies are starting to indicate that introducing allergenic foods early might actually benefit children, Kabourek said.
"Proteins are what cause the food allergy," she said. "The general thought is if you get these proteins in your system right away, your immune system can recognize them and say, 'Those are OK.' Whereas if you prolong introducing those foods, your immune system might decide to react to them."
For mothers who are breast-feeding, the current recommendations state there's also no reason to limit allergenic foods during pregnancy or lactation.
Parents should be wary, however, of some foods. Never give honey to a baby because of the risk of botulism. Also, be sure to avoid any foods that might cause choking, such as grapes or nuts. Infants generally are unable to digest cow's milk, so it should not be started until 1 year of age. However, most babies can tolerate other dairy products such as yogurt or cottage cheese.
Parents should generally start solids when a baby is 4 to 6 months old, when the baby has lost the tongue thrust reflex and is able to sit up with good head control. Introduce one food at a time and wait two to four days before adding another food to the diet.
"This does two things," Kabourek said. "It helps the baby become used to that taste and texture. And then it helps if they do have a reaction; then you know which food it is."
Dr. Carrie Dell, a pediatrician at the Lincoln Pediatric Group, said the most common symptoms of food allergy are hives, vomiting, diarrhea and breathing difficulties.
It's important to distinguish between a true food allergy and a food intolerance, Dell said. Some babies suffer from milk soy protein intolerance (MSPI), a condition in which milk and/or soy protein irritates the baby's gut lining, causing fussiness and blood or mucus in the stool. This can happen with formula-fed babies or with breast-fed babies who react when the mother eats milk or soy.
Babies with MSPI need to avoid all soy or milk products. Formula-fed babies are given a special formula, and the mothers of breast-fed infants need to follow a specific diet. However, about half of the babies with this condition outgrow it by six months, and nearly all of them outgrow it by 12 months of age.
Dell said parents often become concerned when foods like strawberries or citrus foods cause a rash around the mouth. Usually this is not a food allergy but a reaction to the acid in the food.
If you suspect your child has a food allergy, Dell recommends you see your doctor for testing. Avoid that food until you see the doctor. Treatment includes avoiding the foods that cause the allergy and medicine if the food is accidentally ingested. Extreme cases of breathing difficulties may require a trip to the emergency room.
The good news is that most babies outgrow food allergies by the time they are age 7. Some allergies, however, may be lifelong; generally that includes allergies to peanuts, tree nuts, fish and shellfish. But many other food allergies are only temporary.