Food Allergies: React with Knowledge
By Sue Gilbert, MS, Nutritionist

Your baby just had his first bites of peaches, and hours later has a runny nose and is sneezing. Could it be a reaction to the food?

Quite possibly, yes, and quite possibly, no. Symptoms of food allergies, like diarrhea, vomiting, skin rashes, runny noses and sneezing, resemble common childhood ailments. Only a trained physician can do a true diagnosis of a food allergy. If you suspect a food allergy in your child, take your concern to your pediatrician. All too often parents blame symptoms on a food allergy and needlessly eliminate nutritious foods from their children's diets. This can have negative effects if done incorrectly, such as eliminating dairy products that may result in inadequate intakes of calcium and vitamin D. Not only that, you may be missing an important diagnosis of an underlying illness when you pass off a problem as a food allergy.

Much of the confusion over food allergies lies in the definition. In a true food allergy the allergen (the offending food, usually a protein) triggers an immune system response, producing antibodies called immunoglobulin E. These in turn cause the release of histamines. These histamines are responsible for the multiple symptoms of an allergic reaction, which can range from minor sneezes and sniffles to anaphylaxis, a life-threatening reaction.

Commonly misdiagnosed as food allergies are food sensitivities or food intolerances. They share symptoms of food allergies, but the cause is different. Food intolerances do not involve the immune system. Instead, they can occur for a variety of reasons such as an enzyme deficiency as in lactose intolerance, the inability to digest milk sugar due to a lack of the enzyme, lactase. Or they can occur because the food contains a toxin, such as bacteria or poison. Another adverse reaction is chemical in origin and is called a pharmacologic food reaction. An example would be caffeine. Some people are more "sensitive" to caffeine and can drink only one cup of coffee without getting the jitters, while others can drink several cups and not be affected.

Babies are more likely to suffer from food allergies. Most are outgrown by the age of three, perhaps because of a maturing immune system. In fact, 70 percent to 80 percent of infants with a milk allergy will be able to tolerate milk by the time they are four. The food allergies that seem to be an exception to that, and tend to last a lifetime, are allergies to fish and nuts. For babies with a family history of allergies, one way to help delay the onset and reduce the severity of a food allergy is for the baby to be nursed and for the nursing mom to eliminate from her diet the most potent allergens, (milk, egg, fish, nuts) She should nurse exclusively until at least four to six months. The effects can be long-lasting. Another effective tactic in preventing food allergies is to delay introduction of the common allergens. Wait until at least six months to offer dairy products or egg yolk, eight months for wheat, citrus fruits and cooked tomatoes, and 10 months for fish, shellfish, peanuts, corn, berries, raw tomatoes and chocolate. Wait even longer if there is a family history of allergies.

The method of introducing solids to babies involves a food allergy detection tool. That tool is the introduction of new foods one at a time, with a three day or greater wait before introducing another new food. This is the control mechanism that helps identify which foods are okay and which foods may be a problem. Be on the lookout for allergic responses. The most common allergic skin reaction to a food is red, itchy hives that arise suddenly and disappear quickly. Another skin reaction is a chronic itchy inflammation of the skin known as atopic dermatitis. Itchy, congested nose is a common respiratory tract allergic response. Eyes can react by becoming red, swollen and itchy. Persistent, chronic ear infections may be an indicator of a food allergy. That's because an allergy can cause congestion in the eustachian tubes, which connect the ears to the nose.

However, the most common symptoms overall are vomiting, diarrhea and abdominal cramping. Unfortunately these symptoms are common indicators of food intolerances, especially lactose intolerance. Some of the natural acids in fruits may cause a rash around the mouth, but is not an allergy, and diarrhea may be caused by excess sugar in fruit juice, also a nonallergic response. If you suspect a food allergy, keep a diary for several days of what your child eats and drinks and what reactions you observe. Take this account to your pediatrician to help him with his diagnosis. As you go about increasing the variety of foods in your baby's diet, do it with an eye out for those foods that are most apt to cause a problem. Food allergens are usually proteins. The protein in cow's milk, egg, peanut, fish, wheat and soy are the most common food allergens, although any food may cause an allergic reaction. An allergy to a particular food may indicate an allergy to an entire food family, known as cross-reactivity. For example, an allergy to peanuts may mean an allergy to the legume family (kidney beans, black-eyed peas, soy beans are some members). Fortunately, most children do not suffer from cross-reactivity and are allergic to only one or two foods. If you discover that your child suffers from multiple food allergies, you would be wise to engage the help of a pediatric dietitian to create a diet that eliminates the offending foods without causing nutrient deficiencies and still offering variety.

Once diagnosed, the only way to treat a food allergy is complete elimination of the food. Completely eliminating food for one to two years has been shown to result in the loss of the food allergy for about one third of the allergic people. Because food allergies diagnosed in infancy tend to be outgrown, it's a good idea to have your child undergo food challenges as he gets older to see if he can begin to include the food in his diet.

Eliminating a food from a child's diet can prove to be challenging, especially for such pervasive foods like milk and eggs. You need to be an avid label reader. You need to communicate clearly to others who may be feeding your child and you have to help your child learn how to select the proper foods. You must be careful to find alternative foods that appeal to your child that will make up for the missing nutrients. For a dairy-free diet, that will mean finding other good sources of calcium, protein and vitamin D. For children on a wheat-free diet, look for other sources of B vitamins.

If you are dealing with a child who has a food allergy, or if you suspect you might be, there are several helpful resources available to you:

The Food Allergy Network
http://www.foodallergy.org/

The Allergy Relief Center
http://www.theallergyreliefcenter.com/food_allergy.htm

The American Academy of Allergy and Immunology
http://www.aaaai.org/